Promising effects on ameliorating mitochondrial function and enhancing Akt signaling in SH-SY5Y cells by (M)-bicelaphanol A, a novel dimeric podocarpane type trinorditerpene isolated from Celastrus orbiculatus.

Oxidative stress plays an important role in the pathological processes of various neurodegenerative diseases. In this study, we investigated the neuroprotective effects of (M)-bicelaphanol A, which has been the first dimeric podocarpane type trinorditerpene isolated from Celastrus orbiculatus, against hydrogen peroxide (H2O2)-induced injury in human SH-SY5Y neuroblastoma cells. Our study showed that cells pretreated with (M)-bicelaphanol A significantly attenuated H2O2-induced cell viability reduction and cell apoptosis. These neuroprotective effects of (M)-bicelaphanol A were associated with a reduction of reactive oxygen species and an increase in the level of adenosine triphosphate. In addition, (M)-bicelaphanol A pretreatment markedly increased the phosphorylation level of Akt in SH-SY5Y cells. In conclusion, our results for the first time demonstrate that the protection of (M)-bicelaphanol A on SH-SY5Y cells against H2O2-induced oxidative stress may attribute, at least partially, to its attenuation of mitochondrial dysfunction and activation of Akt signaling pathway. Above results shed more light on the molecular mechanisms involved in the neuroprotective effects of (M)-bicelaphanol A, which could be a potential drug candidate for the treatment of oxidative stress-associated neurodegenerative diseases.

(M)- and (P)-bicelaphanol A, dimeric trinorditerpenes with promising neuroprotective activity from Celastrus orbiculatus.

(M)-Bicelaphanol A (1) and (P)-bicelaphanol A (2), two unprecedented dimeric trinorditerpenes existing as atropisomers, together with their monomer celaphanol A (3), were isolated from the root bark of Celastrus orbiculatus. The structures and absolute configurations of 1 and 2 were determined by spectroscopic and single-crystal X-ray diffraction analyses. Compound 1 exhibited a significant in vitro neuroprotective effect against a hydrogen peroxide-induced cell viability decrease in PC12 cells at 1 µM, while compounds 2 and 3 showed such effects at 10 µM.

New iridoid glycoside and triterpenoid glycoside from Premna fulva.

Liquid chromatography-photodiode array detector-mass spectrometry-based chemical investigation of the leaves and stems of Premna fulva yielded one new iridoid glycoside (1), one new triterpenoid glycoside (2) along with six known compounds isolated for the first time from the genus. Their structures were established on the basis of extensive spectroscopic data analyses and chemical methods.

Structural revision of periplocosides and periperoxides, natural immunosuppressive agents from the genus Periploca.

The structures of a series of peroxy function containing pregnane glycosides isolated from Periploca sepium and Periploca forrestii were revised to be orthoester group bearing ones using 2D NMR spectroscopic techniques, as well as chemical transformations and X-ray crystallographic diffraction analysis. The orthoester function appears to be an essential structural feature for immunosuppressive activity.

Two new glycosides from Breynia vitis-idaea.

A new sulfur-containing spiroketal glycoside, breynin I (1), and a new terpenic glycoside, breyniaionoside E (2), together with 10 known compounds, were isolated from the aerial parts of Breynia vitis-idaea (Euphorbiaceae), a traditional Chinese medicine used for the treatment of chronic bronchitis and wounds. Their structures were elucidated on the basis of spectroscopic analysis and modified Mosher's method.