Evaluation of the alcoholic extract of hibiscus (Hibiscus sabdariffa L.) as a protective antibacterial and antioxidant component

Abstract

The hibiscus (Hibiscus sabdariffa L.) has antioxidant and antimicrobial properties, it can be used as functional food and medicinal plant. This study aimed at determining the intensity of activity inhibition (IINIB) and of inactivation (IINAB) of two alcoholic extracts obtained from calyxes and fruits with seeds of different accesses of hibiscus on international standards bacterial Enterococcus faecalis, Escherichia coli, Salmonella Enteritidis and Staphylococcus aureus. And the correlation between these results and the presence of total polyphenols and anthocyanins was done. The antimicrobial activity of alcoholic extract from both accesses showed a significant difference. While Salmonella Enteritidis (11,5) and Escherichia coli (12) were more susceptible to the alcoholic extract from hibiscus calyxes and fruits with seeds, respectively, the Staphylococcus aureus (5.2 e 0.1) was the most resistant in both extracts. The IINIB values were higher than IINAB values, showing that the bacteriostatic activity was usually higher than the bactericide. Total polyphenols and anthocyanins contents in calyxes alcoholic extract showed a significant difference, and they were higher than in alcohol extract from fruits with seeds. It seems likely that occurs a direct correlation between the anthocyanin concentration and the antibacterial activity in different structures of the hibiscus plant.