Phytochemical composition, ß-glucuronidase inhibition, and antioxidant properties of two fractions of Piper betle leaf aqueous extract.

RATIONALE: Piper betle leaf, used as masticatory in South Asia, is also medicinally important. OBJECTIVE: This work was done to analyze phytochemical composition of two solvent fractions (chloroform and ethyl acetate) of the aqueous extracts obtained from eight varieties of P. betle leaves and to identify the active components against ß-glucuronidase by chemometric analysis. RESULTS: Twenty-four phenolic compounds, in addition to different organic acids, fatty acids, amino acids, sugars, and polyols, were identified from the solvent fractions. The extracts inhibited the enzyme ß-glucuronidase. Piceatannol was the most active constituent against the enzyme (activity 12 times higher than that of silymarin), Chlorogenic acid also inhibited ß-glucuronidase (activity 4.4 times higher when compared to silymarin). 2,2'-Diphenyl-1-picrylhydrazyl and superoxide free radical scavenging activities of both the fractions of eight varieties of P. betle leaf extracts showed very strong antioxidant potentiality. CONCLUSION: The findings validated some medicinal properties of the said leaves. PRACTICAL APPLICATIONS: Edible leaves of Piper betle are medicinally and economically important. Leaves of different local varieties are reported to be used for the treatment of different diseases. The leaves have many biological properties, hepatoprotection being one of them. A large number of rural population is economically dependent on the cultivation of betel vine. But with a rapid change in lifestyle, the chewing habit of P. betle is decreasing ultimately affecting the livelihood of farmers dependent on betel cultivation. Knowledge on ß-glucuronidase inhibitory activity and the mechanism for hepatoprotection of different P. betle varieties may validate the medicinal properties of betel, which would increase consumption of these leaves.

Metabolic profile and β-glucuronidase inhibitory property of three species of Swertia

ABSTRACT β-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 β-glucuronidase inhibitory activity of these three important species of Swertia and to identify the active constituents. S. chirayita (IC50 210.97 µg/ml) and S. decussata (IC50 269.7 µg/ml) showed β-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 (IC50 16.06 µg/ml), swerchirin (IC50 162.84 µg/ml), decussatin (IC50 195.11 µg/ml), 1-hydroxy-3,5,8-trimethoxy xanthone (IC50 245.97 µg/ml), bellidifolin (IC50 390.26 µg/ml) were significantly higher than that of silymarin (IC50 794.62 µg/ml). Quinic acid (IC50 2.91 mg/ml), O-acetylsalicylic acid (IC50 48.4 mg/ml), citric acid (IC50 1.77 mg/ml), D-malic acid (IC50 14.82 mg/ml) and succinic acid (IC50 38.86 mg/ml) also inhibited the enzyme β-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.