Professor Alvaro Viljoen, from the Tshwane University of Technology, discusses the use of indigenous plants in the commercial sector.
‘I come to you as a botanist,’ announced Professor Alvaro Viljoen at the start of his presentation to SAAFoST members, in Johannesburg. His research interest is the phytochemistry and biological activity of medicinal and aromatic plants.
Born in 1969, Prof Viljoen has an extremely accomplished CV. In 2002 he was promoted to senior lecturer at the University of the Witwatersrand and in 2005 to associate professor. In July 2005 he was appointed as a research fellow in the Department of Pharmaceutical Sciences Tshwane University of Technology, Pretoria.
His particular interest and acclaimed expertise lies in the natural flora of SA, a country that boasts 10 per cent of the world’s total flora on less than two per cent of the world’s terrestrial surface. ‘I always tell my students we have the most unique lab in the world to work in,’ says Prof Viljoen.
Prof Viljoen refers to the traditional medicines of the indigenous people, such as the Khoi San, and says, ‘Even today, 60 per cent of SA’s black population relies on natural remedies and there are over 200 000 traditional healers in SA.’ ‘We are seeing more and more of these plants going into nutraceuticals and functional foods,’ he says, warning that in the commercial sector, ‘we need to explore, not exploit, this indigenous knowledge.’
Prof Viljoen is adamant that products stating they contain elements of certain indigenous plants must commit to vigorous and thorough testing by scientific professionals before making any such claims. Hoodia made its debut on the market as a natural appetite-suppressing drug. Traditionally used in times of famine, Khoi would chew on hoodia to suppress their appetites.
Western consumer behaviour today does not resemble that of a Khoi, Prof Viljoen highlights. It may have worked for the Khoi under those conditions, but who’s to say in today’s overindulgent society whether it would have the same effect?
His greatest concern is that the reputation of these plants will be tainted by products on the market that do not fulfil the promises claimed because today’s consumer behaviour has not been considered, and even worse if tested, contain only the faintest trace of the integral ingredient. In many cases, Prof Viljoen says, a product may contain the indigenous plant but in insufficient amounts or in the incorrect form.
After conducting tests on the absorption of antioxidants in rooibos, Prof Viljoen concluded that they cannot be absorbed by the skin. A shocking find for many cosmetic companies using this ingredient in topical applications, but scientifically, Prof Viljoen has proved rooibos must be ingested in order for the antioxidants to be absorbed.
‘For several indigenous species, commercial development precedes basic scientific studies, which has a most unfavourable outcome,’ says Prof Viljoen. An unfavourable outcome for certain manufacturers, who have accused Prof Viljoen of destroying their reputation, but this is not his aim, stresses Prof Viljoen. For the sustainable future of indigenous medicinal plants in SA, proper scientific research must be conducted every step of the way.
‘Despite the common belief that phytocompounds are safe, they all have inherent risks just like synthetic compounds,’ Prof Viljoen points out.
Safety and efficacy depend largely on the quality of the raw materials used and quality assurance protocols are urgently required for indigenous medicinal plants to ensure high value products for both the local and export market. ‘We are blessed to have this bio-diversity and it’s a unique resource,’ concludes Prof Viljoen.
