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Most research on the caffeoylquinic acids was reported during the past two decades. The chemical structure of these compounds are well characterized ( Fig. 1 ). The compounds are ubiquitous in the plant kingdom ( Takenaka et al., 2003 ), and

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-hoc test ( P < 0.05). In the HPLC analysis, the gradient elution applied was able to efficiently separate a wide range of phenolic compounds such as protocatechuic acid; 5- o -caffeoylquinic acid; demethyl-wedelolactone; 4,5-dicaffeoylquinic acid; 3

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of powdered tissue was extracted in 5 mL 60:40 1% HCl methanol:water and 5 mL chloroform in 15-mL glass tubes). Gallic acid, rutin, and 5-caffeoylquinic acid purchased from Sigma Chemical Corp (St. Louis, MO) were used as standards for F-C and HPLC

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(MS) standards were obtained as follows: p-hydroxycinnamic (p-coumaric) acid (HCA), caffeic acid, chlorogenic (3-O-caffeoylquinic) acid, (-)epicatechin, quercetin-3-O-rhamnoside (quercitrin), and quercetin-3-O-glucoside (isoquercetin) were purchased

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. Identification of CGA in bush tea plants exposed to different shade nets and light intensities. The results revealed that there was greater production of CGAs, viz: caffeoylquinic acid, coumaroylquinic acid, dicaffeoylquinic acid, and tricaffeoylquinic acids

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The phenolic content and the radical scavenging activity were compared in leaves of sweetpotato (Ipomoea batatas L.) cultivars Shimon-1, Kyushu-119 and Elegant Summer grown under different temperature and shading conditions. Compared to cultivar differences, there was less effect of temperature and shading on the total phenolic content in sweetpotato leaves, however certain polyphenolic components differed widely among the treatments. The positive correlation between the radical scavenging activity and the level of total phenolics (r = 0.62) suggests that phenolic compounds are important antioxidant components of sweetpotato leaves. All the reverse-phase high-performance liquid chromatography (RP-HPLC) profiles of the cultivars tested showed peaks at the same retention times but peak areas of individual phenolic compounds differed with respective temperature and shading treatments. The phenolic compounds identified in the sweetpotato leaf were caffeic acid, chlorogenic acid, 4,5-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, 3,4-di-O-caffeoylquinic acid, and 3,4,5-tri-O-caffeoylquinic acid. Most of the phenolic compounds were highest in leaves from plants grown at 20 °C without shading except 4,5-di-O-caffeoylquinic acid. The results indicate that growing leaves under moderately high temperatures and in full sun enhances the accumulation of phenolic components. These phenolic components have possible value in enhancing human health.

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Methanol extracts of external (outer 3 mm) and interior root tissue of four sweetpotato [Ipomoea batatas (L.) Lam.] cultivars (`Centennial', `Jewel', `Regal', and `Resisto') having different levels of susceptibility to the sweetpotato weevil [Cylas formicarius elegantulus Summer] were analyzed for simple carbohydrates (fructose, glucose, sucrose, inositol) and organic acids (malic, citric, quinic) by gas chromatography and for phenolics (caffeic acid, caffeoylquinic acids, rutin) by high-performance liquid chromatography. There were significant differences among cultivars in the concentrations of total sugars and phenolics in the external tissue (P < 0.05). In addition, the distribution of carbohydrates, organic acids, and chlorogenic acid [3-O-caffeoylquinic acid] differed between external and interior tissues. Sucrose was the major water-soluble carbohydrate in all cultivars. With the exception of malic acid, the concentration of carbohydrates, organic acids, and phenolics did not correlate with cultivar susceptibility to the sweetpotato weevil.

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The phenolic composition of whole heads and excised midrib sections of iceberg, butter leaf, and romaine lettuce (Lactuca sativa L.) was followed at 5 and 10 °C during the first 3 days after wounding or during continuous exposure to 10 μL·L-1 ethylene in air. After 3 days of storage at 5 and 10 °C, only 5-caffeoylquinic acid (chlorogenic acid), 3,5-dicaffeoylquinic acid (isochlorogenic acid), caffeoyltartaric acid, and dicaffeoyltartaric acid were detected in wounded lettuce midribs. Of these four compounds, chlorogenic acid accumulated to the highest level in all three lettuce types. The content of caffeic acid derivatives increased 3- and 6-fold after 72 hours of storage at 5 and 10 °C, respectively. The synthesis of caffeoyltartaric acid was not induced by wounding in iceberg lettuce, while chlorogenic acid increased 5-fold at 5 °C and 10-fold at 10 °C. Similar relative phenolic compositions were detected in the three lettuce types studied, although at different concentrations. Changes observed in the content of individual phenolic compounds during the first 3 days of ethylene exposure seemed to follow the same pattern observed during wound induction of the synthesis of phenolic compounds. Chlorogenic acid increased 5-fold and isochlorogenic acid increased 10-fold, while the content of caffeoyltartaric derivatives were not significantly altered by ethylene treatment. Isochlorogenic acid, which was only present in low amounts in the control, was synthesized in the later steps of wound and ethylene induction. Similar kinetics for the induction of phenolic compounds were observed in the three lettuce types studied, suggesting that the mechanisms by which wounding induces phenylpropanoid synthesis are common for the different lettuce types.

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, dissolving the ash in 1:25 HCl, and assaying the solution obtained using an inductively coupled plasma emission spectrophotometer (ICP Iris; Thermo Optek, Milano, Italy) ( Karla, 1998 ). Chemicals and standards. Pure caffeoylquinic acids and flavonoids to be

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. (2003b) reported a positive correlation between caffeoylquinic acid derivatives and total phenolic content of sweetpotato leaves. In addition, it has been observed that roots at stage I had higher amounts of individual phenolic acids, which decreased

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