In Vitro Antilipidic and Antithrombotic Activities of Plectranthus glandulosus (Lamiaceae) Leaves Extracts and Fractions

Abstract

Objective. The present study investigated the effect of the leaves extracts and fractions of Plectranthus glandulosus on the inhibition of pancreatic lipase, cholesterol esterase, adipocytes lipid uptake, and antithrombotic activity which may be important in atherosclerosis development. Methods. Aqueous, ethanolic, and hydroethanolic extracts of Plactranthus glandulosus were prepared by maceration. The hydroethanolic extract was fractionated into n-hexane, ethylacetate, and n-butanol fractions and their inhibition of pancreatic lipase, cholesterol esterase, adipocytes lipid uptake, and antithrombotic activities measured. Liquid chromatography-high resolution mass spectrometry (LC-HRMS) analysis was carried out to determine phytochemical constituents present in the extracts. Results. The standard orlistat exhibited a higher inhibitory activity on pancreatic lipase and cholesterol esterase (16.31 μg/mL and 15.75 μg/mL, respectively) compared to ethyl acetate fraction (IC50, 17.70 μg/mL and IC50, 24.8 μg/mL, respectively). Among crude extract, hydroethanolic extract showed a better inhibition against pancreatic lipase (IC50, 21.06 μg/mL) and cholesterol esterase (IC50, 25.14 μg/mL) though not comparable to the effect of orlistat. The best lipid uptake inhibition was observed in the hydroethanolic extract (IC50, 45.42 μg/mL) followed by the ethyl acetate fraction (IC50, 47.77 μg/mL). A better antithrombolytic activity was exhibited by the ethyl acetate fraction at all concentrations (50-800 μ/mL), while hydroethanolic extract exhibited the best activity among crude extract. However, these were not comparable to the standard aspirin. The LC-HRMS analysis revealed the presence of 7-O-methyl luteolin 5-O-β-D-glucopyranoside, chrysoeriol 5-O-β-D-glucopyranoside, 5,7-dihydroxy-3,2 ${}^{\prime }$ ,4 ${}^{\prime }$ -trimethoxyflavone, and plectranmicin as major compounds in both hydroethanolic extract and ethyl acetate fraction. Conclusion. Thus, our finding supports the traditional use of this plant, which might provide a potential source for future antiatherosclerotic drug discovery.