Propolis is a resinous substance from the beehive that has powerful antibacterial, antifungal, antiviral, and antioxidant properties. It is also known to have hepatoprotective and immunomodulating properties.
Several studies demonstrated that Brazilian propolis exerted antimicrobial activity and could reduce the symptoms of allergic rhinitis (nose itching, purulence, sneezing). In diabetic rats, ethanol extract of propolis reduced blood glucose levels and insulin resistance.
The antimicrobial properties of propolis are mainly due to the fact that it contains flavonoids and phenolic compounds, which inhibit bacteria from adhering to the surface of host cells, and interfere with enzymes required for their growth, metabolism and invasion. Propolis has been shown to be effective against many microorganisms, including some pathogens that cause inflammatory diseases in humans such as Candida albicans and Aspergillus flavus.
In addition, the phenolic constituents in propolis interfere with bacterial protein function, thus causing the death of the bacterium. The mode of action of propolis against microorganisms is complex and involves several mechanisms, such as reducing the negative surface charge of the microorganism, increasing permeability of the cell membrane, disrupting the potential energy of the bacterial cell, impairing adenosine triphosphate production and lowering the cellular mobility [118].
It has been shown that propolis has antimicrobial and antifungal activity in vitro. However, the exact mechanism of this action is not fully understood and may depend on several factors, such as (a) geographic origin, since different propolis samples possess a range of bioactivity; (b) strain, since the antimicrobial effect is strongly dependent on the strain; and (c) the protocol used to assess in vitro bioactivity, since the solubility of phenolic compounds can vary with the method of preparation.
Studies using disc diffusion and agar-well diffusion methods, have shown that the ethanol extract of Al-Museiab propolis has high bactericidal activity against Staphylococcus aureus, Salmonella typhi, E. coli, Listeria monocytogenes and Helicobacter pylori. However, the activity of this EEMP is reduced against Staphylococcus epidermidis and Candida albicans. In contrast, the ethanol extract of the propolis from Turkey, Taiwan and Oman exhibited the highest activity against these strains.
Antifungal
Studies have shown that propolis has antifungal properties and enhances the efficacy of some conventional medicines. Its antifungal activity is attributed to its complex chemical composition. The most studied components include flavonoids and phenolic acids. Propolis is also rich in terpenes. The presence of these compounds promotes wound healing and prevents infection. It also reduces the activity of free radicals, which protects against oxidative damage to the cells.
It has been demonstrated that a water-soluble derivative (WSD) of propolis increases resistance to experimental bacterial (Klebsiella pneumoniae and Staphylococcus aureus) and fungal (Candida albicans) infections in mice. The WSD also stimulates peritoneal macrophage proliferation and interleukin 1 secretion. The cytotoxicity of the WSD is associated with its ability to reduce the positive charge on the surface of bacteria, promoting membrane permeability and interfering with ATP production.
The physicochemical properties of propolis differ depending on botanical origin, season of collection, and flora. Ethanol extracts from green propolis show higher polar and nonpolar chemical compositions than hexane extracts. Ethanol is also a more efficient solvent than water for dissolving propolis. In addition to the aforementioned properties, propolis is an antioxidant and possesses antiviral activities. Its antioxidant properties are due to the presence of phenolic and flavonoid compounds. Propolis also possesses hepatoprotective properties, which are attributed to the presence of polyphenols and other bioactive substances.
The hepatoprotective action of propolis is mediated by the inhibition of oxidative stress on liver cells. Oxidative stress is a major cause of cell damage in many diseases, including cardiovascular disease, arthritis, cancer, and aging. Propolis is also an antifungal, and it inhibits the growth of fungi such as Trichophyton, Mycrosporum, and Candida albicans. It also has a direct effect on the cells of these organisms and reduces their ability to form a biofilm.
Antiviral
Propolis has antiviral properties and can be used to treat viral infections. It may protect against rotavirus, influenza virus, human respiratory syncytial and coronaviruses, and herpes simplex viruses [60]. In addition to its antimicrobial, antifungal, and antioxidant activities, propolis can also help stimulate the immune system and prevent inflammation.
The antiviral effect of propolis is mediated by its ability to mask the viral compounds required for viral entry into host cells. Propolis inhibits viral polymerase activity and prevents the binding of virus nucleic acid and capsid proteins to cellular receptors. It also interferes with the process of herpes viral adsorption to host cell surface.
Moreover, the antiviral properties of propolis are mediated by its terpenes. Various studies have demonstrated that certain diterpenes in propolis exhibit significant antiviral activity. For example, one study reported that the ethanolic extracts of Brazilian propolis contain daucane diterpene esters of hydroxybenzoic acids that exhibit high antiviral activity. This property is attributed to the ability of these terpenes to scavenge DPPH and ABTS free radicals.
Another study of 13 ethanolic extracts of South Brazilian propolis showed that they had significant anti-influenza virus activity in vitro. The extracts also protected MDBK cells from infection by pseudo rabies virus. This effect was attributed to the ability of propolis extracts to form an electron-dense layer on host cell surface, masking the viral nucleic acid or proteins required for viral entry into host cells.
A 2020 study published in the journal Phytotherapy Research found that propolis improves the balance of bacteria and yeast in the gut microbiome, which helps prevent leaky gut and other digestive problems. It also strengthens the mucosal barrier of the gastrointestinal tract to let nutrients in but not toxins or food proteins.
Antitumor
The use of propolis is gaining popularity in the health industry due to its anti-cancer properties. It also has a wide range of other benefits including the inhibition of cancer progression, mitigation of parasitic-related symptoms, and improvement of the gut microbiome. Its efficacy as a natural medicine has been confirmed by several in vitro and in vivo studies. It is also a promising candidate for the development of novel drugs for treating various diseases and conditions.
The phenolic compounds in propolis have been found to have potent antitumor activity. Research has shown that these compounds inhibit the proliferation of tumor cells by targeting multiple pathways and causing metabolic interference. These compounds also induce apoptosis by modulating both the extrinsic and intrinsic apoptotic pathways. Propolis can also be used in combination therapy with chemotherapy to treat certain cancers.
Propolis contains flavonoids that are known to be effective antioxidants and reduce the oxidative stress caused by chemotherapy drugs. In addition, the anti-inflammatory effects of propolis are also useful in reducing toxicity and improving survival. The hepatoprotective effect of propolis is also well documented. It has been found that the hepatoprotective properties of propolis are associated with its ability to inhibit the activities of serum transaminases.
In addition to its hepatoprotective effects, propolis is also used in the treatment of indicative vaginitis, such as bacterial vaginosis and vulvovaginal candidiasis. It has been shown that propolis strengthens the mucosal barrier in the gastrointestinal tract, which can prevent leaky gut syndrome. Additionally, it can help balance the bacteria in the gut microbiome and prevent the growth of pathogenic yeasts. In one study, researchers found that propolis significantly improved the balance of bacteria and yeasts in the intestine.
Hepatoprotective
Propolis contains a large number of chemical compounds that have various biological effects, such as antimicrobial, antifungal and antiviral activities. It also has immunomodulatory and chemopreventive properties. These properties are due to its phenolic contents, including apigenin, caffeic acid and flavonoids. It has been shown to induce apoptosis in cancer cells, inhibit cell growth and inflammatory responses. It also has hepatoprotective effects.
Propolis can protect the liver against oxidative damage and prevent inflammation caused by drugs, such as acetaminophen (Tylenol). It may even help reverse damage already done to the liver. Propolis also has been used by beekeepers to treat wounds and injuries.
In a study by El-Mahalaway et al, propolis protected against carbon tetrachloride (CCl4)-induced liver damage in rats. The treatment of propolis resulted in a significant reduction in the levels of hepatic enzymes (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and total protein). Liver histology showed reduced hepatocellular injury and increased cellular viability in the treated group. Propolis also increased the antioxidant status in the hepatocytes of the treated group.
The hepatoprotective properties of propolis are related to its phenolic and flavonoid content, which are known to have high antioxidant activity. Polyphenols and apigenin have been found to suppress the secretion of inflammatory cytokines, such as TNF-a and IL-6, in experimental models of acute hepatitis.
Another benefit of propolis is that it can reduce the symptoms of herpes simplex virus (HSV) infections, which are often referred to as cold sores or fever blisters. In one clinical trial, children who were given a propolis extract for the duration of a cold season had less severe symptoms than those who did not take the propolis extract.