Scientific Evaluation of the Remedies Used in Turkish Folk Medicine to Treat Possible Viral Infections

Background: Plants, with their rich phytochemical treasury, are one of the main sources of drug development. However, a randomized search on plant sources for the discovery of phyto-chemicals with specified pharmacological activity is expensive and tedious. Therefore, it is logical to constrain the sources to increase success. In the recent four decades, the importance of traditional information has been recognized by the scientific community. Consequently, interest in field sur-veys for the documentation of traditional worldwide medicines has significantly increased. Method(s): Infectious diseases induced by pathogenic bacteria, fungi, or viruses have been one of the most common health problems for the public, for which traditional remedies have been practiced. Since laypeople could not distinguish the microbial origin of the infection, the remedies used for treatment could not be delineated. The aim of this study was first to search the plants used in Turkish folk medicine for such infectious diseases. The second step was to find scientific evidence in the online databases for the frequently quoted plants whether they may have potential activity against virus replication. Result(s): A reference survey on the most frequently quoted plants revealed that 16 out of 17 were shown to possess virucide or inhibitory effects on the replication of various viruses. Conclusion(s): Since each virus type may have a different viral replication pattern, further detailed in-vestigations should be carried out to reveal their exact antiviral potentials.Copyright © 2023 Bentham Science Publishers.

Toxicity of the disinfectant benzalkonium chloride (C14) towards cyanobacterium Microcystis results from its impact on the photosynthetic apparatus and cell metabolism

Quaternary ammonium compounds (QACs) are commonly used in a variety of consumer and commercial products, typically as a component of disinfectants. During the COVID-19 pandemic, QACs became one of the primary agents utilized to inactivate the SARS-CoV-2 virus on surfaces. However, the ecotoxicological effects of QACs upon aquatic organisms have not been fully assessed. In this study, we examined the effects of a widely used QAC (benzalkonium chloride-C14, BAC-14) on two toxigenic Microcystis strains and one non-toxigenic freshwater Microcystis strain and carried out an analysis focused on primary, adaptive and compensatory stress responses at apical (growth and photosynthesis) and metabolic levels. This analysis revealed that the two toxic Microcystis strains were more tolerant than the non-toxic strain, with 96 hr-EC50 values of 0.70, 0.76, and 0.38 mg/L BAC-14 for toxigenic M. aeruginosa FACHB-905, toxigenic M. aeruginosa FACHB-469, and non-toxigenic M. wesenbergii FACHB-908, respectively. The photosynthetic activities of the Microcystis, assessed via Fv/Fm values, were significantly suppressed under 0.4 mg/L BAC-14. Furthermore, this analysis revealed that BAC-14 altered 14, 12, and 8 metabolic pathways in M. aeruginosa FACHB-905, M. aeruginosa FACHB-469, and M. wesenbergii FACHB-908, respectively. It is noteworthy that BAC-14 enhanced the level of extracellular microcystin production in the toxigenic Microcystis strains, although cell growth was not significantly affected. Collectively, these data show that BAC-14 disrupted the physiological and metabolic status of Microcystis cells and stimulated the production and release of microcystin, which could result in damage to aquatic systems. © 2022

Interactive adverse effects of low-density polyethylene microplastics on marine microalga Chaetoceros calcitrans.

Low-density polyethylene (LDPE) is broadly utilized worldwide, increasing more dramatically during the COVID-19 pandemic, and the majority ends up in the aquatic environment as microplastics. The influence of polyethylene microplastics (LDPE-MPs) on aquatic ecosystems still needs further investigation, especially on microalgae as typical organisms represented in all aquatic systems and at the base of the trophic chain. Thereby, the biological and toxicity impacts of LDPE-MPs on Chaetoceros calcitrans were examined in this work. The results revealed that LDPE-MPs had a concentration-dependent adverse effect on the growth and performance of C. calcitrans. LDPE-MPs contributed the maximum inhibition rates of 85%, 51.3%, 21.49% and 16.13% on algal growth chlorophyll content, φPSII and Fv/Fm, respectively. The total protein content, superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities were significantly increased at 25 mg L-1 LDPE-MPs by 1.37, 3.52, 2.75 and 1.84 folds higher than those of the controls to sustain the adverse effects of LDPE-MPs. Extracellular polymeric substance (EPS) and monosaccharides contents of C. calcitrans were improved under low concentration of LDPE-MPs, which could facilitate the adsorption of MPs particles on the microalgae cell wall. This adsorption caused significant physical damage to the algal cell structure, as observed by SEM. These results suggest that the ecological footprint of MPs may require more attention, particularly due to the continuing breakdown of plastics in the ecosystem.

Medical oxygen a vital in Covid 19 pandemic: production techniques from natural to man-made

Oxygen is the most important source for the survival of all living organisms. Our daily activities require energy and it comes from the food we consume when the oxygen present in our blood burns that food. The deficiency of oxygen disturbs the entire functioning of organs in the body. Around 50-80% of the natural oxygen production on Earth comes from the ocean. The oxygen production from ocean is the result of drifting plants, algae, and some bacteria that can photosynthesize. Oxygen has many applications like chemical processing, medical application, and many more. Different types of methods are available to produce oxygen at a considerable scale, e.g., cryogenic, pressure swing, electrochemical. In this article, we discuss the stepwise process of various methods to produce oxygen and the challenges associated with details. © 2022 National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.

LsNRL4 enhances photosynthesis and decreases leaf angles in lettuce.

Lettuce (Lactuca sativa) is one of the most important vegetables worldwide and an ideal plant for producing protein drugs. Both well-functioning chloroplasts that perform robust photosynthesis and small leaf angles that enable dense planting are essential for high yields. In this study, we used an F2 population derived from a cross between a lettuce cultivar with pale-green leaves and large leaf angles to a cultivar with dark-green leaves and small leaf angles to clone LsNRL4, which encodes an NPH3/RPT2-Like (NRL) protein. Unlike other NRL proteins in lettuce, the LsNRL4 lacks the BTB domain. Knockout mutants engineered using CRISPR/Cas9 and transgenic lines overexpressing LsNRL4 verified that LsNRL4 contributes to chloroplast development, photosynthesis and leaf angle. The LsNRL4 gene was not present in the parent with pale-green leaves and enlarged leaf angles. Loss of LsNRL4 results in the enlargement of chloroplasts, decreases in the amount of cellular space allocated to chloroplasts and defects in secondary cell wall biosynthesis in lamina joints. Overexpressing LsNRL4 significantly improved photosynthesis and decreased leaf angles. Indeed, the plant architecture of the overexpressing lines is ideal for dense planting. In summary, we identified a novel NRL gene that enhances photosynthesis and influences plant architecture. Our study provides new approaches for the breeding of lettuce that can be grown in dense planting in the open field or in modern plant factories. LsNRL4 homologues may also be used in other crops to increase photosynthesis and improve plant architecture.

Becoming with Wheat

Rooted in a series of images and texts, these artists pages present fragments of Becoming with Wheat: Photosynthesis/Respiration Collaborations, daily collaborative performances presented on Instagram during the first Covid-19 UK national lockdown in June and July 2020.

Shining light on ZnIn2S4 photocatalysts: Promotional effects of surface and heterostructure engineering toward artificial photosynthesis

The gradual depletion of fossil fuel reserves that contribute to ~85% of global energy production and release of toxic effluents urges the transformation toward renewable fuels. Thus, the sustainable utilization of sunlight for water splitting and CO2 reduction with heterogeneous photocatalysts has come to light. As a semiconductor photocatalyst, ZnIn2S4 has hit the limelight owing to its narrow bandgap and visible‐light‐responsive properties. However, the limitations of ZnIn2S4 include limited active sites, fast charge‐carrier recombination, and low photoconversion efficiency. Beginning from the fundamental photocatalytic mechanism, this review then provides in‐depth insights into several modification strategies of ZnIn2S4, extending from defect engineering, facet engineering, cocatalyst loading to junction engineering, enabling the synergistic construction of high‐performance ZnIn2S4‐based systems. Subsequently, the structure‐performance relation of ZnIn2S4‐based photocatalysts for hydrogen evolution (HER), overall water splitting (OWS), and CO2 reduction applications in the last 4 years will be discussed and concluded by the future perspectives of this frontier.

Microclimate control to increase productivity and nutritional quality of leafy vegetables in a cost-effective manner

Food security is one of the key global challenges in this century. In Singapore, our research team has been using novel aeroponic technology to produce fresh vegetables since 1997. Aeroponic systems allow for year-round production of not only tropical, but also sub-tropical and temperate fresh vegetables, by simply cooling the roots suspended in aeroponic systems while the aerial parts grow under tropical ambient environments. It has also been used to investigate the impacts of root-zone CO2 on vegetables by enriching root-zone CO2 while their aerial portions were subjected to constant atmospheric CO2. To compensate for the lack of available land, Singapore also needs to develop a farming system that can increase productivity per unit land area by many-fold. Over the past 10 years, my research team has established a commercially viable LED integrated vertical aeroponic farming system to grow different leafy vegetables under different LED spectra, intensities, and durations in the tropical greenhouse. The results demonstrate that it is possible to increase shoot production and rate of shoot production of leafy vegetables by increasing light intensity and extending the photoperiod under effective LED lighting. Furthermore, temperate vegetable crops such as lettuce were able to acclimate to high light intensity under supplementary LED lights to natural sunlight in the greenhouse. Supplementary LED lightings promote both leaf initiation and expansion with increased photo synthetic pigments, higher Cyt b6f and Rubisco protein contents on a per area basis and thus improve photosynthetic capacity and enhance productivity. Plants sense and respond to changes in their immediate environments (microclimate), manipulating the root zone temperature (RZT) and water supply will impact not only their growth and development but also their nutritional quality. Our on-going research aims to investigate if the nutritional quality of leafy vegetables could be improved under suboptimal RZT and mild water deficit through deficit irrigation. If substantial energy and water savings in urban farming can be achieved without substantial yield penalty but with higher nutritional quality, the amount of water and energy saved can bring substantial benefits to society.

Characterization of selected parameters of Chlorella vulgaris microalgae after short-term exposure to gold nanoparticles with different surface properties

Enhanced production and exploitation of gold nanoparticles (AuNPs), among others in lateral flow assays for the diagnosis of SARS-CoV-2 infection, motivate for extensive studies on their environmental and biological safety. Therefore, the impact of three types of AuNPs on Chlorella vulgaris was studied after short-term exposure. The AuNPs were prepared using sodium borohydride (SB), cysteamine hydrochloride (CH) and trisodium citrate (TC). Microscopic imaging revealed that the AuNPs were characterized by quasi-spherical shape and an average size within the range 9-12nm. CHSBAuNPs were positively charged whereas TCAuNPs and SBAuNPs were negatively charged. The results of studies showed that the exposure to each type of AuNPs led to the dose-dependent decrease of growth rate of C. vulgaris biomass. The swelling of the cells was observed especially at concentration of 5mgL-1. For all treatments, significant changes in efficiency of the photosystem II were detected. Each type of AuNPs applied in concentration of 1mgL-1 caused an increase and in concentration of 5mgL-1 a decrease of photosynthetic pigments content. Based on recorded Raman spectra, it was found that the cell chemical composition was disturbed radically after the treatment with SBAuNPs and CHSBAuNPs. It was established that the changes in the morphology and physiology of C. vulgaris cells, as a result of the exposure on the AuNPs, were strongly dependent on the surface properties of AuNPs. Nevertheless, it was impossible to indicate the most harmful type of AuNPs. Obtained findings did not confirm that the stabilization of AuNPs by molecules of well-documented toxicity lead to the increase of their toxic effects. It was not confirmed that positively charged CHSBAuNPs, stabilized by cysteamine, were more harmful for C. vulgaris than negatively charged TCAuNPs and SBAuNPs.

Optimized canopy structure improves maize grain yield and resource use efficiency

Improved canopy structure was instrumental in setting maize yield records, and yet it has rarely been examined in China. At Qitai Farm in Xinjiang, we conducted a 4‐year field experiment using China's six highest‐yielding maize hybrids sorted into three yield level groups that were grown at similar growth durations and at optimum densities. The average yield of high‐yield level (HL, 22.3 Mg ha−1) was 7.2% and 24.6% higher than that of medium‐yield level (ML) and low‐yield level (LL), respectively. For each yield level, we measured morphological traits that influence canopy structure and yield. They included plant height, ear height, ear ratio, internode length, leaf numbers, leaf angle, LOV, leaf area, and spatial density of leaf area. Among the preceding morphological traits of the three yield levels, HL’s best optimized the canopy structure, as shown by improved light distribution (19.0% light transmission at the ear) and increased light interception per unit leaf area per day (LIPA, 51.7 MJ m−2 day−1) in the canopy. In comparison, light transmission was 12.2% and 15.9% at the ear and the total LIPAs were 37.2 and 29.0 MJ m−2 day−1 at silking for ML and LL, respectively. HL had significantly longer leaf area duration and a higher photosynthetic rate, especially at the grain filling stage, and its total accumulated biomass at maturity was significantly better (by 13.9%) than LL’s. HL’s harvest index (0.54) was significantly higher than that of ML (0.52) and LL (0.48). HL’s radiation and heat use efficiencies were 2.61% and 1.37 g °C−1 day−1 m−2, both significantly greater than those of ML and LL. Therefore, optimum maize plant types can significantly improve canopy structure and increase resource use efficiency and grain yield.

Significant Loss of Ecosystem Services by Environmental Changes in the Mediterranean Coastal Area

Mediterranean coastal areas are among the most threated forest ecosystems in the northern hemisphere due to concurrent biotic and abiotic stresses. These may affect plants functionality and, consequently, their capacity to provide ecosystem services. In this study, we integrated ground-level and satellite-level measurements to estimate the capacity of a 46.3 km2 Estate to sequestrate air pollutants from the atmosphere, transported to the study site from the city of Rome. By means of a multi-layer canopy model, we also evaluated forest capacity to provide regulatory ecosystem services. Due to a significant loss in forest cover, estimated by satellite data as −6.8% between 2014 and 2020, we found that the carbon sink capacity decreased by 34% during the considered period. Furthermore, pollutant deposition on tree crowns has reduced by 39%, 46% and 35% for PM, NO2 and O3, respectively. Our results highlight the importance of developing an integrated approach combining ground measurements, modelling and satellite data to link air quality and plant functionality as key elements to improve the effectiveness of estimate of ecosystem services.

An online case study seminar for teaching C4 photosynthesis in an evolutionary context, by assembling multidisciplinary characters

Photosynthesis is the predominant metabolic process for energy obtention in plants. Here we describe a case study where a set of anatomical, biochemical, and molecular characters are used to reconstruct the evolution of the C4 photosynthetic pathway, within the evolutionary framework provided by the genus Flaveria. Our main educational goal was to engage biology undergraduate students to solve a photosynthesis-related phylogenetic problem by stimulating them to assemble informative characters of diverse nature. This case study was successfully implemented as a seminar in a massive university introductory course, during the COVID19 lockdown. Using an online learning environment, most small groups achieved the Students Learning Outcomes, which were assessed through a questionnaire and an open-ended question. Individual performance was also evaluated through a specific exercise in the course’s midterm test. Finally, students were surveyed for their perception about the seminar through a poll. We concluded that this seminar could be easily adopted to promote the learning of complex and interdisciplinary content like the C4 photosynthetic pathway in undergraduate botanical education, even in a large online introductory course. [ FROM AUTHOR] Copyright of Journal of Biological Education (Routledge) is the property of Routledge and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)

Abstracts of the Joint International Symposia “Vitamin D in Prevention and Therapy” and “Biologic Effects of Light”

The proceedings contain 59 papers. The topics discussed include: impacts of UV and vitamin D on skin cancer;mouse experiments;vitamin D supplementation may improve COVID-19 prognosis? evidence from a systematic review and meta-analysis;vitamin D and the heart: controversies still exist;photosynthesis in plants and algae;vitamin d status in individuals with erythropoietic protoporphyria;impact of vitamin d in Alzheimer's disease;high oral vitamin D intake does not protect against UVR-induced squamous cell carcinoma in hairless mice;nicotinamide and phytochemicals phloroglucinol and syringic acid delay UVR-induced squamous cell carcinoma onset in hairless mice;and modulation of the skin microbiota by optical radiation.

Vegetation Indices Applied to Suborbital Multispectral Images of Healthy Coffee and Coffee Infested with Coffee Leaf Miner

The coffee leaf miner (Leucoptera coffeella) is a primary pest for coffee plants. The attack of this pest reduces the photosynthetic area of the leaves due to necrosis, causing premature leaf falling, decreasing the yield and the lifespan of the plant. Therefore, this study aims to analyze vegetation indices (VI) from images of healthy coffee leaves and those infested by coffee leaf miner, obtained using a multispectral camera, mainly to differentiate and detect infested areas. The study was conducted in two distinct locations: At a farm, where the camera was coupled to a remotely piloted aircraft (RPA) flying at a 3 m altitude from the soil surface;and the second location, in a greenhouse, where the images were obtained manually at a 0.5 m altitude from the support of the plant vessels, in which only healthy plants were located. For the image processing, arithmetic operations with the spectral bands were calculated using the “Raster Calculator” obtaining the indices NormNIR, Normalized Difference Vegetation Index (NDVI), Green-Red NDVI (GRNDVI), and Green NDVI (GNDVI), the values of which on average for healthy leaves were: 0.66;0.64;0.32, and 0.55 and for infested leaves: 0.53;0.41;0.06, and 0.37 respectively. The analysis concluded that healthy leaves presented higher values of VIs when compared to infested leaves. The index GRNDVI was the one that better differentiated infested leaves from the healthy ones.

Nanobionics in Crop Production: An Emerging Approach to Modulate Plant Functionalities.

The "Zero Hunger" goal is one of the key Sustainable Development Goals (SDGs) of the United Nations. Therefore, improvements in crop production have always been a prime objective to meet the demands of an ever-growing population. In the last decade, studies have acknowledged the role of photosynthesis augmentation and enhancing nutrient use efficiency (NUE) in improving crop production. Recently, the applications of nanobionics in crop production have given hope with their lucrative properties to interact with the biological system. Nanobionics have significantly been effective in modulating the photosynthesis capacity of plants. It is documented that nanobionics could assist plants by acting as an artificial photosynthetic system to improve photosynthetic capacity, electron transfer in the photosystems, and pigment content, and enhance the absorption of light across the UV-visible spectrum. Smart nanocarriers, such as nanobionics, are capable of delivering the active ingredient nanocarrier upon receiving external stimuli. This can markedly improve NUE, reduce wastage, and improve cost effectiveness. Thus, this review emphasizes the application of nanobionics for improving crop yield by the two above-mentioned approaches. Major concerns and future prospects associated with the use of nanobionics are also deliberated concisely.

Mycorrhizal Fungi Inoculation Improves Capparis spinosa’s Yield, Nutrient Uptake and Photosynthetic Efficiency under Water Deficit

Agricultural yields are under constant jeopardy as climate change and abiotic pressures spread worldwide. Using rhizospheric microbes as biostimulants/biofertilizers is one of the best ways to improve agro-agriculture in the face of these things. The purpose of this experiment was to investigate whether a native arbuscular mycorrhizal fungi inoculum (AMF-complex) might improve caper (Capparis spinosa) seedlings’ nutritional status, their morphological/growth performance and photosynthetic efficiency under water-deficit stress (WDS). Thus, caper plantlets inoculated with or without an AMF complex (+AMF and −AMF, respectively) were grown under three gradually increasing WDS regimes, i.e., 75, 50 and 25% of field capacity (FC). Overall, measurements of morphological traits, biomass production and nutrient uptake (particularly P, K+, Mg2+, Fe2+ and Zn2+) showed that mycorrhizal fungi inoculation increased these variables significantly, notably in moderate and severe WDS conditions. The increased WDS levels reduced the photochemical efficiency indices (Fv/Fm and Fv/Fo) in −AMF plants, while AMF-complex application significantly augmented these parameters. Furthermore, the photosynthetic pigments content was substantially higher in +AMF seedlings than −AMF controls at all the WDS levels. Favorably, at 25% FC, AMF-colonized plants produce approximately twice as many carotenoids as non-colonized ones. In conclusion, AMF inoculation seems to be a powerful eco-engineering strategy for improving the caper seedling growth rate and drought tolerance in harsh environments.

Covid 19 And Human Immune Function: The Chemistry Of Vitamin - D

The epidemic COVID-19 is the utmost dreadful disaster of current human life that led to public health's global health as a major health care issue. Patients of COVID-19 have the signs, for instance, fever, dry cough, dyspnoea, sore throat, nasal congestion, besides glassy lung opacities. The infection of COVID-19 has two immune protective and damaging phases, and physicians attempt to improve the patient immune reactions. Vitamin D has various ways of action to reduce infection risk and death and has beneficial effects on viral infections. Supplementation of vitamin D during infection conditions of COVID-19 is still controversial. Scientific investigations are required to define improved cut-offs for vitamin D levels and, finally, which quantity will be the better as supplementations. Most of the works showed the people who are deficient in Vitamin D are more prone to infection. Broad familiarity with Vitamin D will make it supportive and protective for health. The present study focused on the worth of Vitamin D for the immune role, its presence in optimal amounts, and its effectiveness in COVID-19. Sun exposure synthesizes vitamin D in the human body, which ultimately enhances immunity, and protects from many viral infections, including COVID-19.

Interactive Effects of Drought and Saline Aerosol Stress on Morphological and Physiological Characteristics of Two Ornamental Shrub Species

Effects of drought and aerosol stresses were studied in a factorial experiment based on a Randomized Complete Design with triplicates on two ornamental shrubs. Treatments consisted of four levels of water container (40%, 30%, 20%, and 10% of water volumetric content of the substrate) and, after 30 days from experiment onset, three aerosol treatments (distilled water and 50% and 100% salt sea water concentrations). The trial was contextually replicated on two species: Callistemon citrinus (Curtis) Skeels and Viburnum tinus L. ‘Lucidum’. In both species, increasing drought stress negatively affected dry biomass, leaf area, net photosynthesis, chlorophyll a fluorescence, and relative water content. The added saline aerosol stress induced a further physiological water deficit in plants of both species, with more emphasis on Callistemon. The interaction between the two stress conditions was found to be additive for almost all the physiological parameters, resulting in enhanced damage on plants under stress combination. Total biomass, for effect of combined stresses, ranged from 120.1 to 86.4 g plant−1 in Callistemon and from 122.3 to 94.6 g plant−1 in Viburnum. The net photosynthesis in Callistemon declined by the 70% after 30 days in WC 10% and by the 45% and 53% in WC 20% and WC 10% respectively after 60 days. In Viburnum plants, since the first measurement (7 days), a decrease of net photosynthesis was observed for the more stressed treatments (WC 20% and WC 10%), by 57%. The overall data suggested that Viburnum was more tolerant compared the Callistemon under the experimental conditions studied.

Seed nutripriming with zinc is an apt tool to alleviate malnutrition.

More than 2 billion people worldwide suffer from micronutrient malnutrition, sometimes known as hidden hunger. Zn malnutrition affects around a third of the world's population. The physicochemical features of soil, which limit the availability of Zn to plants, cause Zn deficiency. The eating habits of certain populations are more depended on Zn-deficient staple foods. Due to the high expense and certain interventions such as diet diversification, zinc supplementation and food fortification cannot be achieved in disadvantaged populations. Biofortification is the most practical technique for alleviating Zn malnutrition. Seed priming with nutrients is a promising biofortification approach for edible crops. Seed nutripriming with zinc is a cost-effective and environmentally benign approach of biofortification. Seeds can be nutriprimed with Zn using a variety of methods such as Zn fertilisers, Zn chelated compounds and Zn nanoparticles. Nutripriming with nanoparticles is gaining popularity these days due to its numerous advantages and vast biofortification potential. Seeds enriched with Zn also aid plant performance in Zn-deficient soil. Zn an essential trace element can regulate physiological, biochemical and molecular processes of plant cells and thus can enhance germination, growth, yield and bioavailable Zn in edible crops. Moreover, zinc emerges as an important element of choice for the management of COVID-19 symptoms.

Vitamin D attenuates COVID-19 complications via modulation of proinflammatory cytokines, antiviral proteins, and autophagy.

INTRODUCTION: Global emergence of coronavirus disease-19 (COVID-19) has clearly shown variable severity, mortality, and frequency between and within populations worldwide. These striking differences have made many biological variables attractive for future investigations. One of these variables, vitamin D, has been implicated in COVID-19 with rapidly growing scientific evidence. AREAS COVERED: The review intended to systematically explore the sources, and immunomodulatory role of vitamin D in COVID-19. Search engines and data sources including Google Scholar, PubMed, NCBI, Scopus, and Web of Science were used for data collection. The search terms used were Vitamin D, COVID-19, immune system, and antiviral mechanism. Overall, 232 sources of information were collected and 188 were included in this review. EXPERT OPINION: Interaction of vitamin D and vitamin D receptor (VDR) triggers the cellular events to modulate the immune system by regulation of many genes. Vitamin D operates as a double-edged sword against COVID-19. First, in macrophages, it promotes the production of antimicrobial and antiviral proteins like ß-defensin 2 and cathelicidin, and these proteins inhibit the replication of viral particles and promote the clearance of virus from the cells by autophagy. Second, it suppresses cytokine storm and inflammatory processes in COVID-19.