IN VITRO ANTIBACTERIAL ACTIVITY OF LEAF, SEED, ROOT, POD AND FLOWER EXTRACTS OF CAJANUS CAJAN (L.) MILLSP

Objective: The aim of this study was to investigate the antibacterial activity of leaf, seed, root, pod and flower extracts of C. cajan with various solvents such as aqueous, acetone, chloroform, ethanol and methanol.Methods: C. cajan was evaluated against certain pathogenic species of gram negative and gram positive bacteria (Staphylococcus aureus and Escherichia coli) by agar well diffusion method.Results: It was observed that the methanolic and ethanolic extracts had shown potent antibacterial activity against gram +ve and gram -ve bacterial species. Among the five solvents used, methanolic extracts showed higher activity against S. aureus (ZI of leaf, 25.5±0.08 mm;  seed, 22.6±0.01 mm;  root, 22.1±0.09 mm;  pod, 20.8±0.14 mm and flower, 21.9±0.05 mm). Whereas ethanolic extracts showed higher activity against E. coli of all the solvent extracts used in C. cajan (ZI of leaf, 25.1±0.05 mm;  seed, 22.4±0.12 mm;  root, 21.9±0.04 mm;  pod, 20.7±0.12 mm and flower, 21.5±0.10 mm). The minimum inhibitory concentration of methanolic and ethanolic leaf, seed, root, pod and flower extracts respectively was determined to be ranging between 0.38 and 0.512mg/mL for both the bacterial species.Conclusion: The results of this study support that the crop species C. cajan had potential antibacterial activity against S. aureus and E. coli and these extracts may be used for production of drugs commercially to treat diseases caused by the respective pathogens.Â

Preliminary phytochemical screening from leaf and seed extracts of Senna alata L. Roxb-an Ethnomedicinalplant

ABSTRACT: Aim: The bioactive compounds present in the plant are responsible for the medicinal properties of the plant. The present investigation is aimed in screening the bioactive compounds present in the seed and fresh, dry leaves of S.alata -an important ethnomedicinal plant. The objectives of the work includes i) the screening of various bioactive compounds present in the seed, fresh and dry leaves of S.alata. ii) To identify the bio active compounds present in the fresh leaf extracts by Thin layer chromatography. Methodology: Qualitative analysis for the presence of phytochemicals was performed using methanol, chloroform, petroleum ether and aqueous extracts of seed and both fresh and dry leaves of Senna alata by various standard techniques availabl

Structural and functional studies of ferredoxin and oxygenase components of 3-nitrotoluene dioxygenase from Diaphorobacter sp. strain DS2.

3-nitrotoluene dioxygenase (3NTDO) from Diaphorobacter sp. strain DS2 catalyses the conversion of 3-nitrotoluene (3NT) into a mixture of 3- and 4-methylcatechols with release of nitrite. We report here, X-ray crystal structures of oxygenase and ferredoxin components of 3NTDO at 2.9 Å and 2.4 Å, respectively. The residues responsible for nitrite release in 3NTDO were further probed by four single and two double mutations in the catalytic site of α-subunit of the dioxygenase. Modification of Val 350 to Phe, Ile 204 to Ala, and Asn258 to Val by site directed mutagenesis resulted in inactive enzymes revealing the importance of these residues in catalysis. Docking studies of meta nitrotoluene to the active site of 3NTDO suggested possible orientations of binding that favor the formation of 3-methylcatechol (3MC) over 4-methylcatechol energetically. The electron transfer pathway from ferredoxin subunit to the active site of the oxygenase subunit is also proposed

Proposed electron transfer pathway between 3NTDO-F_DS2 and 3NTDO-O_DS2.

<p>(A) Ferredoxin is shown in brown color at the top of 3NTDO-O_DS2; Iron and sulphur are shown in magenta and yellow. (B) A line is drawn from Rieske center of 3NTDO-F_DS2 to the mononuclear iron of 3NTDO-O_DS2 through the Rieske cluster of 3NTDO-O_DS2. (C) Proposed electron transfer pathway from Rieske cluster of ferredoxin to active site mononuclear iron of oxygenase of NDO is plotted in ball and stick model, the residues of chain A and chain C of oxygenase are shown in green and cyan color.</p

Oxidation products ratios^b (%) formed by 3NTDO and its variants with mononitrotoluenes.

<p>^bProduct ratios were determined from by theintegration of Gas chromatography mass spectrometry (GC-MS) total ion current chromatogram. Results reported are the average of at least three independent experiments, and standard deviations were less than 7%.</p

Comparison of active site residues of 3NTDO-O_DS2 and NBDO.

<p>The residues responsible for regioselectivity of 3NTDO-O_DS2 (A) and NBDO (B) are shown in green and orange stick model, respectively. The mononuclear iron center (large magenta sphere) is coordinated with two histidine and one aspartic residue.</p

Overall structure of ferredoxin and oxygenase components of 3NTDO.

<p>(A) 3NTDO-F_DS2, the Rieske center and coordinating side chain residues are shown in stick representation. (B) 2Fo-Fc electron density contoured at 1.0 σ level in the Rieske cluster of ferredoxin shown as a ball and stick model and in blue wire mesh. (C) 3NTDO-O_DS2, the three αsubunits are colored green, blue and red and β subunits are in yellow, grey and cyan. The Rieske center and the catalytic iron are shown in CPK model representation. (D) 2Fo-Fc electron density contoured at 1.5σ level in the vicinity of catalytic iron center with the ligand His206, His211 and Asp360 shown as a ball and stick model. (E) View along the molecular threefold axis of 3NTDO-O_DS2. The iron, sulphur, nitrogen and water are shown in magenta, yellow, blue and red colors, respectively.</p

Docked conformations of 3-nitrotoluene in the active site of 3NTDO-O_DS2.

<p>(A) 3-methylcatechol product orientation (B) 4-methyl-2-nitrophenol orientation. The distance between mononuclear iron and carbon atoms of benzene ring is shown in red dotted lines. The ligands His208, His211, Asp360 and mononuclear iron (magenta) are shown in ball and stick model. The active site residues are shown in stick and 3-nitrotoluene is in orange color.</p