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- Ulex europaeus: from noxious weed to source of valuable isoflavones and flavanonesPublication . Spínola, Vítor; Llorent-Martínez, Eulogio J.; Gouveia-Figueira, Sandra; Castilho, Paula C.The screening and quantification of the main phenolic compounds in leaves and flowers of Ulex europaeus (gorse) was carried out by high-performance liquid chromatography with electrospray ionization mass spectrometric detection (HPLC-ESI–MSn) after ultrasound-assisted extraction with methanol. About 98% of compounds corresponded to flavonoids, distributed as flavonols, flavones, isoflavones and flavanones. Flavonols were mainly quercetin glucosides; most of the found flavones were apigenin derivatives and the isoflavone group was dominated by glycitin. The flavanone group was composed mainly of liquiritigenin derivatives, substances usually found in liquorice (Glycyrrhiza ssp) and associated with high pharmacological relevance; in Ulex they represent about 25% of total polyphenols content. Phenolic acids and saponins were also detected, as minor components. In vitro antioxidant activity (nitric oxide, superoxide assays, ABTS and DPPH assays) of leaves and flowers, and their inhibitory effects towards digestive enzymes related to carbohydrate metabolism (-glucosidase and -amylase) were also studied.
- HPLC-ESI-MSn characterization of phenolic compounds, terpenoid saponins, and other minor compounds in Bituminaria bituminosaPublication . Llorent-Martínez, Eulogio J.; Spínola, Vítor; Gouveia, Sandra; Castilho, Paula C.Bituminaria bituminosa is a wild legume that can endure drastic conditions, including contaminated and degraded soils. It has been traditionally used as feeding for livestock, and different uses in folk medicine are known. The chemical composition of leaves and flowers from B. bituminosa is presented for the first time. The screening of phytochemical compounds was carried out using high-performance liquid chromatography with electrospray ionization mass spectrometric detection (HPLC-ESI-MSn). More than 40 compounds were identified or tentatively characterized. A high percentage of the detected compounds corresponded to glycosylated flavonoids, especially from apigenin, although phenolic acids, lignans, and saponins were also identified.
- Myrica faya: a new source of antioxidant phytochemicalsPublication . Spínola, Vítor; Llorent-Martínez, Eulogio J.; Gouveia, Sandra; Castilho, Paula C.Myrica faya is a fruit tree endemic of the Macaronesia (Azores, Madeira, and Canary Island), and its edible fruits are known as "amorinhos" (little loves), bright red to purple berries, used fresh and in jams and liquors. The phenolic composition and antioxidant capacity of leaves and berries from M. faya are presented here for the first time. The screening of phytochemical compounds was carried out using high-performance liquid chromatography with online UV and electrospray ionization mass spectrometric detection (HPLC-DAD-ESI-MS(n)). There were 55 compounds characterized, mostly galloyl esters of flavonoids and phenolic acids; 26 of the identified compounds (anthocyanins, isoflavonoids, lignans, terpenes, fatty acids, and phenylethanoids) have not been reported in Myrica genus so far. From the data presented here, it can be concluded that faya berries represent a rich source of cyanidin-3-glucoside, flavonoids, and vitamin C. In fact, higher antioxidant activity than that of the well-known Myrica rubra berries (Chinese bayberry) has been observed.