Exogenous nitric oxide promotes salinity tolerance in plants: A meta-analysis.

Nitric oxide (NO) has received much attention since it can boost plant defense mechanisms, and plenty of studies have shown that exogenous NO improves salinity tolerance in plants. However, because of the wide range of experimental settings, it is difficult to assess the administration of optimal dosages, frequency, timing, and method of application and the overall favorable effects of NO on growth and yield improvements. Therefore, we conducted a meta-analysis to reveal the exact physiological and biochemical mechanisms and to understand the influence of plant-related or method-related factors on NO-mediated salt tolerance. Exogenous application of NO significantly influenced biomass accumulation, growth, and yield irrespective of salinity stress. According to this analysis, seed priming and foliar pre-treatment were the most effective methods of NO application to plants. Moreover, one-time and regular intervals of NO treatment were more beneficial for plant growth. The optimum concentration of NO ranges from 0.1 to 0.2 mM, and it alleviates salinity stress up to 150 mM NaCl. Furthermore, the beneficial effect of NO treatment was more pronounced as salinity stress was prolonged (>21 days). This meta-analysis showed that NO supplementation was significantly applicable at germination and seedling stages. Interestingly, exogenous NO treatment boosted plant growth most efficiently in dicots. This meta-analysis showed that exogenous NO alleviates salt-induced oxidative damage and improves plant growth and yield potential by regulating osmotic balance, mineral homeostasis, photosynthetic machinery, the metabolism of reactive oxygen species, and the antioxidant defense mechanism. Our analysis pointed out several research gaps, such as lipid metabolism regulation, reproductive stage performance, C4 plant responses, field-level yield impact, and economic profitability of farmers in response to exogenous NO, which need to be evaluated in the subsequent investigation.

Molecular pharmacology and therapeutic advances of the pentacyclic triterpene lupeol.

BACKGROUND: Plant triterpenoids are major sources of nutraceuticals that provide many health benefits to humans. Lupeol is one of the pentacyclic dietary triterpenoids commonly found in many fruits and vegetables, which is highly investigated for its pharmacological effect and benefit to human health. PURPOSE: This systematic review critically discussed the potential pharmacological benefits of lupeol and its derivatives as evidenced by various cellular and animal model studies. To gain insight into the pharmacological effects of lupeol, the network pharmacological approach is applied. Pharmacokinetics and recent developments in nanotechnology-based approaches to targeted delivery of lupeol along with its safety use are also discussed. METHODS: This study is dependent on the systematic and non-exhaustive literature survey for related research articles, papers, and books on the chemistry, pharmacological benefits, pharmacokinetics, and safety of lupeol published between 2011 and 2021. For online materials, the popular academic search engines viz. Google Scholar, PubMed, Science Direct, Scopus, ResearchGate, Springer, as well as official websites were explored with selected keywords. RESULTS: Lupeol has shown promising benefits in the management of cancer and many other human diseases such as diabetes, obesity, cardiovascular diseases, kidney and liver problems, skin diseases, and neurological disorders. The pharmacological effects of lupeol primarily rely on its capacity to revitalize the cellular antioxidant, anti-inflammatory and anti-apoptotic mechanisms. Network pharmacological approach revealed some prospective molecular targets and pathways and presented some significant information that could help explain the pharmacological effects of lupeol and its derivatives. Despite significant progress in molecular pharmacology, the clinical application of lupeol is limited due to poor bioavailability and insufficient knowledge on its mode of action. Structural modification and nanotechnology-guided targeted delivery of lupeol improve the bioavailability and bioactivity of lupeol. CONCLUSION: The pentacyclic triterpene lupeol possesses numerous human health-benefiting properties. This review updates current knowledge and critically discusses the pharmacological effects and potential applications of lupeol and its derivatives in human health and diseases. Future studies are needed to evaluate the efficacies of lupeol and its derivatives in the management and pathobiology of human diseases.

Black Cumin (Nigella sativa L.): A Comprehensive Review on Phytochemistry, Health Benefits, Molecular Pharmacology, and Safety.

Mounting evidence support the potential benefits of functional foods or nutraceuticals for human health and diseases. Black cumin (Nigella sativa L.), a highly valued nutraceutical herb with a wide array of health benefits, has attracted growing interest from health-conscious individuals, the scientific community, and pharmaceutical industries. The pleiotropic pharmacological effects of black cumin, and its main bioactive component thymoquinone (TQ), have been manifested by their ability to attenuate oxidative stress and inflammation, and to promote immunity, cell survival, and energy metabolism, which underlie diverse health benefits, including protection against metabolic, cardiovascular, digestive, hepatic, renal, respiratory, reproductive, and neurological disorders, cancer, and so on. Furthermore, black cumin acts as an antidote, mitigating various toxicities and drug-induced side effects. Despite significant advances in pharmacological benefits, this miracle herb and its active components are still far from their clinical application. This review begins with highlighting the research trends in black cumin and revisiting phytochemical profiles. Subsequently, pharmacological attributes and health benefits of black cumin and TQ are critically reviewed. We overview molecular pharmacology to gain insight into the underlying mechanism of health benefits. Issues related to pharmacokinetic herb-drug interactions, drug delivery, and safety are also addressed. Identifying knowledge gaps, our current effort will direct future research to advance potential applications of black cumin and TQ in health and diseases.

Repositioning Vitamin C as a Promising Option to Alleviate Complications associated with COVID-19.

Vitamin C, also known as L-ascorbic acid, is an essential vitamin with pleiotropic functions, ranging from antioxidant to anti-microbial functions. Evidence suggests that vitamin C acts against inflammation, oxidative stress, autophagy chaos, and immune dysfunction. The ability to activate and enhance the immune system makes this versatile vitamin a prospective therapeutic agent amid the current situation of coronavirus disease 2019 (COVID-19). Being highly effective against the influenza virus, causing the common cold, vitamin C may also function against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and its associated complications. Severe infections need higher doses of the vitamin to compensate for the augmented inflammatory response and metabolic demand that commonly occur during COVID-19. Compelling evidence also suggests that a high dose of vitamin C (1.5 g/kg body weight) in inflammatory conditions can result in effective clinical outcomes and thus can be employed to combat COVID-19. However, further studies are crucial to delineate the mechanism underlying the action of vitamin C against COVID-19. The current review aims to reposition vitamin C as an alternative approach for alleviating COVID-19-associated complications.

Neuroprotective Potentials of Marine Algae and Their Bioactive Metabolites: Pharmacological Insights and Therapeutic Advances.

Beyond their significant contribution to the dietary and industrial supplies, marine algae are considered to be a potential source of some unique metabolites with diverse health benefits. The pharmacological properties, such as antioxidant, anti-inflammatory, cholesterol homeostasis, protein clearance and anti-amyloidogenic potentials of algal metabolites endorse their protective efficacy against oxidative stress, neuroinflammation, mitochondrial dysfunction, and impaired proteostasis which are known to be implicated in the pathophysiology of neurodegenerative disorders and the associated complications after cerebral ischemia and brain injuries. As was evident in various preclinical studies, algal compounds conferred neuroprotection against a wide range of neurotoxic stressors, such as oxygen/glucose deprivation, hydrogen peroxide, glutamate, amyloid ß, or 1-methyl-4-phenylpyridinium (MPP+) and, therefore, hold therapeutic promise for brain disorders. While a significant number of algal compounds with promising neuroprotective capacity have been identified over the last decades, a few of them have had access to clinical trials. However, the recent approval of an algal oligosaccharide, sodium oligomannate, for the treatment of Alzheimer's disease enlightened the future of marine algae-based drug discovery. In this review, we briefly outline the pathophysiology of neurodegenerative diseases and brain injuries for identifying the targets of pharmacological intervention, and then review the literature on the neuroprotective potentials of algal compounds along with the underlying pharmacological mechanism, and present an appraisal on the recent therapeutic advances. We also propose a rational strategy to facilitate algal metabolites-based drug development.

Phytosterols of marine algae: Insights into the potential health benefits and molecular pharmacology.

BACKGROUND: Marine algae are rich in some unique biologically active secondary metabolites having diverse pharmacological benefits. Of these, sterols comprise a group of functional lipid compounds that have attracted much attention to natural product scientists. PURPOSE: This review was aimed to update information on the health effects of algae-derived phytosterols and their molecular interactions in various aspects of human health and diseases and to address some future perspectives that may open up a new dimension of pharmacological potentials of algal sterols. METHODS: A literature-based search was carried out to retrieve published research information on the potential health effects of algal phytosterols with their pharmacological mechanisms from accessible online databases, such as Pubmed, Google Scholar, Web of Science, and Scopus, using the key search terms of 'marine algae sterol' and 'health potentials such as antioxidant or anti-inflammatory or anti-Alzheimer's or anti-obesity or cholesterol homeostasis or hepatoprotective, antiproliferative, etc.' RESULTS: Phytosterols of marine algae, particularly fucosterol, have been investigated for a plethora of health benefits, including anti-diabetes, anti-obesity, anti-Alzheimer's, antiaging, anticancer, and hepatoprotection, among many others, which are attributed to their antioxidant, anti-inflammatory, immunomodulatory and cholesterol-lowering properties, indicating their potentiality as therapeutic leads. These sterols interact with enzymes and various other proteins that are actively participating in different cellular pathways, including antioxidant defense system, apoptosis and cell survival, metabolism, and homeostasis. CONCLUSION: In this review, we briefly overview the chemistry, pharmacokinetics, and distribution of algal sterols, and provide critical insights into their potential health effects and the underlying pharmacological mechanisms, beyond the well-known cholesterol-lowering paradigm.