Ficus L. is one of the largest genera of angiosperms, with about 750 species of terrestrial trees, shrubs, hemi-epiphytes, climbers and creepers occurring in the tropics and subtropics of the world [Berg and Corner, 2005]. Medicinal values of many Ficus species have been well documented both in traditional and folklore medicine [Ghosh et al., 2004; Sirisha et al., 2010; Salem et al., 2013].
Ficus hispida L.f., commonly known as the hairy fig or the rough-leafed stem fig, is a shrub or tree that can grow up to 15 m tall [Lee et al., 2013]. It is a dioecious, bat-dispersed species [Hodgkison et al., 2007], distributed from Sri Lanka to India, and from South China across Southeast Asia to Australia [Berg and Corner, 2005]. This species is used for treatment of several disorder, e.g., ulcers, psoriasis, anemia, piles jaundice, vitiligo, hemorrhage, diabetes, convulsion, hepatitis, dysentery, biliousness, and as lactagogue and purgative agents [Ali and Chaudhary, 2011]. In India, it is commonly cultivated for its pharmacological properties such as antidiarrheal activity, as well as neuroprotective and hepatoprotective effects [Ali &Chaudhary, 2011]. It was reported that almost all parts of this plant are used as a folklore remedy for the treatment of various ailments by the Indian traditional healers, but the leaves are of particular interest, among other parts, from a medicinal point of view [Ali & Chaudhary, 2011]. Additionally, the fruit is known to be active as aphrodisiac, tonic, lactagogue and emetic [Ali & Chaudhary, 2011]. F. hispida was chosen for its abundance of alkaloids, carbohydrates, proteins and amino acids, sterols, phenols, flavonoids, gums and mucilage, glycosides, saponins, and terpenes [Ghosh et al., 2004]. Therefore, the aim of this study was to test the efficacy of ethanolic extract prepared from F. hispida leaves against Gram-positive and Gram-negative bacteria to evaluate the possible use of this plant in preventing infections.
The leaves of F. hispida were sampled in M.M. Gryshko National Botanical Garden (Kyiv, Ukraine) and Botanical Garden of Ivan Franko Lviv National University (Lviv, Ukraine) during March, 2015. The whole collection of tropical and subtropical plants at M.M. Gryshko National Botanical Garden (Kyiv, Ukraine) (including Ficus spp. plants) has the status of a National Heritage Collection of Ukraine. The collected leaves were brought into the laboratory for antimicrobial studies. Freshly crushed leaves were washed, weighted, and homogenized in 96% ethanol (in ratio 1:10) at room temperature.
Antimicrobial activity was determined using the agar diffusion method [Bauer et al., 1966]. Gram-negative bacteria Klebsiella pneumoniae (ATCC 700603), Pseudomonas aeruginosa (ATCC 27853), and Escherichia coli (ATCC 25922), as well as Gram-positive bacteria Staphylococcus aureus (ATCC 25923), methicillin-resistant Staphylococcus aureus and Streptococcus pneumoniae (ATCC 49619), as well as fungus Candida albicans were used as test organisms.
Antimicrobial activity of crude extract of the plant sample was evaluated by the paper disc diffusion method [Bauer et al., 1966]. Zone diameters were determined and averaged. Results for the antimicrobial activities are presented as mean ± standard error of the mean. All statistical calculation was performed on separate data from each bacterial and fungal strains.
Our results showed that the ethanolic extract of F. hispida leaves possessed moderate activity against both the Gram-positive bacteria (15.06 mm inhibition zone diameter for S. aureus) and the Gram-negative bacteria (13.13 mm for E. coli, 11.63 mm for K. pneumonia), as well as against C. albicans (14.25 mm inhibition zone diameter) (Fig. 1). Methicillin-resistant S. aureus, P. aeruginosa and S. pneumoniae appeared to be less sensitive to the F. hispida extract; the inhibition zones were 9.88 mm, 9.44 mm, and 8.88 mm, respectively (Fig. 1).
The broad antibacterial activities of this extract, apparently, could be explained as a result of the plant secondary metabolites. Previously have been reported [Sirisha et al., 2010; Salem et al., 2013], that the therapeutic properties of Ficus species may be attributed to the presence of a wide range of phytochemical compounds. In general, Ficus species are rich sources of polyphenolic compounds. In particular, flavonoids and isoflavonoids are responsible for the extract's strong antioxidant activity that may be useful in preventing diseases involving oxidative stress [Sirisha et al., 2010]. Ali and Chaudhary (2011) have reported that F. hispida contains wide varieties of bioactive compounds from different phytochemical groups like alkaloids, carbohydrates, proteins and amino acids, sterols, phenols, flavonoids, gums and mucilage, glycosides, saponins, and terpenes. Two substantial phenanthroindolizidine alkaloids, 6-O-methyltylophorinidine and 2-demethoxytylophorine, and a novel biphenylhexahydroindolizine hispidine from stem and leaves of F. hispida were isolated by Venkatachalam and Mulchandani (1982). Recently, hispidin has been reported to have anticancer activity [Ali and Chaudhary, 2011]. All the detected phenolic acids are known to have antimicrobial and antioxidant properties [Jaafar et al., 2012]. The antimicrobial property of F. hispida extract may be due to its constituents. Antibacterial flavonoids might be having multiple cellular targets, rather than one specific site of action [Kumar and Pandey, 2013]. One of their molecular actions is to form complex with proteins through nonspecific forces such as hydrogen bonding and hydrophobic effects, as well as by covalent bond formation. Thus, their mode of antimicrobial action may be related to their ability to inactivate microbial adhesins, enzymes, cell envelope transport proteins, and so forth. Lipophilic flavonoids may also disrupt microbial membranes [Kumar and Pandey, 2013].
To conclude, the ethanolic extract obtained from F. hispida leaves showed varying inhibitory activities against all the test organisms. Thus, F. hispida leaves possess great medicinal potential for the therapy of bacterial and fungal infections and may be used as a natural antiseptic and antimicrobial agent in medicine. Further investigation is necessary to identify those bioactive compounds, which will be a platform for further pharmacological studies and clinical applications.