Polyphenols from Bee Pollen: Structure, Absorption, Metabolism and Biological Activity.

Bee pollen constitutes a natural source of antioxidants such as phenolic acids and flavonoids, which are responsible for its biological activity. Research has indicated the correlation between dietary polyphenols and cardioprotective, hepatoprotective, anti-inflammatory, antibacterial, anticancerogenic, immunostimulating, antianaemic effects, as well as their beneficial influence on osseous tissue. The beneficial effects of bee pollen on health result from the presence of phenolic acids and flavonoids which possess anti-inflammatory properties, phytosterol and linolenic acid which play an anticancerogenic role, and polysaccharides which stimulate immunological activity. Polyphenols are absorbed in the alimentary tract, metabolised by CYP450 enzymes, and excreted with urine and faeces. Flavonoids and phenolic acids are characterised by high antioxidative potential, which is closely related to their chemical structure. The high antioxidant potential of phenolic acids is due to the presence and location of hydroxyl groups, a carboxyl group in the immediate vicinity of ortho-diphenolic substituents, and the ethylene group between the phenyl ring and the carboxyl group. As regards flavonoids, essential structural elements are hydroxyl groups at the C5 and C7 positions in the A ring, and at the C3' and C4' positions in the B ring, and a hydroxyl group at the C3 position in the C ring. Furthermore, both, the double bond between C2 and C3, and a ketone group at the C4 position in the C ring enhance the antioxidative potential of these compounds. Polyphenols have an ideal chemical structure for scavenging free radicals and for creating chelates with metal ions, which makes them effective antioxidants in vivo.

Caffeic Acid phenethyl ester and ethanol extract of propolis induce the complementary cytotoxic effect on triple-negative breast cancer cell lines.

Chemotherapy of breast cancer could be improved by bioactive natural substances, which may potentially sensitize the carcinoma cells' susceptibility to drugs. Numerous phytochemicals, including propolis, have been reported to interfere with the viability of carcinoma cells. We evaluated the in vitro cytotoxic activity of ethanol extract of propolis (EEP) and its derivative caffeic acid phenethyl ester (CAPE) towards two triple-negative breast cancer (TNBC) cell lines, MDA-MB-231 and Hs578T, by implementation of the MTT and lactate dehydrogenase (LDH) assays. The morphological changes of breast carcinoma cells were observed following exposure to EEP and CAPE. The IC50 of EEP was 48.35 µg∙mL-1 for MDA-MB-23 cells and 33.68 µg∙mL-1 for Hs578T cells, whereas the CAPE IC50 was 14.08 µM and 8.01 µM for the MDA-MB-231 and Hs578T cell line, respectively. Here, we report that propolis and CAPE inhibited the growth of the MDA-MB-231 and Hs578T lines in a dose-dependent and exposure time-dependent manner. EEP showed less cytotoxic activity against both types of TNBC cells. EEP and, particularly, CAPE may markedly affect the viability of breast cancer cells, suggesting the potential role of bioactive compounds in chemoprevention/chemotherapy by potentiating the action of standard anti-cancer drugs.

[The role of nicotine as a modulator of the activity of acid phosphotase and cathepsin D and L in the liver and kidney of mice]. / Nikotyna jako modulator aktywnosci fosfatazy kwasnej oraz katepsyny D i katepsyny L w watrobie i nerkach myszy.

To our knowledge, no reports on the impact of nicotine on the enzyme activity of the lysosomal system have been published yet. The study which is reported here is probably one of the first analyses of the models of lysosomal hydrolases of the liver and kidney of experimental mice which were exposed to various doses of nicotine. The aim of our experimental study was to analyze the impact of nicotine administered for 4 or 8 days in the dosage of 12 and 20 mg/kg body weight, respectively, on the activity of acid phosphatase and cathepsins D and L, i.e. lysosomal hydrolases of the liver and kidney of mice. The experimental group constituted 60 Swiss male mice, aged 8-9 weeks, of average body weight of 23.4 +/- 1.2 grams. We came to the following conclusions after the completion of the experimental study and laboratory analyses: - nicotine injected once a day in the dosage of 12 mg and 20 mg/kg body weight for 4 and 8 days caused a significant increase in the activity of acid phosphatase, and cathepsins D and L in the liver and kidney of the studied mice. The range of observed changes was related to the organ, the dosage and administration time; - the increase in the activity of studied enzymes after administering nicotine may indicate that the alkaloid exhibits destabilizing activity in lysosomal membranes of the liver and kidney cells, therefore it may affect metabolic pathways of those organs.