Polyphenolic compounds in the fruits of Egyptian medicinal plants (Terminalia bellerica, Terminalia chebula and Terminalia horrida): Characterization, quantitation and determination of antioxidant capacities |
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Authors: | Beate Pfundstein Samy K El Desouky Roswitha Haubner Robert W Owen |
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Institution: | a Division of Preventive Oncology, German Cancer Research Center (DKFZ)/National Tumor Center, Im Neuenheimer Feld 517, 69120 Heidelberg, Germany b Phytochemistry and Plant Systematic Department, National Research Center, 12622 Dokki, Cairo, Egypt c Core Facility for Molecular Structure Analysis, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany |
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Abstract: | Thirty-four polyphenolic substances in methanol extracts of the fruits of Terminalia bellerica, Terminalia chebula and Terminalia horrida, three plants used in Egyptian folk medicine, were initially identified by HPLC-ESI-MS and quantitated by analytical HPLC after column chromatography on Sephadex LH-20. After purification by semi-preparative HPLC the compounds were identified by their mass and fragmentation patterns using ESI-MS-MS. For several compounds detailed 1H/13C NMR analysis at 600 MHz was performed. Two polyphenolics, namely 4-O-(4″-O-galloyl-α-l-rhamnopyranosyl)ellagic acid and 4-O-(3″,4″-di-O-galloyl-α-l-rhamnopyranosyl)ellagic acid were identified by NMR. Antioxidant capacities of the raw fruit extracts and the major isolated substances were determined using the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), oxygen radical absorbance capacity (ORAC) and ferric reducing ability of plasma (FRAP) in vitro assays and indicated that chebulic ellagitannins have high activity which may correlate with high potential as cancer chemopreventive agents. Therefore, further studies (metabolism, bioavailability and toxicity) of the polyphenolics in Terminalia species using preclinical models and in vivo human intervention trials are warranted. |
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Keywords: | AAPH 2 2&prime -azobis (2-amidino-propane)-dihydrochloride COLOC C-H correlation via long-range coupling COSY-45 2D proton correlation spectroscopy with 45° readout pulse cROESY compensated rotating-frame Overhauser spectroscopy DEPT distortionless enhanced polarization transfer DPPH 1 1-diphenyl-2-picrylhydrazyl radical ESI electrospray ionization FRAP ferric reducing ability of plasma HHDP hexahydroxydiphenoyl moiety (6 6&prime -dicarbonyl-2 2&prime 3 3&prime 4 4&prime -hexahydroxybiphenyl) HMBC heteronuclear multiple-bond correlation 2D NMR HSQC heteronuclear single-quantum correlation 2D NMR NOE nuclear Overhauser effect ORAC oxygen radical absorbance capacity ROESY rotating-frame Overhauser effect SERM selective estrogen receptor modulator SPS secondary plant substance TMS tetramethylsilane TPTZ 2 4 6 -tri(2-pyridyl)-1 3 5-triazine CAS: 3682-35-7 Trolox 6-hydroxy-2 5 7 8-tetramethyl-2-carboxylic acid CAS: 56305-04-5 |
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