Search

Ilex rotunda Thunb., has been used to treat common cold, tonsillitis, and eczema. It is also a source of antioxidants. However, information regarding its antioxidative phytochemical composition is still incomplete and limited. In this present study, we initially determined DPPH radical scavenging activity of the extracts of I. rotunda fruits, twigs, and leaves. Among them, the twig extract exhibited a potential of antioxidant capacity. Based on antioxidant effect guided experiments, extraction condition using 80% EtOH was then optimized. DPPH and ABTS radical scavenging assays were also performed for fractions. The n-butanol fraction showed the highest antioxidant effect. Using chromatographic methods, eight marker compounds (1–8) were further isolated. Their structures were determined by spectroscopic and mass data. Method validation was employed to quantitate contents of these eight marker compounds. Subsequently, the HPLC-DPPH method was used to evaluate the contribution of certain compounds to total antioxidant activity of the extract. Lastly, parallel artificial membrane permeability assay for blood–brain barrier (PAMPA-BBB) was applied to investigate brain-penetrable antioxidants from I. rotunda extract. As a result, compound 7 (4,5-dicaffeoylquinic acid) showed significant antioxidant activity and penetration across the BBB via transcellular passive diffusion. Our findings suggested that compound 7 can be used as a therapeutic potential candidate in natural product-based central nervous system (CNS) drug discovery. [ABSTRACT FROM AUTHOR]

Semen Oroxyli, derived from the seed of Oroxylum indicum L., is a commonly used Traditional Chinese Medicine with beneficial effects against several respiratory disorders. Antioxidative flavonoids may be partly responsible for its medicinal functions. The aim of this study was to rapidly determine the antioxidants in Semen Oroxyli based on a HPLC-DPPH method. Four major flavonoids, baicalein-7-O-gentiobioside, baicalein-7-O-glucoside, baicalein, and baicalin, were identified as the active components against DPPH free radicals, which is in accord with the results of our former traditional activity-guided phytochemical study. The oxidative products of the four antioxidant flavonoids were studied in the DPPH spiking HPLC assay, it was suggested that the three active flavonoid glycosides were converted into 5,6-dihydroxy-7-methoxyflavone, which implied that an additional hydroxyl at C-6 in 5,7-dihydroxyflavones plays an important role in the DPPH assay. [ABSTRACT FROM AUTHOR]

The goal of this study was to explore the potential of carob extracts to act as lipid inhibitors in model food systems. First, the extraction efficacy of fourteen solvents on the phenolic and flavonoid contents as well as on the antioxidant activity was assessed. Results showed that the phenolic composition and antioxidant activity of the extracts were strongly affected by solvents. Subsequently, the antioxidant potential of the most promising extracts (water, methanol, acidic acetone, and acetone–water) against four model food systems were evaluated. The acidic acetone extract had the highest antioxidant activity (70.3 ± 5.3%) in the β-carotene-linoleic acid system, followed by the acetone–water extract (62.1 ± 4.9%). Both extracts significantly prevented the lipid oxidation in sunflower oil and cooked comminuted pork; the inhibition activity at the end of storage period was 36.7–50.5% and 17.4–24.8%, respectively. A reduction of 49.5–54.8% in the formation of dienes in the oil-in-water emulsion was also found. The inhibitory effect of methanolic and aqueous extracts was significantly lower. Qualitative and quantitative variations in extracts are responsible for this antioxidant behavior in food systems. Gallic acid, myrecetin, rutin, and catechin are the main components of the extracts while myricetin and quercetin play an essential role in the antioxidant activity, according to the biochromatograms. [ABSTRACT FROM AUTHOR]