Chemical composition, antioxidant and antimicrobial activities of volatile oils of Periscopsis laxiflora leaf and stem

Abstract

ABSTRACT. Pericopsis laxiflora (Fabaceae) is a savannah shrub used traditionally to treat headache, stomach ulcers, heart pain and abdominal pain. Air-dried leaves and stem of the plant were extracted by hydrodistillation and the oils obtained were characterized using gas chromatography-mass spectrometry. Antimicrobial assay was carried out by agar well diffusion method against Pseudomonas aeruginosa, Escherichia coli, Klebsiellae pneumonia, (gram negative bacteria), Staphylococcus aureus,  Salmonella typhi, Bacillus subtilis, (gram positive bacteria);  Candida albicans, Aspergillus niger, Penicillum notatum and Rhizopus stolonifer (fungi) while antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical method. Oxygenated monoterpenes (32.92%), monoterpenes (22.58%) and sesquiterpenes (21.63%) hydrocarbons dominated the leaves’ oil and monoterpenes (33.63%), sesquiterpenes (18.42%) and diterpenes (21.48%) hydrocarbons dominated the stem’ oil. The leaf oil showed better scavenging activity at 1.0 mL (60.56%) than the stem oil (46.58%) comparing activity with ascorbic acid and butylated hydroxyl anisole (BHA) in the antioxidant assay. P. laxiflora stem oil showed highest activity against K. pneumonia and E. coli at 100 µg/mL and 50 µg/mL with comparable activity to gentamicin and tioconazole which are antibacterial and antifungal standards respectively. This study therefore showed that the colourless volatile oils exhibited comparable bioactivity with standards thus, justifying the plant’s ethno medicinal application.

KEY WORDS: Pericopsis laxiflora, Fabaceae, Monoterpenes hydrocarbons, Antimicrobial, antioxidant 

Bull. Chem. Soc. Ethiop. 2022, 36(3), 717-725.                                                              

DOI: https://dx.doi.org/10.4314/bcse.v36i3.20