Antimicrobial Activity of Hibiscus Sabdariffa Against Clinical Isolates of Bacteria

ABSTRACT

There have been several reports on the antimicrobial activity of different herbal extracts. Medicinal plants are believed to be the best source for obtaining a variety of drugs. Hibiscus sabdariffa L. is a medicinal plant known for its nutritional delicacy and medicinal properties such as the treatment of diseases like hypertension, coughs, biliousness, boils and wounds. Currently, the main therapy for bacterial infections is the use of synthetic antibiotics. However, the misuse and overuse of antibiotics has become the key factor for the emergence of drug resistant strains of several groups of microorganisms. Hence, the need to investigate the antimicrobial properties of medicinal plants. The objectives of the study were to investigate the in vitro inhibitory activity of Hibiscus sabdariffa calyces, leaves and roots preparation against some clinical isolates of bacteria. Secondly, to assess the antimicrobial property of Hibiscus sabdariffa against the clinical resistant strains of bacteria. Lastly, to compare the Hibiscus sabdariffa aqueous and ethanolic extract effects on clinical isolates of bacteria. The antibacterial activities of H. sabdariffa calyces, leaves and roots extracts (12.5, 25, 50, 100, 200mg/ml) were tested against clinical isolates of bacteria (Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Klebsiella sp., Salmonella typhi, Staphylococcus aureus); with reference strains of Escherichia coli ATCC 25922, Proteus mirabilis ATCC 49565, Salmonella typhi ATCC 19430, Klebsiella pneumoniae ATCC 33495, Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 25923; and two each Extended Spectrum Beta-Lactamases and Methicillin-Resistant iii Staphylococcus aureus strains using Agar Diffusion and Minimum Inhibitory Concentration Methods. The calyces of the plant gave the highest inhibitory effect (P 0.05). The calyces extract was potent against all the test organisms except Proteus mirabilis which was resistant to all the plant extracts. Staphylococcus aureus showed the highest susceptibility to the calyces extract. The aqueous leaves extracts were active against Pseudomonas aeruginosa and Escherichia coli. The resistant strains especially MRSA were highly susceptible to the calyces extract with Minimum Inhibitory Concentration Methods values of 6.25mg/ml. Ethanolic extract of the calyces had a slightly higher antibacterial activity while the leaves were effective when extracted by water. Therefore, the plant’s calyces and leaves can be a source for the production of antibiotics which could significantly inhibit the growth of bacteria. It is recommended that more studies should be done using different solvents for extracting only the important compounds from the H. sabdariffa plant. Purification measures would also be necessary. Additionally, there is a need to investigate the phytochemical compounds from the H. sabdariffa plant part extracts.