Rooibos is not tea in the strict sense of the word, it’s a completely different plant with a different set of bioactive alkaloids.
”The MeOH extract exhibited significant inhibition of the major human CYP450 isozymes (CYP3A4, CYP1A2, CYP2D6, CYP2C9, and CYP2C19). The strongest inhibition was observed by the extract for CYP3A4 (IC50 1.7 ± 0.1 μg/mL) followed by CYP2C19 (IC50 4.0 ± 0.3 μg/mL). Among the tested phytochemicals, the most potent inhibitors were isovitexin on CYP3A4 (IC50 3.4 ± 0.2 μM), vitexin on CYP2C9 (IC50 8.0 ± 0.2 μM), and thermopsoside on CYP2C19 (IC50 9.5 ± 0.2 μM). The two major, structurally related compounds aspalathin and nothofagin exhibited a moderate pregnane-X receptor (PXR) activation, which was associated with increased mRNA expression of CYP3A4 and CYP1A2, respectively. These results indicate that a high intake of nutraceuticals containing rooibos extracts may pose a risk of herb–drug interactions when consumed concomitantly with clinical drugs that are substrates of CYP enzymes.”
I don't drink decaffeinated tea, but I do drink quite a lot of naturally caffeine-free herbal teas. My local supermarket stocks dozens of varieties. I rather like peppermint but also enjoy other infusions depending on my mood.
