The inhibitory effect of rooibos on cytochromes P450 and downstream in vitro modulation of steroid hormones
Year: 2015
Type: dissertation
Abstract: ENGLISH ABSTRACT: This study describes: 1. Substrate binding assays investigating the effects of methanolic extracts of unfermented and fermented Rooibos on the binding of natural substrates to ovine adrenal microsomal and mitochondrial P450 enzymes, demonstrating the interference of substrate binding in the presence of the Rooibos extracts. 2. The effects of selected flavonoids (quercetin, rutin and aspalathin) on the binding of natural substrates to ovine adrenal microsomal and mitochondrial P450 enzymes, demonstrating interference of substrate binding in the presence of the flavonoid compounds. 3. Substrate conversion assays in non-steroidogenic COS-1 cells to investigate the effects of methanolic extracts of unfermented and fermented Rooibos on the activity of key steroidogenic P450 enzymes (CYP17A1, CYP21A2, CYP11B1, and CYP11B2), demonstrating inhibition of the catalytic activity in the presence of Rooibos extracts. 4. The effects of selected flavonoids on the substrate conversion of the aforementioned key steroidogenic enzymes expressed in COS-1 cells. 5. An investigation of the effect of methanolic extracts of unfermented and fermented Rooibos on steroid hormone production in human adrenal H295R cells under basal and stimulated conditions, demonstrating the modulating effects of unfermented and fermented Rooibos extracts. Basal and stimulated steroid hormone production was decreased in the presence of unfermented and fermented Rooibos.
Author: Mufaro Buhlebenkosi Mugari
Language: English
Subfield: Pharmacology
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W823053065