Computational and experimental validation of free radical scavenging properties of high-performance thin-layer chromatography quantified phenyl myristate in Homalium nepalense.

Phenyl myristate was isolated from Homalium nepalense, which is known for its therapeutic virtues in traditional medicine. However, the study of radical scavenging-capacity of phenyl myristate is limited by its relatively low abundance in medicinal plants. We have studied the isolation, structure-elucidation, and bioactivities of high-performance thin-layer chromatography validated phenyl myristate from hydroalcohol-extract of bark of H. nepalense. The chemical structure of phenyl myristate was elucidated by spectroscopic methods. The chromatography was performed on high-performance thin-layer chromatography aluminum plates coated with silica-gel 60 F254 . Determination and quantitation of phenyl myristate were performed by densitometric-scanning at 254 nm (chloroform-methanol, 9:1, v/v; Rf 0.49). The method was validated according to International Council for Harmonisation guidelines in terms of linearity, specificity, sensitivity, accuracy, precision, robustness, and stability. Linearity-range of phenyl myristate was 100-500 ng/5 µL with correlation-coefficient r2  = 0.9997. Limits of detection and quantitation were 3.35 and 10.17 ng, respectively. Phenyl myristate showed significant free-radical-scavenging activities in 2,2-diphenyl-1-picrylhydrazyl, oxygen-radical-absorbance-capacity, and ex vivo cell-based-antioxidant-protection-in-erythrocytes assays. Molecular-docking approach of phenyl myristate showed effective binding at active sites of human serum albumin (HSA) with the lowest binding energy (-8.4 kcal/mol) that was comparable with ascorbic acid (-5.0 kcal/mol). These studies provide mechanistic insight into the potential free radical scavenging activities of phenyl myristate.