Da-Qing Jin

Neuroprotective labdane diterpenes from Fritillaria ebeiensis.

By bioactivity-guided isolation, two labdane diterpenes (1 and 2) have been isolated from the bulbs of Fritillaria ebeiensis. Their structures were elucidated as 6α,7β-dihydroxy-labda-8(17),12(E),14-triene (1) and 6-oxo-2α-hydroxy-labda-7,12(E), 14-triene (2), on the basis of spectroscopic data analysis (IR, ESI-MS, HR-ESI-MS, 1D and 2D NMR). Both of the isolates showed neuroprotective effects against MPP(+)-induced neuronal cell death in human dopaminergic neuroblastoma SH-SY5Y cells.

Iridoids from the roots of Valeriana jatamansi and their neuroprotective effects.

Three new iridoids, valeriandoids A-C (1-3), together with three known analogues (4-6), were isolated from the roots of Valeriana jatamansi. Their structures and relative configurations were elucidated by spectroscopic methods (IR, ESIMS, HRESIMS, 1D and 2D NMR) and by comparison of their NMR data with those of related compounds. All the isolated compounds were evaluated for their neuroprotective effects and compounds 1, 3, 4 and 6 showed moderate neuroprotective effects.

Absolute Configurations and NO Inhibitory Activities of Terpenoids from Curcuma longa

Curcuma longa L., belonging to the Zingiberaceae family, is a perennial herb and has been used as a spice and a pigment in the food industry. In the ongoing search for inhibitory reagents of NO production and survey of the chemical composition of natural vegetable foods, the chemical constituents of C. longa used as spice were investigated. This investigation resulted in the isolation of 2 new terpenoids and 14 known analogues. Their structures were established on the basis of the extensive analyses of 1D and 2D NMR spectroscopic data, and the absolute configurations of 1-4 were elucidated by comparison of the calculated and experimental ECD spectra. Among them, compound 1 is a rare norditerpene with an ent-labdane skeleton, and 2 is a skeletally novel sesquiterpene having an eight-membered ring. All of the compounds were found to possess NO inhibitory activities in murine microglial BV-2 cells. The discovery of two new compounds in this chemical investigation further disclosed the chemical composition of C. longa used a food spice, and the bioassay implied that the natural food spice C. longa, containing terpenoids with NO inhibitory activities, may be potentially promotive to human health.

Lathyrane diterpenes from Euphorbia prolifera and their inhibitory activities on LPS-induced NO production

A new lathyrane diterpene (1), an unreported spectroscopic data lathyrane diterpenene (2), and two known analaogues (3 and 4) have been isolated from Euphorbia prolifera. Their structures were elucidated as (12E,2S,3S,4R,5R,6S,9S,11S,15R)-3-butyryloxy-5,15-diacetoxy-6,17-epoxylathyra- 12-en-14-one (1), (12E,2S,3S,4R,5R,6S,9S,11S,15R)-3-propionyloxy-5,15-diacetoxy-6,17- epoxylathyra-12-en-14-one (2), (12E,2S,3S,4R,5R,6S,9S,11S,15R)-3-benzoyloxy-5,15-diacetoxy -6,17-epoxylathyra-12-en-14-one (3), and 15-O-acetyl-17-hydroxyjolkinol (4) by spectroscopic methods (IR, ESIMS, HR-ESIMS, NMR, and X-ray crystallography). The inhibitory activities on LPS-induced NO production of these diterpenes were evaluated and compounds 1, 3 and 4 showed inhibitory effects.

Neuroprotective bakkenolides from the roots of Valeriana jatamansi

Two new bakkenolides, valerilactones A (1), and B (2), and two known analogues, bakkenolide-H (3) and bakkenolide-B (4), were isolated from the roots of Valeriana jatamansi. Their structures and relative configurations were elucidated by spectroscopic methods (IR, ESIMS, HRESIMS, 1D and 2D NMR) and by comparison of their NMR data with those of related compounds. Compounds 1, 2, and 3 exhibited potent neuroprotective effects against MPP(+)-induced neuronal cell death in human dopaminergic neuroblastoma SH-SY5Y cells.

Diterpenes inhibiting NO production from Euphorbia helioscopia

Three new jatrophane diterpenes (1-3), an unreported spectroscopic data jatrophane diterpenene (4), and nine known analogues (5-13) have been isolated from the whole plants of Euphorbia helioscopia. Their structures were established by detailed spectroscopic data analyses (IR, ESIMS, HR-ESIMS, and 1D and 2D NMR), and the structure of 1 was confirmed by X-ray crystallography. The diterpenes showed inhibitory activities on LPS-induced NO production in murine microglial BV-2 cells.

Isolation, Characterization, and NO Inhibitory Activities of Sesquiterpenes from Blumea balsamifera

Blumea balsamifera belongs to the family Compositae, and its leaves have been used as a flavoring ingredient and a tea. A phytochemical investigation of the aerial parts of B. balsamifera led to the isolation of 10 new (1-10) and 1 known (11) sesquiterpenes. Their structures were elucidated on the basis of extensive one- and two-dimensional nuclear magnetic resonance (heteronuclear multiple-quantum coherence, heteronuclear multiple-bond correlation, (1)H-(1)H correlation spectroscopy, and nuclear Overhauser effect spectrometry) spectroscopic data analyses, and the structure of compound 1 was confirmed by X-ray crystallography. The inhibitory activities on lipopolysaccharide-induced NO production in murine microglial BV-2 cells of these sesquiterpenes were evaluated, and all of the compounds showed inhibitory effects.

Two novel clerodane diterpenenes with NGF-potentiating activities from the twigs of Croton yanhuii.

Nerve growth factor (NGF) and analog reagents to promote the neurite outgrowth of nerve cells against the neuron degeneration are expected to be potentially useful for the medical treatment of Alzheimers disease. In our focus on the discovery of bioactive diterpenes, we investigated the chemical constituents of the plant Croton yanhuii. This investigation led to the isolation and identification of two novel clerodane diterpenes (1 and 2). Their structures were elucidated on the basis of extensive 1D and 2D NMR (COSY, HMQC, HMBC, and NOESY) and mass (ESIMS and HR-ESIMS) spectroscopic data analyses. Further biological screenings showed that both of the compounds enhanced NGF-mediated neurite outgrowth from PC12 cells.

Isolation, characterization, and neuroprotective activities of sesquiterpenes from Petasites japonicus.

Neuroprotective reagents to protect the nerve cells against oxidative stress and other damages are potentially effective for the medical treatment of Parkinsons disease. Petasites japonicus, a wild vegetable, belongs to the family Compositae and its extract has shown the neuroprotective effects. A further phytochemical investigation of P. japonicus for neuroprotective substances led to the isolation of eight new (1-8) and two known (9 and 10) sesquiterpenes. Their structures were elucidated on the basis of extensive 1D and 2D NMR (HMQC, HMBC, (1)H-(1)H COSY, and NOESY) spectroscopic data analyses, and the structure of 1 was confirmed by X-ray crystallography. The neuroprotective activities of these sesquiterpenes were evaluated against cobalt chloride (CoCl2)-induced neuronal cell death in human dopaminergic SH-SY5Y cells. Five compounds showed a neuroprotective activity.

Bioactive Clerodane Diterpenoids from the Twigs of Casearia balansae

Eight new clerodane diterpenes, balanspenes A-H (1-8), along with two known analogues (9 and 10), were isolated from the twigs of Casearia balansae. The structures of 1-8 were elucidated on the basis of extensive 1D and 2D NMR spectroscopic data analysis, and the absolute configurations of compounds 1, 4, and 7 were confirmed by comparing their experimental CD spectra with those calculated by the time-dependent density functional theory method. Compounds 4-7, 9, and 10 were found to possess the property of being able to stimulate NGF-mediated neurite outgrowth from PC12 cells.