69 research outputs found
An early gene of the flavonoid pathway, flavanone 3-hydroxylase, exhibits a positive relationship with the concentration of catechins in tea (Camellia sinensis)
Tea (Camellia sinensis (L.) O. Kuntze) leaves are a major source of flavonoids that mainly belong to the flavan 3-ols or catechins. Apart from being, responsible for test duality. these compounds have medicinal properties. Flavanone 3-hydroxylase (F3H) is an abundant enzyme in tea leaves that catalyzes the stereospecific hydroxylation of (2S)-naringenin to form (2R.3R)-dihdrokaempferol. We report full-length cDNA sequence of F3H from tea (CsF3H Accessionno. AY641730). CsE3H comprised 1365 by with an open reading frame of 1107 it (from 43 to 1149) encoding a polypeptide of 368 amino, acids. Expression of CsF3H in an expression vector in Escherichia coli yielded a frictional protein with a specific activity of 32 nmol min(-1) mg protein(-1). There was a positive correlation between the concentration of catechins and CsF3H expression in leaves of different developmental stages. CsF3H expression was clown-regulated in response to drought, abscisic acid and gibberellic acid treatment, but up-regulated in response to wounding. The concentration of catechins paralleled the expression data. Exposure of tea shoots to 50-100 mu M catechins led to down-regulation of CSF3H expression suggesting substrate mediated feedback regulation of the gene. The strong correlation between the concentration of catechins and CsF3H expression indicates a critical role of F3H in catechin biosynthesis
Inhibition of H2O2-induced DNA damage in single cell gel electrophoresis assay(comet assay) by castasterone isolated from leaves of Centella asiatica.
Modulatory role of alizarin from Rubia cordifolia L. against genotoxicity of mutagens.
Rubia cordifolia L. (Rubiaceae) is an important medicinal plant used in the Ayurvedic medicinal system. Its use as a traditional therapeutic has been related to the treatment of skin disorders and cancer. Besides its medicinal value, anthraquinones from this plant are used as natural food colourants and as natural hair dyes. Dyes derived from natural sources have emerged as important alternatives to synthetic dyes. Alizarin (1,2-dihydroxyanthraquinone) was isolated and characterized from R. cordifolia L. and evaluated for its antigenotoxic potential against a battery of mutagens viz. 4-nitro-o-phenylenediamine (NPD) and 2-aminofluorene (2-AF) in Ames assay using TA98 tester strain of Salmonella typhimurium; hydrogen peroxide (H2O2) and 4-nitroquinoline-1-oxide (4NQO) in SOS chromotest using PQ37 strain of Escherichia coli and in Comet assay using human blood lymphocytes. Our results showed that alizarin possessed significant modulatory role against the genotoxicity of mutagens
Phosphane-Free Green Protocol for Selective Nitro Reduction with an Iron-Based Catalyst
Abstract: Iron phthalocyanine with
iron sulfate has been successfully applied
for high chemo- and regioselective
reduction of aromatic nitro compounds
to give the corresponding
amines in a green solvent system without
using any toxic ligand. The catalytic
systems were also compatible with a
large range of other reducible functional
groups, such as keto, acid, amide,
ester, halogen, lactone, nitrile, Nbenzyl,
O-benzyl, hydroxy, and heterocycles.
In the present study, dinitro
compounds have been regioselectively
reduced to the corresponding amines
with high yield. In most of the cases
the conversion and selectivity was
greater than 99% as determined by
GC-MS analysis
Chemical composition and antimicrobial activity of the leaf essential oil of Skimmia laureola growing wild in Jammu and Kashmir, India
The analysis of Skimmia laureola hydrodistillate by gas chromatography coupled
with mass spectrometry revealed the presence of 20 constituents, representing
94.6% of the total oil. The major constituents of oil were linalyl acetate (33.0%),
linalool (25.0%), limonene (8.1%), α-terpineol (5.9%) and geranyl acetate
(5.9%). The monoterpene (93.4%) rich essential oil was evaluated for its
antibacterial and antifungal activities against seven microorganisms by agar
diffusion and microdilution methods. The oil showed appreciable antimicrobial
effects against all Gram-positive bacteria tested, including methicillin-resistant
Staphylococcus aureus and Staphylococcus epidermidis with MIC values 32 and
64 mgmL-1, respectively. The oil also exhibited strong fungicidal activity
against Aspergillus niger and Penicillium chrysogenum with MIC value in the
range 32–16 mgmL-1. The oil could be used in the formulation of antimicrobial
agents
Water-Mediated Synthesis of Benzazole and Thiourea Motifs by Reacting Naturally Occurring Isothiocyanate with Amines
- …