Comparative Evaluation of the Phytochemical Contents, Antioxidant and some Biological Activities of Khaya grandifoliola Methanol and Ethyl Acetate Stem Bark, Root and leaf Extracts

Abstract

Khaya grandifoliola extracts have been conventionally found to be effective in the treatment of wounds and ulcers. This study assessed the phytochemical content of K. grandifoliola methanol and ethyl acetate extracts and used in vitro bioassays for bioactivity testing to confirm the ethnomedicinal uses. Phytochemical content and bioactivity of K. grandifoliola ethyl acetate and methanol extracts; (stem bark, root, leaf) were assessed using spectrophotometric analysis with standard calibration curves for respective phytochemicals and in vitro bioactivity assays including MTT, free radical scavenging activity, lipopolysaccharide-activated RAW 264.7 macrophages assay for cytotoxicity, anti-inflammatory antioxidant, and antimicrobial activities. The polyphenolic content of methanol extracts (37.49±1.40 -53.57±1.50 mg GAEQ/100 mg) was the highest phytochemical content measured. The methanol root extract had the highest terpenoid concentration (35.78±2.14 mg LIN EQ/100 mg). Methanol stem bark and root extracts exhibited anti-inflammation activity at 200 μg/mL, potent antioxidant activity (IC50; 38.68±5.09 µg/mL and 46.34±9.56μg/mL), and growth inhibition against Staphylococcus aureus (MIC; 1 and 2 mg/mg). Ethyl acetate root and leaf extracts inhibited the growth of Streptococcus pyogenes (MIC; 0.25 mg/mL). In conclusion, the high phenolic and terpenoid content of extracts which correlated positively with their biological activities could be the contributing factor to the biological effects such as wound healing of the extracts.