Herbs from Distant Lands: Opuntia

PLANT PROFILE

Opuntia is a genus of cactuses native to dry parts of North and South America, especially abundant in Mexico, but now widespread all around the world in home or garden cultivation. The later often caused the plants naturalization and in some regions it become an invasive weed (Australia, South Africa, Ethiopia, Sri Lanka, Hawaii). It is very characteristic for its evergreen flattened stems segments called cladodes, clads or pads (also often incorrectly called as leaves), covered with long, short or tiny spines or micro prickles, depend of a species. Some Opuntia species grow very low and 1-3 meters wide, while other can reach even more than 7m in height. There are approximately 200 species of Opuntia, which cross-polinate easily creating new hybrids and that makes classification of the species very problematic. With proper conditions Opuntia plants produces abundance of duck egg size edible fruits called Prickly Pear, due to the spots with micro prickles called glochids, on its skin surface. Other popular names of this fruit are Cactus Fig and simply Cactus Fruit.

As you look globally Opuntia species are one of the most popular cactuses grown as an ornamental plants in gardens and where it is too cold as a houseplant. Many people are familiar with its edible fruits and even might have heard about health benefits of it (as the raw fruits, jams, candies, juices or even diet supplements from Prickly Pear are quite commonly available in some countries, and Opuntia fruit industry is trying to promote it by spreading information about scientific discoveries on the fruit medicinal properties).

But outside of Mexico where it is a staple vegetable (economically as important as maize), and few other countries like Brazil, Morocco or South Africa. Most people never heard that Opuntia flat stem segments are edible, end even less people ever heard about the pads medicinal use.

That makes Opuntia one of the most underutilized vegetables and medicinal plants. Uniquely valuable for the fact that it can grow in extremely hot and dry conditions, that no other edible plants or herbs can grow.

That is why I see promotion of the fact that that Opuntia stems are good food and medicine, very important (fruits are less important as it is more seasonal and in some conditions never appear, while the pads are good to harvest all year round without any care required for the plants). This knowledge can help many communities that have problem with utilization of their dry lands for any food crops. Growing Opuntia for food and medicine can increasing their food security and income, while over the years also help to re-cultivate arid, dessert lands changing it into more fertile, by erosion protection and soil buildup process. And in perspective of years or decades that soil restoration can in many cases makes way for other food crops to be able to grow on those lands.

But even for those that don't have such a problems, but grows Opuntia as an ornamentals on their gardens or houses. The knowledge about that stems of this plant are great, easy to use, vegetable with medicinal applications can be very useful indeed.

I remember when in 90's, Opuntia species was being the most commonly grown cactuses in Poland. Its attractive look, due to its uniqueness. And the fact that you can just take one piece of it broken off from your friend's plant, stick it in the soil, and you have your own cactus. Have caused that in most of the houses, apartments or even offices in those days there was at least one Opuntia pot. But due to our frozy winters it is impossible to replant cactuses to the gardens as it gets too big. And so, many overgrown Opuntias was ending up in garbage bins or compost heaps, when it become to problematic as a massive, spiky plant in small room spaces.

Later, a lots of people started also to get rid of Opuntias simply as they get bored with it. Or because they didn't like the fact that they grow the plant that become so common that everyone have it. If only we all new back then how we could get the best out of it, instead of just throwing out and wasting it, we would be all much happier. But it took me many years of research on edible and medicinal plants, before I've found this information (As most of the books about edible or medicinal plants never mention Opuntia, except for Mexican one. And I found out about it from '' The Mexican Kitchen Garden'' by John Meeker). Which I hope will get to all people interested soon.

In Mexico, Brazil, Morocco, Algeria, Tunisia and Italy, Opuntias are not only commonly utilized and economically important as a fruit and vegetable plants, but it is also commonly used as a fodder. In recent years interest about potential of Opuntia as a food crop and fodder has grew also in other countries with vast arid lands, like Ethiopia, Israel, India and Saudi Arabia. And the knowledge about medicinal potential of this cactus has been scientifically evaluated in many of those countries. Although herbalists and folk healers outside of Central America region, are still usually not familiar with healing properties of Opuntias. Even in countries where this plant is commonly cultivated or get naturalized and become a weed.

The most commercially important species of Opuntia is Opuntia ficus-indica, but there are also few other domesticated Opuntia species, like Opuntia stricta. Many of which has its cultivars that has no spines or glochids, which makes its cultivation and harvesting much easier. Some of the cultivars has also been selected for its seedless fruits or lower content of mucilage in pads.

Although mainly used for cattle, grown both as a feed source and a boundary fence, Opuntia has also been used as feed for sheep, goats and pigs. However, it must be combined with other fodder to complete the daily diet, because Opuntias stems are poor in proteins, although rich in carbohydrates and calcium. The digestibility of cactus cladodes decreases with age and only those not older than 3 years are suitable for animal feed.

While spineless types of Opuntia can be feed to animals straight away, the spiny types are treated first with spines burners (usually propane torches). In Mexico, Tunisia and Brazil, Opuntia is highly valued, as a fodder as it is available during worst drought, when even arid land grasses became scarce. Opuntia feed imparts better flavor and quality to the milk and also enhances the color of the butter. The milk from cows fed with Opuntia stems were found to contain more medium and long chain fatty acids, than milk form cows fed corn and tifton hay.

Opuntia plants has also other commercial use potential. The pads, fruits and the seeds can be used for production of cosmetics like skincare products, soaps and shampoos. And the red fruits can be used to obtain natural red colorants.

But it is an elegant very deep, maroon red pigment extracted from scale insects Dactylopius coccus - Opuntia plants parasite feeding on its sap, that is the most important colorant associated with cultivation of this cacti. This dye known around the world as the Cochineal, was used on commercial scale by the Aztec, Maya and Inca for centuries. And when Spanish colonists learned about this highly valued dye (for its quality of being strong and not fading away on textiles), they made a very lucrative business out of it, shipping it to Europe and later even as far as to India. For long time cochineal was Mexico's second-most valued export after silver. And it was for the dye production and not for the fruits or edible pads, that Opuntia species was first introduced by British colonial companies to South Africa, India and Australia.

Nowadays the biggest producers of cochineal are Peru, the Canary Islands and Chile, with increased demand around the world. As the pigment is used primarily as a red food coloring and for cosmetics, as a healthy alternative to synthetic colorings.

Opuntia is also traditionally used to purify water in the field, which gives very good results. Its mucilage becomes a flocculant and collects clusters of bacteria and other pathogenic microbes with around 96% filtration rate of said microbes. The pads are simply cut into half inch squares and put into water container. Depends on how dirty the water is, Opuntia cubes can be used to fill 30-60% of the volume capacity.

Opuntia mucilage can be used as an edible coating to extend the shelf life of strawberries and other fruits, it can be also used to produce bioplastic. Shredded Opuntia pads can be mixed with soil for better water retention of that soil, thanks to the mucilage's water binding properties. The plant can be used as an ingredient in adobe to bind and waterproof roofs. Opuntia mucilage may work as a natural, non-toxic dispersant for oil spills.

Opuntia can be also a source of "vegan leather" - environmentally-friendly leather replacement made from thick skin of older pads of the cacti. The dried stalks of the older Opuntia plants consist of a network of coarse fiber. Sections of it can be used as an eco-friendly scouring pads for washing pots and pans or for making artistic designs on stationery, etc. While the pads sticky mucilage is traditionally used for improving house paint.

Opuntia is a good biomass producing plant, able to produce lots of biomass in poor soil in dry regions where no other plants can create significant amount of it. The biomass can be used to produce bioethanol fuel and biogas (one acre of this cactus produces 43,200 m3 of biogas or the equivalent in energy terms to 25,000 liters of diesel, the same land planted with jatropha-commonly used for that purpose will produce only 3,000 liters of biodiesel). Opuntia biogas is the same molecule of natural gas, but its production does not require machines or devices of high complexity. Also, unlike natural gas, contains primarily methane (75%), carbon dioxide (24%) and other minor gases (1%), giving the same capacity heat while being cleaner. Its calorific value is 7,000 kcal/m3.

In English Opuntia species are usually commonly called Prickly Pear and sometimes Nopal (especially when the plant is mentioned in context of culinary uses of the pads called Nopales), Indian Fig, Barbary Fig, Tuna Cactus or Cactus Pear.

Nopal is also the most popular common name used for Opuntia in Spanish, and the word derived from Nahuatl word 'Nopalli' used for the pads. Other popular common names for Opuntia plants in Spanish are Tuna de Espana or Tuna Espanola, Chumbera, Chumbo or Chumbua, Higo de Pala, Higuera de Pala, Higo Chimbo.

In Portugese its common names are : Palma Forrageira, Figo da India, Figo de Pitoira, Figueira da India, Tabaido. In French: Chardon d’Inde, Figue de Barbarie, Opunce. Italian - Fichi d’India. Afrikaans - Turksvy. German - Indianische Feige. Turkish - Kaynanadili. Polish - Opuncja.

In India it is called : Haththathoira, Nagphana, Nagphani (Hindi), Hathlo Thor, Chorhthlo (Gujarati), Snuhi, Vajrakantaka, Bahushala (Sanskrit), Nagadali, Nagakkali, Chapati Balli

(Tamil), Nagamulla, Nagajemudu (Telugu), Nagphani, Thuar (Urdu).

Strict botanical classification of Opuntia species is in my opinion a nightmare and usually unnecessary waste of time. Opuntia hybridizes easily between its all (probably) approx. 200 species, creating multiple of varieties or new species, that are usually very similar. And as it is agriculture where the classification of Opuntia realistically matters, it is much more important what are the characteristics of particular Opuntia plant from a perspective of a cultivar recognition. As it is very easy to grow from piece of stems new totally identical plants, a clones of particular cultivar, selected for for best quality of Opuntia Nopales or Prickly Pear fruit crops.

CULTIVATION AND HARVESTING

Opuntia species grow as a perennial cactus shrubs or small trees, that can end up as small as 0.5m or as high as 7m. Its low growing species sometimes spread as wide as 4m in diameter, while the tall one can have crown over 3m wide with a trunk diameter of 1 m. Opuntia's thick, flat stem segments called cladodes, pads or platyclades are evergreen and plays role of a leaves (although the real Opuntia leaves are tiny, pointy, green or red and comes out only from young pads and fall off as soon as it matured). It is usually oval or oblong in shape and in some species can be as big as 50cm and 2cm thick. It is covered with many spots from which comes one or few hard thin spines (up to 4cm long), or many micro spines called glochids, rarely both a spine or two with some glochids. But nowadays there are also many Opuntia cultivars that has neither spines nor glochids, which makes them easy and safe to grow and harvest.

Opuntias grows easily from seeds, which germinate any time of the year (the seeds may remain viable for 20 years), but the seedlings are delicate (most of it wont survive in nature) and grow slowly. But any of Opuntia stem segment, or even just cut off or broken piece of the pad, after touching soil, will quickly grow roots and young new segments (detached stem segments can remain viable indoors for 3 years). And although Opuntia is generally resistant to strong winds, its young pads broke off easily due to winds or because of animals, etc.

In natural environment, it cause this cactus to create colonies, often very large, which makes it easily to became noxious weed. Both in its homeland and in many regions with hot climate where it was introduced. Some Opuntia species can withstand short term light frosts, but like all cactuses it won't survive for long in strong shade. It will also die if its soil will be continually overwatered or the air humidity will be very high. But well established plants will survive long months without a drop of water even in scorching sun and extreme heat. As its crassulacean acid metabolism (CAM) helps Opuntia to preserve water. The plants stays mainly dormant during dry months (in most regions it is the time for no new growth but for the flowers to bloom and fruits to get ripe), but during regular rains (or watering) its growth can be pretty rapid even on poor sandy soils. This makes Opuntias an unique vegetable, fruit and medicinal plant, perfect for arid lands where no other food crops can grow.

Opuntia grows mainly on arid grasslands, desserts, dry hillsides and mountain slopes, but also in dry woodlands in places with enough sun, in tropical, subtropical or warm temperate climate. It grows well in different kinds of well drained soils, ranging from lightly acid to lightly alkaline. Tolerate moderate clay content, and sandy lands with very little organic matter.

Due to its abilities to grow in dessert like areas, it is often planted as hedges to stop land erosion. The dense branching, big and wide flat stems of low growing Opuntia species, significantly inhibits sand movement caused by wind and generate soil by accumulation of organic matter between its ground touching stems. It is also giving shade, preventing surrounding soil from fast drying and therefore further improving the soil properties. That can be used for changing local environment, as the cactus can create opportunity for other plants to grow on previously sandy lands by soil buildup. Giving the way for cultivation of other food crops in places where it was not able to grow before introducing of Opuntia.

And the varieties with long spines are also great for a living fence, impenetrable both for humans, cattle or other big animals.

Opuntia is one of those crops that is generally unproblematic in terms of pests and diseases. But some insects can destroy its whole local populations. For example larva of South American moth Cactoblastis cactorum that feed on Opuntia. Which was successfully used as the first large scale biological weed control, against overspreading of this cactus in Australia in 1925. The problem with Opuntia rapidly overtaking more and more land, threating local species and crops cultivation, was such a huge problem (tens of thousands of square kilometers affected). That successful solution which ended up with very few of the cactuses left, was commemorated with erection of the monument dedicated to the savior moth species and building of the Cactoblastis Memorial Hall (and it is worth to note that mechanical and chemical eradication attempts prior to moth introduction failed).

But it was the other serious pest of those plants, that was the reason for which few Opuntia species was introduced into Australia in 18th century. A small scale insect Dactylopius opuntiae commonly known as Cochineal, was so valued in those times, as it was used to obtain from it the high quality red dye. That the British rulers brought the bug and Opuntia as a host for it, to establish mass production of the expensive pigment.

The cactus pads are also eaten by some snails and iguanas, while its fruits are food for many wild animals, especially birds. Opuntias can be also affected by pathogens like fungus Colletotrichum coccodes and Sammons' Opuntia virus.

Opuntia produce flowers once a year, the time vary strongly due to different weather patterns in different regions of the world (in some regions though, it can produce flowers and fruits throughout the whole year). The flowers last open only for one day. It comes in wide range of shades of yellow, red, pink, magenta, purple, orange or white, and in the plants favorable conditions it appears in abundance. With no negative impact, this result in abundance of fruits. Which can be red, magenta, orange, yellow or green in color when ripe, usually not much bigger than duck egg-size.

Harvesting of edible pads, flower buds, flower petals or fruits of Opuntia can be quite tricky, if it is not from a spineless and glochidless varieties, in which case it is pretty simple. The spines can be around 4cm long, and as it is super sharp and tough it can cause a serious harm. And because it comes from every part of the pads pointing in different directions, it is hard to avoid. When harvesting Opuntia from long spines species, you not only have to focus with cautious on the plant and keep your body at safe distance. But you also need to watch your steps, as stepping on fallen Nopal pad can result in pierced sole of your shoe. Even if the pad is years old, brown, dried or rotten away, because the spines can lasts strong and sharp for many years after the piece of stem will loose its live.

Yet it is the glochids, a tiny only 2mm or less long prickles that are a real curse. There are species of Opuntia that has both one spine and few glochids coming out from each tuft spot on the pads, while other has no spines but in each of its spots there can be tuft of around 100 nasty glochids. Unfortunately Prickly Pear fruits are also covered more or less densely with tufts of glochids.

The glochids are very nasty, as although it enable to cause serious harm due to its minute size. With just a slight touch of a skin it pierce it and attach firmly inside due to its structure. Hard to see and hard to grab to pull out, it can irritate your skin for hours, or if it brakes apart its piece inside your skin can cause discomfort, often inflammation for weeks.

Gloves are a good solution to avoid glochids getting to your skin. But observe if no glochids get stuck to the gloves or to your clothes, as it can be then accidentally transferred into your skin. If you felt a slight prickling of the glochids, check the part of your body immediately and carefully. It is usually not hard to pull it out with your fingers, fingernails or tweezers, but if it will get pressed deeper into your skin, you might need to take it out using needle or a similar object, damaging your skin or even the tissue underneath.

One of the recommended ways to get rid if the glochids that get on your skin, is to put glue and a gauze on it and let it dry, or to stick adhesive tape, and then quickly pull it all out. Melted wax can also be used, in a same way as for wax hair removal.

Opuntia pads are easy to brake off in a joint by single twist, but you can also cut it off with a knife. Due to the plants diurnal acidity modification, the cladodes are said to be the best for harvesting a couple of hours after sunshine. Small, young, not fully developed pads are more soft and crunchy than the older one, and it is best for eating raw. But the baby Nopales loses its tenderness the faster the younger it is, becoming fluffy and chewy after few days of storage.

For cooking, pickling or other culinary processing, even the 3 years old pads can be picked. Once harvested, adult Nopales can last for weeks in room temperatures kept in a plastic bag, and for many days it will not lose any of its quality (Unless it was the pads with long spines, then when put together the pads are piercing each other flesh, which eventually lead to water loss and losing its firmness and crunchiness, or even rotting from the wounds).

Opuntia fruits when fully ripe are quite soft and delicate. When picked slightly underripe, the fruits can be storaged for 3-4 weeks. To remove the glochids it is often rubbed in a sand or abrasive surface, or swept with grass or leaves. Using open fire to burn out the glochids is another practical way to prepare Prickly Pears for safe consumption, but it shorten the possible storage time for those fruits.

CULINARY USES

Opuntia flat stem segments are best known in culinary world under its Mexican name Nopal (plural Nopales or Nopalitos). As it is in cuisine of this country, that it is commonly used in hundreds of different recipes, and from where the knowledge about edibility of the stems usually comes to other countries. Nopal pads can be eaten raw (especially when it is young and its skin is soft and crunchy), added chopped to salads, sandwiches etc. (older Nopales has tougher skin but contain more nutrients while less water). But due to its slimy (mucilage rich) nature it is mainly used for cooking and frying, in the similar way to Okra pods or green beans. The pads has mild, slightly sour taste, and if not overcooked it stays nicely crunchy and juicy. Some Opuntia species has more fleshy, thicker and bigger pads, while the other one are tougher and thin, but generally most of it can be eaten and it all tastes much the same.

Nopales are usually chopped into small cubes or stripes, after removing of spines or glochids, which can be a bit of a labour, so it is best to cultivate spineless varieties (in Mexico the fresh pads are available on vegetable markets and grocery stores). Chopped Nopales are added to soups (its mucilage is a good thickener), gulashes, stir fries, scrambled eggs, or served boiled as a side dish. But the whole pads are also great for grilling or roasting, and usually are cut threw the middle like a pita and stuffed inside with meat or vegetarian filling. Nopales are also cooked and mashed, used for jams and candies, pickled, and deep-fried battered as fries or crispy chips. Dehydrated pads flour is used to make green tortilla, while chopped fresh or cooked Nopales are used for tacos filling. Nopales mucilage can be used as a natural food thickener or edible coating (for example to extent shelf life of strawberries or other fruits).

Opuntia pads are good source of dietary fibers (1-2%), calcium, magnesium and vitamin C, giving around 41 kilocalories per 100g of raw serving. It generally contain 80-90% water, 3-10% carbohydrates and sometimes even less then 1% proteins, but composition of its constituents can vary hugely due to season, environment conditions, stage of maturity or storage of harvested Nopales. For example, wild Opuntia robusta species can contain even 17-19% protein, while five out of six other opuntia species show 11%, with O. humifosa 4.7%.

Opuntia flower buds picked before it bloom (whole green parts with unopened petals), can be eaten prepared in many ways like the pads, with it being especially good for pickles (just like the green unripe Prickly Pear fruits).

Flower petals of Opuntia can be eaten raw and it has nice texture, it is soft, tender and juicy, tastes slightly sweet and fruity. And therefore it is great to use for fruit salads and desserts, and can be a beautiful edible decoration for a savory dishes too (so far I've tried only yellow petals of probably O. stricta, and pinky-red O. cochenillifera, but I'm guessing that all the red, pink, purple, orange and white petals of any species tastes just as good). Due to its character the petals should be also great for preparations of jams, jellies, pies or to be added to smoothies (just like we use Rose petals of Rosa rugosa in Poland).

The antibacterial activity tests showed that O. inermis flowers hexane extracts have high effectiveness against Escherichia coli and Staphylococcus aureus, which shows its potential as a food preservative.

Opuntia fruit known in most of countries as Prickly Pear or Tuna (its Mexican name), can be red, purple, yellow, orange or green when ripe. Its flesh is soft, juicy, usually sweet, very refreshing and contain multiple tiny seeds. Its skin need to be cleared from glochids or peeled before eating, alternatively you can just hold it with gloves cut in half and just spoon out its flesh from the thick skin. Pickly Pear is eaten raw, cooked, chilled in refrigerator or frozen as ice pops, turned into juice, nectar, jam, sirop, jelly, sweetener, candies, wine, liqueur spirit, beer or alcoholic drink called colonche.

The fruit has high sugar content and low acidity, contains good amount of fiber and ascorbic acid, and also vitamin A, E and K, amino acids, minerals and antioxidant compounds such as phenols, flavonoids, carotenoids, betaxanthin and betacyanin.

The fresh Prickly Pears are commonly available on fruit markets and in supermarkets in Mexico and other countries that has many commercial plantations of Opuntia, like Italy, Morocco and Egypt. It is also exported as a delicacy to other countries, but due to its short shelf live it is not widely available (ripe fruits can stay fresh even for many days, but if it get just a bit pressed it spoils quickly). Prickly Pear juice or fruit juice blends that contains it, are on the other hand more and more common product on a food shelfs of supermarkets across the globe. In Mexico and few other countries you can also buy jams, candies, wines and other food products made from the fruit.

Each fruit can contain more than hundred of seeds, but nowadays some of the new cultivars of Opuntia produces fruits with little or no seeds at all. Prickly Pear seeds are around the size of sezame seeds, but are much harder to bite threw. It can be spit out or swallowed with the fruit pulp, but eating of too much of those seeds can cause indigestion.

The seeds contain around 15% protein and are rich in essential fatty acids, sterols and vitamin E. It can be dried and ground into flour or pressed to obtain oil, that can be used both for culinary and cosmetic purposes.

Natural food colorants are obtained from the fruits and flowers of Opuntia, but also from Cochineal insects feeding on the plant.

Contraindications : Opuntia consumption is not adviced for people with insulin dependent diabetes mellitus. Excessive consumption of the cactus is known to cause cactus fever (which is typically self-resolving but an unpleasant experience), mild diarrhea, nausea, increased stool volume, increased stool frequency and abdominal fullness.

COSMETIC USES

Opuntia pads are traditionally used to strengthen hair, make it fine, delicate and give them bounce and sheen. The fresh stems are simply sliced to take its gel-like sap out and apply it straight on hair as a hair conditioner. The plant mucilage based shampoo is said to remove dandruff, it can be easily made by mixing small slices of Nopal in water. The pads gel is also used to make body lotions and soaps, as it is moisturizing, nurturing, soothing and antibacterial.

Opuntia gel can be apply fresh on itself or in cream formulas, on skin disorders, inflammations, burns and wounds (for better healing) just like the famous Aloe Vera gel, and its dermatologic healing efficacy has been proved at the molecular and cellular levels. It softens the skin very well as it has hydrophilic hypertonic nature.

Opuntia mucilage is often used as a drawing agent for infections pus, splinters and other disturbances, from deeper layers of the skin. And is said to be more effective in such actions when heated.

Prickly Pear fruit flesh is sometimes also used in preparations for skin problems like inflammations, burns and infections. The fruits juice is used as a treatment for warts.

Powder made from Prickly Pear seeds is used in cosmetics as exfoliant, anti-aging, wrinkles reducing and antioxidant agent.

Prickly Pear seeds oil is highly priced, sold pure or in cosmetic preparations for skin or hair care. It is valued as an anti-wrinkle and moisturizer, due to its high vitamin E content. It was also confirmed to posses some antibacterial, antifungal and anti-yeast properties.

Essential oils obtained from Opuntia flowers are used to make perfumes.

MEDICINAL USES

Although Opuntia has been used as a medicinal plant for centuries by Aztec and Maya people, nowadays even in Mexico it is not that very common to hear about it being used for herbal treatments. But for some people living in Central and South America, or in countries where this cactus become popular after introduction, it has good significance as a traditional remedy. And even modern mainstream herbalism in some countries embraced Opuntia, since scientific medicinal studies on the plant has been conducted in Mexico, USA, India, Morocco, Saudi Arabia, Zambia and few other countries. Which confirmed many of medicinal properties traditionally attributed to this cactus, and revealed its biochemical profile. Thus stimulating herbal remedies industry to produce medicinal preparations and diet supplements from this plant.

Yet, if you compare the number of people worldwide that are familiar with Opuntia medicinal uses, to astonishing number of people that grow it on all continents either in gardens or houses, without ever heard of its healing virtues. You will see that it is one of the most underutilized medicinal plants in the world.

Most of Opuntia species has the same or very similar medicinal qualities, but the most commonly used species for healing purposes and the most researched for its pharmacological properties. Are those Opuntia species that become the most commonly found worldwide, like Opuntia ficus-indica, O. dillenii and O. eliator.

STEMS - called Opuntia pads, cladodes or Nopales

Opuntia flat green stems are taken orally fresh or cooked, more like a functional food than a medicinal herb, as it is a vegetable which can be consumed in bigger quantities. But dehydrated Opuntia pads are also ingested in form of pills, capsules and Nopal Powder, that can be added to many different meals.

Nopales medicinal properties are described as : anti-inflammatory, antioxidant, emollient, demulcent, antiulcerogenic, laxative, diuretic (increase diuresis, natriuresis and kaliuresis), antiuric, antidiabetic, hypoglycemic, anti-hypercholesterolemic, anti-hyperlipidemic, hepatoprotective, alexiteric, carminative, stomachic, vulnerary, cicatrizant, cooling, antipyretic, antiviral, antibacterial, antiparasitic, cardiotonic, hypotensive, anti-cancer, analgesic and neuroprotective.

Opuntia pads are consumed as a remedy for :

- Stomach ulcers. The most common purpose of oral administration of Opuntia pads in folk medicine is for treatment of stomach ulcers or for prevention of formation of it. Its emollient, mucilage rich gel-like flesh and sap sooths the linings of gastrointestinal tract, easing irritations caused by stomach acid reflux, hyperacidity, overconsumption of alcohol or hot spicy food, or by infections. Also helping with the regeneration of the membrane tissue by creating the protective layer and due to its vulnerary properties (Its cytoprotective mechanism of action is associated with an interaction between Opuntia mucilage monosaccharides and membrane phospholipids).

The pads can be simply eaten fresh in slices before the meal, but often its flesh is mixed in water or infusion of grounded stem is prepared for drinking.

- Other problems of digestive system. Beside for being used as a gastric ulcers remedy, Opuntia pads are traditionally taken as a treatment for many digestive ailments of other kinds. For indigestion, stomach inflammations, burning, nausea, alcohol hangover, stomach swelling, gastrointestinal parasites, anorexia, and as a help in treatment of obesity.

In vitro studies showed that Opuntia cladodes extracts are able to induce apoptosis on human colon cancer cells.

- Diabetes and high cholesterol. Opuntia has been used as a treatment of diabetes and high cholesterol since immemorial times. As it was recorded that native American Pima people traditionally used it as a remedy that reduce blood sugar level and lover high cholesterol. Nowadays many Mexicans consume raw or cooked Opuntia pads for such effect, and few modern studies confirmed its hypoglycemic and hypolipidemic actions. The plant is said to have the ability to reduce blood sugar by up to 20% in individuals with non-insulin dependent diabetes mellitus. Its mucilage reduces rate of sugar absorption, and therefore effectively reduce symptoms of insulin shock. And it has high content of soluble fiber, which binds with cholesterol increasing its excretion and lowering LDL.

There are reports of people being able to stop their insulin injections thanks to eating the cactus, with opinions that it helps the pancreas to produce insulin.

In Australia, Opuntia pads decoction or water macerate is drunk with sodium bicarbonate (baking soda) added, taken one big cup thrice a day to relieve the symptoms and lower the blood sugar level in diabetes.

- Inflammatory conditions. Consumption of Opuntia pads flesh was for centuries the common treatment for inflammatory diseases in folk medicine of Mexico. It is effective anti-inflammatory remedy bringing relief in digestive tract inflammation, edema, rheumatism, osteoarthritis and hemorrhoids.

- Infectious diseases. Nopales are traditionally taken orally to treat infections of gastrointestinal and urinary tracts, it is also used to help in pulmonary infections such as whooping cough, baby's cold and wheezing, and for treating tuberculosis scar tissue (Opuntia stem jelly-like flesh is even more often applied externally to treat skin infections - more about it below)

Methanol, ethanol and chloroform extracts of Opuntia ficus-indica cladodes have demonstrated great antibacterial activity, against both gram positive and gram negative bacteria.

Extracts of Opuntia ficus-indica have marked bactericidal effects on the growth of Campylobacter jejuni and Campylobacter coli (one of the most common agent causative of food-borne bacterial gastroenteritis in the humans). It also strongly reduced adherence of Campylobacter to Vero cells.

Antimicrobial activities of methanolic, ethanolic and aqueous extracts of Opuntia ficus indica have also been studied on Vibrio cholerae (of which some strains cause cholera), indicating that the methanolic extract was the most efficient and causes membrane disruption, leading to increased membrane permeability and consequent marked decreases in pH and ATP.

Study on Opuntia streptacantha showed that administration of stem extract to mice, horses and humans inhibits intracellular replication of a number of DNA and RNA viruses, such as Herpes simplex virus Type 2, Equine herpes virus, pseudorabies virus, influenza virus, respiratory syncytial disease virus and HIV-1. And also inactivation of extra-cellular viruses was reported.

- Respiratory tract problems. Opuntia sap or tea made from crushed pads is often used as a demulcent antibacterial remedy for respiratory tract ailments like catarrhs, wheezing, asthma, dyspnea, whooping cough and allergic reactions. It is given to children in cases of bronchitis and for baby's suffering colds.

- Gum infections, mouth sores and dry mouth. Chewing or holding a piece of Nopal's flesh between the gum and cheek is a treatment used for inflammations, infections and small injuries of gum and mouth, as well as for the problem of dry mouth.

- Liver and Spleen Problems. Opuntia pads are traditionally consumed as a treatment for different liver and spleen complaints, including enlargement of the spleen and fatty liver.

Study showed that adding Opuntia ficus indica to rats diet is lowering hepatic triglycerides with a reduction of hepatomegaly and biomarkers of hepatocyte injury. Thus supporting claims that consumption of Nopales attenuates hepatic steatosis.

- Kidneys and urinary tract complains. Infusions and macerations of crushed Opuntia pads are traditionally drunk to treat kidney and urinary tract infections, swollen prostate, to relieve urinary burning and remove urinary stones.

Studies showed that O. ficus-indica cladode, fruit and flower, increase diuresis, natriuresis and kaliuresis. Gel and aqueous extract of Opuntia ficus-indica cladode showed a significant diuretic effect on rats, and the lyophilized extract a diuretic and hypotensive effect on normotensive rabbits without deterioration in renal function test.

- Abnormal fluid retention. Thanks to its good diuretic action and beneficial effect on kidneys, liver and heart, Opuntia pads consumption helps in cases of edema and ascites.

- Chronic cardiovascular problems. Nopales beneficial effect on blood circulation was known for centuries and the plant is still used in folk medicine to treat cardiovascular conditions. Studies has showed that Opuntia pads consumption has good potential in treatment of chronic cardiovascular ailments such as hypertension and hyperlipidemia, due to its hypotensive, hypoglycemic, anti-hypercholesterolemic, anti-hyperlipidemic, cardiotonic and diuretic actions.

- Headache, migraine, loss of consciousness, neurological problems. Nopales are traditionally used as a help in headaches and migraines as well as for loss of consciousness. Opuntia ficus-indica cladodes are rich in nicotiflorin which is anti-inflammatory and neuroprotective.

Oral administration of methanol extracts of Opuntia ficus indica was observed to have protective effects against neuronal damages caused by global ischemia in the hippocampal region, in gerbils. Water-partitioned fractions of pads and fruits of O. humifusa were reported to suppress the growth of U87MG glioblastoma cells, in association to an increase in ROS production in the cells.

- Eyes problems. Nopales consumption and topical application of cladodes pulp is helpful in cases of ophthalmia and glaucoma.

Opuntia pads are rich in nicotiflorin, which is neuroprotective against hypoxia-, glutamate- or oxidative stress-induced retinal ganglion cell death at nanomolar concentrations.

- Women's problems. In Mexican folk medicine Opuntia pads are used for menopause and hot flashes, to induce and ease childbirth, and to alleviate premenstrual syndrome (it inhibit the synthesis of prostaglandins).

Opuntia cladodes are also taken orally as a traditional treatment for fatigue, anemia, vitiligo, piles, lumbago and to improve wound healing.

Studies results suggest that Nopales consumption help increase bones density in cases of osteoporosis. The clads has higher content of calcium (627-1968mg/100g) than most of vegetables, fruits and nuts, including spinach, lettuce and cabbage.

In Ayurvedic medicine Opuntia pads are considered to be remedy for vata diseases.

Externally Opuntia cladodes are used in form of :

- Poultices made from fresh gel-like Opuntia pad's flesh are used topically (in the same way as Aloe gel) to treat : wounds including open wounds (its antiseptic, coagulant, cicatrizing and vulnerary - wound healing stimulation properties, was confirmed in tests), ulcers, burns, bruises, skin irritations (it has emollient and soothing anti-inflammatory effect), fungal skin infections, erysipelas, measles, whitlow, spiders and insect bites, swellings, swollen glands in the neck, tumors, rheumatism, gout, cellulitis, ophthalmia, earaches, toothaches and gums infections, warts, calluses, leukoderma, also applied on foot as a cold remedy, on body in fever, on abdomen in inflammations of the intestines, on kidney area in kidney problems, and on congested purplish breasts in lactating women.

Opuntia flesh poultices also softens the skin and helps to drawing out splinters, spikes, etc. or pus from the skin inner layers (for which it is said to be more effective when heated).

- Heated pads are applied to the body to reduce swelling, remove boils (hastens suppuration) and to treat pleurisy. Mexican Pima tribe used warm pads to increase milk flow in nursing women.

- Roasted cladodes are sliced and applied as poultice to relieve pain, swelling, and localized burning from filaria. Roasted Nopales are also held on the side of the neck or below the chin to treat rheumatism and mumps.

- Freshly cut or heated pieces of Opuntia pads are placed between the gum and cheek in cases of tooth or gum infection (before inserting the piece can be sprinkled with powdered antiseptic herbs like Salvia officinalis or Zanthoxylum species). The side touching the teeth and gum need to be the skinned off, fleshy, jelly part of the pad.

- Grated Nopal is tied on the throat as a treatment for sore throat.

- Grated pads mixed with soft grease and corn meal, are warmed and applied externally for chest colds and fever associated with pneumonia.

- The pads split in half, have been bound around injured limbs as a first aid measure.

- Opuntia sticky juice mixed with honey and egg yolk is applied to cure burns.

- A small piece of the stem is put in a glass of water, which is later used for removing mucus from inflamed eyes.

Opuntia cladodes are rich in mucilage, fiber, malic acid and minerals including calcium (627-1968 mg/100g, other source states 235 to 5520 mg/100 g ), potassium (161 mg/100 g), also contain magnesium (8.80 mg/100 g) sodium, phosphorus, manganese iron and zinc. The mucilage consist primarily of amylose and polysaccharides containing varying proportions of L-arabinose, D-galactose, L-rhamnose, D-xylose, glucose as well as galacturonic acid.

The pads has high content of polyphenols, flavonoids (quercetin 3-methyl ether, kaempferol, luteolin, quercetin, kaempferide, rhamnetins) and sterols (beta-sitosterol, opuntisterol, opuntisteroside, taraxerol, 7-oxositosterol, daucosterol), also contain amino acids (mainly glutamine, also leucine, lysine, valine, arginine, phenylalanine and isoleucine), methyl eucomate, eucomic acid, friedelin, methyl linoleate, palmitic acid, oleic acid, linoleic acid, linolenic acid, alkaloids and terpenoids (furanoid forms of cis-linalool oxide (10.8%) and trans-linalool oxide (8.8%)).

Mature pads contain calcium oxalate crystals (4.3 to 11.5 mg/100 g) that are insoluble and may cause health problems in excess.

FRUIT

Fruits of many Opuntia species are collectively known as Prickly Pear. Despite its difference in color of skin (different shades of red, orange, golden, pink or purple) and flesh, it all has generally similar medicinal value and are used to treat same conditions.

Opuntia fruits are often considered to posses stronger anti-inflammatory and antioxidant actions than the cladodes. The fruit also posses properties such as diuretic, antidiabetic, hypoglycemic, hypolipidemic, hypocholesterolemic, anti-allergic, analgesic, refrigerant and anticlotting. It is low in acidity.

Ripe Prickly Pear is simply consumed raw, or in form of preserves or extracts (both liquid and dry), to treat ailments such as :

- Gastrointestinal problems. Opuntia fruit is traditionally used as a treatment for ulcers and other gastrointestinal ailments, like indigestion, diarrhea, colics and alcohol hangover symptoms.

Syrup made of Prickly Pear appears to increase the secretion of bile when given in teaspoonful doses three or four times a day.

The milky juice of unripe fruits is given as a purgative in doses of ten drops mixed in a little sugar.

- Respiratory ailments. Syrups and liquid extracts from Opuntia fruits are traditionally used as expectorant for cough, and to treat bronchial troubles, spasmodic cough, asthma and whooping cough.

- Infectious diseases. Prickly Pear is consumed to treat stomach infections causing diarrhea, and is said to be useful in treatment of gonorrhea and syphilis. In the Deccan, the baked fruit is given as a remedy for whooping cough.

- Cancer. Opuntia fruits are traditionally recommended as an remedy for tumors. Recent studies has shown that the fruit has not only powerful antioxidant actions thanks to its pigments, but can also exhibit cytotoxic action on cancer cells. The fruit extracts or isolated pigments showed potential to inhibits the proliferation of colon, cervical, ovarian, bladder and prostate cancer, and even to inhibit the growth of the human chronic myeloid leukemia cells.

- Postmenopausal bone deficit. Study results show that the aqueous extract of O. megapotamica fruit increases the number and improves the biological functions of osteoblasts, suggesting its potential use as an alternative treatment for postmenopausal bone deficit.

- Scurvy. In the past Prickly Pear was used to mitigate scurvy. The fresh fruit vitamin C content is 20–40 mg per 100 g.

In Mexican folk medicine Opuntia fruits are also consumed as a treatment for diabetes, inflammatory conditions, and for easier childbirth.

Externally the fruit flesh is applied on wounds, burns, skin inflammation and whitlow.

Opuntia fruit is high in carbohydrates (especially fructose, glucose, rhamnose and galactose), vitamin C, E and K1, potassium (220 mg/100g) and magnesium (85 mg/100g), also contains significant amounts of phosphorus and selenium and good amount of fiber.

Depends of the color that particular Prickly Pear fruit has, it can contain high volume of various proportions mix of pigments such as betalains (betanin and indicaxanthin) and carotenoids. It is also rich in fatty acids (mainly linolenic, oleic and palmitic) and less in amino acids (proline, taurine).

The Fruit pulp contains flavonoids, flavonols (kaempferol, isorhamnetin), isorhamnetin glycosides. sterols (mostly beta-sitosterol and campesterol but also small quantities of stigmasterol, lanosterol, avenasterols and ergosterol) and tocopherols.

SEEDS

Oil extracted from seeds of Prickly Pear fruit is available on the market, sold for both consumption as a healthy diet supplement and cosmetic uses, mostly due to its good reputation for skin anti-aging properties.

Opuntia ficus-indica seeds oil has shown in vivo wound healing activity, as it prevents cutaneous infections and reduces the reepithelialization phase, promoting the scarring process. While in vitro tests results has shown the oil's antimicrobial effect on Enterobacter cloacae and antiyeast effect against Candida parapsilosis and Candida sake, and antifungal activity against three opportunistic cutaneous molds (Penicillium, Aspergillus and Fusarium).

An increase in high-density lipoprotein cholesterol and a reduction in serum cholesterol was observed in rats treated with Opuntia seed oil.

Opuntia seeds contain 3–13% of protein and 6–13% of fatty acids, mainly omega-6 linoleic acid, major amino acids in the seeds are glutamic acid and arginine.

The seeds are rich in minerals, with a predominance of potassium and phosphorus, and large quantities of magnesium, zinc and sodium.

It also contain high amounts of phenolic compounds ranging from 48 to 89 mg/100 g and including feruloyl derivatives, tannins and sinapoyl diglucoside.

FRUIT PEEL

Stripes of Prickly Pear fruit are applied on wounds, burns and skin inflammations as a natural plaster, with the inner side of the peel facing the place on a skin.

Opuntia fruit peel is rich in essential fatty acids, liposoluble antioxidants, alpha-tocopherol and phenols such as kaempferol, isorhamnetin and quercetin. It can be used together with the seeds to prepare cactus oil. The fruit skin contains calcium, iron, potassium, magnesium, manganese, sodium and selenium.

FLOWERS

Opuntia flowers (more precisely its petals) are important herbal remedy in some regions of the world where this cacti is very popular. Petals of freshly opened flowers are quite thick and juicy and can be eaten raw or dried for use in infusions or taken in powdered form, but also turned into preserves.

It acts as : demulcent, anti-inflammatory, diuretic and antispasmodic, depurative, metal chelating activity, vulnerary, antibacterial, antiviral.

Opuntia flowers are traditionally used as medicine for :

- Urinary problems. The blossoms have diuretic properties and benefiting effect of the kidneys and urinary tract. It is used in oliguria (lack of urine production), cystitis, kidney colic, for expulsion of renal stones or reducing uric acid kidney stones and risk of gout-related conditions. In Sicily a decoction made from the flower of this plant is widely used as a strong diuretic and demulcent anti-irritant herb to bring relief in urinary tract irritations due to inflammation or infection. In North America the flowers of Opuntia are combined with barley seeds and corn-silk to treat urine obstruction.

- Prostate problems. Infusions of dried flowers are traditionally taken to prevent prostate cancer. In The British Herbal Pharmacopeia, Opuntia spp. flowers are recommended for treatment of benign prostatic hypertrophy. Clinical studies indicates that a dry flower preparation of Opuntia ficus-indica improved subjectively the discomforts associated with benign prostatic hypertrophy. Patients in this study was given orally, three times a day two gelatin capsules with ground Opuntia flowers.

- Digestive tract problems. In the sub-Saharan traditional medicine the flowers or its infusion are given as a treatment for ulcers and diarrhea, it is also taken orally as an anti-hemorrhoid medication.

- Respiratory problems. The flowers are said to cure bronchitis and asthma. Thanks to its demulcent action it is very effective remedy for dry coughs, irritated and inflamated sinuses.

- Wounds, burns, mucosa damage, varicose veins. Opuntia flowers taken orally help tissue regeneration, speeding up healing of wounds, burns and mucosa damage. It can also strengthen capillaries and reduce risk for varicose veins.

The antibacterial activity tests showed that O. inermis flowers hexane extracts have high effectiveness against Escherichia coli and Staphylococcus aureus.

Methanolic extract of O. dillenii flowers exhibited significant antiviral activity against vaccinia and herpes simplex virus type 1 and 2.

Opuntia flowers contains more polyphenols and flavonoids than other parts of this plant. It is rich in gallic acid, 6-isorhamnetin 3-O-robinobioside, linoleic acid, hexadecanoic acid, kaempferol and quercetin, it also contain luteolin, penduletin, piscidic acids, quercetrin, rutin, and β-sitosterol.

The flowers contains considerable amounts of fiber, protein and minerals such as potassium, calcium, magnesium, sodium, iron and zinc.

VETERINARY USES

Opuntia pads mucilage is applied to open wounds and burns in animals. In Trinidad and Tobago, it is used in ethnoveterinary medicine as an ointment for joint injuries in horses. And for anhidrosis, pounded Nopales in water are given to horses to drink to induce sweating and reduce the temperature. The pads of Opuntia cochenillifera called there Rachette are also used in combination with glycerine and Epsom salts to treat inflammation.

Study results showed that ethanol extracts of different Opuntia species reduces the infection of Peste des Petits ruminant virus in Caprine. PPRV infection is of one of the most widespread and devastating infectious diseases of both domesticated and wild small ruminants.

Opuntia cochenillifera syn. Nopalea cochenillifera

Opuntia stricta or some other species common in Baguio, the Philippines

Sources

'' Ethnobotany of India, Volume 2: Western Ghats and West Coast of Peninsular India '' - T. Pullaiah, K. V. Krishnamurthy, Bir Bahadur, CRC Press 2016

'' Edible Medicinal and Non-Medicinal Plants: Volume 1, Fruits '' - Lim T. K., Springer Science and Business Media 2012

'' Textbook of Natural Medicine '' - Joseph E. Pizzorno, Michael T. Murray, Elsevier Health Sciences 2012

'' Prickly Pear Cactus Medicine: Treatments for Diabetes, Cholesterol, and the Immune System '' - Ran Knishinsky, Inner Traditions 2004

'' Healthy Plants '' - Dr. George D. Pampalona-Roger, Editorial Safeliz 2002

'' Medical flora, or, Manual of the medical botany of the United States of North America '' - C.S. Rafinesque, 1828

Biological Actions of Opuntia Species - Chauhan SP, Sheth NR, Jivani NP, Rathod IS, Shah PI

Opuntia stricta Cladode Extract Reduces Blood Glucose Levels in Alloxan-induced Diabetic Mice - Aubrey Chichonyi Kalungia, Mary Mataka, Patrick Kaonga, Angela Gono Bwalya, Lavina Prashar, Derick Munkombwe

Aqueous extract from Opuntia megapotamica fruit pulp promotes osteoblast activity - Valeria Gili, Juan A Laiuppa and Graciela E Santillán

Treatment of Benign Prostatic Hypertrophy with Opuntia ficus-indica (L.) Miller - Dan Palevitch, Gideon Earon and Israel Levin

Comparison of hypotensive, diuretic and renal effects between cladodes of Opuntia ficus-indica and furosemide - MeryemBakour, NooriAl-Waili, RedouanEl-Haskoury, NawalEl-Menyiy, ThiaAl-Waili, AliAL-Waili, BadiaaLyoussi

IN-VITRO ANTIOXIDANT AND ANTIDIABETIC ACTIVITY OF HYDRO ALCOHOLIC EXTRACT OF OPUNTIA ELATIOR FRUIT AS WELL AS QUERCETIN - Chintu, R. Kotadiya, Urvesh D. Patel, Vipul B. Chauhan, Harshad B. Patel, Chirag M. Modi, Punit R. Bhatt, Kajal B. Pandya and Trushen M. Shah

Cactus ( Opuntia spp.) as forage - Candelario Mondragon-Jacobo, Salvador Perez-Gonzalez