Phytochemical composition and in vitro antioxidant and antimicrobial activities of Bersama abyssinica F. seed extracts

Abstract

Medicinal plants can be potential sources of therapeutic agents. Traditional healers use a medicinal plant from Ethiopia, Bersama abyssinica Fresen, to treat various diseases. This study aimed to investigate the phytochemical components and antioxidant and antimicrobial activities of B. abyssinica seed extracts (BASE). Gas chromatography coupled to mass spectroscopy (GC–MS) analysis was used to determine the phytochemical compositions of BASE. The antioxidant activities were assessed by using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay, thiobarbituric acid-reactive species (TBARS) assay, ferric chloride reducing assay and hydroxyl scavenging capacity assay. Antimicrobial activity was investigated using the agar well diffusion method. Phytochemical screening showed the presence of saponins, glycosides, tannins, steroids, phenols, flavonoids, terpenoids, and alkaloids. GC–MS analysis revealed the presence of 30 volatile compounds; α-pinene (23.85%), eucalyptol (20.74%), β-pinene (5.75%), d-limonene (4.05%), and o-cymene (5.02%). DPPH-induced free radical scavenging (IC ₅₀ = 8.78), TBARS (IC ₅₀ = 0.55 µg/mL), and hydroxyl radicals’ scavenging capacities assays (IC ₅₀ = 329.23) demonstrated high antioxidant effects of BASE. Reducing power was determined based on Fe ³⁺–Fe ²⁺ transformation in the presence of extract. BASE was found to show promising antibacterial activity against S. aureus, E. coli, and P. aeruginosa (zone of inhibition 15.7 ± 2.5 mm, 16.0 ± 0.0 mm, and 16.7 ± 1.5 mm, respectively), but excellent antifungal activities against C. albican and M. furfur (zone of inhibition 22.0 ± 2.0 mm and 22.0 ± 4.0 mm, respectively). The seeds of B. abyssinica grown in Ethiopia possess high antioxidant potential, promising antibacterial and superior antifungal activity. Therefore, seeds of B. abyssinica provide a potential source for drug discovery.