|LETTER TO THE EDITOR
|Year : 2017 | Volume
| Issue : 1 | Page : 53-55
Poor antimicrobial activity of methanol and ethanol extract of leaves of Solanum trilobatum Linn.
Subramani Parasuraman1, Leow Yu Chuen2, Siaw Sze Hoong1, David Lim De Wei1, Lim Nian Zou1, Sunderesan Loshini1
1 Unit of Pharmacology, Faculty of Pharmacy, AIMST University, Bedong, Malaysia
2 Unit of Pharmaceutical Technology, Faculty of Pharmacy, AIMST University, Bedong, Malaysia
|Date of Web Publication||21-Apr-2017|
Units of Pharmacology, Faculty of Pharmacy, AIMST University, Bedong, Kedah
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Parasuraman S, Chuen LY, Hoong SS, Wei DL, Zou LN, Loshini S. Poor antimicrobial activity of methanol and ethanol extract of leaves of Solanum trilobatum Linn. J Pharm Negative Results 2017;8:53-5
|How to cite this URL:|
Parasuraman S, Chuen LY, Hoong SS, Wei DL, Zou LN, Loshini S. Poor antimicrobial activity of methanol and ethanol extract of leaves of Solanum trilobatum Linn. J Pharm Negative Results [serial online] 2017 [cited 2018 Mar 24];8:53-5. Available from: http://www.pnrjournal.com/text.asp?2017/8/1/53/204916
The prevalence of contagious ailment and infections via antibiotic-resistant pathogens elevated greatly over the last few decades. The ever-growing situation of antimicrobial resistance is indeed poses an alarming threat to public health worldwide. World Health Organization (WHO) reports propose that overcoming the antibiotic resistance is the prime issue for WHO in the coming millennium. In old days, plants are most commonly used as the remedy for most known infections and systemic illness. Screening of plants for antimicrobial agents has gained wide attention. Over hundreds of chemical compounds are derived from plants and used as remedial agents to treat different illness. Plants which have medicinal values due to their health-enhancing and restorative ability are commonly known as herbs. Various pharmacologically active compounds are obtained from the plants and they are used as life-saving drugs., Presently, WHO has requested its member countries to contribute monetary aid for traditional practitioners to establish the traditional medical procedure. It is inevitable to employ both the traditional and modern medical procedure to conform the primary global health care.
Solanum trilobatum Linn., (Thuthuvalai in Tamil; climbing brinjal in English) is a rare, perennial, medicinal herb included into the family of Solanaceae and its' parts, such as leaves, flowers and berries, are commonly used as remedies of respiratory ailment, such as cough and chronic bronchitis. S. trilobatum is a medicinal herbal used for treatment of asthma, hematemesis, diabetes mellitus and leprosy. This plant also showed noteworthy hepatoprotective activity against carbon tetrachloride-induced hepatic damage in rats, antimicrobial activity against Escherichia More Details coli, and Staphylococcus aureus and antifungal activity against Aspergillus flavus and A. niger., The antimicrobial activity of the methanol and ethanol extracts of leaves of S. trilobatum remains unclear; hence, the present study is planned to study the antimicrobial activities of methanol extract of leaves of S. trilobatum (MEST) and ethanol extract of leaves of S. trilobatum (EEST).
Taxonomically identified S. trilobatum plant was collected from rural areas of Vellore, Tamil Nadu, India between October and December 2016. Plant was then identified and authenticated by pharmacogenetics. The leaves of the plant were dried under the shade for a week and grounded using a grinder to coarse powder. The powdered dry leaves of S. trilobatum was packed in a soxhlet apparatus and extracted with methanol and absolute ethanol at 65°C. The extraction was considered complete when the solvent becomes clear. The extract was concentrated to a dry mass by evaporation under reduced pressure. The MEST and EEST were stored in a desiccator at room temperature.
The antimicrobial potency of MEST and EEST was tested by disk diffusion assay. The MEST and EEST were dissolved in a minimum volume of methanol and ethanol, respectively. The final concentrations (1, 0.1, 0.05, and 0.01 mg/mL) were made with sterile distilled water. A 1 mg/mL concentration of standard solution was prepared by dissolving 10 mg of gentamicin into 10 mL of sterile distilled water.
The antimicrobial activity of MEST and EEST were tested against five pathogenic microorganisms namely Bacillus cereus (ATCC ® 10876), Enterococcus faecalis [ATCC ® 14506], E. coli [ATCC ® 10799], Pseudomonas aeruginosa [ATCC ® 10145], and S. aureus (ATCC ® BAA-1026). These strains were obtained from Microbiologics KWIK-STIK™. By using stock, the primary culture was prepared and used for the preparation of subcultures of microorganism. Subculture in broth showed turbidity after 18h incubation. Standardization of inoculums was performed based on the spectrophotometer readings at OD 600 nm. Blank was prepared using Mueller–Hinton broth for B. cereus, E. faecalis, E. coli, P. aeruginosa, and S. aureus. The amount of overnight culture required to obtain culture at an OD 600 nm of 0.05 was calculated using the equation M1 × V1 = M2 × V2 to give inoculum concentration of 4.0 × 107 cells/mL. After dilution, the broths were kept on ice to prevent further bacterial growth.
The screening for antimicrobial activity was performed by employing disk diffusion method using Mueller–Hinton agar for all the tested organisms. Disks containing known amounts (1, 0.1, 0.05, and 0.01 mg/mL of MEST/ EEST or 1 mg/mL of gentamicin) of the extracts and they were placed on the surface of the agar plate. The plates were inoculated at 36±1°C for ≃ 18 h or until a strain to give a confluent lawn of growth was observed. The antimicrobial substance diffused into the medium produced a zone of inhibition (ZI) around the disk. Its diameter was measured in millimetre (mm). The assay was duplicated for three times and the average was calculated.
Antimicrobial potential of extracts were assessed in terms of ZI of microbial growth and the results was summarized [Table 1]. MEST showed antimicrobial activity against S. aureus at 0.1 mg/mL onward and MEST 1 mg/mL showed antimicrobial activity against E. coli and E. faecalis. EEST did not show any antimicrobial activity against E. coli, S. aureus, B. cereus, E. faecalis, and P. aeruginosa at a concentration of 0.01, 0.05, and 0.1 mg/mL and has an antimicrobial activity against E. coli, S. aureus, and E. faecalis at 1 mg/mL concentration, whereas gentamicin showed antimicrobial activity against E. coli, S. aureus, B. cereus, E. faecalis, and P. aeruginosa at 1.0 mg/mL.
Latha and Kannabiran also studied the antimicrobial activity of S. trilobatum against S. aureus, B. subtilis, E. coli, and Klebsiella species. The aqueous extract of S. trilobatum is active against S. aureus (ZI = 8 mm), B. subtilis (ZI = 9 mm), and Klebsiella species (ZI = 10 mm), whereas methanol extract of stem of S. trilobatum is active against S. aureus (ZI = 11 mm). The phytochemical analysis of the extracts of S. trilobatum showed presence of carbohydrates, amino acid, fats and oils, saponins, flavonoids, alkaloids, tannins, and phenolic compounds, and the antimicrobial activity of the extract may be presence of secondary metabolites and tannins. Gentamicin is an aminoglycoside antibiotic agent, traditionally used for the treatment of wide range of aerobic gram-negative pathogenic infections and also used empirically in suspected sepsis. Gentamicin retained its bactericidal activity against stationary-phase of bacterial growth and inhibits bacterial protein synthesis via irreversible binding to the 30S bacterial ribosome., In present study, gentamicin showed antibacterial action against few gram-positive strains namely S. aureus and B. cereus and the same was reported elsewhere., The antibacterial action of gentamicin against gram-positive microbes are concentration-dependent.
MEST and EEST are not showing favorable antimicrobial activity against E. coli, B. cereus, and P. aeruginosa. Both the extracts have antimicrobial activity against S. aureus and E. faecalis at 1 mg/mL concentration.
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Conflicts of interest
There are no conflicts of interest.
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