Nutraceutical properties of tuscan bee-pollen: antioxidant, anti-hemolitic and antimicrobial activities

Bee-gathered pollen (bee-pollen) is an apicultural product of great interest owing to its high nutritional and therapeutic properties, as well as an important source of energy, bioactive compounds and proteins for human nutrition. In a previous study we evaluated botanical origin, phytochemical profile and free-radical scavenging activity of a polyfloral organic Tuscan bee-pollen separated by color into three botanical families, specifically Castanea, Rubus and Cistus. Among them, Castanea showed the highest phytochemical content. Moreover, a strong in vitro antioxidant activity has been highlighted. Thus, the aim of this study was to evaluated the cellular antioxidant activity and anti-hemolytic effect of both polyfloral and separate bee-pollen fraction on human erythrocytes, using the CAA-RBC assay and the hemolysis test. Besides, we also evaluated the anti-microbial activity of each separate fraction on three Gram-negative bacteria (Escherichia coli, Salmonella enterica ser. Typhimurium and Enterobacter aerogenes), and on two Gram-positive bacteria (Enterococcus faecalis and Staphylococcus aureus). The minimal inhibitory concentration (MIC) values was determined. Our results showed a good biological activity of both polyfloral and separate bee-pollen samples. Polyfloral bee-pollen exhibited a hemolysis inhibition comparable to Castanea and Cistus sample, significantly higher than Rubus. However, a significantly higher cellular antioxidant activity was detected in polyfloral bee-pollen pre-treated erythrocytes compared to each separate fraction suggesting a biological synergic activity. Furthermore, Cistus and Castanea exhibited antibacterial action against all bacteria, higher than Rubus bee-pollen. For instance, the most sensitive Gram-negative microorganisms were Escherichia coli and Salmonella typhimurium, showing MIC values of 10 mg/ml. Whereas, both Gram-positive bacteria were inhibited at 10 and 5 mg/ml by Cistus and Castanea bee-pollen, respectively. Otherwise, Rubus was effective only against Gram-positive bacteria. In conclusion, Tuscan bee-pollen represents a good natural antibacterial, as well as an excellent food supplement and potential nutraceutical product useful in the prevention of free radical associated diseases.