Long road to herbal medication
According to Dr Merlin Willcox, honorary secretary, Research Initiative for Traditional Antimalarial Methods (RITAM), several herbal treatments could potentially be more cost-effective than Attemisinin-based Combination Therapies (ACTs) in certain contexts. But there is no consensus on what plants, preparations and dosages to use. Still, no herbal treatments have yet been described to be as efficacious as ACTs for parasite clearance.
Yet, malaria remains one of the most prevailing diseases in the tropical world. With 200 to 450 million infections annually occurring worldwide, it causes up to 2.7 million deaths, 90 per cent of them being recorded in Africa. It is this grim scenario in Africa that led to the formation of the Global Roll Back Malaria (RBM) partnership in 1998 and the Abuja Declaration of April 2001. These efforts are using Insecticide Treated Nets (ITNs) and ACTs to reduce by half the incidence of and deaths attributed to malaria by 2010. Sadly, this remains a tall order.
Control of malaria has relied on herbal drugs for centuries. An infusion of Artemisia annua (ginghao; wormwood) has been used in China for at least the last 200 years, yet its active ingredient (artemisinin) has only recently been identified. However, many plant species are known to contribute to either the treatment of the disease or its control when used as insecticides to break the vector (mosquito) attack on humans. Most have been used as herbal remedies in traditional/natural medicine, with some subsequently finding their way into conventional pharmacies.
Whereas herbal medicine is becoming more widely accepted by many authorities including the World Health Organization (WHO) as a viable treatment for various ailments, the efforts of donors, businesses and farmers would benefit from improved co-ordination, thus encouraging further investment and creating a steady supply of effective remedies to those affected by malaria. While a great deal of research and scientific discussion has been going on concerning Artemisia and other new antimalarials, the actual number of authorized drugs on the market is still wholly insufficient to even begin to meet the needs of those who suffer from malaria. The same is true of public and private investment in the cultivation, processing, marketing and distribution of appropriate products throughout Africa.
Against this background, the Centre for Development Enterprise (CDE), the World Bank, EU, World Agroforestry Centre (ICRAF) and the Association for the Promotion of Traditional Medicine (PROMETRA) organized the Africa herbal Antimalaria meeting at the ICRAF campus, Nairobi from 20 to 22 March. The major objective of the meeting was to share information on the current and future use of plant products in the control of malaria and to develop a collaborative action programme for Africa-wide production and distribution of appropriate herbal antimalarials.
Still, lack of clinical data and variable content of active compounds in plants remain major limitations in the use of herbal antimalarials. But they do have the competitive advantage of being affordable, available and able to reach areas that modern drugs cannot reach. According to Dr Willcox, they are more cost-effective for home management, presumptive malaria and in semi-immune patients (Adults and children aged above 5 years). More research is particularly needed in clinical and public health.
“Artemisia annua has been promoted as a herbal remedy for malaria on a limited scale by ANAMED (Action for Natural Medicine)and others. Concerns have arisen, however, with Artemisia tea regarding the wisdom of a monotherapy approach’, says Dr Dennis Garrity, Dierector-general, ICRAF. Dr Garrity argues that with the recent availability of Artemisia germplasm adapted to African conditions and new knowledge on efficacy of indigenous herbal remedies, there is a novel opportunity to combine Artemisia cultivation with growing of other anti-malarial trees such as Annickia, Cryptolepsis, Trichilia, Vernonia, Warburgia and Zanthoxylum to produce a Herbal Combination Therapy (HCT).
But commercialization of herbals in Africa poses another challenge. Notably, the supply chain for raw materials is difficult to build, according to Dr Ulrich Feiter, of South African based pharmaceutical company, Parceval (Pty). Dr Feiter notes that in the beginning, cultivation will be on a small scale, hence the difficulty in finding partners who are willing to take the risk. Sharing knowledge may also be difficult for commercial reasons.
Ghana, however, presents some good news. Trading in Antimalarials has been going on for years, courtesy of herbalists and witchdoctors. The preparation was a tincture from the bark of a tree or an extract from the leaves of a tree. The identity of the select trees was all shrouded in mystery and incantations. Sometimes some other herbs were added and depending on how severe the symptoms of Malaria attack were, these preparations could be made more concentrated, frequency of dosing increased and subsequently the fees charged were determined proportionately. To date, the herbs have been formulated into liquid dosage forms, bottled and well labeled for the shelves in Pharmacies and Chemical Sellers outlets.
But lack of clinical data on efficacy remains a major hinderance in the use of herbal antimalarials.