Osteoarthritis is the most common human joint disease in the world. It is also one of the most common skeletal muscle defects, destructive joint changes, and the leading cause of disability and reduced quality of life. Destructive changes in inflammatory joints are associated with a range of biochemical events, including the overproduction of inflammatory cytokines. Cytokines are protein compounds that play an essential role in causing and regulating inflammation. A balance between pro-inflammatory and anti-inflammatory cytokines is crucial in maintaining a stable body. In some inflammatory diseases, including osteoarthritis, the balance between these compounds is disturbed, and the balance shifts to pre-inflammatory cytokines. For this reason, researchers today are trying to find an effective way to reduce inflammation and treat osteoarthritis by using certain compounds. Current treatments for osteoarthritis, including nonsteroidal antiinflammatory drugs, glucocorticoids, and hyaluronic acid, are mainly based on reducing pain and inflammation. However, they have limited effects in controlling symptoms and improving the patient's quality of life. Also, due to the high level of side effects, synthetic drugs have led to the identification of compounds of natural origin to give patients a chance to use painkillers and antiinflammatory drugs with fewer side effects. This review study aimed to present the role of quercetin as a natural compound in reducing the expression of pro-inflammatory cytokines in osteoarthritis. This study also discusses the relationship between inflammation and cartilage destruction and other inflammation-related factors caused by cytokines.

Plant-based extracts, as alternatives to chemical compounds, are commonly use in pharmaceutical and food industries. Antibacterial properties of extracts are mainly considered in medicine. Because of the high incidence of infectious diseases, it is helpful to identify more agents that are able to treat diseases. Antioxidant effects have been reported for different plant extracts. We aimed to investigate antioxidant activity, total phenolic and flavonoid contents, and antibacterial effect of Quercus brantii L. fruit extract. In this study, Q. brantii L. fruit was extracted by maceration using ethanol 70%. Total phenolic content was determined by Folin-Ciocalceu reagent and gallic acid equivalence, and antioxidant activity was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) compared to butylated hydroxytoluene (BHT). Antibacterial effects were investigated by broth microdilution and measurement of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Then the effects of different concentrations of extract on Staphylococcus aureus and Enterococcus faecalis growth were investigated in comparison with vancomycin and nitrofurantoin. Our findings demonstrate that antioxidant activity of hydroalcoholic extract of Q. brantii L. fruit was more than that of BHT. Total phenolic content was derived (3.010 mg GAE/g DW). Flavonol and flavonoid contents were 1.813 and 0.654 mg/g, respectively. The extract was found to exert significant inhibitory effects on both studied bacteria. S. aureus was more susceptible than E. faecalis to Q. brantii L. fruit extract. Q. brantii L. fruit extract can exert considerable antioxidant effects, contains high amounts of phenolic, flavonol, and flavonoid compounds, and inhibits bacterial growth.

Coronaviruses are a large family of viruses that can cause a variety of diseases in humans. Some coronaviruses cause only mild illnesses like the common cold. While, some coronaviruses such as SARS-CoV (SARS-associated coronavirus) and Middle East respiratory syndrome coronavirus (MERS-CoV) have, in recent years, been able to cause severe respiratory involvement (pneumonia), leading to death in several patients. By identifying the genomic sequence of the new human coronavirus SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) it has been revealed that it belongs to the beta coronavirus genus. COVID-19 appears to be transmitted by a mechanism similar to the influenza virus via person to person, sneezing coughing, or contact with the secretions of infected patients. Early symptoms of these respiratory viruses include fever, cough, and shortness of breath, with an incubation period of 2-14 days. SARS-CoV-2 is an acute respiratory disease that initially causes lung damage. SARS-CoV-2 can affect other organs, including the kidneys. Kidney damage may be caused by alterations that occur during coronavirus infection. It seems that low-oxygen delivery to tissues like the kidney in the setting of this disease may lead to ischemic damage of the kidney. Considering the importance of the kidneys, as one, this review study aimed to investigate the effect of the new coronavirus on the kidneys and its role in the development of renal failure.

Today, finding natural polymers with desirable properties for use in various industries is one of the critical axes of research in the world. Polysaccharides are a group of natural polymers that have various applications in the pharmaceutical industry. The attachment of monosaccharides forms polysaccharides through glycosidic bonds that are widely found in various sources, including plants. Genus Astragalus belongs to the Fabaceae family. Plants belonging to this genus have different polysaccharides. Astragalus polysaccharides (APS) have attracted a great deal of attention among natural polymers because they are non-toxic, biodegradable, and biocompatible. Currently, APS have great drug potential for curing or treating various diseases. Due to the different biological activities of polysaccharides, including Astragalus, this study has investigated the chemical structure of APS, reporting on the antiviral and anti-inflammatory activities as well as stimulation of cytokine secretion by these polysaccharides. Also, in this study, the pharmaceutical approaches of APS compounds, as a natural, new and inexpensive source, have been discussed as suitable candidates for use in pharmaceutical formulations and preparation of new drugs to control COVID-19 infection

Medicinal plants have special importance around the world. Further, they have been noticed for nutrition and illness treatment such as preparation of anticancer new drugs. Therefore, a wide range of studies have been done on different plants, and their anticancer effects have been investigated. Nowadays, cancer is the most important factor of death rate in the developed and developing countries. Among them, stomach cancer is one of the most common malignancies around the world. At present, it is recognized as the fourth common cancer and the second factor of death rate due to cancer. So far, there has been wide range of effort for cancer treatment; however, in most cases, the response to the treatment has been very weak and often accompanied improper subsidiary effects. The present problems as a consequence of chemical treatment and radiotherapy and many subsidiary problems created due to their use for patients, and also, the resistance to the current treatment has motivated researchers to apply new medicines with more effect and less toxicity. The secondary metabolisms existent in the plants have an important role in the treatment of several diseases such as cancer. This study was conducted to investigate and collect scientific results for stomach cancer and to clarify the role of medicinal plants and secondary plant compounds on its treatment.