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