Bilal Ahmad Wani

Chemical composition, antioxidant and antibacterial activities of the leaf essential oil of Juglans regia L. and its constituents

The essential oil from the leaves of Juglans regia L. (Juglandaceae) growing wild in Kashmir (India) was obtained by hydrodistillation and analysed by a combination of capillary GC-FID and GC-MS. A total of 38 compounds, representing 92.7% of the oil, were identified and the major components were found to be α-pinene (15.1%), β-pinene (30.5%), β-caryophyllene (15.5%) germacrene D (14.4%) and limonene (3.6%). The essential oil and the main individual constituents were screened for antibacterial activity and the essential oil evaluated for antioxidant activity. Antibacterial activity was evaluated using the disc diffusion and microdilution methods against a group of clinically significant Gram-positive (Staphylococcus epidermidis MTCC-435, Bacillus subtilis MTCC-441, Staphylococcus aureus) and Gram-negative bacteria (Proteus vulgaris MTCC-321, Pseudomonas aeruginosa MTCC-1688, Salmonella typhi, Shigella dyssenteriae, Klebsiella pneumonia and Escherichia coli). The essential oil and its major components exhibited broad spectrum inhibition against all the bacterial strains with Gram-positive being more susceptible to the oil than Gram-negative bacteria. Antioxidant activity of the oil was evaluated by the scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) and hydroxyl radicals. In general, the essential oil exhibited high antioxidant activity which was comparable to the reference standards at the same dose (ascorbic acid and butylated hydroxyl toluene, BHT) with IC(50) values of 34.5 and 56.4μg/ml calculated by DPPH and hydroxyl radical scavenging assays respectively.

Wood fiber variability in stems of Juglans regia L. from temperate climate of Kashmir Himalaya

Juglans regia L. is an important natural resource almost throughout the temperate regions of the world but relatively little is known about the within-tree variability of the anatomical characteristics of its wood. For this purpose three sites were selected and from each site three trees were felled and five discs were extracted from base up to merchantable top of the each tree, equally spaced along vertical direction. The wood anatomical features viz. fiber length, fiber diameter, fiber wall thickness, varied significantly from different positions of trees. Also the derived wood properties like Runkel ratio, Slenderness ratio, Luce’s shape factor were evaluated from wood anatomical features as these parameters are directly related to industrial utility of wood.