Multitarget protection of Pterospartum tridentatum phenolic-rich extracts against a wide range of free radical species, antidiabetic activity and effects on human colon carcinoma (Caco-2) cells.

Pterospartum tridentatum is an edible endemic plant common in Portugal. Its flowers are used in culinary and are part of the popular medicine owing to its therapeutic properties. In this study, P. tridentatum flower infusion and hydroethanolic extracts were characterized concerning their phenolic composition and biological potential. By high-performance liquid chromatography method coupled to a diode array detector analysis were detected 13 phenolics. Genistein was the major one. Concerning the biological potential, the hydroethanolic extract was the most active against 2,2-diphenyl-1-picrylhydrazyl● and also as α-glucosidase inhibitor, while the infusion proved to be a remarkable free radical scavenger. Concerning human epithelial colorectal adenocarcinoma (Caco-2) cells, it was observed that both extracts displayed dose-dependent cytotoxicity on the viability of Caco-2 cells, presenting cytotoxic selectivity for these cancer cells when compared to the NHDF normal cell line. Additionally, they also showed protective effects against oxidative stress induced by tert-butyl hydroperoxide on Caco-2 cells. The obtained results suggest that these extracts may be interesting to enrich nutraceutical, pharmaceutical and food industries; however, more studies need to be done for their inclusion in pharmaceutical preparations and/or food additives. PRACTICAL APPLICATION: Pterospartum tridentatum is an endemic plant commonly used in folk medicine due to its depurative and hypoglycaemic properties. For this reason, we decided to determine the phenolic content of infusion and hydroethanolic extracts of P. tridentatum and their biological potential. The obtained results proved that P. tridentatum extracts are a rich source of bioactive compounds and possess great antioxidant and antidiabetic activities, ability to protect human erythrocytes against oxidative damage, inhibiting hemolysis, hemoglobin oxidation, and lipid peroxidation, and to interfere with Caco-2 cells growth and to protect these cells when subject to tert-butyl hydroperoxide oxidative stress conditions.

Sweet cherries from Fundão possess antidiabetic potential and protect human erythrocytes against oxidative damage.

Cherries are one of the most appreciated summer fruits due to their attractive colour, sweet taste, high water content, low level of calories and composition in bioactive compounds which, in turn, are important to prevent some pathologies like diabetes, cardiovascular diseases and cancer. In this work we evaluated the phenolic profile and biological potential of 5 varieties of sweet cherries from Fundão region (Portugal) (Saco, Sweetheart, Satin, Maring and Hedelfinger). A total of 23 phenolic compounds were identified by LC-DAD and distributed by the several classes: 6 anthocyanins, 1 hydroxybenzoic acid, 8 hydroxycinnamic acids, 3 flavan-3-ols and 5 flavonols. Maring revealed higher contents in anthocyanins, while Hedelfinger was the richest in non-coloured phenolics. The antioxidant capacity was evaluated against DPPH and nitric oxide radicals. Hedelfinger was the most active against DPPH• (IC50=12.1µg/mL) and Maring against nitric oxide (IC50=140.9µg/mL). Afterwards, antidiabetic capacity was evaluated through the inhibition of α-glucosidase activity, pointing Hedelfinger as the most active (IC50=10.3µg/mL). The capacity of Saco extracts to inhibit the hemoglobin oxidation and the hemolysis of human erythrocytes was also evaluated. Both assays revealed a concentration-dependent inhibitory effect (IC50=38.6µg/mL and IC50=73.0µg/mL, respectively). The results obtained in this study allow us to conclude that sweet cherries possess a great biological potential, and further investigation should be done to promote commercialization and encourage its use in food supplements and in new pharmaceutical and nutraceutical applications.

Legume bioactive compounds: influence of rhizobial inoculation.

Legumes consumption has been recognized as beneficial for human health, due to their content in proteins, fiber, minerals and vitamins, and their cultivation as beneficial for sustainable agriculture due to their ability to fix atmospheric nitrogen in symbiosis with soil bacteria known as rhizobia. The inoculation with these baceria induces metabolic changes in the plant, from which the more studied to date are the increases in the nitrogen and protein contents, and has been exploited in agriculture to improve the crop yield of several legumes. Nevertheless, legumes also contain several bioactive compounds such as polysaccharides, bioactive peptides, isoflavones and other phenolic compounds, carotenoids, tocopherols and fatty acids, which makes them functional foods included into the nutraceutical products. Therefore, the study of the effect of the rhizobial inoculation in the legume bioactive compounds content is gaining interest in the last decade. Several works reported that the inoculation of different genera and species of rhizobia in several grain legumes, such as soybean, cowpea, chickpea, faba bean or peanut, produced increases in the antioxidant potential and in the content of some bioactive compounds, such as phenolics, flavonoids, organic acids, proteins and fatty acids. Therefore, the rhizobial inoculation is a good tool to enhance the yield and quality of legumes and further studies on this field will allow us to have plant probiotic bacteria that promote the plant growth of legumes improving their functionality.