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- Effect of processing conditions on the bioactive compounds and biological properties of bee pollenPublication . Dias, L.G.; Tolentino, Georgina Santos; Pascoal, Ananias; Estevinho, Leticia M.Bee pollen has had a valued place in traditional medicine for centuries, even though its use in modern medicine is still limited by the lack of scientific evidence. In this study, we characterized and compared nine types of bee pollen, submitted to two preservation methods (lyophilization and drying), in relation to the content of phenolic compound and total flavonoids. The biological properties were also evaluated and compared. Pollen analysis allowed us to classify two samples as heterofloral, whilst the remaining were monofloral. The concentrations of flavonoid and phenolic compounds were greater in the lyophilized samples. Even though all samples presented antimicrobial activity, the lyophilized ones induced stronger inhibition against both Gram-negative and Gram-positive bacteria. For the yeasts studied, the difference between the two preservation procedures was not so relevant. The antioxidant activity was also greater in the lyophilized samples. Antimutagenic capacity was observed in all samples, independently of the preservation method, even though some bee pollen types decreased the number of gene conversion and mutant colonies more efficiently. In conclusion, the results suggest that lyophilization is better to preserve the bioactive compounds and biological properties of this natural product.
- Biological activities of commercial bee pollens: antimicrobial, antimutagenic, antioxidant and anti-inflammatoryPublication . Pascoal, Ananias; Rodrigues, Sandra; Teixeira, Alfredo; Feás, Xesús; Estevinho, Leticia M.Bee pollen is considered, since memorable times, a good source of nourishing substances and energy. The present study aimed to evaluate the biological activities of eight commercial bee pollens purchased from the market. The origin of sample A was not specified in the labeling; samples B, C, D and G were from Portugal and the remaining were from Spain. The sample E presented the highest value of phenolics (32.15 ± 2.12 mg/g) and the H the lowest (18.55 ± 095 mg/g). Sample C had the highest value of flavonoids (10.14 ± 1.57 mg/g) and sample H the lowest (3.92 ± 0.68 mg/g). All the samples exhibited antimicrobial activity, being Staphylococcus aureus the most sensitive and Candida glabrata the most resistant of the microorganisms studied. All the samples exhibited antimutagenic activity, even though some samples were more effective in decreasing the number of gene conversion colonies and mutant colonies. Regarding the antioxidant activity, assessed using two methods, the more effective was sample B. The anti-inflammatory activity, assessed using the hyaluronidase enzyme, was highest in samples B and D. Pearson’s correlation coefficients between polyphenols, flavonoids, antioxidant activity and antimicrobial activity were computed. It was also performed a discriminant analysis.