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The development of resistance, instability and high doses are some drawbacks of biologically active natural products. Modification of natural compounds to make it broad spectrum is the standard approach in drug design. This paper sets to modify the naringenin by silver nanoparticle conjugation to enhance its already reported pharmacological activities. The naringenin-nano silver conjugate was synthesized by one-step green synthesis, that is, sunlight exposure confirmed by UV spectroscopy. The biosynthesized naringenin-nanosilver conjugate was tested for antiacanthamoebal and antimicrobial potential. The antibacterial potential was increased by 5.8-6.14 fold against Gram positive bacteria, that is, S. aureus and Bacillus subtilis and 4.5-13.6 fold against Gram negative bacteria, that is, Escherichia coli and Pseudomonas aeruginosa. The standard naringenin-nanosilver conjugate significantly reduced the LC50 values against the Acanthamoeba cells, by, 66% and 36%, as compared to substrate naringin and standard naringenin respectively while biotransformed naringinin-nanosilver conjugate reduced LC50 by 50.56%, compared with biotransformed naringenin. Hence modification of natural product as nanoconjugate is the best practice for improvement as an effective drug.

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Purpose of Review: Worldwide occurring Moringa plant is commonly famous as a fruit vegetable, known as drumstick or shevga all over India. The miraculous nutritional potential of the drumstick plant was already proved by worldwide research. But in the common population, it is unknown for the nutritional potential of its leaves. The majority of the population is known it only as a fruit vegetable. The Moringa leaves contain almost all essential nutrients, growth factors, vitamins, amino acids, proteins, minerals, and metals like potassium, iron, and zinc. Besides these, nowadays, plant leaves may be used to prepare various nutritional supplements and medicine. Recent Findings: Besides this, this review takes into account some joint efforts of NASI, Allahabad-funded project to use these Moringa leaves for different formulations and its popularization efforts for malnutrition eradication in tribal, i.e., development of recipes of Moringa leaves that will not only make easy preparations but also help to make habitual use of Moringa leaves today. Summary: This review describes the morphology, occurrence, and distribution of Moringa sp., chemical constitutions of Moringa leaves, its potential as anticancer, antidiabetes, and antimicrobial agent and as a nutritional supplement and the commercial future of various products.

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This study aims to explore the fermentative production and physicochemical properties of an exopolysaccharide (EPS) produced from agricultural isolate, Bacillus subtilis S1 in submerged culture. The structural characterization (Ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, and 13 C Nuclear magnetic resonance spectrometry) revealed that the EPS is an acidic heteropolymer consisting of glucose, glucuronic acid, pyruvic acid, and succinic acid. The non-Newtonian shear thickening nature of EPS with a 1.55 × 107  Da molecular weight is confirmed by rheology analysis. The extracted EPS was 61.3% amorphous with partial crystallinity (38.7%) as confirmed by X-ray diffraction analysis. The EPS shows two-step decomposition and thermal stability up to 300 °C as confirmed by thermogravimetric analysis and differential scanning calorimetry analysis. The EPS has a small Z-average particle size (74.29 nm), high porosity (92.99%), high water holding (92.39%), and absorption capacity (1,198%). The biocompatible nature is confirmed by cytotoxic testing on the human keratinocytes cell line. The demonstrated unique characteristics of Bacillus EPS presents it as a choice of biomaterial for diverse applications.

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Naringinase has high industrial importance, and the progress in naringinase research is still quite slow. The unavailability of an effective, simple screening method, which will be applicable to different microorganisms such as bacteria, fungi, and actinomycetes, is one of the main reasons for this gap. Therefore, a simple plate assay was developed for effective screening of microorganisms for naringinase by exposing to iodine vapors. This plate assay will fill the technological void for simple screening method and will lead to screen more potent industrially important naringinase-producing microorganisms.

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Currently, the heavy metal pollution is of grave concern, and the part of microorganism for metal bioremediation should take into account as an efficient and economic strategy. On this framework, the heavy metal stress consequences on exopolysaccharide (EPS)-producing agricultural isolate, Pantoea agglomerans, were studied. The EPS production is a protective response to stress to survive and grow in the metal-contaminated environment. P. agglomerans show tolerance and mucoid growth in the presence of heavy metals, i.e., mercury, copper, silver, arsenic, lead, chromium, and cadmium. EDX first confirmed the metal accumulation and further, FTIR determined the functional groups involved in metal binding. The ICP-AES identified the location of cell-bound and intracellular metal accumulation. Metal deposition on cell surface has released more Ca2+. The effect on bacterial morphology investigated with SEM and TEM revealed the sites of metal accumulation, as well as possible structural changes. Each heavy metal caused distinct change and accumulated on cell-bound EPS with some intracellular deposits. The metal stress caused a decrease in total protein content and increased in total carbohydrate with a boost in EPS. Thus, the performance of P. agglomerans under metal stress indicated a potential candidate for metal bioremediation. Graphical Abstract ᅟ.

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The development of a safe and eco-friendly method for metal nanoparticle synthesis has an increasing demand, due to emerging environmental and biological harms of hazardous chemicals used in existing nanosynthesis methods. The present investigation reports a rapid one-step, eco-friendly and green approach for the formation of nanosized silver particles (AgNPs) using extracellular non-toxic-colored fungal metabolites (Monascus pigments-MPs). The formation of nanosized silver particles utilizing Monascus pigments was confirmed after exposure of reaction mixture to sunlight, by visually color change and further established by spectrophotometric analysis. The size, shape, and topography of synthesized MPs-AgNPs were well-defined using different microscopic and spectroscopic techniques, i.e., FE-SEM, HR-TEM, and DLS. The average size of MPs-AgNPs was found to be 10-40 nm with a spherical shape which was highly stable and dispersed in the solution. HR-TEM and XRD confirmed crystalline nature of MPs-AgNPs. The biocidal potential of MPs-AgNPs was evaluated against three bacterial pathogens such as Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus and it was observed that the MPs-AgNPs significantly inhibited the growth of all three bacterial pathogens. The anti-biofilm activity of MPs-AgNPs was recorded against antibiotic-resistant P. aeruginosa. Besides, the colorimetric metal sensing using MPs-AgNPs was studied. Among the metals tested, the selective Hg2+-sensing potential at micromolar concentration was observed. In conclusion, this is the rapid one-step (within 12-15 min), environment-friendly method for synthesis of AgNPs and synthesized MPs-AgNPs could be used as a potential antibacterial agent against antibiotic-resistant bacterial pathogens.

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Metals as a resource are depleting, and on another side, it fetches serious environmental pollution causing a threat to human health and ecosystem. The heavy metal accumulation due to anthropogenic activities results in toxicological manifestation. The traditional methods of remediation are not cost effective, efficient, and ecofriendly which necessitate and motivate towards the safe, effective, and ecofriendly biological methods. The increasing presence of heavy metals in the microbial habitat compels the microbes to develop the ability to tolerate or resist the presence of heavy metals. Exopolysaccharide (EPS) production is one of the strategies of microbes to fight against metal stress. EPS is a microbial biopolymer which is generally produced under stress from harsh environment and nutrition conditions. EPSs are cell-associated or secreted outside the cell and comprised organic macromolecules such as polysaccharides, proteins, and phospholipids in addition to some non-polymeric molecules. EPSs work as competent biosorbents with an anionic reactant group that effectively sequesters cationic heavy metals by electrostatic interactions. The present paper summarizes the EPSs with its types, role, and biosynthesis and an endeavor to elucidate the interaction mechanism of EPSs with heavy metal with supportive and distinctive applications for heavy metal exclusion. The review concluded with the current challenges and future prospects to make the EPS an efficient biosorbent.

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The problem of chemically synthesized nanoproducts motivated scientific community to explore ecofriendly methods of nanosynthesis. Diatoms belong to a group of aquatic, unicellular, photosynthetic microalgae have been scarcely investigated as a source of reducing and capping agents for nanosynthesis of pesticides and antibiotics. The present study reports a novel ecofriendly method for the fabrication of bioactive gold nanoparticles using locally isolated Nitzschia diatoms. The diatom-fabricated gold nanoparticles show characteristic ruby red colored with sharp absorbance peak at 529 nm. Electron microscopy confirmed irregular shape of gold nanoparticles, with average size of 43 nm and zeta potential of -16.8 mV. The effects of gold nanoparticles on diatom viability were investigated using light and electron microscopy. The mechanistic approach to shed light on how diatoms reacted after exposure to gold metal salt revealed that exposure to gold chloride triggers elevated levels of catalase and peroxidase (12.76 and 14.43 unit/mg protein, respectively) to relieve reactive oxygen species (ROS) stress induced by gold salt exposure. Investigation studies on mechanisms behind Nitzschia-mediated gold nanoparticles fabrication outlined the role of diatom proteins, polysaccharides in reduction, and stabilization of nanoparticles as confirmed by FT-IR analysis. Bioactivity of gold nanoparticles was accessed by coupling them with antibiotics (penicillin and streptomycin), which increased their antibacterial activity compared to individual nanoparticles and antibiotics (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus). Overall, the present novel phyco-nanotechnological approach is a promising tool to be used as sustainable strategy in green nanotechnology as well as to reduce use of antibiotics in microbial control.

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PURPOSE: Bacterial cellulose (BC) is an interesting biomaterial found application in various fields due to its novel characteristics like purity, water holding capacity, degree of polymerization and mechanical strength. BC as wound dressing material has limitation because it has no antimicrobial activity. To circumvent this problem, the present study was carried out by impregnation of silver on bacterial cellulose surface. METHODS: Bacterial cellulose was produced by Gluconoacetobacter hansenii (strain NCIM 2529) by shaking culture method. The sodium borohydride and classical Tollens reaction was used for silver nanoparticle synthesis. RESULTS: The effectiveness of sodium borohydride method compared with Tollens reaction was evaluated on the basis of silver nanoparticle formation and its impregnation on BC as evidenced by UV-Vis spectrum analysis, FE-SEM-EDS analysis and FT-IR spectrum. The potential of nano silver impregnated BC was determined for sustained release antimicrobial wound dressing material by swelling ratio, mechanical properties and antimicrobial activity against Staphylococcus aureus. CONCLUSIONS: Thus the nanosilver impregnated bacterial cellulose as promising antimicrobial wound dressing material was evidenced.

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