Isolation and antimicrobial activities of protocatechuic acid from Hibiscus sabdariffa calyces

Abstract

Protocatechuic acid (PCA) is a type of widely distributed naturally occurring phenolic acid. PCA has structural similarity with gallic acid, caffeic acid, vanillic acid, and syringic acid which are well-known antioxidant compounds. Isolated protocatechuic acid by Soxhlet Instrument form H. sabdariffa calyces in pure form, The IR (KBr disc) spectrum of protocatechuic acid (Fig.4.1.2) showed 3500 (OH). 2955.04, 2926.11 (C-H, Aliph). 1700 (COOH). 1454.02, 1431.23, 1367.58 (C=C, Ar), 804,678 cm-1 (C-H, Ar, bending). Also Investigated its antimicrobial activities. Two gram-negative and two gram-positive bacterial strains, representing common human bacterial pathogens were used for the antibacterial screenings. Protocatechuic acid inhibit common human bacterial pathogens were used for the antibacterial screenings. The gram-negative bacteria were Escherichia coli and Pseudomonas aeruginosa; the gram-positive were Staphylococcus aureus and Bacillus subtilis. Also protocatechuic acid was unable to inhibit Candida albicans and Aspergillus niger which implies that they could not be used to treat fungal diseases.