Raj Kumar Salar

Studies on leaf spot disease of Withania somnifera and its impact on secondary metabolites

During an investigation of the disease profile of Withania somnifera, it was observed that leaf spot is the most prevalent disease. Repeated isolations from infected leaf tissues and pathogenicity tests showed the association of fungal pathogen identified as Alternaria alternata (Fr.) Keissler. Scanning electron microscopy showed various histological changes in the leaf tissues of infected plants. A decrease in total content of reducing sugars (20%) and chlorophyll (26.5%) was observed in diseased leaves whereas an increase was noticed in proline (25%), free amino acids (3%) and proteins (74.3%). High performance thin layer chromatography (HPTLC) analysis of secondary metabolites viz. withanolides, withaferin-A and total alkaloids of the diseased leaves vis-à-vis control revealed reduction in withaferin-A and withanolides contents by 15.4% and 76.3% respectively, in contrast to an increase in total alkaloids by 49.3%, information hitherto unreported in W. somnifera.

Modulation of phenolic content and antioxidant activity of maize by solid state fermentation with Thamnidium elegans CCF 1456

Thamnidium elegans CCF 1456, a filamentous fungus, was used to enhance the total phenolic content and radical scavenging activity of maize via solid-state fermentation. Thamnidium fermented maize (TFM) and unfermented maize (UFM) grains were extracted with 65% ethanol and dimethylsulfoxide (DMSO). Total phenolic content (TPC), and radical scavenging capacity — determined with 1,1-diphenyl-2-picrylhydrazyl (DPPH) and radical cations of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS·+) found for TFM — were significantly (P < 0.05) higher on the 5th day of incubation than that of UFM extracts. A linear correlation was observed among TPC, DPPH and ABTS scavenging activities, and also among TPC and various carbohydrate-cleaving enzymes (α-amylase, β-glucosidase and xylanase), suggesting that this? strategy may help to enrich? TFM with improved phytochemical properties and antioxidant activities.

Free radical scavenging activity, phenolic contents and phytochemical evaluation of different extracts of stem bark of Butea monosperma (Lam.) Kuntze

The antioxidant activity, phenolic contents and phytochemical profile of acetone, methanol, water and ethyl acetate extracts of the stem bark of B. monosperma were investigated. Extracts showed highest antioxidant activity at 100 μg ml−1 with application of different assays: 2′-2′ diphenyl–2′ picrylhydrazyl (DPPH) scavenging (83.5% and 78.1%), reducing power (1.85 and 1.78), deoxyribose degradation site-specific (65.5% and 61.5%) and non-site-specific (67.1% and 66.5%) and chelating power (63.4% and 58.9%) in decreasing and increasing polarity of acetone extracts, respectively. However, nitroblue tetrazolium (NBT) showed scavenging of O2• radicals by 56.4% and 53.1% in decreasing and increasing polarity methanol extracts, respectively. Similarly, electron paramagnetic resonance (EPR)/spin-trapping exhibited highest radical scavenging activity with acetone extracts (12.6 mg g−1 Trolox). The results pointed to the significant antioxidant activities in acetone and methanol extracts. In most cases, the extracts obtained through decreasing polarity showed higher antioxidant activity. The phenolic content exhibited a strong association (r 2>0.9) with antioxidant activity. These results suggest that bark of B. monosperma can be a potential source of natural antioxidants.

Optimization of tannase production by a novel Klebsiella pneumoniae KP715242 using central composite design

A novel tannase producing bacterial strain was isolated from rhizospheric soil of Acacia species and identified as Klebsiella pneumoniae KP715242. A 3.25-fold increase in tannase production was achieved upon optimization with central composite design using response surface methodology. Four variables namely pH, temperature, incubation period, and agitation speed were used to optimize significant correlation between the effects of these variables on tannase production. A second-order polynomial was fitted to data and validated by ANOVA. The results showed a complex relationship between variables and response given that all factors were significant and could explain 99.6% of the total variation. The maximum production was obtained at 5.2 pH, 34.97 °C temperature, 103.34 rpm agitation speed and 91.34 h of incubation time. The experimental values were in good agreement with the predicted ones and the models were highly significant with a correlation coefficient (R2) of 0.99 and a highly significant F-value of 319.37.

Leaf spot disease adversely affects human health promoting constituents and withanolide biosynthesis in Withania somnifera (L.) Dunal

The present work investigates the implication of leaf spot disease on the antioxidant potential and commercial value of pharmaceutically important constituents of Withania somnifera, a high‐valued medicinal plant.

Evaluation of Antioxidant Activity and Radical Scavenging Property of Ficus bengalensis L. Applying Various Spectroscopic and Spin-trapping Methods

Abstract The search for sources of new antioxidants of natural origin derived from plants is very important in the wake of decreasing resistance of human beings to various diseases. In the present study, antioxidant activity, phenolic contents and phytochemical profile of various extracts of Ficus bengalensis were investigated and discussed. Extracts (100 μg/ml) showed highest inhibitory potential with application of different methodologies: DPPH• scavenging (76.6 % and 67.6 %), deoxyribose degradation non-site-specific (67.4 % and 66.2 %), chelating power (56.5 % and 57.5 %) and NBT scavenging (55.4 % and 59.6 %) in decreasing and increasing polarity of methanol extracts, respectively. However, reducing power (1.72 and 1.28) and deoxyribose degradation site-specific (55.1 % and 57.7 %) assay exhibited their maximum activity in acetone extracts of increasing and decreasing solvent polarity, respectively. Similarly, EPR/spin-trapping exhibited 10.9 mg Trolox g-1 radical scavenging capacity with acetone extracts (increasing polarity). The differences in antioxidant activity of extracts are attributed to the presence of various phytochemicals. The IC50 values of different extracts were also calculated and presented in the results. This is perhaps the first report of potential utilization of prop roots of F. bengalensis as a source of natural antioxidants.

Fermented pearl millet (Pennisetum glaucum) with in vitro DNA damage protection activity, bioactive compounds and antioxidant potential

In the present study, pearl millet cultivar PUSA-415 was fermented by solid state fermentation (SSF) process using Aspergillus sojae (MTCC-8779) as starter culture. The fermentation was carried out for the period of ten days. The effect of SSF on phenolic content, condensed tannin content, antioxidant potential and DNA damage protection of pearl millet during different fermentation period was determined. Results showed that SSF and thermal processing significantly affect the bioactive profile and antioxidant potential of bio-transformed pearl millet. Extracts prepared from 6th days fermented pearl millet flour exhibited the highest TPC, antioxidant potential and DNA damage protection activity. Qualitative and quantitative analysis of bioactive compounds were done by HPLC. During SSF, production of enzymes (α-amylase, β-glucosidase and xylanase) as well as specific bioactive compounds (ascorbic acid, gallic acid and p-Coumaric acid) was significantly increased. Thus, bio-transformed Aspergillus sojae fermented pearl millet could be used in preparation of functional foods and novel nutraceuticals in health promotions. Chapatti was formulated from unfermented as well as fermented flour and the effect of thermal processing on bioactive compounds and antioxidant potential was studied. Thermal processing resulted in decrease in TPC of both, AFM and UFM by 4.75-16.27% and increase in CTC by 38.52-67.41%.

Control of Gene Expression by RNAi: A Revolution in Functional Genomics

RNA interference is an evolutionarily preserved gene-silencing phenomenon in eukaryotic organisms, which is triggered by double-stranded RNA (dsRNA) derived from viral replication intermediates or transposable elements or an introduced synthetic oligonucleotide. Dicer, an endonuclease, processes dsRNA into 21- to 23-base-pair (bp) small interfering RNA (siRNA) with 2-nucleotide 3′ overhangs, which are further linked with the RNA-induced silencing complex (RISC). Argonaute, an active (AGO)-family protein of RISC remove the sense strand of siRNA, guided by the antisense strand, mediates the destruction of cognate target RNA with exquisite potency and selectivity. RNAi is employed to downregulate the activity of a gene with hereditability, and other significant advantages have revolutionized functional genomics to discover genes involved in disease progression and validate gene function, holding promise for the expansion of new therapeutics to treat several diseases. RNAi has enormous exciting applications in plant biotechnology, generating new hopes to produce flowers with desired colors, and to enhance crop yield and shelf life, while in humans it is used to treat various forms of cancer, infectious diseases, and neurodegenerative disorders, though the stability, off-target activity, and in vivo delivery of small interfering RNAs remain significant obstacles. This chapter reviews the mechanism of RNA interference, its applications, and challenges encountered while using this technology for research purposes.

Chitosan Nanoparticles as Carrier for Anticancer Drugs: An Overview

Cancer is the leading cause of death worldwide. Chemotherapy and radiotherapy have been used to treat cancer; however, these methods have serious side effects. Nanomedicine has emerged as a hope for cancer patients in the recent past. Various nanomedical carriers such as liposomal nanoparticles, polymeric nanoparticles, etc. have been developed to carry anticancer drugs to target site. Among these, polymeric nanoparticles have been used extensively due to their unique properties. Of various natural and synthetic polymers, chitosan is most suitable as a carrier of anticancer drugs. It is a natural polymer obtained from deacetylation of chitin. Researchers have worked on the anticancer drug encapsulation in chitosan nanoparticles and its targeted drug delivery. Chitosan nanoparticles are safe and biodegradable and can release drugs at controlled rates to the target site. Chitosan nanoparticles can be synthesized by various methods such as ionic gelation method, emulsion polymerization method, etc. Although research is going on worldwide, more research is needed in the area of anticancer drug encapsulation in chitosan nanoparticles and its delivery to target sites.

Synthesis, characterization and anticancer activity of vincristine loaded folic acid-chitosan conjugated nanoparticles on NCI-H460 non-small cell lung cancer cell line

Abstract Vincristine is used to treat different type of cancers. But unwanted side effects limit their applications in medicine. To overcome these side effects by targeted drug delivery approach, we synthesized vincristine loaded folic acid-chitosan conjugated nanoparticles by ionic gelation method. The nanoparticles were characterized using Dynamic Light Scattering (DLS), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy. DLS confirmed small sized nanoparticles (<200 nm) while FTIR confirmed different functional groups associated with synthesized nanoparticles. SEM showed spherical shaped nanoparticles with smooth surface, whereas, TEM confirmed loading of vincristine in folic acid-chitosan conjugated nanoparticles. Anticancer activity of vincristine loaded folic acid-chitosan conjugated nanoparticles was checked by MTT assay on NCI-H460 cells followed by reactive oxygen species level, mitochondrial transmembrane potential and apoptotic morphological changes, which confirmed the cytotoxicity of nanoparticles. Erythrocyte aggregation assay confirmed non-toxicity of nanoparticles. Hence, these nanoparticles can be used to treat NCI-H460 cells.