Rooibos influences glucocorticoid levels and steroid ratios in vivo and in vitro: a natural approach in the management of stress and metabolic disorders?
SCOPE
To determine the effect of Rooibos (Aspalathus linearis) on glucocorticoid biosynthesis and inactivation in vivo and in vitro.


METHODS AND RESULTS
Ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) analyses of in vivo studies showed that human Rooibos consumption increased cortisone plasma levels in males (p = 0.0465) and reduced cortisol:cortisone ratios in males and females (p = 0.0486) at risk for cardiovascular disease. In rats, corticosterone (CORT) (p = 0.0275) and deoxycorticosterone (p = 0.0298) levels as well as the CORT:testosterone ratio (p = 0.0009) decreased following Rooibos consumption. The inactivation of cortisol was investigated in vitro by expressing 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) and type 2 (11βHSD2) in CHO-K1 cells. Rooibos inhibited 11βHSD1, which resulted in a significant reduction in the cortisol:cortisone ratio (p < 0.01). No significant effect was detected on 11βHSD2. In vitro studies in adrenal H295R cells showed that Rooibos and rutin, one of the more stable flavonoid compounds present in Rooibos, significantly reduced the levels of cortisol and CORT in cells stimulated with forskolin to mimic a stress response.


CONCLUSION
In vivo studies demonstrate that Rooibos significantly decreased glucocorticoid levels in rats and steroid metabolite ratios linked to metabolic disorders--cortisol:cortisone in humans and CORT:testosterone in rats. Results obtained at cellular level elucidate possible mechanisms by which these effects were achieved.
['Schloms|Lindie|L|', 'Smith|Carine|C|', 'Storbeck|Karl-Heinz|KH|', 'Marnewick|Jeanine L|JL|', 'Swart|Pieter|P|', 'Swart|Amanda C|AC|']
D042842:11-beta-Hydroxysteroid Dehydrogenases D000311:Adrenal Glands D000818:Animals D036903:Aspalathus D016466:CHO Cells D002318:Cardiovascular Diseases D003345:Corticosterone D003348:Cortisone D003412:Cricetulus D019587:Dietary Supplements D005260:Female D005938:Glucocorticoids D006854:Hydrocortisone D008297:Male D018384:Oxidative Stress D010936:Plant Extracts D017208:Rats, Wistar D012431:Rutin D013256:Steroids
Adrenal H295R cells Cytochrome P450 Functional food Metabolic syndrome Rooibos tea polyphenol flavonoids