Browsing by Author "Larbi, Samar"
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- Differentiating between monofloral portuguese bee pollens using phenolic and volatile profiles and their impact on bioactive propertiesPublication . Larbi, Samar; Aylanc, Volkan; Rodriguez-Flores, Maria Shantal; Calhelha, Ricardo C.; Barros, Lillian; Rezouga, Feriel; Seijo-Coello, M. Carmen; Falcão, Soraia; Vilas-Boas, MiguelNowadays, bee products are commended by consumers for their medicinal and dietary properties. This study aimed to differentiate between monofloral bee pollens originating from Portugal using phenolic and volatile profiles and investigate their antioxidant and cytotoxic activity. Total phenolic and flavonoid compounds were recorded between 2.9-35.8 mg GAE/g and 0.7-4.8 mg QE/g, respectively. The LC/DAD/ESI-MSn analytical results allowed us to identify and quantify a total of 72 compounds, including phenolic and phenylamide compounds, whereas GC-MS results revealed the presence of 49 different compounds, mostly ketones, aldehydes, esters, hydrocarbons, and terpenes. The highest DPPH center dot radical scavenging activity, EC50: 0.07 mg/mL, was recorded in the sample dominated by Castanae sp. pollen, whereas the Rubus sp. (1.59 mM Trolox/mg) and Cistaceae sp. (0.09 mg GAE/g) pollen species exhibited the highest antioxidant activity in ABTS center dot+ and reducing power assays, respectively. Regarding the anti-carcinogenic activity, only Carduus sp. showed remarkable cytotoxic potential against MCF-7.
- Differentiation of bee pollen origin through phenolic and volatile profilesPublication . Larbi, Samar; Falcão, Soraia; Vilas-Boas, Miguel; Rezouga, FerielNowadays, bee products are notably commended by consumers for medicinal and dietary purposes. Bee pollen is particularly used as a precious source of nutritious compounds like proteins (which includes enzymes), carbohydrates, lipids, minerals as well as a large range of secondary plant metabolites (polyphenols, carotenoids, tocopherol and vitamins). According to the literature, bee pollen possesses great potentialities such as antioxidant, anti-inflammatory, antibacterial activities, among other . Therefore, it can be used as a food supplement to promote the human body resistance against numerous diseases including cancer. However, the bee pollen composition varies depending on the botanical and the geographical origin, which represents the major difficulty in the application of this matrix. The aim of the present study was to differentiate bee pollen origin through the phenolic and volatile profiles of samples from Portugal and Morocco. Also, the contribution of their phenolic compounds to the antioxidant and cytotoxic activities were investigated. After the determination of the total phenolics and flavonoid content analysis through UV-Vis analysis, the phenolic composition was assessed by liquid chromatography coupled to mass spectrometry (LC-MS). The volatile profile of the samples was access through gas chromatography coupled to mass spectrometry (GC-MS) after solid-phase microextraction (SPME). The antioxidant properties were measured by DPPH and ABTS scavenging activity and reducing power assays. Finally, the cytotoxicity of the extracts was examined employing different human tumor cell lines. Our results showed that bee pollen has a rich phenolic profile. Samples from Portugal displayed diverse phenylamides and flavonoid glycosides, while the Moroccan ones presented mostly flavonoid glycosides, phenylamides and some phenolic acids, except M7 which contained important phenylamide quantity. Concerning volatile compounds, plenty of compounds were detected majorly aldehydes, alcohols and some ketones. Some samples presented a high antioxidant capacity particularly the chestnut bee pollen from Bragança. In terms of anti-carcinogenic activity, only P1, Asteraceae carduus bee pollen, exhibited a remarkable anti-tumor potential against MCF-7 (breast carcinoma). Overall, Bee pollen samples belonging to the same floral origin presented similarities in both phenolic and volatile compounds profiles. Also, some detected phenolic and volatile compounds can be considered as fliral and geographical biomarkers.
- Evaluation of antioxidant and anticancer activity of mono- and polyfloral moroccan bee pollen by characterizing phenolic and volatile compoundsPublication . Aylanc, Volkan; Larbi, Samar; Calhelha, Ricardo C.; Barros, Lillian; Rezouga, Feriel; Rodriguez-Flores, Maria Shantal; Seijo-Coello, M. Carmen; El Ghouizi, Asmae; Lyoussi, Badiâa; Falcão, Soraia; Vilas-Boas, MiguelBee pollen is frequently characterized as a natural source of bioactive components, such as phenolic compounds, which are responsible for its pharmaceutical potential and nutritional properties. In this study, we evaluated the bioactive compound contents of mono- and polyfloral bee pollen samples using spectroscopic and chromatographic methods and established links with their antioxidant and antitumor activity. The findings demonstrated that the botanical origin of bee pollen has a remarkable impact on its phenolic (3-17 mg GAE/g) and flavonoid (0.5-3.2 mg QE/g) contents. Liquid chromatography-mass spectrometry analysis revealed the presence of 35 phenolic and 13 phenylamide compounds in bee pollen, while gas chromatography-mass spectrometry showed its richness in volatiles, such as hydrocarbons, fatty acids, alcohols, ketones, etc. The concentration of bioactive compounds in each sample resulted in a substantial distinction in their antioxidant activity, DPPH (EC50: 0.3-0.7 mg/mL), ABTS (0.8-1.3 mM Trolox/mg), and reducing power (0.03-0.05 mg GAE/g), with the most bioactive pollens being the monofloral samples from Olea europaea and Ononis spinosa. Complementarily, some samples revealed a moderate effect on cervical carcinoma (GI(50): 495 mu g/mL) and breast adenocarcinoma (GI(50): 734 mu g/mL) cell lines. This may be associated with compounds such as quercetin-O-diglucoside and kaempferol-3-O-rhamnoside, which are present in pollens from Olea europaea and Coriandrum, respectively. Overall, the results highlighted the potentiality of bee pollen to serve health-promoting formulations in the future.