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In this study, the methanolic and infusion extracts of two species, Thymbra capitata and Thymus sipyleus subsp. rosulans, were tested for their chemical composition and biological abilities (antioxidant, enzyme inhibitory and anti-inflammatory effects). The extracts yielded total phenolic and flavonoid contents in the range of 83.43–127.52 mg GAE/g and 9.41–46.34 mg RE/g, respectively. HPLC analysis revealed rosmarinic acid to be a major component of the studied extracts (15.85–26.43%). The best ABTS radical scavenging ability was observed in the methanol extract of T. capitata with 379.11 mg TE/g, followed by in the methanol extract of T. sipylus (360.93 mg TE/g). In the CUPRAC assay, the highest reducing ability was also found in the methanol extract of T. capitata with 802.22 mg TE/g. The phosphomolybdenum ability ranged from 2.39 to 3.61 mmol TE/g. In terms of tyrosinase inhibitory effects, the tested methanol extracts (83.18–89.66 mg KAE/g) were higher than the tested water extracts (18.74–19.11 mg KAE/g). Regarding the BChE inhibitory effects, the methanol extracts were active on the enzyme while the water extracts showed no inhibitory effect on it. Overall, the methanolic extracts showed better enzyme inhibition compared to the infusion extracts. Molecular docking also showed the selected exhibited potential binding affinities with all enzymes, with a preference for cholinesterases. Additionally, the extracts were effective in attenuating the LPS-induced increase in COX-2 and IL-6 gene expression in isolated colon, thus indicating promising anti-inflammatory effects. The preliminary results of this study suggest that these species are good natural sources of antioxidants and also provide some scope as enzyme inhibitors, most likely due to their bioactive contents such as phenolic acids, and thus can be exploited for different applications related to health promotion and disease prevention. [ABSTRACT FROM AUTHOR]

Here is reported the phenolic profile obtained by high-performance liquid chromatography with diode array and mass spectrometry detection and the antioxidant activity using the ABTS and DPPH assays of leaves of Berberis hispanica Boiss. & Reut. The most abundant compounds were caffeoylquinic acids, in particular chlorogenic acid with 19.3 mg g−1 dried extract, caffeoylglucaric acids and quercetin glycosides. Also, the compound dihydro-roseoside is reported for the first time in a Berberis species. The antioxidant potential was in agreement with the phenolic content: the highest concentration of phenolics corresponded to the highest antioxidant activity in both of the assays equal to 648 and 547 µmol Trolox equivalents g−1 dried extract methanolic fraction for the ABTS and DPPH assays, respectively. These results contribute to the limited bibliographic information concerning this plant species and represent a starting point to evaluate its potential as a novel source of bioactive compounds. [ABSTRACT FROM AUTHOR]

We propose an alternative approach for the development of analytical methods based on terbium-sensitized luminescence (TSL). TSL is based on the complexation between Tb(III) ions and fluorescent organic compounds that have appropriate functional groups to complex with Tb(III). We report the use of graphene quantum dot (GQDs) nanoparticles to improve the sensitivity and selectivity of TSL detection. GQDs can react with terbium ions through the carboxylic groups present in their structure. These Tb(III)-GQD complexes, formed in situ in aqueous solution, can be used as time-resolved luminescent probes. Ascorbic acid was selected as a target analyte to demonstrate the suitability of the proposed method. The selectivity of the TSL method was highly improved for most of the interferences tested. Under the optimum conditions [Tb(III) concentration 5 × 10 mol L, GQD concentration 4 mg L], a minimum 100% increase in selectivity was observed for several vitamins and common cations that may be present in the samples to be analyzed. In addition, the analytical signal showed a 30% enhancement with the use of GQDs compared with the use of merely Tb(III) ions, with a detection limit of 0.12 μg mL. The repeatability and intermediate precision were lower than 3% and 5%, respectively. From the results obtained, the implementation of GQDs in TSL can lead to the development of novel time-resolved luminescent probes with high analytical potential. [ABSTRACT FROM AUTHOR]

This paper reports the determination of aflatoxin B1 (AFB1), one of the most carcinogenic substances known. A multi-commuted flow injection–solid phase spectroscopy (FI–SPS) system combined with photochemically induced fluorescence (PIF) was developed, for the first time, for its quantitative determination. A strongly fluorescent degradation product was obtained on-line by irradiation with ultraviolet light. The determination was carried out by measuring the fluorescence intensity of the photo-product at 353/424 (λex/λem), once retained on C18 silica-gel filling the flow-cell. A linear dynamic range of 0.09–12 µg l−1, detection limit as sensitive as 29 ng l−1 and a relative standard deviation (RSD) of 1.4% were obtained. The method proposed was satisfactorily applied to the determination of AFB1 in different types of beer (normal and non-alcoholic). Hydrophobic compounds were eliminated from beer samples and AFB1 was extracted with acetonitrile by solid-phase extraction on C18 sorbent. Recoveries of the target compound from spiked beers were between 94 and 106%. The results obtained in the analysis of real samples are in good agreement with those provided by a reference chromatographic method. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]