Environmental arsenic exposure and its contribution to human diseases, toxicity mechanism and management.

Dietary polyphenols including phenolic acids, flavonoids, catechins, tannins, lignans, stilbenes, and anthocyanidins are widely found in grains, cereals, pulses, vegetables, spices, fruits, chocolates, and beverages like fruit juices, tea, coffee and wine. In recent years, dietary polyphenols have gained significant interest among researchers due to their potential chemopreventive/protective functions in the maintenance of human health and diseases. It is believed that dietary polyphenols/flavonoids exert powerful antioxidant action for protection against reactive oxygen species (ROS)/cellular oxidative stress (OS) towards the prevention of OS-related pathological conditions or diseases. Pre-clinical and clinical evidence strongly suggest that long term consumption of diets rich in polyphenols offer protection against the development of various chronic diseases such as neurodegenerative diseases, cardiovascular diseases (CVDs), cancer, diabetes, inflammatory disorders and infectious illness. Increased intake of foods containing polyphenols (for example, quercetin, epigallocatechin-3-gallate, resveratrol, cyanidin etc.) has been claimed to reduce the extent of a majority of chronic oxidative cellular damage, DNA damage, tissue inflammations, viral/bacterial infections, and neurodegenerative diseases. It has been suggested that the antioxidant activity of dietary polyphenols plays a pivotal role in the prevention of OS-induced human diseases. In this narrative review, the biological/pharmacological significance of dietary polyphenols in the prevention of and/or protection against OS-induced major human diseases such as cancers, neurodegenerative diseases, CVDs, diabetes mellitus, cancer, inflammatory disorders and infectious diseases have been delineated. This review specifically focuses a current understanding on the dietary sources of polyphenols and their protective effects including mechanisms of action against various major human diseases.

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Dietary Polyphenols and Their Role in Oxidative Stress-Induced Human Diseases: Insights Into Protective Effects, Antioxidant Potentials and Mechanism(s) of Action

Rational nanostructure manipulation has been used to prepare nanocomposites in which multiwalled carbon nanotubes (MWCNTs) were embedded inside mesoporous layers of oxides (TiO(2), ZrO(2), or CeO(2)), which in turn contained dispersed metal nanoparticles (Pd or Pt). We show that the MWCNTs induce the crystallization of the oxide layer at room temperature and that the mesoporous oxide shell allows the particles to be accessible for catalytic reactions. In contrast to samples prepared in the absence of MWCNTs, both the activity and the stability of core-shell catalysts is largely enhanced, resulting in nanocomposites with remarkable performance for the water-gas-shift reaction, photocatalytic reforming of methanol, and Suzuki coupling. The modular approach shown here demonstrates that high-performance catalytic materials can be obtained through the precise organization of nanoscale building blocks.

Document Multiwalled carbon nanotubes drive the activity of Metal@Oxide core-shell catalysts in modular nanocomposites

A review on biomass and wind as renewable energy for sustainable environment

Recent advances on botanical biosynthesis of nanoparticles for catalytic, water treatment and agricultural applications: A review.

The heavy metal contamination, which causes toxic effects on plants, has evolved into a significant constraint to plant quality and yield. This scenario has been exacerbated by booming population expansion and intrinsic food insecurity. Numerous studies have found that counteracting heavy metal tolerance and accumulation necessitates complex mechanisms at the biochemical, molecular, tissue, cellular and whole plant levels, which may demonstrate increased crop yields. Essential and non-essential elements have similar harmful impacts on plants including reduced biomass production, growth and photosynthesis inhibition, chlorosis, altered fluid balance and nutrient absorption, as well as senescence, all of which led to plant death. Notable biotechnological strategies for effective remediation require knowledge of metal stress and tolerance mechanisms in plants. Assimilation, cooperation and integration, of biotechnological improvements, are required for adequate environmental rehabilitation in the emerging area of bioremediation. This review emphasizes a deeper understanding of metal toxicity, stress, and potential tolerance mechanisms in plants exposed to metal stress. The microbe-mediated metal toxic effects and stress mitigation knowledge can be used to create a new strategic plan as feasible, sustainable, and environmentally friendly bioremediation techniques. 

Metal tolerance mechanisms in plants and microbe-mediated bioremediation.

This research was designed to evaluate the fine quality of silver nanoparticles (AgNPs) fabricating proficiency of aqueous leaf extract of Aristolochia bracteolata and evaluate their larvicidal potential against I-IV th instar larvae and pupa of Culex quinquefasciatus. Within 24 h, the A. bracteolata aqueous leaf extract significantly reduced the AgNO 3 and yielded AgNPs. It was initially confirmed by a visible color change from pale yellow to dark reddish brown in reaction mix and under UV–vis spectrum analysis the absorbance peak related to AgNPs was found at 430 nm. The nature of the phyto-synthesized AgNPs was characterized by standard analytical techniques such as Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Energy Dispersive X-Ray analyses (EDX). The A. bracteolata synthesized AgNPs were predominantly spherical in shape and size ranging from 29.30 to 46.32 nm. The percentage of Ag elemental composition was found as 57.61 % using EDX analysis. The A. bracteolata yielded AgNPs showed significant larvicidal and pupicidal efficiency on youngster (I-IV th instar larvae and pupa) of Culex quinquefasciatus mosquito vector. These results conclude that the aqueous leaf extract of A. bracteolata can produce biologically active AgNPs. • The A. bracteolate aqueous leaf extract has the potential to synthesize AgNPs. • The AgNPs ranged in size from 29.30 to 46.32 nm and were spherical in shape. • First report on the larvicidal activities of A. bracteolata -derived AgNPs. • C. quinquefasciatus youngsters (I-IV & Pupa) were all sensitive to this AgNPs. • A small amount of this AgNPs is enough to kill C. quinquefasciatus juveniles. 

Phyto-fabrication of Silver nanoparticle using leaf extracts of Aristolochia bracteolata Lam and their mosquito larvicidal potential

Pyrite biomining proficiency of sulfur dioxygenase (SDO) enzyme extracted from Acidithiobacillus thiooxidans

The primary goal of this research was to evaluate the phytochemicals, including bioactive components of Ocimum americanum extracts and assess their larvicidal potential against 3rd and 4th instar larvae of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus. The aqueous extraction process on O. americanum provides higher yield (9.61 ± 0.11%) and a significant volume of phytochemicals (tannins, saponins, terpenoids, flavonoids, alkaloids, protein, and carbohydrate) than other solvents (methanol, ethanol, acetone, petroleum ether, and chloroform) extracts. Fourier-transform infrared spectroscopy and high-performance liquid chromatography analyses revealed about eight predominant phytochemicals/functional groups in O. americanum aqueous extract. Surprisingly, in gas chromatography–mass spectrometry analysis, about 30 bioactive components were found in the aqueous extract of O. americanum, the majority of which had previously been identified as medicinally valuable bioactive components. Furthermore, these bioactive components containing aqueous extract demonstrated significant larvicidal activity against 3rd and 4th instar larvae of A. aegypti, An. stephensi, and C. quinquefasciatus after 24 h of treatment at concentrations ranging from 35 to 50 mg mL−1. Thus, their outstanding larvicidal potential on 3rd and 4th instar larvae, the phytochemicals present in the aqueous extract of O. americanum could be used to control mosquito duplication and vector-borne diseases.

Mathiyazhagan Narayanan

Papers

Metal tolerance mechanisms in plants and microbe-mediated bioremediation.

Phyto-fabrication of Silver nanoparticle using leaf extracts of Aristolochia bracteolata Lam and their mosquito larvicidal potential

Pyrite biomining proficiency of sulfur dioxygenase (SDO) enzyme extracted from Acidithiobacillus thiooxidans

Phytochemical profile and larvicidal activity of aqueous extract of Ocimum americanum against mosquito vectors

Evaluation of probiotic susceptibility of virulent Aeromonas sp. by a study on gut histology of Cyprinus carpio