South African plants as a source of drugs to treat infectious diseases - TB, malaria and HIV.

Abstract

CSIR Biosciences is actively involved in identifying new medicines effective against tuberculosis (TB), malaria and HIV based on South Africa’s rich biodiversity. As part of a national multidisciplinary consortium, the Bioprospecting research group and the South African National Biodiversity Institute (SANBI) established a database of 566 plant taxa that are reportedly used for the treatment of TB and 623 taxa associated with malaria and/or fever. A process of prioritization using selection criteria led to 162 plant extracts, representing 24 taxa, being tested in a preliminary in vitro screen against Mycobacterium aurum. Thirteen extracts demonstrated significant antibacterial activity and were subsequently tested against M. tuberculosis. This led to 7 extracts (5 taxa) with significant anti- TB activity. Of the 134 plant taxa tested for in vitro antimalarial activity against a chloroquine-sensitive strain of Plasmodium falciparum, 23 species were found to be highly active. Bioprospecting has screened 30 plants with traditional use related to the treatment of HIV for their anti-HIV properties, resulting in the identification of four biologically active plant extracts (4 taxa), which are currently being further developed. A recent research collaboration with Esperanza Medicines Foundation (EMF) also provided a unique opportunity to evaluate South African medicinal plants in HIV/AIDS-related biological assays exclusive to the Swiss-based institute. Overall, compelling evidence has been provided for the rational exploration of South African plants as sources of new drugs to treat TB, malaria and HIV