In the present study, zinc oxide nanoparticles (ZnO NPs) were synthesized using leaf extract of Catharanthus roseus (C. roseus) under different physical parameters. Biosynthesis of ZnO NPs was confirmed by UV-Visible spectrophotometer and further, characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray spectroscopy (EDX), Atomic Force Microscopy (AFM), Photoluminescence study and Dynamic Light Scattering (DLS). We have also confirmed that several physical parameters such as pH, temperature, concentration of metal ions and reaction time were able to regulate shape and size of synthesized ZnO NPs. XRD and TEM analysis provided the information about the average size and hexagonal morphology of ZnO NPs. FTIR spectra analysis suggested that phenolic compounds played crucial role in the biosynthesis of ZnO NPs. The significant antibacterial activity of ZnO NPs was observed against Staphylococcus aureus MTCC 9760 (S. aureus), Streptococcus pyogenes MTCC 1926 (S. pyogenes), Bacillus cereus MTCC 430 (B. cereus), Pseudomonas aeruginosa MTCC 424 (P. aeruginosa), Proteus mirabilis MTCC 3310 (P. mirabilis) and Escherichia coli MTCC 40 (E. coli). The synthesized ZnO NPs have shown antibacterial efficacy against both Gram-positive and Gram-negative pathogens. Synergistic effects of ZnO NPs and streptomycin showed increased efficacy as indicated by the increased zone of clearance in comparison to their individual effects (either ZnO NPs or streptomycin). Overall, the results elucidated a rapid, cost-effective, environmentally friendly and convenient method for ZnO NPs synthesis, which could be used as a potential antimicrobial agent against drug resistant microbes.
Objective: This study was performed to identify the phytochemicals and comparatively evaluate the antioxidant activity of Calotropis procera and Azadirachta indica by detection of total phenolics, hydrogen peroxide radical scavenging activity, and estimation of condensed tannins in different solvent systems and at different temperatures.Methods: Leaves of C. procera and A. indica were extracted in water, methanol by soaking dried leaf powder at room temperature and also by boiling the leaf powder in water for 30 minutes. Phytochemical tests were performed in all of the extracts. The antioxidant activity was determined by hydrogen peroxide radical scavenging activity. Quantitative estimation of total phenolics and hydrolysable tannins was also performed.
Results:The total phenolics in both leaf extracts was obtained maximum in boiled extract (40.7±1.20 mg gallic acid equivalent [GAE]/g dry extract in C. procera and 33.66±1.45 mg GAE/g dry extract in A. indica). The amount of hydrolysable tannins in both leaf extracts was found to be highest in methanol (150±1.88 mg catechin equivalent/g dry extract in C. procera and 144.8±2.63 mg catechin equivalent/g dry extract in A. indica).
Conclusion:The study showed promising results indicating that these plants are a good source of antioxidants. The majority of phytochemicals were extracted in distilled water and methanol acts as a good solvent for extraction of tannins, whereas an increase in temperature leads to poor extraction of tannins.
Present study was conducted to analyze bacterial contaminants /pathogens in Khoa samples sold in Chambal region of Madhya Pradesh. Total Fifty samples of Khoa were brought from different localities of Chambal region at random and processed. Bacterial colony counts were also performed. Staphylococcus species and Streptococcus species were the predominant isolates. The viable counts obtained ranged from 1.3X10 4 to 2.1X10 6 CFU/g. Contamination of Khoa by pathogenic bacteria could be an important factor of gastrointestinal infections including food poisoning and food borne illness. Adequate consumer protection can be achieved by measuring the microbiological data of product.
The quality of food is highly affected by different types of biological, chemical, and physical contaminants. Microbial contaminations that are transferred through direct or indirect pathways such as through saliva, pest droppings, blood, or fecal matter affect the quality of food worldwide. Food can be spoiled by bacteria as well as fungus. The fungal microbes secrete toxins to intoxicate the food material rendering it unfit for consumption. The objective of the present review is to explore the application of essential oil (EO) as potent antifungal agent and thus good sources of food preservative. We have reviewed previously published papers on antimicrobial activity of EOs. The antimicrobial activity of these natural plant products has been assayed by different approaches. Apart from their activity against microbes, the other beneficial effects of these plant products such as antioxidant activity and enhancing the food quality are also observed by various groups of scientists all over the globe. On the basis of results obtained by different researchers worldwide, the EOs can be authenticated as a food preservative. For the preservation of food, several chemicals are being used by different food industries at large scale; however, they have some limitations. Recently much attention has been directed toward the development of less or negligibly toxic ethno-products which may be utilized for human use for several purposes such as food preservatives, in cosmetics, and medicines. The plant-based volatile EOs and non-volatile secondary metabolites have wide applications in dietary supplements, food flavoring and preservation, folk medicine, and fragrance industry. Several reports have confirmed the antioxidant efficacy of plant-based EOs in vitro and in vivo. Application of plant materials as dietary supplements and preservatives is mainly due to their antioxidant, antimicrobial, and other biological as well as pharmaceutical potentials. Nowadays, EOs and their components are gaining increased attention because of their relatively safe status, their wide acceptance by consumers and the possibility of their exploitation for potential multipurpose uses. It will be relevant to extract EOs, since these extracted oils may have antimicrobial potential which can be utilized for their possible roles against food spoilage microbes.
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