Killing time on a recent shopping trip led Dr Des Corrigan to consider the therapeutic role of exotic herbs for a range of purposes

Like most males, I hate shopping and the only way I can keep sane while doing so is to nosy around health food shops and other outlets, including different pharmacies, looking at what herbal and related products might have appeared on the market. I continue to be astounded at the level of innovation in the ‘supplement’ industry, with novel plants and products reaching consumers from the far corners of the globe. Among recent products I noted were two materials originating from South America, namely Quebra Pedra tea infusion and Cupuaçu, with a third (Moringa) coming from the Indian sub-continent. 

Quebra Pedra is the local name for Phyllanthus niruri, a plant  grown widely in the tropics. It is used in Indian Ayurvedic medicine for stomach, genito-urinary, liver, kidney and spleen problems and to treat chronic fevers. As Quebra, it is used by Amazon tribes to treat kidney and gallstones, hence its common name of ‘stone-breaker’ or Chanca Piedra in Portuguese. 

There is some evidence of effectiveness reported by Brazilian research groups. A 2011 study in the International Brazilian Journal of Urology reported on in vivo studies in rats implanted with calcium oxalate crystals into the bladder. The animals were then treated with Quebra Pedra and showed reduced growth of stones. The result was similar to those of a number of other animal studies. 

A number of human studies conducted in Brazil showed some positive effects on reduced calcium excretion in patients with hypercalciuria.

 A 2018 study in the same Brazilian journal  involved 56 patients with kidney stones with a diameter less than 10mm who were given Phyllanthus infusion for 12 weeks, followed by a 12-week washout. The researchers found that the kidney stones decreased in size by 2-to-3mm per patient. In patients with high levels of urinary oxalate (hyperoxaluria), there was a significant reduction of urinary oxalate, from 59 to 29mg per 24 hours. In patients with hyperuricosuria, urinary uric acid decreased from 0.77 to 0.54mg per 24 hours. A Romanian study published earlier this year in Medicine & Pharmacy Reports investigated 48 patients with uncomplicated nephrolithiasis confirmed by non-contrast enhanced computer tomography. Maximum stone diameter was 15mm. The patients were given a standardised extract of Phyllanthus, as well as magnesium and vitamin B6 for three months. After treatment, the stones were again imaged. The researchers concluded that the treatment had the highest efficacy in producing stone-free status in patients with stones of 3mm or less. Indicative of potential, but hardly a ringing endorsement of activity.

The plant also features in traditional Chinese medicine (TCM) to treat chronic liver disease and it was added to the Chinese Pharmacopoeia in 1992. A number of preclinical studies have shown effects against hepatitis B virus (HBV) both in vitro and in vivo. A Cochrane systematic review of Phyllanthus for chronic HBV infection was published in 2011. This included 16 randomised trials with 1,326 patients. One trial compared Phyllanthus with placebo and found no significant difference in HBeAg seroconversion after treatment or on follow-up. The remaining trials compared Phyllanthus combined with various antivirals, such as interferon alpha, with conventional treatment with the same antiviral on its own. There was a significant effect on serum HBAg and on HBeAg seroconversion to inactive status, but there was no information on mortality levels or on liver histology. The review concluded that there was no convincing evidence that Phyllanthus on its own benefits patients with HBV. Combining Phyllanthus with standard antivirals might be better than antivirals alone, but the reviewers raised questions about the validity of the results, leading to the usual mantra of ‘more research needed’.

Cupuaçu is another tree native to the Amazon rain forest. Botanically, it is Theobroma grandiflorum and thus is related to Theobroma cacao, the source of chocolate. It is listed as the national fruit of Brazil, but is also cultivated in Bolivia, Colombia and Peru. I came across it in a list of ingredients in a natural exfoliating gel. As a Theobroma species, it contains a small amount of caffeine as well as theophylline and of course, theobromine. Also, just as cocoa seeds produce cocoa butter (aka Theobroma oil), Cupuaçu does likewise and it is this butter which has cosmetic uses. It is a triglyceride based on both saturated and unsaturated fatty acids, with a melting point of approx. 30oC.  The main fatty acids are stearic, oleic, palmitic and arachidic acids. It is used in confectionary, where it resembles white chocolate. Having much the same texture and emollient properties as cocoa butter, one can see how it would be useful in skincare products. It will be interesting to see whether its low melting point results in it also being used in ointments and suppositories. 

I came across Moringa oleifera in the ‘Lifestyle’ section on my RTÉ News Now app that referred to it as “this new superfood that wellness types are getting hyped about”. It gushingly described the plant as “gaining popularity with health buffs thanks to its rich nutrient profile and powerful anti-inflammatory and antioxidant properties” that could help beat stress and fatigue. After I got over my initial queasiness at expressions such as “wellness types” and “health buffs”, I set out to find out more about this plant. I soon learned that India produces over 1.2 million tonnes of Moringa fruits per year, mainly for food use, but the leaves are also used. The literature claims with some justification that the fruits provide seven times more vitamin C than oranges, 10 times more vitamin D than carrots, 17 times more calcium than milk, nine times more protein than yoghurt, 15 times more potassium than bananas, and 25 times more iron than spinach.

Not surprisingly, it has been extensively studied in India. It was found to have hepatoprotective effects in rats exposed to hepatotoxins such as paracetamol, isoniazid and rifampicin. Moringa also showed anti-diabetic effects, such as lowered fasting blood glucose and improved glucose tolerance in normal and diabetic rats and in diabetic rabbits. Human studies have largely been open studies, which rather limits their value.  Several, involving type 2 diabetic patients, resulted in marked (29 per cent) reductions in post-prandial blood glucose and glycosylated haemoglobin levels. In a randomised study, individuals with LDL greater than 100mg per decilitre were given a commercial extract in capsule form for 30 days. A significant reduction in LDL concentration versus control was observed and the extract prevented any rise in serum glucose after a 75g oral challenge. Whether this herbal material will be of any benefit to the ‘worried well’ who are not type 2 diabetics remains a matter of conjecture and hype at this time.