Nopal (Nopal opuntia spp)
Background
Also known as prickly pear and beaver tail, nopal is native to arid and semi-arid areas of North America and South America. Nopal has no leaves, except at the start of new growth. These leaves are actually stems called cladodes that grow one on top of another in an irregular, beavertail shaped pattern. It has spiny, thickened stems that form the plant and produce yellow, orange, and red rose-like flowers in the spring. These flowers mature into prickly pears, which are yellow, orange, red, or purple. The fruits are sweet, with numerous hard seeds. They survive under a variety of severe climates and can regenerate themselves. The pads are skinned, diced, and prepared in Mexican salads and tacos.
Pharmacology
The mechanism of nopal is unknown; however, one study suggested it was associated with gastric distension and enterohormones. In another study, the mechanisms of cellular sensitivity to insulin in addition to dietary fiber was suspected, because blood sugar was reduced in the absence of an oral carbohydrate load; this study further showed that serum insulin concentration diminished after taking nopal, thus ruling out an enhancement of insulin release. A different study ruled out the involvement of insulin antagonist hormones, like glucagon, cortisol, and growth hormone.
Nopal contains vitamin B, vitamin C, calcium, iron, potassium, B-carotene, and the carbohydrates: hexoses, pentoses, cellulose hemicellulose, and mucilage. Nopal is high in fiber, protein, and amino acid composition.
Clinical Applications
Nopal is hypoglycemic, hypolipidemic, antimicrobial, vulnerary, demulcent, and nutritive. It is used for gastritis and peptic ulcers, high cholesterol, enlargement of the prostate gland, and diabetes. Externally, it is used for dry, itchy scalp and wound healing.
In patients with NIDDM, studies have shown that nopal significantly reduced glucose and fasting insulin serum concentrations. Nopal lowered blood sugar when orally administered to animals with induced states of moderate hyperglycemia. Nopal does not significantly modify fasting glucose levels and insulin serum concentrations in healthy individuals; however, it reduces the elevation of glucose and insulin serum concentrations after an oral glucose load.
In addition to the diabetic effect, nopal reduced LDL cholesterol, total cholesterol, and triglycerides when taken before each meal for 10 days. The triglyceride levels were decreased in obese and diabetic patients, but not in healthy subjects with low triglyceride levels.
Drug Interactions
Since nopal has no effect in lowering blood sugar, it is highly unlikely that hypoglycemia might occur; however, hypoglycemia drugs might need to be decreased.
Dosage
Recommended dose is 100 g of nopal stems grilled or 3 tablespoons of prickly pear fruit concentrate daily.
