Exploration of South African biodiversity associated with indigenous knowledge for the discovery of natural ingredients as potential drug leads

South Africa, recognized as one of the world’s biodiversity hotspots, with a rich tapestry of indigenous knowledge systems, presents unique opportunities for sustainable bioprospecting and development of innovative natural ingredients. The research highlights a multidisciplinary approach using modern scientific methodologies to harness South Africa’s rich biodiversity and the wealth of associated indigenous knowledge for the discovery, development, and commercialisation of new natural products. Surveys were conducted at communities in South Africa and the traditional uses of identified medicinal plants were recorded. Plants were collected, dried, ground and extracted using aqueous and organic solvents. Each extract was fractionated using solid-phase extraction to produce seven corresponding fractions in 96-well plate format for high throughput screening. Extracts and fractions were tested in vitro for cytotoxicity and efficacy to identify ingredients with medicinal properties, including analgesic, anticancer, antidiabetic, antiviral and antimicrobial properties. The fractions showing good biological activity were analysed by ultra performance liquid chromatography – quadrupole time-of-flight – mass spectrometry to tentatively identify the compounds responsible for bioactivity. Antidiabetic ingredients, from Buddleja saligna Willd. (Scrophulariaceae) and Crassula muscosa L. (Crassulaceae), have been identified through this approach. Seventy two samples were screened for enzyme inhibition activity against α-amylase and α-glucosidase, and glucose-uptake activity in liver cells. Two extracts and their corresponding fractions showed good antidiabetic activity (IC 50