Propolis is a complex sticky substance produced by the honey bees (Apis mellifera) from the resinous materials they collect from various parts of plant and used by the bees to defend their hives from pathogenic microorganisms. This research aimed to compare the antioxidant properties of propolis extracts produced by using different solvents and extraction methods. To obtain propolis extracts, both classical and ultrasonic extraction methods were used with distilled water and 20% propylene glycol as solvents. Folin-Ciocalteau method was used to record the total phenolic content of propolis extracts. In this study, to measure the antioxidant activity of extracts, three methods were used that are FRAP, DPPH, and ABTS. Moreover, the aluminum chloride colorimetric method was used for total flavonoid content analysis. According to analysis, °brix values recorded between 14.40 and 27.50. The total phenolic content changed from 721 mg GAE/L to 33621 mg GAE/L. Also, the total amount of flavonoid content was measured between 1138 mg QE/L extract and 74021 mg QE/L extract. DPPH radical scavenging activity of the samples ranged from 0.46 IC50 µl/ml to 31.86 IC50 µl/ml, ABTS+ values changed from 0.09 IC50 µl/ml to 4.64 IC50 µl/ml, and FRAP values measured between 29.22 µM TE/g 1783.02 µM TE/g. More studies and analysis are needed to investigate the effects of solvents and extraction methods on propolis extracts, as well as on the antioxidant properties of these extracts.

Recently, the novel coronavirus, which is called severe acute respiratory syndrome coronavirus 2, has been responsible for the highly rapid spread of COVID-19 disease, globally. Until now, 535 million people were affected and 6.3 million people died due to this outbreak throughout the World. Although the lethality of this disease is lower than the severe acute respiratory syndrome coronavirus and Middle East respiratory syndrome, severe complications of this disease are attributed to "cytokine storm" that is the reason for the severe lung damage. The cytokine storm causes systemic inflammation, acute respiratory distress syndrome, septic shock, stroke, multiple organ dysfunction, and death. As a result of these symptoms, there are pivotal studies about vaccination, drug, and medication to prevent severe complications and treat patients with COVID-19. Besides these studies, some research shows that nutrients are able to manage the cytokine storm such as many types of vitamins, trace elements, and omega 3 fatty acids. Omega 3 polyunsaturated fatty acids have specific roles in the inflammatory process. Omega 3 fatty acids have a role in the improvement of the inflammatory balance. They interact with viral infection in disparate stages such as viral entry and replication. This study highlights the roles of omega 3 polyunsaturated fatty acids in the prevention and treatment of the COVID-19. In addition, omega 3 fatty acids show anti-viral and anti-inflammatory effects on the severe acute respiratory syndrome coronavirus 2 and increase survival rates in patients infected with COVID-19.

The new type of coronavirus infection (COVID-19), caused by coronavirus-2 (SARS-CoV-2), has led to a world pandemic due to severe acute respiratory syndrome. In addition to drug and vaccine studies for COVID-19, studies on various foods maintain to increase immunity and alternative treatment, and in this context, bee products are also being researched. Although many studies are showing that bee products have antimicrobial properties and immune-enhancing effects, there are limited studies on the effectiveness of these products against coronavirus. Some peptides in royal jelly are reported to be potent antibacterial and antifungal agents that may be beneficial for avoiding co-infections in COVID-19 patients. Positive results have been found Pollen, a fine and powder-like substance produced by flowering plants and collected by bees, in many studies investigating the effects of pollen on health such as antimicrobial, antiviral and anti-inflammatory. Bee venom; It is a yellowish-colored, bitter-sweet, pungent-smelling substance that is produced in the venom sac of bees, normally in liquid form, but dries up and crystallizes after contact with air. Melittin, the primary component of bee venom having more than 40 biologically and pharmacologically active compounds including phospholipase A2, histamine, epinephrine, free amino acids, peptide and apamin, has been stated to have antitumor, antimicrobial, anti-nociceptive and anti-inflammatory activities. Phospholipase A2 (PLA2) secreted from bee and snake venom is known to have strong anti-HIV activities. Melittin, phosphorylase A2 and hyaluronidan, which are the most significant components of bee venom, constitute 50% of bee venom. Moreover, researches on the relationship between bee venom and COVID-19 are limited. The target of this review is to bring together the studies on the health effects of royal jelly, bee pollen and bee venom, and to contribute to the existing studies.