Secondary Metabolite Content and Bioactivity of Leaf Afrika (Vernonia amygdalina)

Kandungan Metabolit Sekunder dan Bioaktivitas Daun Afrika (Vernonia amygdalina)

Abstract

African The Bitter Leaf plant (Vernonia amygdalina) is widely used in traditional medicine across tropical regions. This species possesses a diverse range of pharmacological properties, including antibacterial, antioxidant, and antidiabetic activities. These bioactivities are attributed to secondary metabolites synthesized through natural defense mechanisms, such as flavonoids, alkaloids, triterpenoids, tannins, saponins, and steroids. This research aimed to characterize the phytochemical profile of the plant using Fourier-Transform Infrared Spectroscopy (FTIR) and Gas Chromatography-Mass Spectrometry (GC-MS), alongside evaluating its antibacterial and antioxidant potential. Phytochemical screening of the ethyl acetate extract confirmed the presence of alkaloids, flavonoids, and triterpenoids. Bioactivity assays demonstrated that the ethyl acetate extract exhibits: strong antibacterial activity against Escherichia coli with an inhibition zone of 12.1 mm and very strong antibacterial activity against Staphylococcus aureus with an inhibition zone of 91 mm at a concentration of 1000 µg/mL. Moderate antioxidant activity: the extract yielded an IC50 value of 149.10 ppm. FTIR analysis identified functional groups including hydroxyl (O-H), aliphatic (C-H), and ether/alcohol (C-O) moieties. These findings were further corroborated by GC-MS analysis, which identified major terpenoid compounds such as Linalool (89,23%), Neral (86,06%), Neophytadiene (91,78%), 2,6-octadienal, 3,7-dimethyl-,(E) (95,93%), Phytol (96,86%) dan 6,11-Dimethyl-2,6,10-dodecatrien-1-ol (69,85%). These constituents are likely responsible for the observed antibacterial and antioxidant effects.