Chemical and antioxidant evaluation of Indian gooseberry (Emblica officinalis Gaertn., syn. Phyllanthus emblica L.) supplements

Abstract

Indian gooseberry (Emblica officinalis Gaertn.) (Euphorbiaceae) has a distinguished history in Ayurveda medicine and is ascribed a number of medicinal properties and as a dietary supplement, its use is increasing in Western countries. It is thought that its beneficial properties are a function of its antioxidant potency. The study investigated the chemistry and antioxidant properties of four commercial E. officinalis fruit extracts in order to determine if there are any qualitative-quantitative differences. All extracts produced positive responses in the total phenol, total flavonoid and total tannin assays. The presence of predominantly (poly)phenolic analytes, e.g. ellagic and gallic acids and corilagin, was confirmed by RP-HPLC coupled with photodiode array detection. Despite ascorbic acid being a major constituent of E. officinalis fruits, the furanolactone could not be identified in one of the samples. The extracts demonstrated varying degrees of antioxidative efficacy. The extract designated IG-3 was consistently amongst the most effective extracts in the iron(III) reduction and 1,1-diphenyl-2-picrylhydrazyl and superoxide anion radical scavenging assays while the extract designated IG-1 demonstrated the best hydroxyl radical scavenging activity. All extracts appeared to be incapable of chelating iron(II) at realistic concentrations.