Flavonoids, a group of natural substances with variable phenolic structures, are found in fruits, vegetables, grains, bark, roots, stems, flowers, tea and wine. These natural products are well known for their beneficial effects on health and efforts are being made to isolate the ingredients so called flavonoids. Flavonoids are now considered as an indispensable component in a variety of nutraceutical, pharmaceutical, medicinal and cosmetic applications. This is attributed to their anti-oxidative, anti-inflammatory, anti-mutagenic and anti-carcinogenic properties coupled with their capacity to modulate key cellular enzyme function. Research on flavonoids received an added impulse with the discovery of the low cardiovascular mortality rate and also prevention of CHD. Information on the working mechanisms of flavonoids is still not understood properly. However, it has widely been known for centuries that derivatives of plant origin possess a broad spectrum of biological activity. Current trends of research and development activities on flavonoids relate to isolation, identification, characterisation and functions of flavonoids and finally their applications on health benefits. Molecular docking and knowledge of bioinformatics are also being used to predict potential applications and manufacturing by industry. In the present review, attempts have been made to discuss the current trends of research and development on flavonoids, working mechanisms of flavonoids, flavonoid functions and applications, prediction of flavonoids as potential drugs in preventing chronic diseases and future research directions.

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Flavonoids: an overview

An outbreak of a novel coronavirus (COVID-19 or 2019-CoV) infection has posed significant threats to international health and the economy. In the absence of treatment for this virus, there is an urgent need to find alternative methods to control the spread of disease. Here, we have conducted an online search for all treatment options related to coronavirus infections as well as some RNA-virus infection and we have found that general treatments, coronavirus-specific treatments, and antiviral treatments should be useful in fighting COVID-19. We suggest that the nutritional status of each infected patient should be evaluated before the administration of general treatments and the current children's RNA-virus vaccines including influenza vaccine should be immunized for uninfected people and health care workers. In addition, convalescent plasma should be given to COVID-19 patients if it is available. In conclusion, we suggest that all the potential interventions be implemented to control the emerging COVID-19 if the infection is uncontrollable.

https://www.onlinelibrary.wiley.com/doi/epdf/10.1002/jmv.25707

Potential Interventions for Novel Coronavirus in China: A Systematic Review

Chlorogenic acid (CGA): A pharmacological review and call for further research.

Aging is the progressive loss of organ and tissue function over time. Growing older is positively linked to cognitive and biological degeneration such as physical frailty, psychological impairment, and cognitive decline. Oxidative stress is considered as an imbalance between pro- and antioxidant species, which results in molecular and cellular damage. Oxidative stress plays a crucial role in the development of age-related diseases. Emerging research evidence has suggested that antioxidant can control the autoxidation by interrupting the propagation of free radicals or by inhibiting the formation of free radicals and subsequently reduce oxidative stress, improve immune function, and increase healthy longevity. Indeed, oxidation damage is highly dependent on the inherited or acquired defects in enzymes involved in the redox-mediated signaling pathways. Therefore, the role of molecules with antioxidant activity that promote healthy aging and counteract oxidative stress is worth to discuss further. Of particular interest in this article, we highlighted the molecular mechanisms of antioxidants involved in the prevention of age-related diseases. Taken together, a better understanding of the role of antioxidants involved in redox modulation of inflammation would provide a useful approach for potential interventions, and subsequently promoting healthy longevity.

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Antioxidant and Oxidative Stress: A Mutual Interplay in Age-Related Diseases

Eight selected wild vegetables from Nepal (Alternanthera sessilis, Basella alba, Cassia tora, Digera muricata, Ipomoea aquatica, Leucas cephalotes, Portulaca oleracea and Solanum nigrum) were investigated for their antioxidative potential using 2,2-dyphenyl-1-picrylhydrazyl (DPPH) scavenging, hydrogen peroxide (H2O2), ferric reducing antioxidant power (FRAP), and ferric thiocyanate (FTC) methods. Among the selected plant extracts C. tora displayed the highest DPPH radical scavenging activity with an IC50 value 9.898 μg/mL, whereas A. sessilis had the maximum H2O2 scavenging activity with an IC50 value 16.25 μg/mL—very close to that of ascorbic acid (16.26 μg/mL). C. tora showed the highest absorbance in the FRAP assay and the lowest lipid peroxidation in the FTC assay. A methanol extract of A. sessilis resulted in the greatest phenolic content (292.65 ± 0.42 mg gallic acid equivalent (GAE)/g) measured by the Folin–Ciocalteu reagent method, while the smallest content was recorded for B. alba (72.66 ± 0.46 GAE/g). The greatest flavonoid content was observed with extracts of P. oleracea (39.38 ± 0.57 mg quercetin equivalents (QE)/g) as measured by an aluminium chloride colorimetric method, while the least was recorded for I. aquatica (6.61 ± 0.42 QE/g). There was a strong correlation between antioxidant activity with total phenolic (DPPH, R2 = 0.75; H2O2, R2 = 0.71) and total flavonoid content (DPPH, R2 = 0.84; H2O2, R2 = 0.66). This study demonstrates that these wild edible leafy plants could be a potential source of natural antioxidants.

Total Phenolic Content, Flavonoid Content and Antioxidant Potential of Wild Vegetables from Western Nepal.

The microbiome actually deals with micro-organisms that are associated with indigenous body parts and the entire gut system in all animals, including human beings. These microbes are linked with roles involving hereditary traits, defence against diseases and strengthening overall immunity, which determines the health status of an organism. Considerable efforts have been made to find out the microbiome diversity and their taxonomic identification in finfish and shellfish and its importance has been correlated with various physiological functions and activities. In recent past due to the availability of advanced molecular tools, some efforts have also been made on DNA sequencing of these microbes to understand the environmental impact and other stress factors on their genomic structural profile. There are reports on the use of next-generation sequencing (NGS) technology, including amplicon and shot-gun approaches, and associated bioinformatics tools to count and classify commensal microbiome at the species level. The microbiome present in the whole body, particularly in the gut systems of finfish and shellfish, not only contributes to digestion but also has an impact on nutrition, growth, reproduction, immune system and vulnerability of the host fish to diseases. Therefore, the study of such microbial communities is highly relevant for the development of new and innovative bio-products which will be a vital source to build bio and pharmaceutical industries, including aquaculture. In recent years, attempts have been made to discover the chemical ingredients present in these microbes in the form of biomolecules/bioactive compounds with their functions and usefulness for various health benefits, particularly for the treatment of different types of disorders in animals. Therefore, it has been speculated that microbiomes hold great promise not only as a cure for ailments but also as a preventive measure for the number of infectious diseases. This kind of exploration of new breeds of microbes with their miraculous ingredients will definitely help to accelerate the development of the drugs, pharmaceutical and other biological related industries. Probiotic research and bioinformatics skills will further escalate these opportunities in the sector. In the present review, efforts have been made to collect comprehensive information on the finfish and shellfish microbiome, their diversity and functional properties, relationship with diseases, health status, data on species-specific metagenomics, probiotic research and bioinformatics skills. Further, emphasis has also been made to carry out microbiome research on priority basis not only to keep healthy environment of the fish farming sector but also for the sustainable growth of biological related industries, including aquaculture.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/jpn.13619

Aquaculture industry prospective from gut microbiome of fish and shellfish: An overview.

Natural products derived from plants play a vital role in the discovery of new drug candidates, and these are used for novel therapeutic drug development Andrographis paniculata and Spilanthes paniculata are used extensively as medicinal herbs for the treatment of various ailments, and are reported to have neuroprotective properties β-amyloid is a microscopic brain protein whose significant aggregation is detected in mild cognitive impairment and Alzheimer’s disease (AD) brains The accumulation of β-amyloid disrupts cell communication and triggers inflammation by activating immune cells, leading to neuronal cell death and cognitive disabilities The proteases acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and beta secretase-1 (BACE-1) have been reported to be correlated with the synthesis and growth of β-amyloid plaques in the brains of AD patients In the present study, the phenolic compounds from A paniculata and S paniculata that have been reported in the literature were selected for the current investigation Furthermore, we employed molecular docking and molecular dynamics studies of the phenolic compounds with the proteins AChE, BChE, and BACE-1 in order to evaluate the binding characteristics and identify potent anti-amyloid agents against the neurodegenerative diseases such as AD In this investigation, we predicted three compounds from A paniculata with maximum binding affinities with cholinesterases and BACE-1 The computational investigations predicted that these compounds follow the rule of five We further evaluated these molecules for in vitro inhibition activity against all the enzymes In the in vitro investigations, 3,4-di-o-caffeoylquinic acid (5281780), apigenin (5280443), and 7-o-methylwogonin (188316) were found to be strong inhibitors of AChE, BChE, and BACE-1 These findings suggest that these compounds can be potent multi-target inhibitors of the proteases that might cumulatively work and inhibit the initiation and formation of β-amyloid plaques, which is a prime cause of neurotoxicity and dementia According to our knowledge, these findings are the first report on natural compounds isolated from A paniculata as multi-target potent inhibitors and anti-amyloid agents

https://www.mdpi.com/2223-7747/8/7/231/pdf

Multi-Target β-Protease Inhibitors from Andrographis paniculata: In Silico and In Vitro Studies

Number of attempts has been made to cryopreserve fish and shellfish gametes and success has been achieved to establish only sperm banks in case of some commercially important fish. In shellfish also particularly in shrimps though the sperm cryopreservation was successful, no attempts were made to develop sperm banks. As far as cryobanking of egg and embryos of fish and shellfish is concerned, less research efforts were made that too with limited success. Number of reasons has been given for the failure of egg /embryo cryopreservation and the main barriers speculated are low membrane permeability in the eggs, and the large yolk mass of the oocyte and the presence of compartments in early developing embryos. Both these factors result in ice crystal formation during the freezing process. In addition, the oocytes and embryos are prone to chilling injuries unrelated to ice crystal damage. There are number of other problems reported by several workers in the egg/embryo cryobanking protocols which are elaborately discussed in the present paper. There is an urgent need to develop a viable cryobanking technology for fish egg/embryos to enhance fish production in captive condition. Attempt to cryopreserve larvae of aquatic animals is another challenge coming up in recent past. The purpose of the present review is to collect comprehensive information on the efforts so far made on fish and shellfish egg and embryo cryobanking, assess the challenges in the development of viable technology and plan for future research for making this technology viable and cost effective.

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Cryobanking of Fish and Shellfish Egg, Embryos and Larvae: An Overview

In recent past several efforts have been made to analyze the symptoms, causes, and cure of Alzheimer’s disease (AD) and also to reveal biochemical changes and pathogenesis of the brain affected with AD. Several studies indicated the main cause of the disease is deposition of necrotic β-amyloid plaques in the brain. The enzymes β-secretase and γ-secretase catalyze the β-amyloid production. It has also been observed that the cells producing acetylcholine, a major neurotransmitter, are destroyed by two closely related enzymes namely acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in AD progression leading to cognitive disabilities. Hence, the research is going on in finding the inhibitors for these enzymes which will help to either prolong or cure the AD. Discovering the inhibitors for AChE and BChE without side effects remains a major challenge as the AChE and BChE inhibiting drugs available possess several side effects. Several new drugs are being discovered utilizing medicinal plant resources. Uses of flavonoids as plant secondary metabolites are being tried for the treatment of AD. Efforts are being made to apply computational knowledge to streamline the drug discovery process. Nevertheless, blood-brain barrier (BBB) permeation plays a vital role in drug discovery. BBB a physical barrier in the brain through which the central nervous system therapeutic molecule has to permeate for its activity. Finding the potent lead candidates capable of crossing the BBB remains to be a major challenge in neurodegenerative diseases. In the present review, attempts have been made to discuss on all these important aspects. Keywords: Alzheimer’s disease, Amyloid precursor protein, β-amyloid, Blood-brain barrier, Flavonoids, Molecular docking, Multi-enzyme targeting.

A. D. Diwan

Papers

Flavonoids: an overview

Aquaculture industry prospective from gut microbiome of fish and shellfish: An overview.

Multi-Target β-Protease Inhibitors from Andrographis paniculata: In Silico and In Vitro Studies

Cryobanking of Fish and Shellfish Egg, Embryos and Larvae: An Overview

Alzheimer’s and current therapeutics: a review