Jayanta Kumar Patra

Endophytes: A Treasure House of Bioactive Compounds of Medicinal Importance

Endophytes are an endosymbiotic group of microorganisms that colonize in plants and microbes that can be readily isolated from any microbial or plant growth medium. They act as reservoirs of novel bioactive secondary metabolites, such as alkaloids, phenolic acids, quinones, steroids, saponins, tannins, and terpenoids that serve as a potential candidate for antimicrobial, anti-insect, anticancer and many more properties. While plant sources are being extensively explored for new chemical entities for therapeutic purposes, endophytic microbes also constitute an important source for drug discovery. This review aims to comprehend the contribution and uses of endophytes as an impending source of drugs against various forms of diseases and other possible medicinal use.

Antibacterial Activity and Synergistic Antibacterial Potential of Biosynthesized Silver Nanoparticles against Foodborne Pathogenic Bacteria along with its Anticandidal and Antioxidant Effects

Silver nanoparticles plays a vital role in the development of new antimicrobial substances against a number of pathogenic microorganisms. These nanoparticles due to their smaller size could be very effective as they can improve the antibacterial activity through lysis of bacterial cell wall. Green synthesis of metal nanoparticles using various plants and plant products has recently been successfully accomplished. However, few studies have investigated the use of industrial waste materials in nanoparticle synthesis. In the present investigation, synthesis of silver nanoparticles (AgNPs) was attempted using the aqueous extract of corn leaf waste of Zea mays, which is a waste material from the corn industry. The synthesized AgNPs were evaluated for their antibacterial activity against foodborne pathogenic bacteria (Bacillus cereus ATCC 13061, Listeria monocytogenes ATCC 19115, Staphylococcus aureus ATCC 49444, Escherichia coli ATCC 43890, and Salmonella Typhimurium ATCC 43174) along with the study of its synergistic antibacterial activity. The anticandidal activity of AgNPs were evaluated against Candida species (C. albicans KACC 30003 and KACC 30062, C. glabrata KBNO6P00368, C. geochares KACC 30061, and C. saitoana KACC 41238), together with the antioxidant potential. The biosynthesized AgNPs were characterized by UV-Vis spectrophotometry with surface plasmon resonance at 450 nm followed by the analysis using scanning electron microscope, X-ray diffraction, Fourier-transform infrared spectroscopy and thermogravimetric analysis. The AgNPs displayed moderate antibacterial activity (9.26–11.57 mm inhibition zone) against all five foodborne pathogenic bacteria. When AgNPs were mixed with standard antibacterial or anticandidal agent, they displayed strong synergistic antibacterial (10.62–12.80 mm inhibition zones) and anticandidal activity (11.43–14.33 mm inhibition zones). In addition, the AgNPs exhibited strong antioxidant potential. The overall results highlighted the potential use of maize industrial waste materials in the synthesis of AgNPs and their utilization in various applications particularly as antibacterial substance in food packaging, food preservation to protect against various dreadful foodborne pathogenic bacteria together with its biomedical, pharmaceutical based activities.

Novel green synthesis of gold nanoparticles using Citrullus lanatus rind and investigation of proteasome inhibitory activity, antibacterial, and antioxidant potential

Biological synthesis of nanoparticles using nontoxic, eco-friendly approaches is gaining importance owing to their fascinating biocompatibility and environmentally benign nature. This study describes the green synthesis approach for synthesis of gold nanoparticles (ANPs) using aqueous extract of the rind of watermelon as a fruit waste and evaluate its biopotential in terms of proteasome inhibitory activity, antibacterial, and antioxidant potential. The synthesized ANPs were characterized using UV–vis spectroscopy, scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The surface plasmon resonance spectra of ANPs were obtained at 560 nm. Scanning electron microscopy image revealed that particles had a spherical shape and have a size distribution of 20–140 nm, followed by the elemental analysis by energy-dispersive X-ray spectroscopy. X-ray diffraction analysis confirmed the crystallite nature of the ANPs and Fourier-transform infrared spectroscopy revealed the involvement of bioactive compounds from watermelon rind in the synthesis, capping, and stabilization of ANPs. ANPs exhibited potential antibacterial activity against five different foodborne pathogenic bacteria with diameter of inhibition zones ranged between 9.23 and 11.58 mm. They also displayed strong synergistic antibacterial activity together with kanamycin (11.93–21.08 mm inhibition zones) and rifampicin (10.32–24.84 mm inhibition zones). ANPs displayed strong antioxidant activity in terms of DPPH radical scavenging (24.69%), nitric oxide scavenging (25.62%), ABTS scavenging (29.42%), and reducing power. Significantly high proteasome inhibitory potential of the ANPs (28.16%) could be highly useful for cancer treatment and targeted cancer drug delivery. Overall, results highlight a potential low-cost green method of synthesizing ANPs from food waste materials. Significant biopotentials of synthesized ANPs could make it a potential candidate for its application in the biomedical, pharmaceutical, cosmetics, and food sectors.

Photo-mediated green synthesis of silver and zinc oxide nanoparticles using aqueous extracts of two mangrove plant species, Heritiera fomes and Sonneratia apetala and investigation of their biomedical applications.

Green synthesis by using biological agents has been a simple and effective approach for the synthesis of various forms of nanoparticles. The present investigation was intended to synthesis Ag-NPs and ZnO-NPs under photo-condition using the aqueous extracts of two mangrove plants namely Heritiera fomes and Sonneratia apetala and evaluate their potential biomedical applications. The formation of nanoparticles in aqueous solution of H. fomes and S. apetala under exposure to sun light was validated by change in color and formation of monodispersed NPs with a narrow particle size distribution. Fourier transform infrared spectroscopy (FT-IR) reveals the presence of Oxime and other heterocyclic compounds to be the most probable compounds responsible for the reduction and stability of nanoparticles in the solutions. The synthesized NPs displayed moderate free radical scavenging properties. The anti-inflammatory potential of ZnO-NPs was recorded to be comparatively higher than that of Ag-NP with 79% and 69.1% respectively. The Ag-NPs with unique properties of inhibiting α-amylase (91.14% and 89.16%) were found to be significantly high indicating its antidiabetic property. The synthesized NPs showed varied zone of inhibition (9-16mm) against the tested microbial pathogens. The synthesized nanoparticles possess strong biological activities in terms of antioxidant, anti-inflammatory, antidiabetic and antibacterial, potentials which could be utilized in various biological applications by the cosmetic, food and biomedical industries.

Phyto-mediated biosynthesis of silver nanoparticles using the rind extract of watermelon (Citrullus lanatus) under photo-catalyzed condition and investigation of its antibacterial, anticandidal and antioxidant efficacy

The biological synthesis of nanoparticles has gained tremendous interest, and plants and plant extracts are preferred over other biological sources for this process because of their rich content of bioactive metabolites. In this study, silver nanoparticles (AgNPs) were produced utilizing the aqueous extract of watermelon rind (WRA), an agricultural waste material under photo exposed condition at room temperature, and tested for their antibacterial, anticandidal and antioxidant activities. The synthesized AgNPs showed surface plasmon resonance at 425nm with an average size of 109.97nm. The morphology and elemental composition was confirmed by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric and differential thermogravimetric analysis (TG/DTG) confirmed that the bioactive compounds from the WRA extract were involved in the synthesis and capping of AgNPs. X-ray diffraction (XRD) revealed the crystallite nature of the AgNPs. The AgNPs exhibited strong broad spectrum antibacterial activity against five different foodborne bacteria with zones of inhibition 9.12-14.54mm in diameter. When AgNPs were mixed with kanamycin and rifampicin the mixture exhibited strong antibacterial synergistic activity. The AgNPs also exerted strong synergistic anticandidal activity when they were combined with amphotericin b. The AgNPs had high antioxidant activity and reducing power. Overall, the results confirmed the bio-potentials of the synthesized AgNPs using WRA, which could have applications in the biomedical, cosmetic, pharmaceutical, food preservation and packaging industries.

Kimchi and Other Widely Consumed Traditional Fermented Foods of Korea: A Review

Different types of fermented foods such as chongkukjang, doenjang, ganjang, gochujang, and kimchi are plentifully available and widely consumed in north eastern Asian countries including Korea. Among them, kimchi is one of the most popular Korean traditional food. It is prepared by fermenting the baechu cabbage together with other vegetables and lactic acid bacteria (LAB) with functional potential. Many types of ingredients are added to kimchi to enhance its taste, flavor, nutritional value, texture etc. A number of bacteria are involved in the fermentation of kimchi, but LAB are the dominant species in the fermentation process. The addition of other sub ingredients and formation of different by-products during fermentation eventually leads to eradication of putrefactive and pathogenic bacteria, and also increase the functionalities, nutritional and nutraceutical potential of kimchi. Kimchi possesses anti-inflammatory, antibacterial, antioxidant, anticancer, antiobesity, probiotic properties, cholesterol reduction, and antiaging properties. In the present review an attempt has been made to review the different types of fermented foods found in the Korean peninsula with detailed scientific research regarding preparation, processing, structure of the microecosystem, and health benefits of kimchi.

Green nanobiotechnology: factors affecting synthesis and characterization techniques

Nanobiotechnology is gaining tremendous impetus in this era owing to its ability to modulate metals into their nanosize, which efficiently changes their chemical, physical, and optical properties. Accordingly, considerable attention is being given to the development of novel strategies for the synthesis of different kinds of nanoparticles of specific composition and size using biological sources. However, most of the currently available techniques are expensive, environmentally harmful, and inefficient with respect to materials and energy use. Several factors such as the method used for synthesis, pH, temperature, pressure, time, particle size, pore size, environment, and proximity greatly influence the quality and quantity of the synthesized nanoparticles and their characterization and applications. Additionally, characterization of the synthesized nanoparticles is essential to their potential use in various drug delivery and biomedical applications.The present review highlights various parameters affecting the synthesis of nanoparticles by green nanobiotechnology and different techniques used for characterizing the nanoparticles for their potential use in biomedical and environmental applications.

Revitalization of plant growth promoting rhizobacteria for sustainable development in agriculture

The progression of life in all forms is not only dependent on agricultural and food security but also on the soil characteristics. The dynamic nature of soil is a direct manifestation of soil microbes, bio-mineralization, and synergistic co-evolution with plants. With the increase in worlds population the demand for agriculture yield has increased tremendously and thereby leading to large scale production of chemical fertilizers. Since the use of fertilizers and pesticides in the agricultural fields have caused degradation of soil quality and fertility, thus the expansion of agricultural land with fertile soil is near impossible, hence researchers and scientists have sifted their attention for a safer and productive means of agricultural practices. Plant growth promoting rhizobacteria (PGPR) has been functioning as a co-evolution between plants and microbes showing antagonistic and synergistic interactions with microorganisms and the soil. Microbial revitalization using plant growth promoters had been achieved through direct and indirect approaches like bio-fertilization, invigorating root growth, rhizoremediation, disease resistance etc. Although, there are a wide variety of PGPR and its allies, their role and usages for sustainable agriculture remains controversial and restricted. There is also variability in the performance of PGPR that may be due to various environmental factors that might affect their growth and proliferation in the plants. These gaps and limitations can be addressed through use of modern approaches and techniques such as nano-encapsulation and micro-encapsulation along with exploring multidisciplinary research that combines applications in biotechnology, nanotechnology, agro biotechnology, chemical engineering and material science and bringing together different ecological and functional biological approaches to provide new formulations and opportunities with immense potential.

Antibacterial Activity and Action Mechanism of the Essential Oil from Enteromorpha linza L. against Foodborne Pathogenic Bacteria

Foodborne illness and disease caused by foodborne pathogenic bacteria is continuing to increase day by day and it has become an important topic of concern among various food industries. Many types of synthetic antibacterial agents have been used in food processing and food preservation; however, they are not safe and have resulted in various health-related issues. Therefore, in the present study, essential oil from an edible seaweed, Enteromorpha linza (AEO), was evaluated for its antibacterial activity against foodborne pathogens, along with the mechanism of its antibacterial action. AEO at 25 mg/disc was highly active against Bacillus cereus (12.3–12.7 mm inhibition zone) and Staphylococcus aureus (12.7–13.3 mm inhibition zone). The minimum inhibitory concentration and minimum bactericidal concentration values of AEO ranged from 12.5–25 mg/mL. Further investigation of the mechanism of action of AEO revealed its strong impairing effect on the viability of bacterial cells and membrane permeability, as indicated by a significant increase in leakage of 260 nm absorbing materials and K+ ions from the cell membrane and loss of high salt tolerance. Taken together, these data suggest that AEO has the potential for use as an effective antibacterial agent that functions by impairing cell membrane permeability via morphological alternations, resulting in cellular lysis and cell death.

Chemical Composition and Antioxidant and Antibacterial Activities of an Essential Oil Extracted from an Edible Seaweed, Laminaria japonica L.

Laminaria japonica L. is among the most commonly consumed seaweeds in northeast Asia. In the present study, L. japonica essential oil (LJEO) was extracted by microwave-hydrodistillation and analyzed by gas chromatography and mass spectroscopy. LJEO contained 21 volatile compounds, comprising 99.76% of the total volume of the essential oil, primarily tetradeconoic acid (51.75%), hexadecanoic acid (16.57%), (9Z,12Z)-9,12-Octadecadienoic acid (12.09%), and (9Z)-hexadec-9-enoic acid (9.25%). Evaluation of the antibacterial potential against three foodborne pathogens, Bacillus cereus ATCC 10876, Escherichia coli O157:H7 ATCC 43890, and Staphylococcus aureus ATCC 49444, revealed that LJEO at a concentration of 25 mg/paper disc exerted high antibacterial activity against S. aureus (11.5 ± 0.58 mm inhibition zone) and B. cereus (10.5 ± 0.57 mm inhibition zone), but no inhibition of E. coli O157:H7. LJEO also displayed DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical scavenging activity (80.45%), superoxide anion scavenging activity (54.03%), and ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical and hydroxyl radical scavenging at 500 µg/mL. Finally, LJEO showed high inhibition of lipid peroxidation with strong reducing power. In conclusion, LJEO from edible seaweed is an inexpensive but favorable resource with strong antibacterial capacity as well as free radical scavenging and antioxidant activity; therefore, it has the potential for use in the food, cosmetics, and pharmaceutical industries.