Quantitative determination of total polyphenols in Chrysophyllum cainito L. (Sapotaceae) leaves using a validated UV–Vis spectrophotometric method

Abstract

A UV–Vis spectrophotometric method based on the Folin–Ciocalteu assay was developed, validated, and applied for the determination of total polyphenol content in C. cainito  leaf extracts. Gallic acid was used as the reference standard, and method validation was conducted in accordance with ICH Q2(R2) guidelines, including evaluation of linearity, specificity, precision, accuracy, and sensitivity. The method exhibited excellent linearity over the concentration range of 10–50 µg/mL, with a correlation coefficient (R² = 0.9994). Good sensitivity was achieved, with limits of detection and quantification of 0.12 µg/mL and 0.33 µg/mL, respectively. Precision studies showed low relative standard deviation values, with intra-day and inter-day RSD not exceeding 0.28 % and 0.18 %, respectively, while accuracy assessment yielded recovery values ranging from 90.94 % to 108.28 %. The validated method was successfully applied to quantify total polyphenols in independently prepared C. cainito leaf extract samples, with total polyphenol contents ranging from 261.38 to 266.04 mg gallic acid equivalents per gram of extract. Overall, the established method provides a simple, cost-effective, and robust analytical tool suitable for routine quality control and supports further phytochemical and pharmacological investigations of C. cainito  leaves as a promising source of phenolic compounds.