Chromatographic-Mass Spectrometric Identification of Antistress Phytochemicals from Anacardium coromandelica and in vitro Appraisal of its Antioxidant Potential

Abstract

Anacardium coromandelica is widely distributed in South and South East Asia having immense economic importance. The present study was designed to explore antistress phytoconstituents by comparing HPLC-DAD-ESI-MS profile of healthy and affected leaves with galls. After determining antistress metabolites, the next target was to isolate flavonoid glycosides from HLAC. This purpose was achieved by column chromatography using Sephadex LH-20 as a stationary phase. Preliminary analysis of hydromethanolic extracts of HLAC, ALAC and GAC provided an indication for the presence of flavonoid glycosides, phenolic acids and tannins. As phenolic acids provide defense to the plants against pathogens hence they were determined in galls of A. coromandelica through LC-MS. Identified antistress compounds included gallic acid and epigallocatechin derivatives. Furthermore, two compounds were also isolated from healthy leaves of A. coromandelica i.e., myricetin-3-O-glucuronide and quercetin-3-O-glucuronide. After polar phytoconstituents identification, non-polar compounds were assessed in n-hexane extract of A. coromandelica using GC-MS. Results of qualitative methods were validated further using quantitative assays for the estimation of reducing sugar, thiamine, total phenolic and flavonoid content. Total phenolic and reducing sugar contents were higher in galls whereas total flavonoid and thiamine contents were estimated to be higher in healthy leaves. Plant was also bioevaluated in terms of its antioxidant potential by comparing the IC50 values of its different samples. Galls extract exhibited the highest antioxidant activity in comparison to healthy and affected leaves. This was the first qualitative and quantitative determination of phytoconstituents in HLAC, ALAC and GAC on comparative basis. Hence, it is rationalized that antistress compounds determined from galls cannot only serve as a natural source to treat the inflammation of plants but proved to be worthwhile for human beings as well.