ABSTRACT
Biodiversity plays vital roles in maintaining human and animal health. A wide variety of plants, animals, and fungi are used as medicine, essential vitamins, painkillers. Natural products have been recognized and used as medicines by ancient cultures all around the world. About 119 pure chemicals are extracted from less than 90 species of higher plants and used as medicines throughout the world, for example, artemisinin and quinine for treatment of malaria. Malaria is the most important public health problem in tropical and sub-tropical Africa, and it is becoming more and more difficult to control. Although several attempts have been made on vaccine development, chemotherapy and vector control are currently the mainstays of malaria control. However, with increasing cases of drug-resistant strains of malaria parasites and expensive anti-malarial drugs coupled with the poor distribution of modern health facilities, there is a resurgence in use of herbal remedies to treat malaria and other infectious diseases, before seeking the conventional western remedies. Although the use of herbal preparations for malaria is widespread in the Lake Victoria basin, there has been no previous validation of their efficacy and safety. Furthermore, there are no standard practices for quality assurance in sourcing of the herbal anti-malarial drugs. In this paper, a survey of the plants used for treatment and management of malaria in the Lake Victoria was carried out. Organic and water extracts from these plants were subjected to in vitro anti-plasmodial assays using W2 (CQ resistant) and D6 (CQ sensitive) strains. The results obtained to authenticate the use of these plants as anti-malarial herbs. A set of compounds have been isolated and characterized from the plant species that exhibited high anti-plasmodial activity.
ABSTRACT
Post-harvest pests are known to cause severe losses of beans in particular the bean weevil, Acanthoscelides obtectus, necessitating immediate and long term control measures. Convectional pesticides have been used for decades to protect stored grain from pests, but their harmful environmental impact and pest resistance resulting from the need for increased pesticide use have triggered researchers to search for eco-friendly, biodegradable and potent biopesticides. The use of natural products derived from metabolic activity of plants may constitute a new avenue of pest control. This paper describes phytochemical and biological investigations of leaves, root, and stem bark crude extracts and isolated compounds of selected Kenyan plants used to control the bean weevil. Bioassays tests of the compounds were done against brine shrimp to test their insecticidal activity against the bean weevil. Antibacterial and antifungal activity of the crude extracts of S. didymobotrya was also done. The extracts of S. didymobotrya showed high toxicity as well as adulticidal activity against bean weevil.