Hispanamide: An Antioxidant Phenolic Propanamide from the Leaves of Acalypha Hispida (Burn.F)

Abstract

Acalypha hispida (family Euphorbiaceae) is widely known for its medicinal applications in ethno-medicine. The most active antioxidant fraction of the leaf methanol extract was investigated with the aim of isolating and elucidating the active constituents. Bioassay guided isolation and purification was achieved using standard chromatographic techniques and invitro evaluation of ability of fractions, isolates and standards to scavenge 2, 2- Diphenyl-1-picrylhydrazyl radical (DPPH). The concentration of the pure isolate and standards required to scavenge 50% of the hydroxyl radical (IC₅₀) was carried out to assess their antioxidant effectiveness. The lower the IC₅₀ value, the greater the antioxidant effectiveness of the compound. Various spectroscopic techniques were used in the structural elucidation. The active isolate was identified as 4-hydroxy-N-[1-(hydroxymethyl)-2-phenylethyl-benzenepropanamide and named Hispanamide. Hispanamide exhibited a higher antioxidant effectiveness (IC₅₀ of 0.339 mg/ml) than the antioxidant standards Ascorbic acid (IC₅₀ of 0.373 mg/ml) and α-Tocopherol (IC₅₀ of 0.482 mg/ml) used for the assay. The order of decreasing antioxidant effectiveness is hispanamide > Ascorbic acid > α-Tocopherol. This is the first report of the isolation of this phenyl propanamide from plant source and its occurrence in the plant validates the ethnomedicinal uses of Acalypha hispida.

Keywords: Hispanamide, Phenolic propanamide, Antioxidant effectiveness, hydroxyl radical, Acalypha hispida.

DOI: 10.7176/JNSR/11-14-02

Publication date:July 31^st 2020