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PubMed2002

[Chemical composition of fructus Liquidambaris--lulutong].

AIM: To study the chemical composition in the fruits of Liquidambar formana Hance. METHODS: Various column chromatographic techniques were used to separate and purify the constituents. Their physical and chemical properties and spectral data were measured for structural elucidation. RESULTS: Eleven compounds were isolated and identified as beta-sitosterol (1), 3-oxo-11 alpha, 12 alpha-epoxyleanan-28, 13 beta-olide (2), 3-oxo-12 alpha-hydroxy-oleanan-28, 13 beta-olide (3), 3 alpha-acetyloxy-25-hydroxyolean-12-en-28-oic acid (4), oleanolic acid (5), ursolic acid (6), daucosterol (7), betulonic acid (8), gallic acid (9), nonacosane (10) and n-triacontanoic acid (11). CONCLUSION: Among the isolated constituents, compound 4 is new compound, compound 3 is firstly isolated from the natural product and compound 5, 6, 7, 9, 10 and 11 are isolated from LuLuTong for the first time.

Fruit↗
PubMed2003

[Studies on chemical constituents of Choerospondias axillaris].

Ten compounds were isolated from the dry fruit of Choerospondias axillaris (Roxb.) Burtt et Hill. Their structures were elucidated as dihydroquercetin(1), quercetin(2), protocatechuic acid(3), gallic acid(4), 3,3'-di-o-methylellagic acid(5), beta-sitosterol(6), daucosterol (7), stearic acid(8), triacontanoic acid(9), octacosanol(10) by IR, EI-MS and NMR.

Anacardiaceae↗
PubMed2006

[Studies on phenolic compounds from Polygonum aviculane].

OBJECTIVE: To study the chemical constituents from the aerial parts of Polygomun aviculane. METHOD: The chemical constituents were isolated by silica gel column chromatography and preparative silica thin layer chromatography, and their structures were elucidated on the basis of physico-chemical evidences and spectroscopic analysis (IR, MS, 1H and 13C-NMR). RESULT: Seven phenolic compounds were identified as rosmarinic acid (1), gallic acid (2), gentisic acid 5-O-(6'-O-galloyl)-beta-D-glucopyranoside (3), caffeic acid (4), p-coumaric acid (5), ethyl caffeate (6) and acteoside (7), respectively. CONCLUSION: Compounds 1, 3, 6 and 7 were isolated from this plant for the first time. These results provided theoretical evidences for the further bioactive investigation on this plant.

Caffeic Acids↗
PubMed2006

[Chemical constituents of mangrove plant Barringtonia racemosa].

OBJECTIVE: To study the chemical constituents of mangrove plant Barringtonia racemosa. METHODS: Chemical constituents from the ethyl acetate extract of the stem bark of this plant were isolated by silica, Sephadex LH-20 column chromatography and identified by NMR analysis. RESULTS: Five compounds were isolated and identified. They are 3,3'-dimethoxy ellagic acid (1), dihydromyticetin (2), gallic acid (3), bartogenic acid (4) and stigmasterol (5). CONCLUSION: Compounds 1-3 were isolated from this plant for the first time.

Barringtonia↗
PubMed1994

The blocking effect of phenolic acid on N-nitrosomorpholine formation in vitro.

Phenolic acids (PAs) are widely found in many daily consumed vegetables and fruits. The inhibitory effects of PAs on N-nitrosomorpholine (NMOR) formation in vitro under simulated gastric juice condition were studied. The results showed that the inhibitory potency of thirteen varieties of PAs differed greatly, which may be related to their chemical structures; the blocking rate (BR) of different kinds of PAs were as follows: caffeic acid, 92.5%; tannic acid, 90.0%; gallic acid, 86.8%; sinapinic acid, 86.2%; ferulic acid, 81.1%; chlorogenic acid, 69.4%; gentisic acid, 69.2%; syringic acid, 62.1%; protocatechuic acid, 56.0%; p-coumaric acid, 52.5%; vanillic acid, 35.4%; moreover, p-hydroxybenzoic acid and m-coumaric acid had the least blocking effect or even slight catalyzing effect. The results also demonstrated that amounts of NMOR formed were negatively correlated with molar ratio of PAs to nitrite and that the optimum pH for inhibition was between 2 and 3.

Carcinogens↗
PubMed1994

Suppression of hydroperoxide-induced cytotoxicity by polyphenols.

A variety of synthetic and dietary polyphenols protect mammalian and bacterial cells from cytotoxicity induced by hydroperoxides, especially hydrogen peroxide (H2O2). Cytotoxicity of H2O2 on Chinese hamster V79 cells was assessed with a colony formation assay. Cytotoxicity and mutagenicity of H2O2 on Salmonella TA104 were assessed with the Ames test. SOS response induced by H2O2 was investigated in the SOS chromotest with Escherichia coli PQ37. The polyphenol-bearing o-dihydroxy (catechol) structure, i.e., nordihydroguaiaretic acid, caffeic acid ester, gallic acid ester, quercetin, and catechin, were effective for suppression of H2O2-induced cytotoxicity in these assay systems. In contrast, neither ferulic acid ester-bearing o-methoxyphenol structure nor alpha-tocopherol were effective, indicating that o-dihydroxy or its equivalent structure in flavonoids is essential for the protection. There are many reports describing that polyphenols act as prooxidants in the presence of metal ions. Our results suggest, however, that they act as antioxidants in the cells, when no metal ions are added to the medium.

Animals↗
PubMed1991

Complexing of toxic hydrolysable tannins of yellow-wood (Terminalia oblongata) and harendong (Clidemia hirta) with reactive substances: an approach to preventing toxicity.

Ruminants consuming either tannic acid or hydrolysable tannins from the Australian yellow-wood tree (Terminalia oblongata) and the Indonesian shrub Clidemia hirta are intoxicated by simple phenolics liberated in the gut. The affinity of these tannins and of the simple phenolic gallic acid for the two proteins casein and pepsin, polyvinylpyrolidone (PVP), activated charcoal and Ca(OH)2 was examined in vitro. The studies were undertaken to predict the effect of these phenolics on digestion and to identify substances that would act as antidotes by precipitating phenolics. Tannins but not gallic acid were precipitated as stable complexes with both pepsin and casein at pH 3-5. Optimal complexing of tannin with protein occurred at a weight ratio of 1:1. Ionic strength and temperature did not affect the amount of tannin precipitated from solution with protein. The precipitation of tannins with PVP and Ca(OH)2 was unaffected by pH within the range 2-8 while maximum binding with activated charcoal occurred between pH 3 and 7. In contrast to protein, the other substances complexed with gallic acid; only gallic acid-PVP complexes were affected by pH. Calcium hydroxide bound more tannin and gallic acid on a weight basis than PVP and charcoal. Both Ca(OH)2 and activated charcoal should complex with phenolics in the forestomach, abomasum and intestines. The reaction of hydrolysable tannins and proteins at the pH found in the abomasum suggests that hydrolysable tannins would interfere with enzyme function and protein digestion post-ruminally rather than in the forestomach.

Animals↗
PubMed1999

[Detection of drug-drug interaction by ESR spectroscopy].

Vitamin C (sodium ascorbate), gallic acid and dopamine induced apoptosis (characterized by internucleosomal DNA cleavage, nuclear fragmentation, chromatin condensation near nuclear membrane and loss of cell surface microvilli) in human promyelocytic leukemic HL-60 cells. ESR spectroscopy demonstrated the connection between the radical intensity and apoptosis-inducing activity of derivatives of these compounds. When vitamin C and gallic acid were mixed together, the radical intensity and cytotoxic activity of gallic acid was completely scavenged by one or two orders lower concentrations of vitamin C, suggesting the predominant action of vitamin C over gallic acid. When vitamin C and dopamine were mixed together, their radical intensity and apoptosis-inducing activity counteracted with each other. On the other hand, lignins significantly enhanced both the radical intensity and apoptosis-inducing activity of vitamin C. ESR spectroscopy might be applicable for the detection of drug-drug interaction.

Apoptosis↗
PubMed2005

Inhibitory activity of polyhydroxycarboxylate chelators against recombinant NF-kappaB p50 protein-DNA binding.

The inhibitory effect of 7,8-dihydroxy-4-methylcoumarin (7,8-DHMC), 5,7-dihydroxy-4-methylcoumarin (5,7-DHMC), and gallic acid on the DNA binding of recombinant p50 protein and their interaction with zinc ion were studied. Electrophoretic mobility shift assay (EMSA) using p50 and biotin labeled DNA has shown that gallic acid is more effective than the dihydroxycoumarins in inhibiting the p50-DNA binding. Molecular modeling studies suggest an explanation for these observations. Effect of the addition of zinc after p50-DNA-binding inhibition by gallic acid was also studied. Chemical speciation and formation constant studies show that gallic acid forms a more stable 1:1 complex with zinc ion in comparison to the dihydroxycoumarins.

Cations, Divalent↗
PubMedDate not supplied

Production of hydrogen peroxide and methionine sulfoxide by epigallocatechin gallate and antioxidants.

Epigallocatechin gallate (EGCG) induced apoptosis-associated characteristics in human oral tumor cell lines more efficiently than ascorbates, gallic acid, vitamin K, flavonoids or steroidal saponins. Since catalase partially inhibited the cytotoxic activity of EGCG, the possible involvement of hydrogen peroxide (H2O2) in cell death induction was investigated, using TCPO chemiluminescence method. Production of H2O2 by EGCG, sodium ascorbate, gallic acid or catechin reached a maximum level within 30 minutes, and was increased up to a plateau level above pH 8. Under optimal conditions, 1 mM EGCG was converted to 1 mM H2O2. At neutral pH, EGCG produced the highest amount of H2O2, followed by gallic acid, sodium ascorbate and catechin. EGCG produced methionine sulfoxide from methionine in the culture medium, while the methionine oxidation by EGCG was significantly reduced in the presence of serum. ESR spectroscopy showed that EGCG, gallic acid and sodium ascorbate, but not catechin, produced radicals under alkaline condition and that all these compounds scavenged superoxide anion, produced by hypoxanthine-xanthine oxidase reaction. EGCG also effectively scavenged the ascorbate and gallate radicals, more efficiently than other compounds. These data suggest that the apoptosis induction by EGCG may be mediated by H2O2 produced in the culture medium.

Antineoplastic Agents↗
PubMed2004

Allelochemicals of Polygonella myriophylla: chemistry and soil degradation.

Gallic acid and hydroquinone have been identified as the major allelochemicals of the known allelopathic plant Polygonella myriophylla. Both of these compounds occur in the foliage as glycosides. Quercetin and rhamnetin were identified as the major flavonoid constituents, but in much lower concentration. The behavior of gallic acid, hydroquinone, the hydroquinone glycoside arbutin, and benzoquinone in sterile and nonsterile soil from beneath Polygonella was investigated. Sterilization effectively stabilized arbutin, hydroquinone, and gallic acid. Concentrations of benzoquinone rapidly diminished in sterilized soil, and the compound was almost completely gone after 7 days. In nonsterile soils, all four compounds degraded rapidly. The order of persistence was hydroquinone > benzoquinone > gallic acid > arbutin. Persistence was rate-dependent. Arbutin degraded to hydroquinone, and benzoquinone formed as a degradation product of hydroquinone. Hydroquinone was also observed as a degradation product of benzoquinone. Benzoquinone degrades rapidly by nonmicrobial oxidative processes. These results support the hypothesis that microbial and nonmicrobial oxidative transformations of soil allelochemicals are crucial in mediating the allelopathic effects of Polygonella myriophylla.

Arbutin↗
PubMed2005

Antioxidant properties of palm fruit extracts.

Phenolic compounds have been shown to exhibit bioactive properties, and in particular antioxidant effects. A phenolic-rich fraction has been isolated from the aqueous by-product obtained during the milling of oil palm fruits. The objectives of the study were to determine the phenolic content of the crude and ethanolic extracts of oil palm fruits and to evaluate the antioxidant properties of these extracts. The total phenolics content of the crude and ethanol extracts as determined by the Folin-Ciocalteu method were found to be 40.3 +/- 0.5 and 49.6 +/- 0.6 mg GAE/g extract (dry basis), respectively. The radical scavenging activity of the extracts determined using 2,2 diphenyl-1-picrylhydrazyl radical (DPPH.) indicated that both crude and ethanol extracts exhibit hydrogen-donating capacity, and have antiradical power (ARP) comparable to ascorbic acid. The DPPH radical scavenging activity of the extracts were less than that of gallic acid, but the time-course variations of the scavenging curves suggest that the extracts acted by a mechanism similar to that of gallic acid. The electron-donating potentials of the extracts were inferred from the hydrogen peroxide scavenging and reducing power assays. The reducing power of crude and ethanol extracts at 1 mM GAE were found to be comparable to that of 0.3 mM gallic acid. The extracts indicated complete scavenging of hydrogen peroxide at concentrations above 0.4 mM GAE. These findings suggest that the crude and ethanol extracts are able to scavenge free radicals, by either hydrogen or electron donating mechanisms, and can therefore act as primary antioxidants.

Antioxidants↗
PubMed2004

[Studies on chemical constituents from Polygonum macrophyllum].

OBJECTIVE: To study the chemical structures from Polygonum macrophyllum D. Don. METHODS: To isolate the constituents by reverse phase chromatography and characterize their structures by the analysis of chemical property and spectral data. RESULT: Six compounds were isolated from the 70% acetone extract from the complete herb of P. macrophyllum. Their structures were elucidated as (-)-epicatechin-5-O-beta-D-glucopyranoside (I), (+)-catechin-7-O-beta-D-glucopyranoside (II), 1-(3-O-beta-D-glucopyranosyl 4,5-dihydroxy-phenyl)-ethanone (III) (-)-epicatechin (IV), chlorogenic acid (V) and gallic acid (VI). CONCLUSION: Compounds I-VI were isolated from the plant for the first time.

Catechin↗
PubMed2006

[Simultaneous determination of three active constituents in cortex moutan by RP-HPLC].

OBJECTIVE: To establish a RP-HPLC method for the simultaneous determination of gallic acid, paeoniflorin and paeonol in Cortex Moutan. METHOD: The analysis was carried out on a column of YMC-C18 (4. 6 mm x 250 mm, 5 microm), and gradient elution was used for the baseline separation of these three constituents with the different detection wavelength. RESULT: The linear ranges for gallic acid, paeoniflorin and paeonol were 0.0130-0.267, 0.0880-1.76 and 0.164-3.28 microg, respectively. Their average recoveries were 104.3%, 101.7% and 99.5%, respectively. CONCLUSION: The method was successfully applied to the determination of gallic acid, paeoniflorin and paeonol in Cortex Moutan from the different drugstores. It was shown in this study that the proposed method could be used to evaluate the quality of the medicinal plants or herbal preparations containing gallic acid, paeoniflorin and paeonol.

Acetophenones↗
PubMed2005

Antioxidative constituents from Paeonia lactiflora.

The ethanol extract of the peony root (Paeonia Lactiflora Pall, Paeoniaceae) as well as its major active components including gallic acid and methyl gallate were evaluated for their protective effects against free radical generation and lipid peroxidation. In addition, the protective effects against hydrogen peroxide-induced oxidative DNA damage in a mammalian cell line were examined. The ethanol extracts of the peony root (PREs) and its active constituents, gallic acid and methyl gallate, exhibited a significant free radical scavenging effect against 1,1-diphenyl-2-picryl hydrazine (DPPH) radical generation and had an inhibitory effect on lipid peroxidation, as measured by the level of malondialdehyde (MDA) formation. The PREs did not have any pro-oxidant effect. They strongly inhibited the hydrogen peroxide-induced DNA damage from NIH/3T3 fibroblasts, as assessed by single cell gel electrophoresis. Furthermore, the oral administration of 50% PRE (50% ethanol extract of peony root), gallic acid and methyl gallate potently inhibited the formation of micronucleated reticulocytes (MNRET) in the mouse peripheral blood induced by a KBrO3 treatment in vivo. Therefore, PREs containing gallic acid and methyl gallate may be a useful antigenotoxic antioxidant by scavenging free radicals, inhibiting lipid peroxidation and protecting against oxidative DNA damage without exhibiting any pro-oxidant effect.

Animals↗
PubMed2003

Inhibition of inducible nitric oxide synthase and cyclooxygenase-2 activity by 1,2,3,4,6-penta-O-galloyl-beta-D-glucose in murine macrophage cells.

Activated macrophages express inducible isoforms of nitric oxide synthase (iNOS) and cyclooxygenase (COX-2), and produce excessive amounts of nitric oxide (NO) and prostaglandin E2 (PGE2), which play key roles in the processes of inflammation and carcinogenesis. The root of Paeonia lactiflora Pall., and the root cortex of Paeonia suffruticosa Andr., are important Chinese crude drugs used in many traditional prescriptions. 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG) is a major bioactive constituent of both crude drugs. PGG has been shown to possess potent anti-oxidant, anti-mutagenic, anti-proliferative and anti-invasive effects. In this study, we examined the inhibitory effects of 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG) isolated from the root of Paeonia lactiflora Pall. on the COX-2 and iNOS activity in LPS-activated Raw 264.7 cells, COX-1 in HEL cells. To investigate the structure-activity relationships of gallate and gallic acid for the inhibition of iNOS and COX-2 activity, we also examined (-)-epigallocatechin gallate (EGCG), gallic acid, and gallacetophenone. The results of the present study indicated that PGG, EGCG, and gallacetophenone treatment except gallic acid significantly inhibited LPS-induced NO production in LPS-activated macrophages. All of the four compounds significantly inhibited COX-2 activity in LPS-activated macrophages. Among the four compounds examined, PGG revealed the most potent in both iNOS (IC50 approximately 18 microg/mL) and COX-2 inhibitory activity (PGE2: IC50 approximately 8 microg/mL and PGD2: IC50 approximately 12 microg/mL), respectively. Although further studies are needed to elucidate the molecular mechanisms and structure-activity relationship by which PGG exerts its inhibitory actions, our results suggest that PGG might be a candidate for developing anti-inflammatory and cancer chemopreventive agents.

Acetophenones↗
PubMed2003

Anticancer activity of phenolic acids of natural or synthetic origin: a structure-activity study.

Several phenolic acids-caffeic and gallic acid derivatives-were synthesized and screened for their potential antiproliferative and cytotoxic properties, in different human cancer cell lines: mammary gland and cervix adenocarcinomas and lymphoblastic leukemia. The selected phenols were structurally related, which allowed us to gather important information regarding the structure-activity relationships underlying the biological activity of such compounds. This is proposed to be due to a balance between the antioxidant and pro-oxidant properties of this kind of agent. Distinct effects were found for different cell lines, which points to a significant specificity of action of the drugs tested. It was verified, for the types of cancer investigated, that the trihydroxylated derivatives yielded better results than the dihydroxylated ones. Tests in noncancerous cells, human lung fibroblasts, were also undertaken, in view of determining the toxic side effects of the compounds studied.

Adenocarcinoma↗
PubMed2003

Determination of tea components with antioxidant activity.

Levels of essential elements with antioxidant activity, as well as catechins, gallic acid, and caffeine levels, in a total of 45 samples of different teas commercialized in Spain have been evaluated. Chromium, manganese, selenium, and zinc were determined in the samples mineralized with HNO(3) and V(2)O(5), using ETAAS as the analytical technique. The reliability of the procedure was checked by analysis of a certified reference material. Large variations in the trace element composition of teas were observed. The levels ranged from 50.6 to 371.4 ng/g for Cr, from 76.1 to 987.6 microg/g for Mn, from 48.5 to 114.6 ng/g for Se, and from 56.3 to 78.6 ng/g for Zn. The four major catechins [(-)-epigallocatechin gallate (EGCG), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECG), and (-)-epicatechin (EC)], gallic acid (GA), and caffeine were simultaneously determined by a simple and fast HPLC method using a photodiode array detector. In all analyzed samples, EGCG ranged from 1.4 to 103.5 mg/g, EGC from 3.9 to 45.3 mg/g, ECG from 0.2 to 45.6 mg/g, and EC ranged from 0.6 to 21.2 mg/g. These results indicated that green tea has a higher content of catechins than both oolong and fermented teas (red and black teas); the fermentation process during tea manufacturing reduces the levels of catechins significantly. Gallic acid content ranged from 0.039 to 6.7 mg/g; the fermentation process also elevated remarkably gallic acid levels in black teas (mean level of 3.9 +/- 1.5 mg/g). The amount of caffeine in the analyzed samples ranged from 7.5 to 86.6 mg/g, and the lower values were detected in green and oolong teas. This study will be useful for the appraisal of trace elements and antioxidant components in various teas, and it will also be of interest for people who like drinking this beverage.

Antioxidants↗