Influence of phenolic compounds of Kangra tea [Camellia sinensis (L) O Kuntze] on bacterial pathogens and indigenous bacterial probiotics of Western Himalayas

Phenolic compounds of nutraceutical importance viz., catechins (C), (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin-3-gallate (ECG) were estimated in fresh green tea shoots of Camellia sinensis (L) O Kuntze cultivar. The total polyphenols and total catechins were in the range of 219.90 to 317.81 and 140.83 to 271.39 g/kg, respectively in monthly samples of tea. The values of C, EC, EGC, EGCG and ECG in tea powders as analyzed through high performance liquid chromatography (HPLC) were in the range of 1.560 to 3.661, 13.338 to 27.766, 26.515 to 39.597, 62.903 to 102.168 and 18.969 to 39.469 mg/g, respectively. Effect of tea extracts and standard flavanols against five pathogenic bacteria viz., Listeria monocytogenes (MTCC-839), Pseudomonas aeruginosa (MTCC-741), Bacillus cereus (MTCC-1272), Staphylococcus aureus (MTCC-96) and Escherichia coli (MTCC-443), and eleven indigenous potential bacterial probiotics belonging to genera Enterococcus, Bacillus and Lactobacillus spp. obtained from fermented foods of Western Himalayas, was investigated. EGCG, ECG and EGC exhibited antibacterial activity but, C and EC did not show this activity. Tea extracts having high concentrations of EGCG and ECG were more potent in antibacterial action against bacterial pathogens. Tea extracts and standard flavan-3-ols augmented viability of potential probiotics in an order of EGCG > EGC > ECG > EC > C. Tea extracts and standard flavanols had no antibacterial activity against Escherichia coli (MTCC-443) but, in combination with probiotic culture supernatants, this activity was seen. The Kangra tea thus, exerts antibacterial effect on bacterial pathogens through EGCG, ECG and EGC constituents while stimulatory effect on growth of indigenous potential probiotics.

Influence of phenolic compounds of Kangra tea [Camellia sinensis (L) O Kuntze] on bacterial pathogens and indigenous bacterial probiotics of Western Himalayas.

Phenolic compounds of nutraceutical importance viz., catechins (C), (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin-3-gallate (ECG) were estimated in fresh green tea shoots of Camellia sinensis (L) O Kuntze cultivar. The total polyphenols and total catechins were in the range of 219.90 to 317.81 and 140.83 to 271.39 g/kg, respectively in monthly samples of tea. The values of C, EC, EGC, EGCG and ECG in tea powders as analyzed through high performance liquid chromatography (HPLC) were in the range of 1.560 to 3.661, 13.338 to 27.766, 26.515 to 39.597, 62.903 to 102.168 and 18.969 to 39.469 mg/g, respectively. Effect of tea extracts and standard flavanols against five pathogenic bacteria viz., Listeria monocytogenes (MTCC-839), Pseudomonas aeruginosa (MTCC-741), Bacillus cereus (MTCC-1272), Staphylococcus aureus (MTCC-96) and Escherichia coli (MTCC-443), and eleven indigenous potential bacterial probiotics belonging to genera Enterococcus, Bacillus and Lactobacillus spp. obtained from fermented foods of Western Himalayas, was investigated. EGCG, ECG and EGC exhibited antibacterial activity but, C and EC did not show this activity. Tea extracts having high concentrations of EGCG and ECG were more potent in antibacterial action against bacterial pathogens. Tea extracts and standard flavan-3-ols augmented viability of potential probiotics in an order of EGCG > EGC > ECG > EC > C. Tea extracts and standard flavanols had no antibacterial activity against Escherichia coli (MTCC-443) but, in combination with probiotic culture supernatants, this activity was seen. The Kangra tea thus, exerts antibacterial effect on bacterial pathogens through EGCG, ECG and EGC constituents while stimulatory effect on growth of indigenous potential probiotics.

N-acetylcysteine exposure on lead-induced lipid peroxidative damage and oxidative defense system in brain regions of rats.

Lead (Pb) is known to disrupt the pro-oxidant/antioxidant balance of tissues, which leads to biochemical and physiological dysfunction. Oxidative stress is considered a possible molecular mechanism involved in Pb neurotoxicity. Considering the vulnerability of the brain to oxidative stress under Pb neurotoxicity, this study investigated the effects of exposure of the thiol antioxidant N-acetylcysteine (NAC) on lead-induced oxidative damage and lipid peroxidation in brain regions of the rat. Wister strain rats were exposed to lead in the form of lead acetate (20 mg/kg body wt/d) for a period of 2 wk and the effects of NAC on lead-induced neurotoxicity in rat brain regions were assessed by postadministration of NAC (160 mg/kg body wt/d) for a period of 3 wk. The lipid peroxidation byproduct, malondialdehyde (MDA) increased following lead exposure in both of the regions, and the antioxidant capacities of the cell in terms of the activity of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) was diminished. Following NAC treatment, lead-induced lipid peroxidation decreased and antioxidant enzyme activities improved, with CAT showing enhancement in the cerebral region only and SOD showing enhancements in the cerebellar region. Our result suggests that thiol-antioxidant supplementation following Pb exposure might enhance the reductive status of brain regions by arresting the lipid peroxidative damage in brain regions.

Simultaneous saccharification and fermentation of rice straw into ethanol.

The physicochemical pretreatment of ball milled rice straw with different oxidizing agents, peracetic acid, alkali-peroxide, manganese-peroxide compounds under steaming pressure were studied. The pretreatment resulted in major changes in chemical composition of rice straw. The peroxide treated substrates were found to be most susceptible to enzymatic saccharification. A maximum saccharification (77.4%) of alkaline-peroxide treated rice straw (5%, w/v) was achieved using cellulase enzyme produced by mixed cultivation of Trichoderma reesei Rut C-30 and Aspergillus ochraceus containing 1.83 FPU, 1.63 cellobiase and xylanase 2.03 IU/ml. The hydrolysate was fermented using coculture of a temperature resistant strain of Saccharomyces cerevisiae and Pachysolen tannophilus resulting in 1.5% (w/v) ethanol. The SSF of 10.0% (w/v) H2O2-MnSO4 treated straw yielded maximum ethanol (2.9%, w/v) after 72 h at 40 degrees C. As a consequence of the well-balanced cellulase production by mixed fungal culture, the supplementation of cellobiase or xylanase was not necessary in the simultaneous saccharification and fermentation process.