South African botanical resources: A gold mine of natural pro-inflammatory enzyme inhibitors?

Abstract

Inflammation is implicated in the pathogenesis of many diseases such as Alzheimer's disease, rheumatoid arthritis and cancer. Inflammation is a complex process, involving the activation of specific mediators such as enzymes, cytokines, as well as growth and nuclear factors. The inhibition of pro-inflammatory enzymes is regarded as an effective strategy to combat inflammation. The undesirable side effects associated with many current anti-inflammation drugs have necessitated an increased search for natural principles with the capacity to suppress or inhibit inflammation mediators and with much reduced side effects. South Africa has a rich floral biodiversity coupled with indigenous knowledge systems on the use of medicinal plants, which has become widely explored for meeting primary health care needs, especially in resource-limited areas. Using electronic search engines and library resources, this review highlights the successes, challenges and prospects associated with the exploration of the South African floral diversity for inflammatory inhibitors. Several South African plant extracts demonstrated pro-inflammatory enzyme inhibitory potential with very low cytotoxicity. However, these reports have been based largely on in vitro evaluation. This has resulted in, at least, partial valorisation of their traditional uses. Notwithstanding the vast natural endowment and the available technology in bioprospecting the floral diversity for natural inflammatory enzyme inhibitors, only a limited number of plant species has been exploited and a relatively negligible fraction has been developed into natural products. The current limited bioprospecting ‘success’, when examined in the light of relatively untapped opportunity, underscores the potential for the discovery of new sources of natural inflammatory enzyme inhibitors.