Analysis of isoflavones and flavonoids in human urine by UHPLC

A rapid, ultra high-performance liquid chromatographic (UHPLC) method has been developed and validated for simultaneous identification and analysis of the isoflavones genistein, daidzein, glycitin, puerarin, and biochanin A, and the flavonoids (±)-catechin, (−)-epicatechin, rutin, hesperidin, neohesperidin, quercitrin, and hesperetin in human urine. Urine samples were incubated with β-glucuronidase/sulfatase. UHPLC was performed with a Hypersil Gold (50 × 2.1 mm, 1.9 μm) analytical column. Elution was with a gradient prepared from aqueous trifluoroacetic acid (0.05%) and acetonitrile. UV detection was performed at 254 and 280 nm. The calibration curves were indicative of good linearity (r2 ≥ 0.9992) in the range of interest for each analyte. LODs ranged between 15.4 and 107.0 ng mL−1 and 3.9 and 20.4 ng mL−1 for flavonoids and isoflavones, respectively. Intra-day and inter-day precision (C.V., %) was less than 3.9% and 3.8%, respectively, and accuracy was between 0.03% and 5.0%. Recovery was 70.35–96.58%. The method is very rapid, simple, and reliable, and suitable for pharmacokinetic analysis. It can be routinely used for simultaneous determination of these five isoflavones and seven flavonoids in human urine. The method can also be applied to studies after administration of pharmaceutical preparations containing isoflavones and flavonoids to humans

The antioxidant and antiproliferative activities of methanolic extracts from Njavara rice bran

<p>Abstract</p> <p>Background</p> <p>Free radical-induced oxidative stress is the root cause for many human diseases. Naturally occurring antioxidant supplements from plants are vital to counter the oxidative damage in cells. The main objective of the present study was to characterize the antioxidant and antiproliferative potential of rice bran extracted from an important Indian rice variety, Njavara and to compare the same with two commercially available basmati rice varieties: Vasumathi, Yamini and a non medicinal variety, Jyothi.</p> <p>Methods</p> <p>Methanolic extracts of rice bran from four varieties; Vasumathi, Yamini, Jyothi and Njavara were used to study their total phenolic and flavonoid contents, <it>in vitro </it>antioxidant activities including total antioxidant activity, scavenging of nitric oxide and 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical, reducing power and cytotoxic activity in C6 glioma cells. Correlation coefficient and regression analysis were done by using Sigmastat version 3.1 and Stata statistical package respectively.</p> <p>Results</p> <p>Rice bran methanolic extract from Njavara showed the highest antioxidant and cell cytotoxic properties compared to the other three rice varieties. IC₅₀values for scavenging DPPH and nitric oxide were in the range of 30.85-87.72 μg/ml and 52.25-107.18 μg/ml respectively. Total antioxidant activity and reducing power were increased with increasing amounts of the extract. Total phenolic and flavonoid contents were in the range of 3.2-12.4 mg gallic acid-equivalent (GAE)/g bran and 1.68-8.5 mg quercetin-equivalent (QEE)/g bran respectively. IC₅₀values of cytotoxic assay (MTT assay) were 17.53-57.78 μg/ml. Correlation coefficient and regression analysis of phenolic content with DPPH and NO scavenging, MTT (-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay, total antioxidant assay and reducing power showed a highly significant correlation coefficient values (96-99%) and regression values (91-98%).</p> <p>Conclusion</p> <p>The results of the present study show that the crude methanolic extract from Njavara rice bran contains significantly high polyphenolic compounds with superior antioxidant activity as evidenced by scavenging of free radicals including DPPH and NO. Njavara extracts also showed highest reducing power activity, anti-proliferative property in C6 glioma cells. In conclusion, it is conceivable that the Njavara rice variety could be exploited as one of the potential sources for plant - based pharmaceutical products.</p

From functional food to medicinal product: Systematic approach in analysis of polyphenolics from propolis and wine

In the last decade we have been working on standardization of propolis extract and determination of active constituents of wine those are rich in polyphenolics and have nutritional as well as therapeutic value. Here we are summarizing our results and providing overview on systematic approach how to analyse natural products rich in flavonoids and phenolic acids

Stability and sensory assessment of emulsions containing propolis extract and/or tocopheryl acetate

The prevention of skin aging has been one of the main aims of cosmetic products. Propolis and tocopheryl acetate can be promising substances because of their antioxidant properties. In this study, propolis extract was obtained and associated with tocopheryl acetate in a cream formulation, which then underwent stability and sensory assessment. The formulation containing propolis extract and tocopheryl acetate proved to be stable in the preliminary stability study, demonstrating gradual darkening and slight pH decrease when subjected to 60ºC for 28 days, but showing stability on rheological study. In the sensory analysis, the formulation containing these two components was preferred by the product testers over the base cream and creams containing propolis extract or tocopheryl acetate alone. In conclusion, given the stability of the formulation and the preference of the product testers for this formulation, this association proved promising for use in cosmetic formulations.A prevenção do envelhecimento cutâneo tem sido um dos principais focos dos produtos dermocosméticos. A própolis contém substâncias com atividade antioxidante, bem como o acetato de tocoferila é conhecido por apresentar esta atividade. Porém, a própolis apresenta odor muito característico e intenso, que pode interferir no sensorial do produto. Assim, no presente trabalho, obteve-se o extrato de própolis, que foi associado ao acetato de tocoferila em uma formulação de uso tópico, que foi avaliada quanto à estabilidade e às características sensoriais. Conduziu-se um estudo de estabilidade, no qual as formulações contendo ambos os compostos apresentaram escurecimento gradual e ligeira queda no pH após 28 dias sob 60 °C, tendo sido estável no estudo reológico. Na análise sensorial, realizada com 28 provadores, a formulação contendo extrato de própolis em associação com acetato de tocoferila foi a preferida, quando comparada com o creme base e o creme contendo somente extrato de própolis ou acetato de tocoferila. Em conclusão, devido à preferência dos provadores e ao estudo de estabilidade, a associação de extrato de própolis e de acetato de tocoferila mostrou ser promissora para uso em produtos dermocosméticos