ABSTRACT
Phytochemical investigation of the fruits of Crataegus pinnatifida Bunge led to the isolation of four pairs enantiomeric benzofuran lignans (1a/1b-4a/4b) including four undescribed compounds (1a, 2b, 3b and 4b). Their structures were determined by extensive spectroscopic methods and the absolute configurations were further determined by the comparison of experimental and calculated ECD spectra. All the enantiomeric lignans were evaluated for their inhibitory activities to tyrosinase. Among them, compound 4a showed moderate inhibition activity (IC50 = 0.54 mM).
Subject(s)
Benzofurans , Crataegus , Lignans , Lignans/chemistry , Fruit/chemistry , Crataegus/chemistry , Stereoisomerism , Benzofurans/analysis , Molecular StructureABSTRACT
Five pairs of enantiomeric 8-O-4' neolignans (1a/1b-5a/5b), including seven new compounds (1a/1b, 2a, 3a, 4a/4b and 5b), were obtained from the fruits of Crataegus pinnatifida Bge. Their structures were determined by comprehensive spectroscopic analyses. The absolute configurations of the enantiomers were determined by comparison of the experimental ECD with the calculated data. Additionally, all the enantiomeric neolignans were evaluated for their neuroprotective activity against H2O2-induced cell injury in human neuroblastoma SH-SY5Y cells, and most of them showed potent selective neuroprotective activity. Especially, 3b (72.98%) showed the best protective effect, better than 3a (63.49%) and trolox (62.86%) at 25⯵M.
Subject(s)
Crataegus/chemistry , Fruit/chemistry , Lignans/pharmacology , Neuroblastoma/pathology , Neuroprotective Agents/pharmacology , Oxidative Stress/drug effects , Cell Line, Tumor , Humans , Lignans/isolation & purification , Molecular Structure , Neuroprotective Agents/isolation & purification , Phytochemicals/isolation & purification , Phytochemicals/pharmacology , StereoisomerismABSTRACT
Seven undescribed triterpene saponins, named kakisaponin I-VII (1-7), together with nine known ones (8-16) were isolated from the leaves of Diospyros kaki Thunb. by various chromatographic methods. Compounds 1-5 were novel 18, 19-secoursane triterpenoids, which were an uncommon type of triterpenoids. Their structures were elucidated by different spectroscopic methods, combining HRESIMS, 1D and 2D NMR. All isolated compounds were evaluated for their protective effects on H2O2-induced damage in human dopaminergic neuroblastoma cells (SH-SY5Y). Compound 2 showed significant neuroprotective effect at a certain concentration, and compounds 3 and 12 exhibited moderate bioactivities. Current study suggests that triterpene saponins in Diospyros kaki may play an important role in the neuroprotective properties.
Subject(s)
Diospyros/chemistry , Neuroprotective Agents/pharmacology , Saponins/pharmacology , Triterpenes/pharmacology , Cell Line, Tumor , Humans , Molecular Structure , Neuroprotective Agents/isolation & purification , Plant Leaves/chemistry , Saponins/isolation & purification , Triterpenes/isolation & purificationABSTRACT
BACKGROUND: Alzheimer's disease (AD) is one of the most prevalent neurodegenerative disorders characterized by neuronal loss in the brain and cognitive impairment. AD is now considered to be the third major cause of death in developed countries, after cardiovascular disease and cancer. Persimmon leaves are used as a popular folk medicine to treat hypertension, angina and internal haemorrhage in Cyangbhina, and it has been reported that ethyl acetate extract of persimmon leaves (EAPL) displays a potential therapeutic effect on neurodegenerative diseases. HYPOTHESIS/PURPOSE: This study was designed to investigate the effects of EAPL on AD, to clarify the possible mechanism by which EAPL exerts its beneficial effects and prevents AD, and to determine the major constituents involved. STUDY DESIGN: AD model was established by bilateral injection of Aß1-42 into the hippocampus of rats. The cognitive performance was determined by the Morris water maze and step-down tests. Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), malondialdehyde (MDA), apoptosis, total and phosphorylated c-Jun NH2-terminal kinase (JNK/p-JNK), caspase-3, Bax and Bcl-2 were determined. In addition, a sensitive and reliable LC-QTOF-MS method was applied to identify the major compounds present in EAPL. RESULTS: EAPL at doses of 200mg/kg, 400mg/kg could markedly reduce the latency, significantly increase the time in the first quadrant and number of the target crossing times in Morris water maze test, markedly increase the latency and reduce the number of errors in the step-down test, significantly inhibit the reductions in SOD and GSH-Px activities, and increase the level of MDA. In addition, EAPL treatment attenuated neuronal apoptosis in the hippocampus, reduced the expression of p-JNK, caspase-3, and the relative ratio of Bax/Bcl-2. Meanwhile, 32 constituents were identified by LC-QTOF-MS/MS assays. CONCLUSION: The results indicate that EAPL has a potent protective effect on cognitive deficits induced by Aß in rats and this effect appears to be associated with the regulation of the antioxidative defense system and the mechanism of mitochondrial-mediated apoptosis. Furthermore, analysis of the LC-MS data suggests that flavonoids and triterpenoids may be responsible for the potential biological effects of EAPL.
