Bee products have been used in medicine around the world since ancient times (in Egypt, Greece and China). Currently, bee products (propolis, honey, royal jelly, beeswax and flower pollen) are accepted as alternative remedies, and their application is in complementary and alternative medicine. The mixture of flower pollen from different plant species is agglutinated using the nectar and enzymes secreted by honey bees (amylase and catalase) through salivary glands and pollen grains are then formed, which are recognized as flower pollen in granular form. The composition of flower pollen is variable and depends on its biogeographic (regional) origin, ecological habitat and weather conditions.
There is a long recorded history of the use of flower pollen by humans. It has been mentioned over the course of centuries because of its healing and health-related properties. Historically, the nutritional and medicinal value of flower pollen has been considered for thousands of years; the Bible mentions the consumption of flower pollen, as it was part of the diet of the inhabitants of ancient China and Egypt. Ancient medical texts from Greece and Rome mention that Aristotle, Hippocrates, Pythagoras, and Pliny the Elder highlighted flower pollen as part of a healthy diet. Information on the sedative properties of flower pollen and its beneficial effect on gastrointestinal and cardiovascular disorders dates back to the Middle Ages. In modern times, the regular use of flower pollen began after World War II, when methods of its easy collection became available.
Advanced analytical techniques (chromatography and spectrometry) allow the identification of approximately 200 chemical compounds in flower pollen from different plant species. Its main components include proteins (5%–60%), essential amino acids, reducing sugars (13%–55%), lipids (4%–7%), nucleic acids (especially RNA) and fibers (0.3%–20%). Given its composition, flower pollen is recognized as a “perfectly rounded food”. The components with lower content are minerals such as Ca, Mg, Fe, Zn and Cu, with a high Na/K ratio, as well as vitamins: provitamin A (beta-carotene), vitamin E (tocopherol), niacin, thiamine, biotin and folic acid, as well as enzymes and coenzymes. Bioactive substances are important compounds. These are unsaturated/saturated fatty acids (1%–10%; linoleic, gamma-linolenic and archaic acid), phospholipids (1.5%), phytosterols, i.e., beta-sitosterol, P-sitosterol (1.1%) and terpenes.
In addition, polyphenols, mainly avonoids (3%–8 % of dry mass), are also important. The most common of the flavonoids are catechins, kaempferol, quercetin and isorhamnetin. Flower pollen is also rich in organic carotenoid pigments (i.e., lycopene or zeaxanthin). Such a variable composition with various secondary metabolites makes flower pollen a very valuable dietary substitute.
The various primary and secondary metabolites contained in flower pollen exhibit a wide range of properties and bioactivity: antioxidant, anti-inflammatory, anticancer, antibacterial, fungicidal, hepatoprotective and anti-atherosclerotic properties, as well as the ability to modify and regulate immune function.
Several studies have shown that flower pollen has greater or lesser antimutagenic properties, depending on the type of cancer. Its anticancer properties can be derived from its antioxidant properties, i.e., the suppression of the formation of reactive oxygen species (ROS) and the removal of the activation of reactive oxygen species. Thus, it can be considered that flower pollen has a cytotoxic effect on cancer cells by inhibiting their development.
The antibacterial effect of flower pollen on the Bacillus cereus, Bacillus subtilis, Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, Yersinia enterocolitica, Enterococcus faecalis and Listeria monocytogenes bacteria is likely associated with the property of glucose oxidase, an enzyme produced by bees. It is added to flower pollen when its granules are formed. It has also been shown that microbiological activity is associated with phenolic acids and avonoids. The mechanism of the effect of avonoids and phenols on bacterial and fungal cells is the degradation of the cytoplasm membrane that leads to the loss of potassium ions and triggers cell autolysis.
In several studies, the bioactive substances of flower pollen improved liver function. Flower pollen extracts reduced the pathological levels of enzymes (e.g., alanine/aspartate transaminase or acid phosphatase) and bilirubin present in the blood of individuals poisoned by organic compounds (ethanol, carbon tetrachloride and trichloroethylene, ethionine or ammonium uoride) or medicinal products (paracetamol and hydrocortisone). The detoxifying activity of flower pollen is associated with polyphenols, mainly avonoids and phenolic acids.
Flower pollen is said to strengthen the immune system. It stimulates the humoral immune response (the increase in specific levels of IgM and IgG). The immunosuppressive action of flower pollen is attributed to avonoids, steroids and volatile oils. Studies have shown that flower pollen can increase anti-allergic reaction by inhibiting the activation of mast cells and thus affect both the early and late stages of allergic reactions. The anti-allergic activity of flower pollen is effected by preventing IgE from binding to its receptor and inhibiting the excretion of histamine, the main stimulator of allergic reaction.
Bosiljka Studen, mag. ing. biotechn.
