BackgroundThe rise of antibiotic resistance among methicillin resistant Staphylococcus aureus (MRSA), have caused concerns for the treatment of MRSA infections. Hence, search for an alternative therapy for these infections is inevitable. Folk Indian medicine refers to the use of leaf and stem bark powder of Tabernaemontana alternifolia (Roxb) in treatment of skin infections, but no scientific report establishes its antibacterial activity.MethodsDirect aqueous extracts and sequential aqueous extracts of the stem bark of T. alternifolia (using petroleum ether and ethyl acetate as other solvents) were prepared by soxhlet extraction. The antibiotic sensitivity profiles of the clinical isolates were determined against 18 antibiotics using disc diffusion method. The isolates were identified by 16S rRNA gene sequencing. The methicillin resistance among S. aureus (MRSA) was confirmed by PCR amplification of mecA gene. The disc diffusion method was used to determine the antibacterial activity of the extracts. The micro-dilution method was used to determine the minimum inhibitory concentration (MIC) of the extract against the test organism. To further evaluate the therapeutic potential of the extract, cell cytotoxicity was checked on Vero cells by MTT assay. Chemical profiling of the extract was done by HPTLC method.ResultsThe aqueous extracts of T. alternifolia stem bark exhibited antibacterial activity against Gram-positive microorganisms, particularly against clinical isolates of MRSA and vancomycin resistant S. aureus (VRSA). The minimum inhibitory concentration (MIC) of extract against the isolates ranged from 600–800 μg/ml. The extract did not exhibit cytotoxic activity against Vero cells even at the concentration of 4 mg/ml. The chemical profiling revealed presence of alkaloids, flavonoids, coumarins, saponins and steroids. Petroleum ether and ethyl acetate extracts did not exhibit antibacterial activity.ConclusionOur results offer a scientific basis for the traditional use of T. alternifolia in the treatment of skin infections, showing that the plant extract has an enormous potential as a prospective alternative therapy against MRSA skin infections. The present study lays the basis for future studies, to validate the possible use of T. alternifolia as a candidate in the treatment of MRSA infections.
Understanding species responses to urbanization is important to realize their specific conservation needs. Odonates (dragonflies and damselflies) are freshwater insects perceived as good ecological indicators. To investigate responses of tropical odonates to an urbanization gradient, we sampled adult odonates along an urbanization gradient at six sites along the Mula River across Pune City, Maharashtra, India. For species–habitat analysis, we first performed a variable reduction using principal component analysis. we analyzed species–habitat data using redundancy analysis and canonical correspondence analysis. We documented 15 odonates across 6 sites. Our statistical analyses on patterns of odonate assemblages across sites and environmental variables did not return significant results. However, we detected site-exclusivity in a few species based on occurrence data and identified urban sensitive, urban tolerant and generalist species. We found that the odonate diversity was highest at a moderately urbanized site. We believe that increase in diversity due to moderate amounts of disturbance can be explained by the intermediate disturbance hypothesis. Based on our data, we suggest that for the conservation of odonates in the urban context, anthropogenic disturbance needs to be regulated. Here, we demonstrate that understanding species–habitat associations is the first step towards understanding their ecological and conservation requirements. To conserve odonates and rivers in metropolitan cities like Pune, restoring original river-side habitat and reducing the disturbance at highly urbanized sites to at least intermediate levels needs to be done on an urgent basis.
The study assesses distribution and population status of Saraca asoca from Sahyadri-Konkan ecological corridor. Eighteen localities at various protection levels ranging from wildlife sanctuary to private forests were selected and spatially mapped to arrive at a distribution map. Kolmogorov-Smirnov test indicated that the size class distribution of S. asoca from the sacred groves differed both from formally protected sites and private forest. S. asoca trees from sacred groves had the highest mean girth at breast height (GBH) values than the other two protection levels. GBH of S. asoca was in inverse proportion with the cumulative disturbance index.
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