The whole-genome sequence analysis of Enterobacter cloacae strain Ghats1: insights into endophytic lifestyle-associated genomic adaptations.

Enterobacter cloacae is normally considered to be an opportunistic human pathogen. Here, we report on the whole-genome sequence of an endophytic E. cloacae, strain "Ghats1", isolated from leaves of the medicinal plant Coscinium fenestratum Gaertn. Functional analysis of the Ghats1 genome revealed an enrichment for genes involved in the uptake and exchange of nutrients, for chemotaxis and for plant colonization. Unexpectedly though, there were no ORFs belonging to the "virulence factors and antibiotic resistance". Moreover, the presence of hydrolytic enzymes and motility functions reveals the characteristics of an endophyte lifestyle of a bacterium that can colonize and adapt to plant environment. These results provide a better understanding of an endophytic lifestyle through plant-microbe interaction, which can be further exploited as a biocontrol agent.

Potent activity of bioconjugated peptide and selenium nanoparticles against colorectal adenocarcinoma cells.

Nanomaterial based anticancer treatment is promising nowadays because of their small size that can penetrate and interact both inside and outside the cell surface. In this study, a simple protocol was followed for the conjugation of the biologically synthesized selenium nanoparticles (SeNPs) and short chain synthetic peptide. SeNPs was synthesized by using the culture supernatant of Streptomyces griseoruber, actinomycetes isolated from the soil. The short chain peptide Boc-L-F-OMe was synthesized by the conventional solution phase chemistry using a racemization-free fragment condensation strategy. Peptide interaction with different anticancer receptors was preliminarily studied by docking studies. Biosynthesized SeNPs was conjugated with short chain synthetic peptides by means of cysteine conjugation. Characterization of SeNPs with peptide was done by UV-visible spectroscopy and DLS that showed the red shift in the peak and increase in average particle size and zeta potential, respectively. Bioconjugated SeNPs- peptide was tested for its cytotoxicity against the colon cancer cell line HT-29. Bioconjugated SeNPs-peptide showed enhanced cytotoxic activity when compared to the peptide and nanoparticle alone that was tested at 10-50 µg/ml concentration. Further apoptotic studies were done by AO/PI staining and DNA fragmentation assay that confirms the cytotoxicity of the conjugates. Novel peptide-SeNPs conjugates tested in our study has a significant anticancer activity that can be potentially used for targeting the cancer cells.

Attenuation of quorum-sensing-dependent virulence factors and biofilm formation by medicinal plants against antibiotic resistant Pseudomonas aeruginosa.

Pseudomonas aeruginosa use small signaling molecules such as acyl homoserine lactones (AHLs), which play an important role in release virulence factors and toxin for further establishment of host infection. Thus, involving with the QS system would provide alternative ways of preventing the pathogenicity. In the present study, totally six medicinal plants (Terminalia bellerica, Celastrus paniculatus, Kingiodendron pinnatum, Schleichera oleosa, Melastoma malabathricum, Garcinia gummi-gutta) were screened for anti-QS activity using biomonitor strain of Chromobacterium violaceum CV12472. The primary screening of antimicrobial activity of all the plant extracts have inhibited the growth of tested bacterial species. Of these at the sub-minimum inhibitory concentration the methanol extract of T. bellerica (0.0625-0.5 mg/ml) has significantly inhibited violacein production (20.07-66.22%) in C. violaceum (CV12472). Consequently, the extract of T. bellerica has reduced the production of pyocyanin, exopolysaccharide and biofilm formation in P. aeruginosa strains. Fluorescence and scanning electron microscopy analysis confirmed the reduction of biofilm formation in P. aeruginosa strains when treated with T. bellerica. GC-MS analysis showed the active compounds inhibited the production of virulence factors of P. aeruginosa. The results suggest the possible use of this T. bellerica as an anti-QS and anti-biofilm agent to control Pseudomonas infection. Interference of QS provides an important means for the inhibition of bacterial virulence and thus aids in treatment strategies.

In vitro biological activity of aromadendrin-4'-methyl ether isolated from root extract of Ventilago madraspatana Gaertn with relevance to anticandidal activity.

In this study, antimicrobial and antioxidant activities of the hexane extract of the root of Ventilago madraspatana were evaluated. Based on the significant bioactivity of crude hexane extract, an active compound was purified from the root extract. The active compound was further purified and identified as aromodendrin-4'-methyl ether by the (1)H NMR spectrum. The isolated compound significantly inhibited Staphylococcus epidermidis with the lowest MIC and MBC at 78 µg/mL (P < 0.05). The compound also exhibited significant anticandidal activity with MIC and MBC values of 312 and 625 µg/mL, respectively. The radical scavenging activity of aromodendrin-4'-methyl ether was evident by its lower IC50 values of 60 µg/mL for DPPH scavenging and 3.2 µg/mL for ABTS scavenging. The compound also exhibited ferrous ion chelation and H2O2 scavenging activities. The study is an attempt to increase the industrial utility of V. madrasapatana.

Evaluation of the antimicrobial activity of three medicinal plants of South India

The present study was carried out to evaluate the antimicrobial activity of the crude methanolic extracts of Memecylon malabaricum Clarke. (leaves), Cochlospermum religiosum Linn. (leaves and flowers) and Andrographis serpyllifolia Vahl. (leaves) using the standard disc diffusion assay against eight strains of bacterial species, viz., Staphylococcus aureus, Salmonella typhi, Enterobacter aerogenes, Pseudomonas aeruginosa, Xanthomonas oryzae pv. oryzae, Xanthomonas axonopodis pv. malvacearum, Bacillus cereus and Micrococcus sp. The extracts of the plants at a concentration of 1.25 mg/disc showed minimum to moderate activity against both Gram positive and Gram negative bacteria indicating a broad spectrum activity. A preliminary phytochemical screening was conducted on the selected plant extracts using standard qualitative procedures that revealed the presence of several secondary metabolites. The extracts failed to show antioxidant activity by reducing power assay. The result indicates the potential usefulness of these plants especially Memecylon malabaricum and Cochlospermum religiosum, in treating microbial infections in humans and plants and justifies the need for further investigations and characterization of the bioactive compounds present in the methanolic extracts of the plants.

Chromium in some herbal drugs.

The use and demand of herbal drug is increasing day by day in both developing and developed countries due to the growing recognition that these are natural products having no or little side effects and can easily be available at affordable prices. Sometimes these are the only source of health care available to poor people particularly in South East Asia where more than 80% population depend on herbal drugs for their health care needs. Thus the quality and safety of herbal products is very important in order to have desired therapeutic efficacy. But in today's polluted environment with increasing automobile consumption and industrialization, WHO is emphasizing emphatically that without heavy metal assessment the herbal drug should not be used. The concentration of heavy metals including Cr is increasing in the environment and many hazardous effects are caused in the inhabitants of that environment (Prasad and Hagemeyer, 1999; Nriagu and Pacyna, 1998). For example, in human beings, due to Cr numbers of disorders occur like damage to liver, kidney, respiratory and nerve tissues. Besides enhancing risk of human lung cancer due to automobile exhaust and even irritation of skin have also been reported by excess of Cr (Anonymous, 1998; Anonymous 1988). Therefore it is mandatory to assess the Cr concentration in herbal drugs before use. Although some work has been carried out by Rai et al., 2001 a, b; Fuh et al., 2003; Al Ajasa et al., 2004 and Ernst 2002 but it is not enough and lot of work is required in this field.

Antimicrobial activity of Memecylon malabaricum leaves.

The petroleum ether, chloroform and methanol extracts of Memecylon malabaricum leaves were tested for antimicrobial activity. Only methanol extract has shown activity against bacteria both Gram (+) and Gram (-), and fungi.

Effect of Tulasi (Ocimum sanctum) leaf powder supplementation on blood sugar levels, serum lipids and tissue lipids in diabetic rats.

Tulasi leaf powder was fed at the 1% level in normal and diabetic rats for a period of one month to explore the effect on fasting blood sugar, uronic acid, total amino acids, and the lipid profile in serum and tissue lipids. The results indicated a significant reduction in fasting blood sugar, uronic acid, total amino acids, total cholesterol, triglyceride, phospholipids and total lipids. In liver, total cholesterol, triglyceride and total lipids were significantly lowered. Total lipids were significantly reduced in kidney. In heart, a significant fall in total cholesterol and phospholipids was observed. All these observations indicate the hypoglycemic and hypolipidemic effect of Tulasi in diabetic rats.

Randomized placebo-controlled, single blind trial of holy basil leaves in patients with noninsulin-dependent diabetes mellitus.

Experimental studies on albino rats reported that leaf extract of Ocimum sanctum and Ocimum album (holy basil) had hypoglycemic effect. To explore further evidence we studied the effects of treatment with holy basil leaves on fasting and postprandial blood glucose and serum cholesterol levels in humans through randomized, placebo-controlled, crossover single blind trial. Results indicated a significant decrease in fasting and postprandial blood glucose levels during treatment with holy basil leaves compared to during treatment with placebo leaves. Fasting blood glucose fell by 21.0 mg/dl, confidence interval of difference -31.4 - (-)11.2 (p < 0.001), and postprandial blood glucose fell by 15.8 mg/dl, confidence interval -27.0 - (-)5.6 (p < 0.02). The lower values of glucose represented reductions of 17.6% and 7.3% in the levels of fasting and postprandial blood glucose, respectively. Urine glucose levels showed similar trend. Mean total cholesterol levels showed mild reduction during basil treatment period. The findings from this study suggest that basil leaves may be prescribed as adjunct to dietary therapy and drug treatment in mild to moderate NIDDM.