Physicochemical, Antimicrobial, and Antioxidant Evaluations of Pentaclethra macrophylla Benth Seed Oil

Abstract

Pentaclethra macrophylla seed oils have been used traditionally for treating wounds and burns and are of commercial importance in cosmetic and wellness industry. The physicochemical, antimicrobial and antioxidant properties of the seed oil were evaluated to validate its therapeutic potentials in this study. The exhaustive extraction of oil was done using a Soxhlet extractor at 50^oC and n-hexane as the extracting solvent. The physicochemical analysis (color density, pH, acid value, ester value) was determined using standard methods. The antimicrobial determination was carried out by the Agar well diffusion method. The in vitro antioxidant activity was determined by potassium permanganate scavenging assay. The physicochemical analysis of the seed oil revealed an orange-colored, sweet odour oil, pH of 5.74 and density of 0.89 g/ml. The acid, saponification, hydroxyl and peroxide values of the seed oil were 5.67, 184.69, 114.6 and 5.46 respectively. The antimicrobial evaluation demonstrated a concentration- dependent effect on the test organisms at concentration range of 2:0.25-1:1 v/v of seed oil:water. The measured inhibition zone diameter (IZD) for B. subtilis and K. pneumoniae were 18.0 mm and 14.0 mm respectively while C. albicans had the least IZD of 8.0 mm. The antioxidant activity was also concentration-dependent (ranged 31.25- 1000 µg/mL) though not as effective as vitamin E. These results lend credence to the use of P. macrophylla oil for dressing wounds and burns due to the observed antimicrobial, and antioxidant activities. Our finding has established potential utilization of the seed oil in cosmetics industry as sunburn and skin protective agents.