Research conducted by medical experts shows that some Rarotongan plant products have antiseptic properties that can reduce the possibility of skin infections, vindicating the long-held beliefs of Maori medicine practitioners.

In particular iripiri kerekere, tuava, ka’ika, tamanu nuts and pistati leaves and fruit were found to be active against local pathogens that cause skin infections.

Lead researcher Dr Richard Everts said their findings confirm tropical antiseptics applied to traumatic wounds reduced the incidence of skin infection. “We tested local plant products against clinically relevant microbes from Rarotongan patients, so as to inform local healers and the public as to what local products are effective antiseptics against skin pathogens,” said Dr Everts, a New Zealand infectious disease specialist and microbiologist.

“We found that piripiri kerekere, tuava, ka’ika, tamanu nuts and pistati leaves and fruit have substantial inhibitory activity against both methicillin-susceptible and methicillin-resistant staphylococcus aureus. These products may be useful for the prevention and treatment of skin infections.”

However the research which was conducted with help of Rarotonga hospital’s chief microbiologist Geoffrey Wuatai and medical student Radhika Sholapurkar said it does not guarantee that a natural product will be effective or safe in real clinical practice.

“Other limitations are that we tested only a small selection of microbes and that antiseptic activity was only measured by diffusion into agar (some antiseptic agents will not do this),” Dr Everts said.

“It is also possible that some natural products are beneficial on skin conditions because of a moisturising or anti-inflammatory effect, rather than an antiseptic effect as measured in this study.

“Despite these limitations, the results of this study suggest that some Rarotongan leaves and nuts may be useful for preventing skin infections after trauma or even to treat minor skin infections.”

Dr Everts said the results also showed that young leaves seem to have better antiseptic activity than old leaves and that freshly prepared leaf mixtures sometimes have better antiseptic activity than stored mixtures.

He said comparison of different options for preparation method showed that using saliva or hot water did not eliminate the antiseptic properties of the leaves but using sterile cold water was the most effective.

“These results should be shared with traditional healers and the public so that herbal products may be chosen that are more likely than others to be effective.

“Health-care professionals should also be aware of these results so they can understand and accept the use of certain natural products alongside commercially accepted topical antiseptics.

“Given the high rate of skin infection and antibiotic consumption in the Pacific Islands, there is potential for the use of natural products with antimicrobial activity to improve patient health and reduce unnecessary use of antibiotics.”

In the future, Dr Everts said more leaves and other products could be tested against a larger number of local staphylococcus aureus and other microbial pathogens.

“It would also be useful to test for adverse effects and one simple way to do this would be a skin-prick study,” he said.

“A clinical trial of different natural Rarotongan products could be done to test efficacy against no treatment or compared with commercial antiseptics.

“There is even the possibility of identification of a useful antiseptic or antibiotic product for international commercial use, but this pharmaceutical development is well outside the scope of this study team.”

- Rashneel Kumar