Berberis species are known for their use in traditional medicine. Here, we report the phenolic composition and bioactivity of methanolic and aqueous extracts of Berberis thunbergii DC. leaves. The phenolic profiling and the quantitation of the main compounds were performed by high-performance liquid chromatography with diode array and mass spectrometry detections. The most abundant compounds in both extracts were caffeoylquinic acids (chlorogenic acid, particularly, with a concentration of 90.1–101.3 mg g−1 dried extract), followed by caffeoylglucaric acids and quercetin glycosides. Antioxidant and radical scavenging assays (phosphomolybdenum, DPPH, ABTS, CUPRAC, FRAP, metal chelating activity), as well as enzyme inhibitory assays (acetylcholinesterase, butyrylcholinesterase, tyrosinase, amylase, glucosidase, and lipase), were carried out to evaluate the potential bioactivity of B. thunbergii. The methanolic extract presented the highest antioxidant and radical scavenging values, in agreement with its higher phenolic content. Regarding enzyme inhibitory potential, the methanolic extract was also more potent than the aqueous one. Hence, B. thunbergii leaves represent a suitable candidate for the preparation of pharmaceutical or nutraceutical products.
In this work, we compared the phenolic composition and antioxidant capacity of methanolic extracts of raw and steamed aerial parts of Portulaca oleracea L. Two new cyclo-dopa amides were identified, named oleraceins X and Y, along with six known ones (oleraceins A, B, C, N, J, and U). Compounds identification and quantification were done by high-performance liquid chromatography with diode array and mass spectrometry detections. The most abundant compounds were phenolic alkaloids (oleraceins), and the main quantified compounds were isocitric and citric acids, with concentrations of 500–550 and 440–600 mg/100 g dried extract, respectively. The study of both the influence of the steaming process in Portulaca oleracea L. and total phenolic content and radical scavenging assays (ABTS·+ and DPPH) were also carried out. The total individual phenolic content of raw Portulaca decreased from 1380 mg/100 g DE to 1140 mg/100 g DE after the steaming process. The antioxidant capacity in ABTS and DPPH assays decreased approximately 50 and 40%, respectively, after samples were cooked by steaming. The raw extracts presented the highest concentration of bioactive compounds, as well as higher antioxidant and radical scavenging values.
The phenolic composition and mineral content of Cornezuelo, Cornicabra and Picual olive fruit varieties were investigated during olive ripening in two different harvesting seasons (2017/2018 and 2018/2019). Phytochemical profiles were evaluated by high-performance liquid chromatography (HPLC) with diode-array and mass spectrometry detection. Mineral contents were determined by inductively coupled plasma-mass spectrometry (ICP-MS). Twenty-five compounds were characterized and the main ones quantified. These compounds corresponded mostly to secoiridoids, the main ones being oleuropein, oleoside/secologanoside, oleoside-11-methylester, and oleuropein and comselogoside isomers. Total phenolic contents reached the highest values between December and January, coinciding with the usual harvesting date. This trend was observed in both harvesting seasons, although higher phenolic contents were recorded in season 2018/2019. This was due to the different weather conditions, which caused a lower olive production in season 2017/2018. No clear tendency was observed between mineral content and harvest time in any of the studied seasons. The highest concentration of total phenolics was obtained in Cornezuelo variety (840 mg/100 g) in January 2019 (season 2018/2019). Picual and Cornicabra varieties reached concentrations of 670 mg/100 g and 530 mg/100 g, respectively, also in the last harvesting dates of season 2018/2019.
TiO2 is the most used material for the photocatalytic removal of organic pollutants in aqueous media. TiO2, specifically its anatase phase, is well-known for its great performance under UV irradiation, high chemical stability, low cost and non-toxicity. Nevertheless, TiO2 presents two main drawbacks: its limited absorption of the visible spectrum; and its relatively low specific surface area and pore volume. Regarding the latter, several works in the literature have addressed the issue by developing new synthesis approaches in which anatase is dispersed and supported on the surface of porous materials. In the present work, two series of materials have been prepared where anatase has been supported on mesoporous silica (MSTiR%) in situ through a hydrothermal synthesis approach, where, in addition to using tetraethoxysilane (TEOS) as a silicon precursor, three organotriethoxysilanes [RTEOS, where R = methyl (M), propyl (P) or phenyl (Ph)] were used at a RTEOS:TEOS molar percentage of 10 and 30%. The materials were thoroughly characterized by several techniques to determine their morphological, textural, chemical, and UV-vis light absorption properties and then the most promising materials were used as photocatalysts in the photodegradation of the emerging contaminant and antiepileptic carbamazepine (CBZ) under UV irradiation. The materials synthesized using 10% molar percentage of RTEOS (MSTiR10) were able to almost completely degrade (~95%), 1 mg L−1 of CBZ after 1 h of irradiation using a 275 nm LED and 0.5 g L−1 of catalyst dose. Therefore, this new synthesis approach has proven useful to develop photoactive TiO2 composites with enhanced textural properties.
TiO2 is the most used material for the photocatalytic removal of organic pollutants in aqueous media. TiO2, specifically its anatase phase, is well-known for its great performance under UV-irradiation, high chemical stability, low-cost and non-toxicity. Nevertheless, TiO2 presents two main drawbacks: its limited absorption of the visible spectrum; and its relatively low specific surface area and pore volume. Regarding the latter, several works in the literature have addressed the issue by developing new synthesis approaches in which anatase is dispersed and supported on the surface of porous materials. In the present work, two series of materials have been prepared where anatase has been supported on mesoporous silica (MSTiR%) in situ through a hydrothermal synthesis approach, where, in addition to using tetraethoxysilane (TEOS) as silicon precursor, three organotriethoxysilanes [RTEOS, where R = methyl (M), propyl (P) or phenyl (Ph)] where used at a RTEOS:TEOS molar percentage of 10 and 30%. The materials where thoroughly characterized by several techniques to determine their morphological, textural, chemical, and UV-vis light absorption properties and then, the most promising materials were used as photocatalyst in the photodegradation of the emerging contaminant and antiepileptic carbamazepine under UV irradiation. The materials synthesised using 10% molar percentage of RTEOS (MSTiR10) where able to almost completely degraded (⁓95%), 1 mg L–1 of carbamazepine (CBZ) after 1 h of irradiation using a 275 nm LED and 0.5 g L–1 of catalyst dose. Therefore, this new synthesis approach has proven useful to develop photoactive TiO2 composites with enhanced textural properties.