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Eight phenolic compounds were isolated from the EtOAc-soluble acidic layer of methanol extracts of Asian pear (Pyrus pyrifolia Nakai cv. Chuhwangbae) fruit peels. These isolated compounds were identified to be arbutin (1), 4-(O-β-d-glucopyranosyl)-3-(3′-methyl-2′-butenyl)benzoic acid (2, malaxinic acid), 3,4-dihydroxybenzoic acid (3), trans-chlorogenic acid (4), cis-chlorogenic acid (5), isorhamnetin 3-O-β-d-glucopyranoside (6), 3,5-dicaffeoylquinic acid (7), and (-)-epicatechin (8) based on electronic spray ionization (ESI)-MS and NMR spectroscopic data. Of the isolated compounds, 2 and 5 were identified in pear for the first time.

Peroxidase activity was characterized in lettuce (Lactuca sativa L.) leaf tissue. Changes in the activity and distribution of the enzyme were examined during the development of a nonhost hypersensitive reaction (HR) induced by Pseudomonas syringae (P.s.) pv phaseolicola and in response to an hrp mutant of the bacterium. Assays of activity in tissue extracts revealed pH optima of 4.5, 6.0, 5.5 to 6.0, and 6.0 to 6.5 for the substrates tetramethylbenzidine, guaiacol, caffeic acid, and chlorogenic acid, respectively. Inoculation with water or with wild-type or hip mutant strains of P. s. pv phaseolicola caused an initial decline in total peroxidase activity; subsequent increases depended on the hydrogen donor used in the assay. Guaiacol peroxidase recovered more rapidly in tissues undergoing the HR, whereas changes in tetramethylbenzidine peroxidase were generally similar in the two interactions. In contrast, increases in chlorogenic acid peroxidase were significantly higher in tissues inoculated with the hrp mutant. During the HR, increased levels of Mn2+/2,4-dichlorophenol-stimulated NADH and NADPH oxidase activities, characteristic of certain peroxidases, were found in intercellular fluids and closely matched the accumulation of H2O2 in the apoplast. Histochemical analysis of peroxidase distribution by electron microscopy revealed a striking, highly localized increase in activity within the endomembrane system and cell wall at the sites of bacterial attachment. However, no clear differences in peroxidase location were observed in tissue challenged by the wild-type strain or the hrp mutant. Our results highlight the significance of the subcellular control of oxidative reactions leading to the generation of reactive oxygen species, cell wall alterations, and the HR

Chlorogenic acid [3-(3,4-dihydroxycinnamoyl)quinic acid, CGA] is one of the main compounds contained in immature pear fruits. In the present study, we established simple purification of CGA in high purity from the immature fruit of pear (Pyrus pyrifolia Nakai cv. Chuhwangbae) which contains CGA in high concentration. The 80 % MeOH extract (1.4 g) of immature pear fruits (20 g fresh wt.) was partitioned with ethyl acetate (EtOAc) under acidic condition (pH 2.65). Then, the EtOAc-soluble acidic layer (110.3 mg) was further purified using Diaion HP-20 column chromatography (H2O/MeOH, step wise). Then, the CGA-contained fractions were finally purified by preparative ODS-HPLC. The isolated CGA (24.3 mg) showed high purity (>99 %) and the total recovery was estimated to be 63.9 %.

The present study was conducted to determine the content of pharmacologically important constituents hypericin, pseudohypericin, chlorogenic acid, rutin, hyperoside, apigenin-7-O-glucoside, quercitrin, quercetin and vitexin in eight Hypericum species namely, H. aviculariifolium Jaup. and Spach subsp. depilatum (Freyn and Bornm.) Robson var. depilatum (endemic), H. lydium Boiss., H. montbretii Spach, H. orientale L., H. origanifolium Willd, H. perfoliatum L., H. perforatum L. and H. pruinatum Boiss. and Bal. growing in different locations of Turkey.

The defensive reaction of apple cultivar Idared was studied after inoculation with three different pathogens (Penicillium expansum, Monilinia fructigena, Gloeosporium spp.). Changes in phenolic concentrations and activity of phenylalanine-ammonia lyase were determined after 7, 14, and 21 days after the inoculation. Significant differences were discovered in the progress of rotting after the inoculation. The increase in phenols concentrations and in phenylalanine-ammonia lyase activity varied in the place of fungal attack, in the tissues around rotten zone and in the healthy part. The response to the infection was different in the fruit peel and flesh. Very good correlation was found between the activity of phenylalanine-ammonia lyase and total phenol concentration (r = 0.76-0.98).

The objective of this research was to evaluate the effect of blackcurrant mash blended with apple pulp on its phenolic composition, antioxidant activity, L-ascorbic acid level and colour during the juice production and storage. Five variants of samples were prepared as follows: apple juices from two cultivars, Shampion and Idared, without and with 20% of blackcurrant pulp, and blackcurrant juice. The juices were stored at 4 deg C and 30 deg C for 6 months. The apple juices had a very low L-ascorbic acid concentrations (1.32 mg/L (Idared cv.) and 6.26 mg/L (Shampion cv.)), whereas the blackcurrant juice showed the highest amount of L-ascorbic acid, i.e. 704.3 mg/L. The addition of 20% of blackcurrant pulp before apple crashing resulted in an increase of L-ascorbic acid concentration in juices. The addition of blackcurrant fruits before apple crushing had a significant influence on phenolic compounds, especially in Idared blended pulp. As compared with the control samples, flavan-3-ol concentration increased 4 times in juices made from 80% of Idared apples blended with 20% of blackcurrant fruits. Apple pulp blended with blackcurrant was richer in hydroxycinnamic acids (especially caffeic, p-coumaric, and neochlorogenic acids) than juices made only from apples. The results ranged from 83.05 to 3,297.6 microM T/100 mL for 1,1-diphenyl-2-picrylhydrazyl radical, from 20.64 to 490.93 microM T/100 mL for 2,2'azinobis-(3-ethylbenzthiazoline-6-sulphonic acid), and from 1.52 to 37.35 microM T/mL for Ferric reducing antioxidant power assay for apple juice made from the Idared cultivar and for blackcurrant juice, respectively. The highest level of the antioxidant capacity observed in the blackcurrant sample was due to the effect of the high anthocyanin and ascorbic acid levels. The apple juice colour showed a moderate degradation with time as indicated by the slight reduction of L* values in the samples stored at 4 deg C for 6 months, and a much higher decrease of L* values in the samples stored at 30 deg C. The lightness of the apple blended with blackcurrant increased during storage as a result of the coloured anthocyanin degradation. The temperature during the sample storage (30 deg C) had a significant influence, resulting in a higher degradation of all phenolics compounds analysed, colour and antioxidant activity.

The genus Hypericum L. (St. John's-wort, Hypericaceae) has received scientific interest in recent years, because it is a source of a variety of bioactive compounds including the phenolics. We determine whether the typical phenolic constituents of Hypericum plants, namely chlorogenic acid, rutin, hyperoside, isoquercetine, quercitrine, and quercetine, may be implicated as part of an inducible plant defence response in two St. John's-wort species, Hypericum perforatum L. and Hypericum triquetrifolium Turra. To achieve this objective, greenhouse-grown plantlets were inoculated with the fungal pathogen Diploceras hypericinum and the plant growth promoting bacterium Pseudonomas putida. Phenolic compounds levels of the Hypericum plantlets increased significantly in response to inoculation with both organisms. So far, little effort has been dedicated to investigate whether phenolic compounds are inducible by pathogen/herbivore attack or if they could play a role in plant defence. Results from the study indicate that the phenolic compounds investigated could be involved in the plant defence system and implicated as part of an inducible plant defence response in both St. John's Wort species.

Inhibition of methanogenesis in ruminal cultures was attempted by hindering thiamine availability through its degradation by 'polyphenols' and competition for active sites on enzymes and transporters using thiamine structural analogs. Effects on fermentation were small and not consistently reversed by adding thiamine. Lack of major effects of the compounds evaluated could be due to intracellular synthesis of thiamine covering most requirements.

Two apple cultivars, Angold and HL 1834, were inoculated with Monilinia fructigena in order to evaluate their defensive reactions, especially enzyme activity and production of phenolic compounds. Changes of phenolic concentration and activity of phenylalanine ammonia lyase (PAL) were determined 7, 14 and 21 days after the inoculation. Progress of rotting was similar for both cultivars at first but defensive reactions were different. The increase of phenolic compounds levels was observed; their concentrations and composition were influenced by location in the fruit. A very good correlation was found between the activity of PAL and total phenolic concentration.

Chlorogenic acid is a well-known nutraceutical, but it is extensively metabolized by the body. More valuable information can be obtained from its metabolites. Dihydrocaffeic acid is a metabolite of chlorogenic acid and has shown antioxidant, cardioprotective, and neuroprotective effects; however, information about its anticancer activity is very scarce. Therefore, the main objective of this study was to determine the anticancer potential of dihydrocaffeic acid. The cancer cell lines used were MCF-7, Hep-G2, PC-3, and HCT-116, while HDFa was used as healthy cells. The cytotoxic concentrations to kill 50%, 75%, and 90% of the cells (CC 50 , CC 75 , CC 90 ) were determined using the MTS assay. Dihydrocaffeic acid was significantly more cytotoxic for most cancer cell lines, including MCF-7, PC-3, and HCT-116, compared with HDFa; however, Hep-G2 was significantly more resistant than HDFa. Dihydrocaffeic acid is a potential candidate for cancer prevention and treatment. The mechanism of action remains to be elucidated.