Ethnobotanical Leaflets 12: 638-42. 2008.
Preliminary Phytochemical Screening and Antibacterial Studies of Leaf Extract of Solanum trilobatum Linn.
*Asirvatham Doss and Rangasamydhanabalan
*Corresponding author: firstname.lastname@example.org
Solanum trilobatum Linn. is
extensively used in Indian traditional and folklore medicines to cure various
human ailments. The preliminary phytochemical
screening of the leaves revealed the presence of Sugar, Protein, Alkaloids, Flavonoids, Saponins, Tannins,
Cardiac glycoside, Terpenoids and Lipids. In vitro
antibacterial studies on the leaf extracts were carried out on eight
medically important bacterial strains, including Staphylococcus aureus, Bacillus subtilis,
aeruginosa, Klebsiella pneumonia, Escherichia
coli, Proteus vulgaris
which were procured from Department of Microbiology,
According to World Health Organization, medicinal plants are the best source to obtain a variety of newer herbal drugs. About 80% of individuals from developed countries use traditional medicine, which has compounds derived from medicinal plants. Therefore, such plants should be investigated to better understand their properties, safety and efficacy (Prusti, A et al., 2008). Plant-derived substances have recently become of great interest owing to their versatile applications. Medicinal plants are the richest bio-resource of drugs of traditional systems of medicine, modern medicines, nutraceuticals, food supplements, folk medicines, pharmaceutical intermediates and chemical entities for synthetic drugs (Ncube N. S.., 2008).
Solanum trilobatum (Solanaceae – herbs) is an important medicinal plant. The leaves contain rich amount of calcium, iron, phosphorus, carbohydrates, protein, fat, crude fibre, and minerals (Jawahar et al., 2004).This herbal plant is used as medicine for asthma, vomiting of blood, reducing blood glucose level and bilious matter phlegmatic rheumatism and several kinds of leprosy. It is also antibacterial, antifungal antimitotic, antioxidant and antitumouours (Subramanian and Madhavan, 1983, Shahjahan et al., 2005, Shahjahan et al., 2004, Purushothaman et al., 1969 and 1972).
Collection of plant materials
Mature leaves were collected from the healthy plant at
Preparation of plant extract
The leaves were washed in tap water, shade dried for 10 days and made into a fine powder of 40 mesh size using the laboratory mill. Following that, 100g of the powder was extracted with different organic solvents viz, Chloroform, methanol, petroleum ether and water and it was stand for over night. The extract was filtered through Whatman no.1 filter paper to remove all unextractable matter, including cellular materials and other constitutions that are insoluble in the extraction solvent. The entire extract was concentrated to dryness using rotary flash evaporator under reduced pressure.
The extract was tested
on the following three Gram positive bacteria: Staphylococcus aureus, Bacillus subtilis,
pyrogens . Five Gram negative bacteria were
also tested, including Salmonella typhi, Pseudomonas
aeruginosa, Klebsiella pneumonia, Escherichia
coli, Proteus vulgaris . All the strains were procured from Department of
Phytochemcial analysis of the extract was conducted by Trease and Evans.,1989 : Harborne (1998). By this analysis, the presence of several phytochemicals like Sugar, Protein, Alkaloids, Flavonoids, Saponins, Tannins, Cardiac glycoside, Terpenoids and Lipids were tested.
Anti bacterial assay
The three different concentrations of the leaf extracts were tested for antibacterial activity using agar disc diffusion assay according to the method of Bauer et al., 1966. The strains of microorganisms obtained were inoculated in conical flask containing 100 ml of nutrient broth. These conical flasks were incubated at 370 C for 24 h and were referred to as seeded broth. Media were prepared using Muller Hinton Agar (Himedia), poured on Petri dishes and inoculated with the test organisms from the seeded broth using cotton swabs. Sterile discs of six millimeter width had been impregnated with 20 µl of test extract and introduced onto the upper layer of the seeded agar plate. The plates were incubated overnight at 370 C. Antibacterial activity was assigned by measuring the inhibition zone formed around the discs. The experiment was done three times and the mean values were presented. Streptomycin (10µg/disc) was used as standards.
The preliminary phytochemical analysis of the leaf extract revealed the presence of Sugar, Protein, Alkaloids, Flavonoids, Saponins, Tannins, Cardiac glycoside, Terpenoids, Lipids as presented in Table 1. The results obtained from the disc diffusion assay showed that there has been an increasing effect on bacterial growth inhibition with increasing concentration of the extract. And the extract showed good inhibitory activity on almost all the bacteria tested. It has been found that among all the tested organisms, the Gram negative bacterial strain, Bacillus subtilis, was found to be more susceptible to the plant extract by showing inhibition zone ranging from 18 mm and the gram negative strain Staphylococcus epidermis was least susceptible with the inhibition zone ranging from 20 mm. The antibacterial activity in terms of zone of inhibition was presented in Table 2. The observed activity may be due to the presence of potent phytoconstituents in the leaf extracts.
plants are known to have beneficial therapeutic effects as noted in the
traditional Indian system of medicine, Ayurveda.
The effects of plant extracts on bacteria have been studied by a very large
number of researchers in different parts of the world. Much work has been
done on ethnomedicinal plants in
4. Jawhar M, Amalan Rabert G and Jeyaseelan M, .Rapid proliferation of multiple shoots in solanum trilobatum L. Plant Tissue Culture 2004; 14 (2) : 107-112.
5. Bauer A.N.Kirby, W.M.M Sherries, J.C and Truck M., Amer. J.Clin.Pathol.1966; 45-493.
6. Shahjahan M, Sabitha .KE,Mallika Devi .R Shyamala CS, Effect of medicinal plants on tumurogenesis Ind.J.Med.Res., 2004; 123 (5-8) : 23-27.
7. Shahjahan M,Vani G and .Shyamaladevi CS,. Effect of Solanum trilobatum on the antioxidant status during diethyl nitrosamine induced and phenobarbital promoted hepatocarcinogenesis in rat ,Chemico-Biological Interactions, 2005; 156,(2-3):113-123.
Subramanian SV and Madhavan
VR, Heritage of the siddha medicine.,
International Institute of Tamil Studies 1983,
9. Purushothaman KK, Saradambal S and Narayanaswamy V, Chemical estimation of solanum trilobatum.L, Aust.J.Chem. 1969; 22 ( 7) : 1569-1570
Table 1. The phytochemical profile of the leaf extract.
Table 2. Antibacterial activity of leaf extracts of Solanum trilobatum.
a, b, c indicates 25, 10, and 5 mg/ml concentrations, respectively. MIC denotes Minimum Inhibitory Concentration. Str- indicates Streptomycin.
All the values are mean ± standard deviations of three determinations.