Pharmacokinetic and Bioavailability Profile of Hyptis capitata Jacq Flavonoids: A Scientific Perspective on Traditional

Abstract

Hyptis capitata Jacq. (knobweed) is a traditional medicinal plant renowned for its bioactive flavonoid content, which exhibits antioxidant, anti-inflammatory, and analgesic activities. This study aimed to comprehensively characterize the pharmacokinetic and bioavailability profile of methanolic leaf extract flavonoids from H. capitata in rabbit (Oryctolagus cuniculus) plasma. An experimental pharmacokinetic design was employed, involving two rabbits orally administered with H. capitata methanolic extract at a dose of 832 mg and quercetin standard at 182 mg as a reference compound. Blood samples were collected via the marginal ear vein at 0, 0.5, 1, 2, 4, 6, 12, and 24 hours post-administration. Plasma was separated by centrifugation and analyzed using UV-Vis spectrophotometry at an optimal wavelength of 362 nm. The pharmacokinetic analysis revealed that H. capitata extract exhibited an absorption rate constant (Ka) of 0.621 h⁻¹, maximum plasma concentration (Cmax) of 19.76 µg/mL at a time to maximum concentration (Tmax) of 4.49 hours, elimination rate constant (K) of 0.034 h⁻¹, elimination half-life (t½) of 20.38 hours, apparent volume of distribution (Vd) of 3924.86 mL, clearance (Cl) of 133.4 mL/h, and area under the concentration–time curve (AUC) of 692.13 µg·h/mL. Compared to quercetin, H. capitata extract demonstrated slower absorption, lower Cmax, and prolonged elimination, indicating extended systemic exposure and the potential for sustained pharmacological effects. These findings provide important insights into the pharmacokinetic behavior of H. capitata flavonoids, supporting their relevance in modern phytopharmacology and the evidence-based development of traditional medicine applications.