orientin and ferulic-acid

A nested analysis of variance combined with simultaneous component analysis, ASCA, was proposed to model high-dimensional chromatographic data. The data were obtained from an experiment designed to investigate the effect of production season, quality grade and post-production processing (steam pasteurization) on the phenolic content of the infusion of the popular herbal tea, rooibos, at 'cup-of-tea' strength. Specifically, a four-way analysis of variance where the experimental design involves nesting in two of the three crossed factors was considered. For the purpose of the study, batches of fermented rooibos plant material were sampled from each of four quality grades during three production seasons (2009, 2010 and 2011) and a sub-sample of each batch was steam-pasteurized. The phenolic content of each rooibos infusion was characterized by high performance liquid chromatography (HPLC)-diode array detection (DAD). In contrast to previous studies, the complete HPLC-DAD signals were used in the chemometric analysis in order to take into account the entire phenolic profile. All factors had a significant effect on the phenolic content of a 'cup-of-tea' strength rooibos infusion. In particular, infusions prepared from the grade A (highest quality) samples contained a higher content of almost all phenolic compounds than the lower quality plant material. The variations of the content of isoorientin and orientin in the different quality grade infusions over production seasons are larger than the variations in the content of aspalathin and quercetin-3-O-robinobioside. Ferulic acid can be used as an indicator of the quality of rooibos tea as its content generally decreases with increasing tea quality. Steam pasteurization decreased the content of the majority of phenolic compounds in a 'cup-of-tea' strength rooibos infusion.

Topics: Analysis of Variance; Aspalathus; Beverages; Chalcones; Chromatography, High Pressure Liquid; Coumaric Acids; Fermentation; Flavonoids; Glucosides; Pasteurization; Phenols; Plant Leaves; Principal Component Analysis; Seasons; Steam

Indocalamus latifolius (Keng) McClure leaf is a popular food material in East Asia due to its antioxidant and anticorrosive activities. To utilize it more effectively, we investigated the discrepancy of antioxidant activities and active compound content in Indocalamus latifolius leaf along with the altitude change. Total flavonoids, phenolics, titerpenoids and eight characteristic active constituents, i.e, orientin, isoorientin, vitexin, homovitexin, p-coumaric acid, chlorogenic acid, caffeic acid, and ferulic acid, were determined by UV-spectrophotometer and synchronous RP-HPLC, respectively. Antioxidant activity was measured using DPPH and FRAP methods. Our data showed that the content of TP and TF, DPPH radical scavenging ability and ferric reduction power of Indocalamus latifolius leaf changed as altitude altered, with the trends of decreasing gradually when lower than 700 m and then increasing to 1,000 m. Chlorogenic acid and orientin were the main characteristic compounds in Indocalamus latifolius leaf and were also affected by altitude. Our result indicated that higher altitude with an adverse environment is conducive to secondary metabolite accumulation for Indocalamus latifolius. It would provide a theoretical basis to regulate the leaf collection conditions in the industrial use of Indocalamus latifolius leaf.

Topics: Antioxidants; Apigenin; Asia; Biphenyl Compounds; Caffeic Acids; Chlorogenic Acid; Coumaric Acids; Diet; Ecosystem; Ferric Compounds; Flavonoids; Glucosides; Picrates; Plant Extracts; Plant Leaves; Poaceae; Polyphenols; Secondary Metabolism; Triterpenes

Sasa argenteastriatus, with abundant active compounds and high antioxidant activity in leaves, is a new leafy bamboo grove suitable for exploitation. To utilize it more effectively and scientifically, we investigate the seasonal variations of antioxidant composition in its leaves and antioxidant activity. The leaves of Sasa argenteastriatus were collected on the 5th day of each month in three same-sized sample plots from May 2009 to May 2011. The total flavonoids (TF): phenolics (TP) and triterpenoid (TT) of bamboo leaves were extracted and the contents analyzed by UV-spectrophotometer. Our data showed that all exhibited variations with the changing seasons, with the highest levels appearing in November to March. Antioxidant activity was measured using DPPH and FRAP methods. The highest antioxidant activity appeared in December with the lowest in May. Correlation analyses demonstrated that TP and TF exhibited high correlation with bamboo antioxidant activity. Eight bamboo characteristic compounds (orientin, isoorientin, vitexin, homovitexin and p-coumaric acid, chlorogenic acid, caffeic acid, ferulic acid) were determined by RP-HPLC synchronously. We found that chlorogenic acid, isoorientin and vitexin are the main compounds in Sasa argenteastriatus leaves and the content of isovitexin and chlorogenic acid showed a similar seasonal variation with the TF, TP and TT. Our results suggested that the optimum season for harvesting Sasa argenteastriatus leaves is between autumn and winter.

Topics: Antioxidants; Apigenin; Caffeic Acids; Chromatography, High Pressure Liquid; Coumaric Acids; Flavonoids; Glucosides; Phenols; Plant Extracts; Plant Leaves; Propionates; Sasa; Seasons; Triterpenes