Proximate analysis and bioactivity study on acoustically isolated elaeis guineensis leaves extract

Abstract

Extracts of bioactive compounds from Elaeis guineensis leaves previously acoustically isolated using a probe sonicator that yielded the highest total phenolic content (TPC) was subjected to proximate analysis and antioxidant capacity tests such as ferric reducing antioxidant power assay (FRAP) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (DPPH) and antibacterial activity. These tests were aimed to gauge the feasibility of incorporating the extract as an active ingredient in a topically applied nanoemulsion. Results revealed that the leaves extract with a TPC of 209.70 mg gallic acid equivalent (GAE)/g) yielded a FRAP value of 1,417.40 μM Fe2+/mg and exhibited strong DPPH radical scavenging capacity with an IC50 value of 9.899 ± 0.050 μg/mL. The value seen here was equivalent to that of positive controls, Trolox and butylated hydroxytoluene (BHT). Consequently, the proximate composition of the leaves was found to comprise of 18.8% moisture content, 5.2% ash, 11.2% protein, 7.1% fat, 57.7% carbohydrate and energy value of 339.5 kcal/100g. E. guineensis leaves extract showed resistance towards the Gram-positive bacteria, Bacillus subtilis at 50 and 100 mg/mL, respectively, but did not inhibit the growth of the Gram-negative bacteria, Escherichia coli, and Pseudomonas aeruginosa.