Metabolic profile and ?2-glucuronidase inhibitory property of three species of Swertia

摘要

?2-Glucuronidase inhibitors are suggested as potential hepatoprotective agents. Swertia chirayita (Roxb.) Buch.-Ham. ex C.B. Clarke, Gentianaceae, is known for its hepatoprotective and anti-hepatotoxic activity in Ayurvedic system of medicine for ages. This plant is substituted by other species like S. decussata Nimmo ex C.B. Clarke and S. bimaculata (Siebold & Zucc.) Hook. f. & Thomson ex C.B. Clarke. The aim of the study was to compare metabolite profile and ?2-glucuronidase inhibitory activity of these three important species of Swertia and to identify the active constituents. S. chirayita (IC 50 210.97 ?μg/ml) and S. decussata (IC 50 269.7 ?μg/ml) showed ?2-glucuronidase inhibitory activity significantly higher than that of silymarin, the known inhibitor of the enzyme. The activity of S. bimaculata was low. The metabolites present in the three species were analyzed by HPLC and GC-MS based metabolomics approach. Five amino acids, twenty one organic acids, one inorganic acid, eight fatty acids, twenty one phenols including xanthones, eight sugars, seven sugar alcohols, five terpenoids and amarogentin were identified. Activities of the xanthones mangiferin (IC 50 16.06 ?μg/ml), swerchirin (IC 50 162.84 ?μg/ml), decussatin (IC 50 195.11 ?μg/ml), 1-hydroxy-3,5,8-trimethoxy xanthone (IC 50 245.97 ?μg/ml), bellidifolin (IC 50 390.26 ?μg/ml) were significantly higher than that of silymarin (IC 50 794.62 ?μg/ml). Quinic acid (IC 50 2.91 mg/ml), O -acetylsalicylic acid (IC 50 48.4 mg/ml), citric acid (IC 50 1.77 mg/ml), D-malic acid (IC 50 14.82 mg/ml) and succinic acid (IC 50 38.86 mg/ml) also inhibited the enzyme ?2-glucuronidase. The findings suggest that constituents, in addition to the xanthones, probably also contribute to the bioactivity of different Swertia species by synergistic effect. Further in vivo study is required to support the claim.