M.A. Thesis:

Evaluation of antimicrobial activity of leaf and callus extracts of Echinophora platyloba

In order to evaluate the antibacterial effect of leaf and callus extracts of Echinophora platyloba, two factorial experiment based on completely randomized design with three replications were carried out on biotechnology laboratory of Islamic Azad university of Sabzevar. At first, the effect of different concentrations of 2,4-D (0.5, 1 and 1.5 mg/l) and BAP (0, 0.5 and 1 mg/l ) on callus induction of leaf explants were studied. The solid MS medium containing 30 g/l sucrose was used in this experiment. The results showed that 2,4-D and BAP concentrations had significant effects on callus production characteristics. The callus induction percentage, callus diameter and fresh weight decreased with increasing 2,4-D concentration. The highest and lowest callus induction percentage, callus diameter and fresh weight were observed at 0.5 and 1.5 mg/l 2,4-D concentrations, respectively. The BAP application in culture medium improved callus production characteristics of Echinophora platyloba. The maximum callus induction percentage, callus diameter and fresh weight were obtained at 0.5 mg/l BAP concentration. After the determination of the best hormonal combination for callus induction, antibacterial effect of leaf and callus methanol extracts were examined. Different concentration of leaf and callus methanol extracts (0(methanol), 1.25, 2.5, 5 and 10 mg/l) were prepared and their effect on growth inhibition of Staphylococcus aureus and Escherichia coli were investigated. The results showed that antibacterial effect of callus extract was significantly higher than leaf extract. None of leaves extract concentrations showed antibacterial effect. However, inhibition zone diameter at 2.5, 5 and 10 mg/l concentrations of callus extract were significantly higher than control treatment. The maximum antibacterial effect of callus extract was observed at 10mg/l concentration. Staphylococcus aureus bacteria were more sensitive to callus extract than Escherichia coli. According to results, application of 10 mg/l methanol extract of callus is recommended for favourable control of Staphylococcus aureus and Escherichia coli.

Keywords: Echinophora platyloba, antibacterial, methanol extract, callus, Staphylococcus aureus, Escherichia