School Of Basic And Applied Sciences

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    Microorganisms: A potential source of bioactive molecules for antioxidant applications
    (MDPI AG, 2021-02-22T00:00:00) Rani, Alka; Saini, Khem Chand; Bast, Felix; Mehariya, Sanjeet; Bhatia, Shashi Kant; Lavecchia, Roberto; Zuorro, Antonio
    Oxidative stress originates from an elevated intracellular level of free oxygen radicals that cause lipid peroxidation, protein denaturation, DNA hydroxylation, and apoptosis, ultimately impairing cell viability. Antioxidants scavenge free radicals and reduce oxidative stress, which further helps to prevent cellular damage. Medicinal plants, fruits, and spices are the primary sources of antioxidants from time immemorial. In contrast to plants, microorganisms can be used as a source of antioxidants with the advantage of fast growth under controlled conditions. Further, microbe-based antioxidants are nontoxic, noncarcinogenic, and biodegradable as compared to synthetic antioxidants. The present review aims to summarize the current state of the research on the antioxidant activity of microorganisms including actinomycetes, bacteria, fungi, protozoa, microalgae, and yeast, which produce a variety of antioxidant compounds, i.e., carotenoids, polyphenols, vitamins, and sterol, etc. Special emphasis is given to the mechanisms and signaling pathways followed by antioxidants to scavenge Reactive Oxygen Species (ROS), especially for those antioxidant compounds that have been scarcely investigated so far. � 2021 by the authors. Licensee MDPI, Basel, Switzerland.
  • Item
    Microorganisms: A potential source of bioactive molecules for antioxidant applications
    (MDPI AG, 2021-02-22T00:00:00) Rani, Alka; Saini, Khem Chand; Bast, Felix; Mehariya, Sanjeet; Bhatia, Shashi Kant; Lavecchia, Roberto; Zuorro, Antonio
    Oxidative stress originates from an elevated intracellular level of free oxygen radicals that cause lipid peroxidation, protein denaturation, DNA hydroxylation, and apoptosis, ultimately impairing cell viability. Antioxidants scavenge free radicals and reduce oxidative stress, which further helps to prevent cellular damage. Medicinal plants, fruits, and spices are the primary sources of antioxidants from time immemorial. In contrast to plants, microorganisms can be used as a source of antioxidants with the advantage of fast growth under controlled conditions. Further, microbe-based antioxidants are nontoxic, noncarcinogenic, and biodegradable as compared to synthetic antioxidants. The present review aims to summarize the current state of the research on the antioxidant activity of microorganisms including actinomycetes, bacteria, fungi, protozoa, microalgae, and yeast, which produce a variety of antioxidant compounds, i.e., carotenoids, polyphenols, vitamins, and sterol, etc. Special emphasis is given to the mechanisms and signaling pathways followed by antioxidants to scavenge Reactive Oxygen Species (ROS), especially for those antioxidant compounds that have been scarcely investigated so far. � 2021 by the authors. Licensee MDPI, Basel, Switzerland.
  • Item
    Overview of extraction of astaxanthin from Haematococcus pluvialis using CO2 supercritical fluid extraction technology vis-a-vis quality demands
    (Elsevier, 2021-04-19T00:00:00) Saini, Khem Chand; Yadav, Digvijay Singh; Mehariya, Sanjeet; Rathore, Parikshita; Kumar, Bikash; Marino, Tiziana; Leone, Gian Paolo; Verma, Pradeep; Musmarra, Dino; Molino, Antonio
    Microalgae biomass have been used as a source of nutrient-rich food, feed, and health-promoting compounds. Among the several commercially available microalgae, Haematococcus pluvialis is the most abundant source of natural astaxanthin (3, 3'-dihydroxy-?, ?-carotene-4, 4'-dione), which is considered as �super antioxidant.� Therefore natural astaxanthin produced by H. pluvialis has a higher antioxidant capacity than the synthetic sources, which reduces oxidative stress and free radicals and helps the human body to maintain a healthy state. However, H. pluvialis contains astaxanthin inside the cells, which need to be extracted using nontoxic extraction technologies for different application. Among the different available extraction technologies, supercritical fluid extraction (SFE) is a modern technology with increasing applications in pharmaceutical and nutraceutical sector. The most frequently employed supercritical solvent in food and natural product processing is carbon dioxide (CO2) due to its low critical temperature and pressure while considered as nontoxic extraction solvent. Therefore, nowadays, supercritical carbon dioxide (SC-CO2) is considered as a new substitute for complete extraction of natural compounds from different matrices. However, the extraction efficiency and purity of astaxanthin in the extract are influenced by different operative conditions such as the extraction pressure, temperature, time, and use of cosolvent. Hence the optimum operative condition of SC-CO2 extraction could enhance the extraction yields of astaxanthin and of its purity the extract. Therefore present chapter summarizes the effects of several extraction parameters on SC-CO2 extraction of astaxanthin from H. pluvialis, which could serve as benchmark for future development of SC-CO2 extraction technology and its commercial implementation in pharmaceutical and nutraceutical sector. � 2021 Elsevier Inc.