Abstract:
This study evaluated the effects of Newbouldia laevis and Cassia abbreviata extracts on
CYP450 enzyme activity. Recombinant CYP450 enzyme and fluorogenic substrates were used for
evaluating inhibition, allowing the assessment of herb–drug interactions (HDI). Phytochemical
fingerprinting was performed using UPLC-MS. The herbal extracts were risk ranked for HDI
based on the IC50 values determined for each CYP enzyme. Newbouldia laevis inhibited CYP1A2,
CYP2C9, and CYP2C19 enzyme activities with Ki of 2.84 µg/mL, 1.55 µg/mL, and 1.23 µg/mL,
respectively. N. laevis exhibited a TDI (4.17) effect on CYP1A2 but not CYP2C9 and CYP2C19
enzyme activities. Cassia abbreviata inhibited CYP1A2, CYP2C9, and CYP2C19 enzyme activities
showing a Ki of 4.86 µg/mL, 5.98 µg/mL, and 1.58 µg/mL, respectively. TDI potency assessment
for Cassia abbreviata showed it as a potential TDI candidate (1.64) for CYP1A2 and CYP2C19 (1.72).
UPLC-MS analysis showed that Newbouldia laevis and Cassia abbreviata possess polyphenols that
likely give them their therapeutic properties; some of them are likely to be responsible for the
observed inhibition. The observations made in this study suggest the potential for these herbal
compounds to interact, especially when co-administered with other medications metabolized by
these CYP450 enzymes.
