Phytochemical constituents, antimicrobial and antioxidant activities of Kumaun Himalayan Hoop Pine bark extract.

The chemical composition of the methanol extract obtained from Araucaria cunninghamii Sweet. bark was determined by GC-MS analysis with its antioxidant and antibacterial potential, for the first time. A total of 73 compounds were identified and the extract was strongly characterised by Viridiflorene; Androstan-17-one, 3-ethyl-3-hydroxy-, (5α)-; 8-Isopropenyl-1,3,3,7-tetramethyl-bicyclo[5.1.0]oct-5-en-2-one; 3,6,9-Triethyl-3,6,9-trimethyl-tetracyclo[6.1.0.0 ∼ 2,4∼.0 ∼ 5,7∼]-nonane; Longifolenaldehyde; (-)-Caryophyllen-(I1); 2-hydroxymethyl-5-furfural; Methyl commate B; 3-Ethyl-3-hydroxyandrostan-17-one; 3-Hydroxybenzoic acid as the main components (55.39%). A. cunninghamii extract presents IC50, 53.52 µg/mL and 65.29 µg/mL using DPPH and H2O2 scavenging assay, respectively. The antibacterial activity of the extract was evaluated for eight microorganisms showed that the extract had a remarkable inhibitory potential with a mean zone diameter of inhibition ranging from 09 to 21 mm. The methanol extract of A. cunninghamii showed significant antibacterial activity against X. campestris (21 mm, ZOI) with MIC and MBC values 15.6 and 31.25 µg/mL, respectively.

Chemical composition, antioxidant and antimicrobial activities of Himalayan Fraxinus micrantha Lingelsh leaf extract.

The present investigation determines the phytochemical analysis, antioxidant and antibacterial potential of methanol extract of Himalayan Fraxinus micrantha (Lingelsh) leaves. Chemical analysis of extract revealed the presence of fifty five compounds. The extract was strongly characterised by tyrosol, esculetin, ß-sitosterin, l-(+)-ascorbic acid 2,6-dihexadecanoate, (Z,Z)-6,9-cis-3,4-epoxy nonadecadiene as main components (62.6%). The F. micrantha extract presents IC50, 43.93 µg/ml and 68.90 µg/ml using DPPH and H2O2 scavenging assay, respectively. The antibacterial activity of F. micrantha was evaluated for five microorganisms showed that the extract had a remarkable inhibitory potential with a mean zone diameter of inhibition ranging from 11 to 22 mm. The MIC of the extracts ranged from 7.8 to 250 µg/ml and MBC value range 31.25 to 125 µg/ml. F. micrantha showed significant antibacterial activity against B. subtilis (22 mm, ZOI) with MIC and MBC values 7.8 and 31.25 µg/ml respectively.

Two antidiabetic constituents from Roylea cinerea (D.Don) Baill.

Two antidiabetic compounds named 4-methoxybenzo[b]azet-2(1H)-one (1) and 3ß-hydroxy-35-(cyclohexyl-5'-propan-7'-one)-33-ethyl-34-methyl-bacteriohop-16-ene (2) together with stigmasterol and ß-sitosterol were isolated from the aerial part of Roylea cinerea (D.Don) Baill. The structures of these compounds were elucidated by advanced spectroscopic methods, including two-dimensional NMR and MS techniques. These compounds were evaluated for their antidiabetic efficacy using in vitro and in vivo methods. Both compounds (1 and 2) showed a significant decline in blood glucose level of alloxan-induced diabetic rats at 10 mg/kg, p.o. when compared with glibenclamide at a similar dose. The in vitro studies revealed that compound 1 reduced α-amylase and α-glucosidase by 83.0 and 78.5%, respectively, whereas compound 2 reduced the same by 58.2 and 58.4%, respectively, at 100 µM. The present study supports the role of R. cinerea in Ayurvedic medicine for diabetes.

Bioactivity of root endophytic freshwater Hyphomycetes Anguillospora longissima (Sacc. & Syd.) Ingold.

Anguillospora longissima, isolated from root as endophytic freshwater hyphomycetes, was evaluated for its bioactivity (antibacterial potential) against five bacterial strains, namely, Gram-positive (Bacillus subtilis MTCC 121) and Gram-negative (Agrobacterium tumefaciens MTCC 609, Escherichia coli MTCC 40, Erwinia chrysanthemum, and Xanthomonas pseudomonas). Antimicrobial activity was assessed by measuring the zone of inhibition with preliminary and secondary antimicrobial assays. The applied fungus was found significant for all tested bacterial strains as showen by their zone of inhibition. In preliminary antimicrobial assay, maximum zone of inhibition was recorded against Gram-negative human pathogenic bacterial strain Escherichia coli (23 mm) followed by Erwinia chrysanthemi (22 mm), Agrobacterium tumefaciens (21 mm), and Xanthomonas phaseoli (21 mm), while minimum zone of inhibition was observed against Bacillus subtilis (20 mm). In secondary antimicrobial assay, the maximum zone of inhibition was recorded against Erwinia chrysanthemi (11 mm) followed by Agrobacterium tumefaciens (10 mm), Xanthomonas phaseoli (10 mm), and Bacillus subtilis (9 mm) and minimum inhibition was found against Escherichia coli (8 mm).

Antibacterial activities of Ginkgo biloba L. leaf extracts.

The antibacterial activity of methanol, ethanol, chloroform, and hexane extracts of the leaves of Himalayan gymnospermous plant Ginkgo biloba L. was assessed against five animal and plant pathogenic strains (Agrobacterium tumefaciens, Bacillus subtilis, Escherichia coli, Erwinia chrysanthemi, and Xanthomonas phaseoli) employing disc-diffusion and broth-dilution assays. The methanol extract showed the highest activity (zone of inhibition of 15-21 mm) followed by ethanol (14-19 mm), chloroform (15-20 mm), and hexane (14-19 mm) extracts at 250 µg/mL. A minimum inhibitory concentration (MIC) of 7.8 µg/mL was found for the methanol extract against most of the pathogens tested.