Studies on the Determination of Antioxidant Activity and Phenolic Content of Plant Products in India (2000-2017).

Ayurveda, the traditional Indian therapeutic system, involves herbs and spices as drug ingredients and a kind of food intake regulation. The health and curative aspects of plant products are often ascribed to their antimicrobial and antioxidant activities (AA). However, it seems somewhat possible to correlate the AA of herbal extracts or plant isolates with their phenolic contents (PC). Indian researchers have carried out some tests for the determination of AA and PC of plant products that are worth mentioning. Among the herbal analysis techniques, the important contributions of Indians and people of Indian origin in this field include the remarkable separation of phenolic compounds, including the use of reversed-phase columns, on-line HPLC, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay to effectively screen and identify antioxidant compounds from herbal extracts, and other chromatographic, spectrographic, and spectroscopic techniques, in the analysis of complex biological matrices. The aim of this paper is to present an overview of such arguments with reference to herbal drugs and food intake regulation for specific ailments. The lack of uniformity in the use of test protocols for antioxidant assays (particularly using the DPPH free radical) and differences in in vitro mechanisms of antiradical activity and in vivo metabolism of polyphenols have been the issues associated with these experiments that have been raised by researchers in the period from 2000 onward.