Purification of nuts of Semecarpus anacardium Linn., a herbal drug for arthritis

Abstract

Although nuts of Semecarpus anacardium Linn. (Anacardiaceae) (SA nuts) are used in the Ayurveda and Siddha systems of medicine for the management of arthritis and other inflammatory diseases, they are always associated with several side effects, if used unpurified. Several traditional methods for purification are available, but they are not free from toxicity and also the scientific basis behind these purification steps is not known. Here, we have hypothesized that the oily part of the nut is toxic and its degree of removal is proportional to its safety margin. To test this hypothesis, we treated the SA nuts with brick powders (traditional method of Ayurveda), silica gel and hexane solvent for various time periods. These defatted nuts were washed and extracted with ethanol and the solvent-free extract was tested on rat peritoneal macrophages in terms of NO production, both in the absence and presence of lipopolysaccharides (LPS). Results suggest that the hexane fraction (oily part) is highly toxic and produces free radicals (FR) in a concentration-dependent manner without affecting the cell viability and the hexane fraction works as a prooxidant, similar to that of LPS. Contrary to this, the alcoholic fraction of hexane-washed SA nuts (defatted nuts) significantly scavenged FR and its yield was directly proportional to the removal of the oily part. Thus it is suggested that the oily part of the nuts is prooxidant, whereas the alcoholic fraction is antioxidant, and that the use of hexane is better for purification of SA nuts than the traditional methods, as it enhances the therapeutic value.