Abstract

Achyranthes aspera (Prickly chaff) seeds contain spines which often cause irritation on the hands of those who collect them. The main objective of this investigation was to evaluate its irritant potential on animal's skin. Skins irritating chemical constituents were separated in the form of various fractions. For this purpose, solvents of different polarities were successively used to extract least-polar compounds (petroleum ether extract), constituents of intermediate polarities (chloroform extract) and polar constituents (methanol extract) from pulverized seeds of A. aspera. Eleven fractions were collected from methanol extract of powdered seeds by liquid column chromatography. The irritant potential of these fractions was evaluated on rabbit’s skin. Fractions eluted by CHCI₃/MeOH (60:40), CHCI₃/MeOH (40:60) and CHCI₃/MeOH (20:80) showed more irritant potential. These biologically active purified fractions were characterized by ultraviolet (UV) and Fourier transform infrared (FTIR) spectroscopy. The presence of –OH, –COOH, or ketonic group and a double bond in these fractions were liable to be reacted with the cell membrane and cellular contents of both the superficial and deeper layers of epidermis causing irritancy. It was concluded that A. aspera contained skin irritant compounds.

Key words: Achyranthes aspera, irritant compounds, liquid column chromatography, ultraviolet (UV) and Fourier transform infrared (FTIR) spectroscopy, solvent extraction.