Antimicrobial activity of Rauvolfia tetraphylla and Physalis minima leaf and callus extracts

The in vitro antimicrobial activity of Rauvolfia tetraphylla and Physalis minima leaf and callus extracts were studied against selected pathogenic fungi and bacteria, following broth dilution assay. Leaves and calli were extracted using absolute alcohol, benzene, chloroform, methanol and petroleum ether. Among the five solvents used, leaf and callus extracted in chloroform of both the plants were found to be more effective against pathogenic bacteria and fungi, where the minimum inhibitory concentration (MIC) ranged between 0.25 to 6 mg/ml. Absolute alcohol extracts showed MIC of 0.25 to 4 mg/ml forbacteria, whereas for fungi it ranged from 0.25 to 100 mg/ml. Extracts of benzene and petroleum ether were ineffective in inhibiting the bacterial and fungal growth or showed poor inhibition. Methanol extract showed MIC of 0.25 to 100 mg/ml against bacterial pathogens and 0.5 to 100 mg/ml againstfungal pathogens. The antimicrobial activities of these two indigenous medicinal plants were discussed in the present pape

Natural occurrence of aflatoxin, aflatoxigenic and nonaflatoxigenic Aspergillus flavus in groundnut seeds across India

A survey across different agro-climatic regions of India was done and 38 groundnut seed samples were collected from various sources. Upon analysis, all samples were found infected with Aspergillus flavus ranging from 2 to 50% incidence with aflatoxin content of 0.0 to 28 ppb. Greenhouse studies revealed no correlation between incidence of A. flavus and aflatoxin content on seedling emergence, root length, shoot length and dry weight. Seeds were predominantly contaminated with aflatoxin B1 followed by aflatoxin B2. Among the tested A. flavus isolates, 31 were found aflatoxigenic and seven were nonaflatoxigenic when analyzed through cultural, thin layer chromatography, competitive direct enzyme linked immunosorbent assay and multiplex polymerase chain reaction. Present study reveals the current scenario of aflatoxin contamination, and aflatoxigenic and non-aflatoxigenic fungal infection in groundnut seeds collected across India.Keywords: Polymerase chain reaction (PCR), Aspergillus flavus, aflatoxin, enzyme-linked immuno sorbent assay (ELISA), groundnutAfrican Journal of Biotechnology Vol. 12(19), pp. 2587-259

Polymer thin film with in situ synthesized silver nanoparticles as a potent reusable bactericide

Silver nanoparticles are well-established antibacterial agents. However, an effective design and formulation that ensures: (i) ease of synthesis and fabrication, (ii) amenability to deployment over large surfaces of variable shape, (iii) high efficacy and (iv) multiple reuses with the possibility of periodic monitoring, is yet to emerge. A nanocomposite thin film of poly(vinyl alcohol) with silver nanoparticles generated within, through a soft-chemical in situ synthesis, is shown to be a good candidate to fulfil most of the above requirements. Efficient antibacterial activity, multiple reuses and facile monitoring of the film through spectroscopy and microscopy are demonstrated. Preliminary studies demonstrate the effective bactericidal action of the thin film coating on stirring rods

Antimicrobial activity of leaf extracts of Indian medicinal plants against clinical and phytopathogenic bacteria

The ethnobotanical efficacy of Indian medicinal plants; Achyranthes aspera, Artemisia parviflora, Azadirachta indica, Calotropis gigantean, Lawsonia inermis, Mimosa pudica, Ixora coccinea, Parthenium hysterophorus and Chromolaena odorata were examined using agar disc diffusion method against clinical bacteria (Escherichia coli and Staphylococcus aureus) and phytopathogenic bacteria (Xanthomonas vesicatoria and Ralstonia solanacearum). Leaves were extracted using different solvents such as methanol, ethanol, ethyl acetate and chloroform. Among treatments, maximum in vitro inhibition was scored in methanol extracts of C. odorata which offered inhibition zone of 10, 9, 12 and 12 mm against E. coli, S. aureus, X. vesicatoria and R. solanaccearum, respectively, followed by chloroform extract of the same plant leaf with inhibition zone of 8, 4, 4 and 4 mm, respectively. A significant inhibition of E. coli was found in aqueous and in all tested solvent extracts of A. indica. In case of S. aureus, maximum inhibition of 8 mm was obtained in aqueous extracts of A. indica and 6 mm from methanol extract of L. inermis. The minimum inhibitory concentration (MIC) value for the clinicalbacteria ranged between 0.35 to 4.0 mg/ml and 0.25 to 4.0 mg/ml for phytopathogenic bacteria when tested with all four solvents extracts of C. odorata. Whereas, extracts of A. aspera, A. parviflora, C. gigantean, L. inermis, M. pudica and I. coccinea were found to be ineffective or showed poor inhibition on tested human and phytopathogenic bacteria

Chemical composition and antimicrobial properties of the rhizome essential oil of Cyperus articulatus L. grown in Karnataka, India

112-118Cyperus articulatus L. is widely distributed in various geographical regions of the world, and it has been used as a folk medicine for treating haemorrhoids, diarrhoea, and other diseases. The present study aimed to analyze the chemical constituents and antimicrobial activities of essential oil (EO) extracted from C. articulatus grown in the Karnataka region to explore its potential pharmaceutical usage. The EO from the rhizomes of C. articulatus was extracted by hydro-distillation and was tested for its antimicrobial activities against selected bacteria (Staphylococcus aureus, Salmonella enterica serovar Abony, and Escherichia coli) and fungi (Candida albicans, Aspergillus flavus, and Aspergillus niger). The EO yield was 1.24 g/100 g of dried rhizome powder. The EO recorded a significant inhibition against S. aureus and A. flavus. The GC-MS analysis of EO showed the predominance of important metabolites such as mustakone (20.2%), longifolenaldehyde (14.9%), cedroxyde (8.7%), α-copaene (4.7%), cyperene (2%), cyperotundone (2.6%), khusinol (2.3%), and corymbolone (1.1%) along with several other monoterpenoids and sesquiterpenoids. The study revealed the EO of C. articulatus as a promising source of antibacterial and antifungal metabolites which may lead to its application in managing bacterial and fungal infections and storage mould