Dhiraj Vyas

Evaluation of nutritional and antioxidant status of Lepidium latifolium Linn.: a novel phytofood from Ladakh.

Lepidium latifolium Linn. (perennial pepperweed) is one of the preferred phytofoods among cold arid region of Ladakh, India and its leaves contribute significantly to peoples diet. This study was conducted to determine its nutritive value and antioxidant activity. Plant samples from three different locations were selected in the present study. Results showed that this plant is an excellent source of glucosinolates, notably sinigrin that is present in very high amount (∼70–90%). Its value ranged from 149 to 199 µg per g fresh weight. Fatty acid composition analysis showed that its leaves were abundant in unsaturated fatty acids, specifically linolenic acid (18∶3) whose percentage is about 50%. Higher glucose and crude protein along with higher nitrogen to sulfur ratio, supplements the nutritive value of this plant. Based on total phenol, flavanoids, free radical scavenging activity and DNA protective activity showed that this ecotype of perennial pepperweed contains high antioxidant properties. The percentage inhibition for O2 − scavenging activity ranged from 41.3% to 83.9%. Higher content of phenols (26.89 to 50.51 mg gallic acid equivalents per g dry weight) and flavanoids (38.66 to 76.00 mg quercetin equivalents per g dry weight) in leaves could be responsible for the free radical scavenging activity of this plant. Depending upon the location of the plants, variations were observed in different activities. Based on the systematic evaluation in this study, preparations of Lepidium latifolium from Ladakh can be promoted as substitute to dietary requirements.

Effect of contrasting climates on antioxidant and bioactive constituents in five medicinal herbs in Western Himalayas

To understand the effect of climate change on constitutive antioxidant and biochemical metabolites in Western Himalayas, five medicinal herbs were selected and grown at two altitudes in Jammu (305 m) and Srinagar (1730 m) with subtropical and temperate climates, respectively. Significant variations were observed in phenols and flavonoids in Hypericum perforatum L., Matricaria chamomilla L., Thymus vulgaris L., Cynara cardunculus L. and Echinacea purpurea L. growing at two locations. High altitude temperate site show variable (up to 13 fold) increase in their content. Proteins (1.3 – 1.8 times), sugars (2.8 – 4.1 times) and free amino acid (1.04 – 1.22 times) were also higher at Srinagar (1730 m). Within these plants, H. perforatum and M. chamomilla have shown higher accumulation of phenols, xanthophylls and proline even at subtropical environment in Jammu (305 m) suggesting potential for increasing their geographical area. The results demonstrate that changing environmental conditions significantly affect the bioactive constituents, which accumulate as a defence strategy by these temperate plants. Their medicinal significance during climate change scenario has also been discussed.

Comparative studies for screening of bioactive constituents from various parts of Incarvillea emodi

A comparative study was performed on various parts (shoots, roots and flowers) of Incarvillea emodi. The alcoholic extracts of different parts were fractionated with solvents of different polarity and studied for the determination of total polyphenol content and total antioxidant potential. Furthermore, we have isolated major iridoid glucosides from the dried flowers of I. emodi followed by the comparative cytotoxicity studies of these iridoids against five different human cancer cell lines. The results have demonstrated that ethyl acetate fraction of all parts have higher phenolic content (167.87–294.31 mg/g as gallic acid equivalent) and higher total antioxidant potential (252.95–384.64 mg/g as trolox equivalent). The results of in vitro cytotoxicity studies have indicated that boschnaloside (2) possesses promising anticancer potential against three human cancer cell lines, THP-1, A-549 and PC-3, which belong to leukaemia, lung and prostate cancers, respectively, while plantarenaloside (1) expressed relevant cytotoxic activity against THP-1 cell lines of leukaemia.

Ethylene and Polyamines in Counteracting Heavy Metal Phytotoxicity: A Crosstalk Perspective

The increasing trend of addition of heavy metals (HMs) to agricultural lands has increased toxicities in plants leading to significant declines in crop productivity. HM toxicity includes alterations in physiological processes, metabolic activities and overall growth and development of plants. The stimulation of oxidative stress is among the common concerns of toxicity in plants at the cellular level. Plant growth hormones/growth regulators have been key signalling molecules in delivering responses to HMs. The important phytohormones, ethylene and polyamines (PAs), play significant roles in the regulation of various developmental processes and signalling networks in plants. Notably, ethylene and PAs are also involved directly or indirectly in a widespread range of abiotic stress responses and tolerance/adaptation. As ethylene and PA biosynthesis involves a common precursor, S-adenosylmethionine, the interplay between ethylene and PAs is suggested in responses of plants to HM stress. The present work emphasizes the roles of these two phytohormones in signalling and regulation of HMs stress in plants based on the recent available reports. This work (a) overviews biosynthesis and signalling of ethylene and PAs; (b) critically appraises the functions of ethylene and PA, and the role of their promoters in HM-exposed plants; and (c) discusses crosstalk on the major mechanisms potentially governing ethylene and PA for plant HM-tolerance/adaptation. HMs in the appraised herein literature exhibited a differential modulation of PAs and ethylene biosynthetic pathways. In particular, the synergism between the PA and ethylene biosynthesis components could be helpful for plants in improving the ratio of root to shoot, increasing water (nutrients) uptake, modulating major signalling compounds, and thereby maintaining optimum cellular metabolism under HM stress.

Two-stage phyto-microremediation of tannery effluent by Spirodela polyrrhiza (L.) Schleid. and chromium resistant bacteria.

Two-stage sequential treatment of tannery effluent was conducted employing a wetland plant, Spirodela polyrrhiza (L.) Schleid., and chromium (Cr) resistant bacterial strains. The bacterial strains were isolated from Cr-enriched environmental matrices and rhizosphere of Spirodela polyrrhiza. The phyto-rhizoremediation of tannery effluent by Spirodela and its rhizospheric bacteria (Cellulomonas biazotea APBR1-6, Bacillus safensis APBR2-12, Staphylococcus warneri APBR3-5, Microbacterium oleivorans APBR2-6), followed by microremediation by Cr resistant bacteria (Micrococcus luteus APBS5-1, Bacillus pumilus APBS5-2, Bacillus flexus APBE3-1, Virgibacillus sediminis APBS6-1) resulted in reduction of pollution parameters [COD (81.2%), total Cr (97.3%), Cr(VI) (99.3%), Pb(II) (97.0%), Ni (95.7%)]. The LC-MS analysis showed that many pollutants detected in untreated tannery effluent were diminished after bioremediation or long chains of alcohol polyethoxylates viz. C18EO6 in untreated effluent were broken down into smaller unit of alcohol polyethoxylate ((+)HHO[CH2CH2O]H), indicating that bacteria and Spirodela polyrrhiza, alongwith its rhizospheric associates utilized them as carbon and energy source.

Purification and Characterization of a Novel Redox-Regulated Isoform of Myrosinase (β-Thioglucoside Glucohydrolase) from Lepidium latifolium L.

Myrosinase (ExPASy entry EC 3.2.1.147) is involved in the hydrolysis of glucosinolates to isothiocyanates, nitriles, and thiocyanates that are responsible for various ecological and health benefits. Myrosinase was purified from the leaves of Lepidium latifolium, a high-altitude plant, to homogeneity in a three-step purification process. Purified enzyme exists as dimer in native form (∼160 kDa) with a subunit size of ∼70 kDa. The enzyme exhibited maximum activity at pH 6.0 and 50 °C. With sinigrin as substrate, the enzyme showed Km and Vmax values of 171 ± 23 μM and 0.302 μmol min(-1) mg(-1), respectively. The enzyme was found to be redox-regulated, with an increase in Vmax and Kcat in the presence of GSH. Reduced forms of the enzyme were found to be more active. This thiol-regulated kinetic behavior of myrosinase signifies enzymes strategy to fine-tune its activity in different redox environments, thus regulating its biological effects.

Dynamics of glucosinolate-myrosinase system during Plutella xylostella interaction to a novel host Lepidium latifolium L.

Plutella xylostella L. is a notorious pest of cruciferous crops causing worldwide losses of

2-D and In Silico Analysis of Some Putative Drought-Induced Differential Boiling Soluble Proteins (hydrophilins) of Triticum aestivum

4-5 billion per year. Developing classical biological control to this pest include an introduction of host plants that act as natural enemies showing deviation from the preference-performance regimen in the evolutionary ecology of plant-insect interactions. The present study was designed to understand the role of glucosinolate-myrosinase system during P. xylostella interactions with a novel host. Adult moth preference and larval performance study were conducted on a novel host Lepidium latifolium L. (LL) that has high sinigrin content and was compared with its laboratory host Arabidopsis thaliana (AT). The glucosinolate-myrosinase system was studied in a time course experiment during larval feeding in choice and no-choice experiments. Adult moths visit and prefers LL over AT for oviposition. Conversely, LL leaves were not preferred and proved detrimental for P. xylostella larvae. Aliphatic and indolic glucosinolates were found to decrease significantly (p≤0.05) in AT during initial 12h of P. xylostella challenge, whereas, they were not affected in LL. Also, MYB transcription factor expression and myrosinase activity in LL do not suggest a typical host response to a specialist insect. This preference-performance mismatch of P. xylostella on LL mediated by glucosinolate pattern suggests that this novel plant could be utilized in P. xylostella management.

Purification and partial characterization of a low temperature responsive Mn-SOD from tea (Camellia sinensis (L.) O. Kuntze).

The analysis of stress response in plants is an important route to the discovery of genetic elements conferring stress tolerance. Cereal seeds are model system to study desiccation tolerance due to their ability to survive extreme water loss during late embryogenesis. In an attempt to determine the adaptation strategy to drought stress, comparative proteome analysis of boiling-soluble proteins were conducted in wheat cultivar (cv.) having tolerance to drought stress. Evaluation of 2-dimensional electrophoresis gels revealed differential expression of many proteins in drought-tolerant cv. Five differentially expressed hydrophilic protein bands were further analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrophotometer. By bioinformatics approach, five differential drought-induced hydrophilic proteins were functionally annotated and identified. Based on results, it was argued that elucidating the function of hydrophilic proteins expressed by genes in stress-tolerant plants will not only advance our understanding of plant adaptation but also tolerance to environmental stresses. Based on hydrophilic proteins, which have been identified by proteomics and bioinformatics approach, the possible functions have been discussed.