Phytochemical profiling, antidiabetic, antiobesity, and antibacterial activities of Cometes abyssinica

Abstract

This study aims to complete my chemical and biological studies on Cometes abyssinica (CA). The chemical profile was reported by LC-ESI-TOF-MS and GC-MS analyses. Antidiabetic (α-Glucosidase and a-amylase inhibitory activity assay), antiobesity (Lipase inhibitory activity assay), and antibacterial activity (agar well diffusion assay) were determined. The GC-MS analysis led to the identification of 27 hydrocarbons representing 93.4% of the total hydrocarbon content in hexane extract. 11-Octadecenoic acid, methyl ester (28.07%), citronellol (9.31%), hexadecanoic acid, methyl ester (7.64%), phytol (5.93%), and 10-epi-γ-eudesmol (4.91%) were the major components. The LC-ESI-TOF-MS analyses of aqueous-methanolic extract led to the identification of 99 secondary metabolites including phenolics, flavonoids, alkaloids, and vitamins. The percentages of inhibition of the n-hexane, chloroform, ethyl acetate, and methanol extracts of CA were evaluated against α-glucosidase, α-amylase, and pancreatic lipase enzymes at different concentrations. Hexane extract showed the most powerful α-glucosidase and α-amylase inhibitory activity with IC50 value of 0.22 and 0.27 mg/ml comparing with acarbose (IC50 0.43 and 0.38), respectively. Among all CA extracts, only ethyl acetate extract revealed potent antiobesity as a lipase inhibitory activity with IC50 value of 0.079 mg/ml comparing with orlistat (IC50 0.11 mg/ml). CA extracts showed mild-weak antibacterial effect against Pseudomonas aeruginosa and Bacillus cereus. KEY WORDS: Cometes abyssinica, Chemical constituents, α-Amylase inhibitors, α-Glucosidase inhibitors, Lipase inhibitors Bull. Chem. Soc. Ethiop. 2024, 38(4), 1051-1067. DOI: https://dx.doi.org/10.4314/bcse.v38i4.19