Deprotonation Processes of Ellagic Acid in Solution and Solid States

Hasegawa, Miki; Terauchi, Mayumi; Kikuchi, Yuko; Akiko, Nakao; Okubo, Jun; Yoshinaga, Tetsutaro; Hiratsuka, Hiroshi; Kobayashi, Michio; Hoshi, Toshihiko

doi:10.1007/s00706-002-0552-1

Cited by 35 publications

(34 citation statements)

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“…When EA was intercalated into ZLH interlayers, the 370 nm band was slightly increased in intensity, indicating doubly deprotonated EA between the interlayers. 50 This verifies that the drug molecules are stabilized by electrostatic interaction with the positive charge of ZLH.…”

Section: Optical Propertiesmentioning

confidence: 65%

“…This indicates that the EA is coordinated to the inorganic layers by the negatively charged oxygen atoms at positions 8 and 8′. 50,54 The successful intercalation of EA into ZLH can be supported by CHNS analysis as shown in Table 1. EAN shows 32.7% carbon (w/w) and 2.6% (w/w) hydrogen, resulted in loading percentage of EA in the nanohybrid of about 58.8%.…”

Section: Ftir Spectroscopymentioning

confidence: 82%

“…A broad absorption band observed at 2500-3600 cm -1 is attributed to OH stretching due to the presence of hydroxyl group within the ZLH and phenolic hydroxide at position 7,7′. 50 A band at 1577 cm -1 can be attributed to C=C stretching vibration of aromatic, 52 and a band for ν(C-O) can be observed at 1107 cm -1 and ν (Zn-O) absorption bands at 472 cm -1 . This indicates that the EA is coordinated to the inorganic layers by the negatively charged oxygen atoms at positions 8 and 8′.…”

Section: Ftir Spectroscopymentioning

confidence: 96%

“…The FTIR spectrum of EA shows an absorption band at 3557 cm -1 , attributed to the stretching mode of OH groups in the phenol at 7,7′, 8 and 8′ positions ( Figure 2A) 52 and broad absorption bands at 3500-2750 cm -1 can be attributed to stretching of C-H aromatic ring 24 and hydrogen bond between EA molecules. 50 A band at 1700 cm -1 is due to stretching of C=O 52,53 and bands at 1620-1511 cm -1 are due to aromatic rings. A band at 1196 and 1058 cm -1 is due to ester linkage of C-O stretching 34,52 and another band at 758 cm -1 is due to C-H aromatic stretching.…”

Section: Ftir Spectroscopymentioning

confidence: 99%

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Development of antiproliferative nanohybrid compound with controlled release property using ellagic acid as the active agent

Ali¹,

Zainal²,

Hakim³

et al. 2011

IJN

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An ellagic acid (EA)–zinc layered hydroxide (ZLH) nanohybrid (EAN) was synthesized under a nonaqueous environment using EA and zinc oxide (ZnO) as the precursors. Powder X-ray diffraction showed that the basal spacing of the nanohybrid was 10.4 Å, resulting in the spatial orientation of EA molecules between the interlayers of 22.5° from z-axis with two negative charges at 8,8′ position of the molecules pointed toward the ZLH interlayers. FTIR study showed that the intercalated EA spectral feature is generally similar to that of EA, but with bands slightly shifted. This indicates that some chemical bonding of EA presence between the nanohybrid interlayers was slightly changed, due to the formation of host–guest interaction. The nanohybrid is of mesopores type with 58.8% drug loading and enhanced thermal stability. The release of the drug active, EA from the nanohybrid was found to be sustained and therefore has good potential to be used as a drug controlled-release formulation. In vitro bioassay study showed that the EAN has a mild effect on the hepatocytes cells, similar to its counterpart, free EA.

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Section: Optical Propertiesmentioning

confidence: 65%

Section: Ftir Spectroscopymentioning

confidence: 82%

Section: Ftir Spectroscopymentioning

confidence: 96%

Section: Ftir Spectroscopymentioning

confidence: 99%

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Development of antiproliferative nanohybrid compound with controlled release property using ellagic acid as the active agent

Ali¹,

Zainal²,

Hakim³

et al. 2011

IJN

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“…As can be seen in Table 2 the values obtained for gallic acid, Trolox and ascorbic acid were similar to that obtained at pH 4.5, but the value obtained for ellagic acid was significantly higher at pH 7.4 in relation to pH 4.5, and at pH 7.4 became the first most antioxidant compound, with a relative antioxidant activity compared to gallic acid of 1.65. The different ABTS discolouration ability of ellagic acid at the two pH's may be due to the fact that ellagic acid exists as a full protonated molecule at the pH < 0.5, as a mixture of full protonated and singly deprotonated molecule in the pH region between 0.5 and 5.6, and as doubly deprotonated molecule at pH > 5.6 (Hasegawa et al, 2003). From this data the percentage of the chestnuts antioxidant activity contributed by gallic and ellagic acid were calculated (Fig.…”

Section: Contribution Of Vitamin C and Polyphenolic Compounds To The mentioning

confidence: 99%

Effect of cooking on total vitamin C contents and antioxidant activity of sweet chestnuts (Castanea sativa Mill.)

et al. 2011

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a b s t r a c tIn this work the total vitamin C contents (ascorbic acid + dehydroascorbic acid) and antioxidant activity of raw and cooked chestnuts was evaluated. The vitamin C contents of raw chestnuts varied significantly between the different cultivars (cv) studied and it varied from 400 mg/kg dry weight (cv Lada) to 693 mg/ kg dry weight (cv Martaínha). The different cultivars behave differently during the cooking process concerning the loss of vitamin C. A significant decrease in the vitamin C content of the chestnuts was observed, 25-54% for the boiling process and 2-77% for the roasting process. Boiled and roasted chestnuts can be good sources of vitamin C since it may represent 22.4%, 16.2%, 26.8% and 19.4%, respectively, of the recommended dietary intake for an adult man and woman. The cooking process significantly changed the antioxidant activity of the chestnuts. A difference was observed between the cultivars during the cooking processes, concerning the antioxidant activity. For the raw chestnuts the variation in vitamin C content of the chestnuts explains 99% of the antioxidant activity variation but for the roasted and boiled chestnuts this percentage significantly decreases to 51% and 88%, respectively. Although a high antioxidant activity is still present in the cooked chestnuts, the cause for this antioxidant activity is less dependent on the vitamin C content of the chestnuts, probably due to the conversion of ascorbic acid to dehydroascorbic acid. The increase in gallic acid during the cooking process, presumably transferred from the peels to the fruit, also contributes to the high antioxidant activity observed for the cooked chestnuts.

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Stability and Oxidation Products of Hydrolysable Tannins in Basic Conditions Detected by HPLC/DAD–ESI/QTOF/MS

Tuominen

Sundman

2013

Phytochemical Analysis

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Deprotonation Processes of Ellagic Acid in Solution and Solid States

Cited by 35 publications

References 0 publications

Development of antiproliferative nanohybrid compound with controlled release property using ellagic acid as the active agent

Development of antiproliferative nanohybrid compound with controlled release property using ellagic acid as the active agent

Effect of cooking on total vitamin C contents and antioxidant activity of sweet chestnuts (Castanea sativa Mill.)

Stability and Oxidation Products of Hydrolysable Tannins in Basic Conditions Detected by HPLC/DAD–ESI/QTOF/MS

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