Authentication of Fruit Extracts of Embica officinalis Gaertn (Euphorbiaceae): Identification of Valid Biomarkers
The fruit extract of Emblica officinalis Gaertn. (Euphorbiaceae), commonly known in India as amla (Indian gooseberry), has been popularized as a dietary supplement in the United States and elsewhere, with its antioxidant benefits being attributed to a high content of ascorbic acid. The presence of ascorbic acid in the extract was questioned by earlier researchers, and hydrolysable tannins, emblicanins A and B were identified  and structurally defined . Our investigations on the emblicanins and ascorbic acid content of the fruit juice and extract, however revealed that ascorbic acid co-elutes with other compounds of similar spectral behavior. Additionally, the hydrolysable tannins, when evaluated were found to be structurally different from the previously reported structures. The earlier reported antioxidant hydrolysable tannins, emblicanins A and B, correspond to beta-glucogallin (1) and mucic acid 1,4-lactone 5-O-gallate (2), respectively. Only trace amounts of free ascorbic acid were detected. β-glucogallin is therefore a more relevant and optimal biomarker in Emblica officinalis extract, than ascorbic acid. References:  Ghosal S, et al. (1996) Indian J Chem 35B: 941–948.  Pozharitskava ON, et al. (2007) J Sep Sci 30: 1250–1254.