Developing a Validated HPLC Method for the Phytochemical Analysis of Antihyperuricemic Phenylethanoid Glycosides and Flavonoids in Lippia nodiflora

The phenylethanoid glycosides and flavonoids of Lippia nod:flora were reported as xanthine oxidase inhibitors that possessed antihyperuricemic effects in chemically-induced hyperuricemic rats. The present study developed a validated high performance liquid chromatography method for the simultaneous phytochemical analysis of five isolated antihyperuricemic constituents in L. nodiflora, comprising two phenylethanoid glycosides, arenarioside (1) and verbascoside (2), and three flavonoids, 6-hydroxyluteolin (3), 6-hydroxyluteolin-7-O-glycoside (4) and nodifloretin (5). These compounds were analysed at 340 nm, using gradient elution of 0.1 % aqueous acetic acid and acetonitrile. The limits of detection were 78.1 ng/mL for 3 and 39.1 ng/mL for the other compounds at a signal-to-noise ratio of 3. The limits of quantification were 312.5 ng/mL for 3 and 156.3 ng/mL for the rest at a signal-to-noise ratio of 12. The intra-day and inter-day accuracy for the five bioactive constituents were between 98.60 % and 100.97 % while their precision values were below 2.11 %. The method was then successfully applied for the quantification of 1-5 in the methanolic extract of L. nodiflora whole plant and its fractions (F1-F4), the methanolic plant part extracts (leaves, stems, roots, and flowers), and water extract of the L. nodiflora whole plant at room temperature.