Comparative evaluation of Ceiba pentandra ethanolic leaf extract, stem bark extract and the combination thereof for in vitro bacterial growth inhibition

Abstract

In spite of the numerous reports on medicinal potentials of Ceiba pentandra, the medicinal values of extract from the combination of the leaf and stem bark has not been adequately exploited. The combination therapy may lead to additive or synergistic effect. The antibacterial activities of the ethanolic extract of leaf (ELE), stem bark (ESE) and their combination (CLSE) were evaluated in vitro using selected human pathogens such as Klebsiella pneumonia, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli. Extracts were screened for phytochemicals and their activities evaluated in vitro using the Agar well diffusion method. Data obtained was analyzed statistically using paired test. P?0.05 was considered significant. Preliminary phytochemical screening showed the presence reducing sugars, saponins, polyuronoids, polyphenols, tannins and phlobatanins in ELE. ESE was found to contain reducing sugars, phlobatanins and alkaloids. All these phytochemicals were found in CLSE. Results from antibacterial assay showed mean diameter of inhibition zone <12 mm for ELE at concentrations ranging between 30 - 50 mg/ml. At a similar concentration range, ESE showed mean diameter of zone of inhibition of <12 mm against all the organisms except Klebsiella pneumonia (13.00+0.66 mm at 50mg/ml). Similarly, the activity of CLSE was < 12 mm against all test organisms except for E. coli (13.00+0.33 mm at 50mg/ml). The activity of the combined extract was not significantly different from those of the stem bark and leaf extracts (P>0.05). In conclusion, ethanolic extract of leaf and stem bark of Ceiba pentandra as well as their combination showed significant antibacterial activity. However, the combined extract did not show synergistic nor additive effects on the test organisms.

Keywords: Ceiba pentandra, Combination therapy, Phytochemistry, Antibacterial assay