PHYTOCHEMICAL TEST METHODS: QUALITATIVE, QUANTITATIVE AND PROXIMATE ANALYSIS

Abstract

Phytochemical analysis involves both qualitative and quantitative analysis. While qualitative analysis is concerned with the presence or absence of a phytochemical, quantitative analysis accounts for the quantity or the concentration of the phytochemical present in the plant sample. The first step in phytochemical analysis is preliminary phytochemical screening before quantitative analysis. Quantitative analysis is a more comprehensive and useful method compared to qualitative analysis because the results obtained from the studies can be useful for drug discovery, standardization of herbal drugs, explanation of the medicinal potentials of plants and determination of the toxicity levels in plants. This chapter details the various simplified methods for the qualitative and quantitative analysis of phytochemicals including proximate composition analysis. It also presents useful hints for reagent preparation, how to determine the concentration of plant extract and make dilute solutions for standard curve making. It also details how to calculate the half maximal inhibitory concentration (IC50) of plant extracts on a given biological system among other calculations commonly encountered during phytochemical studies.