WATER SOLUBLE FRACTION OF METHANOLIC EXTRACTS OF CURCUMA LONGA (L.) ON THE ABSORPTION SPECTRUM OF DEOXYRIBONUCLEIC ACID

Abstract

This study was carried out to examine the staining of fractions prepared from defatted methanolic extract of Curcuma longa (L.) as a natural product in interacting with nucleic acid of Calf Thymus DNA to ascertain the DNA binding property of the fractions using Thin Layer Chromatography. Dry powdered sample of Curcuma longa was subjected to cold maceration using 95% methanol. The cold liquid extract was concentrated with rotary evaporator and subsequently evaporated to dryness in water bath at 50ºC. The water soluble portion of the dark brown crude extract was partitioned subsequently in a separating funnel using solvents of varying polarity (chloroform, ethyl acetate, n-butanol.) Three dry fractions obtained from separating funnel system were further subjected to thin layer chromatography from where a total of 3 fractions were obtained. Each thin layer fraction (6.6×10³µg/ml) were mixed with 13.5µg/ml of DNA and the absorption spectrum where compared with control. Of the three fractions obtained, three (100%) showed fluorescence when viewed under UV light. The effect of Thymus DNA observed for fraction 1A seems to be unique and may perhaps bind to Calf Thymus DNA. Fractions 2A and 2B showed loss of some peaks and bands which may be probably due to toxic effect on DNA or other mechanisms not presently clear. Thus we propose that fractions 1A, from preparative TLC of defatted methanolic extract of Curcuma longa, had effect on absorption spectrum of Calf Thymus DNA and could probably serve as basis for search of alternative DNA binding stain