Development of reverse phase-high performance liquid chromatography (RP-HPLC) method for determination of selected antihypertensive active flavonoids (rutin, myricetin, quercetin, and kaempferol) in medicinal plants found in Botswana

Abstract The aim of the study was to develop a rapid, efficient, and cheap chromatographic method for determining four selected antihypertensive active flavonoid compounds in medicinal plants in Botswana. The determination of rutin, quercetin, and kaempferol in selected medicinal plants was conducted in less than 6 min using the developed reverse phase-high performance liquid chromatography (RP-HPLC) method with a 2.7 µm Ascentis C18 express column (150 × 4.60 mm i.d) at 340, 360, and 368 nm detection wavelengths and mobile phase of methanol and 0.068% of formic acid solution in isocratic elution. Validation results showed good selectivity, linearity (r 2 > 0.99), high percentage recoveries (90.2–104.7%), and precision (% RSD < 2) for n = 3, confirming suitability of the method for determination of the investigated flavonoids in Zingiber officinale (ginger). Application of the developed RP-HPLC method was performed in selected medicinal plants (Lippia javanica ) (mosukujane), Myrothanmus flabellious (galalatshwene), and Elephantorrhiza elephantina (mositsana) used to manage hypertension by herbalists in Botswana. M. flabellious a very commonly used plant for managing hypertension was found to contain highest amounts of rutin and myricetin, whereas nothing was detected for E. elephantina.