ABSTRACT
Our investigation of phenolic constituents of fruits, flower buds, and leaves of Feijoa sellowiana led to the isolation of twenty-one phenolics including three new gossypetin glycosides 1-3, and also the purification of a proanthocyanidin fraction. A high-performance liquid chromatography method for simultaneous analysis of phenolic constituents was established and then used to investigate the phenolic profiles of the parts of the plant species, to show the presence of characteristic flavonoids and ellagic acid derivatives or ellagitannins in the extracts from fruits, flower buds, and leaves. The branch extract profile also suggested the presence of alkylated ellagic acids as characteristic constituents. Inhibitory effects of feijoa flavonoids on mushroom tyrosinase were seen, although in some cases this may have resulted from direct interaction with the enzyme. Cytotoxic effect of the proanthocyanidin fraction was also shown.
Subject(s)
Feijoa/chemistry , Flavonoids/classification , Phenols/chemistry , Proanthocyanidins/chemistry , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Chromatography, High Pressure Liquid , Flavonoids/pharmacology , Flowers/chemistry , Fruit/chemistry , Plant Leaves/chemistry , Plant Stems/chemistry , Proanthocyanidins/pharmacologyABSTRACT
We isolated a new ellagitannin, davicratinic acid A (5), together with four known ellagitannins, davidiin (1), granatin A (2), pedunculagin (3), and 3-O-galloylgranatin A (4), from an aqueous acetone extract of dried Davidia involucrata leaves. The known ellagitannins were identified based on spectroscopic data. The structure of davicratinic acid A (5), a monomeric ellagitannin possessing a unique, skew-boat glucopyranose core, was established based on spectroscopic data. Additionally, we examined the effects of several tannins with good yields from this plant on drug-resistant bacteria and human oral squamous cell carcinomas, and found that davidiin (1) exhibited the most potent antibacterial and antitumor properties among the tannins examined.
Subject(s)
Carcinoma, Squamous Cell/drug therapy , Cornaceae/chemistry , Drug Resistance, Bacterial/drug effects , Hydrolyzable Tannins/chemistry , Mouth Neoplasms/drug therapy , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Survival/drug effects , Drug Screening Assays, Antitumor , Humans , Hydrolyzable Tannins/pharmacology , Molecular Structure , Plant Extracts/chemistry , Plant Extracts/pharmacologyABSTRACT
Licorice, which is the underground part of Glycyrrhiza species, has been used widely in Asian and Western countries as a traditional medicine and as a food additive. Our continuous investigation on the constituents of roots and stolons of Glycyrrhiza uralensis led to the isolation of two new phenolics, in addition to 14 known compounds. Structural studies including spectroscopic and simple chemical derivatizations revealed that both of the new compounds had 2-aryl-3-methylbenzofuran structures. An examination of the effectiveness of licorice phenolics obtained in this study on vancomycin-resistant strains Enterococcus faecium FN-1 and Enterococcus faecalis NCTC12201 revealed that licoricidin showed the most potent antibacterial effects against both of E. faecalis and E. faecium with a minimum inhibitory concentration (MIC) of 1.9 × 10-5 M. 8-(γ,γ-Dimethylallyl)-wighteone, isoangustone A, 3'-(γ,γ-dimethylallyl)-kievitone, glyasperin C, and one of the new 3-methyl-2-phenylbenzofuran named neoglycybenzofuran also showed potent anti-vancomycin-resistant Enterococci effects (MIC 1.9 × 10-5-4.5 × 10-5 M for E. faecium and E. faecalis). The HPLC condition for simultaneous detection of the phenolics in the extract was investigated to assess the quality control of the natural antibacterial resource, and quantitative estimation of several major phenolics in the extract with the established HPLC condition was also performed. The results showed individual contents of 0.08%-0.57% w/w of EtOAc extract for the major phenolics in the materials examined.
Subject(s)
Glycyrrhiza/chemistry , Hydroxybenzoates/chemistry , Phenols/chemistry , Plant Extracts/chemistry , Anti-Bacterial Agents/pharmacology , Humans , Hydroxybenzoates/administration & dosage , Isoflavones/chemistry , Medicine, Traditional , Microbial Sensitivity Tests , Vancomycin/pharmacology , Vancomycin-Resistant Enterococci/drug effectsABSTRACT
Since our previous study revealed that several licorice phenolics have antibacterial effects on methicillin-resistant Staphylococcus aureus (MRSA), and suppressive effects on the oxacillin resistance of MRSA, we further investigated effectiveness of licorice constituents on vancomycin-resistant Enterococcus (VRE) bacteria, and purified 32 phenolic compounds. Two flavonoids among them were characterized structurally, and identified their structures as demethylglycyrol (31) and 5,7-di-O-methylluteone (32), respectively. Examination of antibacterial effects of licorice phenolics showed that 3-arylcoumarins such as licoarylcoumarin (9) and glycycoumarin (26), and 2-arylcoumarones such as gancaonin I (17), have moderate to potent antibacterial effects on the VRE strains used in this study.
