Shuangzhu Liu

Appetite suppressing pregnane glycosides from the roots of Cynanchum auriculatum

In the search for plant alternatives to Hoodia gordonii containing P57, a pregnane glycoside with potential appetite suppressant effect, the roots of Cynanchum auriculatum were investigated. As a result, 15 pregnane glycosides including nine never previously reported were isolated. Their structures were elucidated on the basis of extensive spectroscopic analyses and chemical methods. Appetite suppressant effect and body weight loss were observed when tested with the most abundant pregnane glycoside, wilfoside K1N, in an in vivo test with rats.

(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.

Natural β-Dihydroagarofuran-Type Sesquiterpenoids as Cognition-Enhancing and Neuroprotective Agents from Medicinal Plants of the Genus Celastrus

Alzheimers disease (AD) is an irreversible, multifaceted, and progressive neurodegenerative disorder. Over the past 30 years, the search for anti-AD drugs has been primarily based on the cholinergic deficiency hypothesis and/or the β-amyloid (Aβ) cascade hypothesis. In this study, we report the identification of 16 new and 38 known β-dihydroagarofuran-type sesquiterpenoids from Celastrus flagellaris and Celastrus angulatus. The β-dihydroagarofuran-type sesquiterpenoids 58, 59, 61, and 63 significantly attenuated scopolamine-induced prolonged escape latency and increased number of errors compared with the control group. At 10 μM, 21 of the 62 tested β-dihydroagarofuran-type sesquiterpenoids rescued Aβ25-35-induced SH-SY5Y cells from viability reduction, which increased the cell viability from 64.6% for the model to more than 74.0%. The majority of the β-dihydroagarofuran-type sesquiterpenoids with ester groups exhibited stronger activity than those with free hydroxy groups or without substituents at the same positions. These results identified a new chemical skeleton as drug lead for the investigation of novel therapeutic agents against AD.

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.

Four new triterpenoids isolated from the resin of Garcinia hanburyi.

Four new triterpenoids, 2-O-acetyl-3-O-(4′-O-acetyl)-α-l-arabinopyranosylmaslinic acid (1), 2-O-acetyl-3-O-(3′-O-acetyl)-α-l-arabinopyranosylmaslinic acid (2), 2-O-acetyl-3-O-(3′,4′-O-diacetyl)-α-l-arabinopyranosylmaslinic acid (3), and 3-O-(3′-O-acetyl)-α-l-arabinopyranosyloleanolic acid (4), together with six known triterpenoids, 3-O-(4′-O-acetyl)-α-l-arabinopyranosyloleanolic acid (5), maslinic acid (6), 2-O-acetylmaslinic acid (7), 3-O-acetylmaslinic acid (8), betulinic acid (9), and 2α-hydroxy-3β-O-acetylbetulinic acid (10), were isolated from the EtOAc extract of Garcinia hanburyi resin. Their structures were elucidated by analysis of the spectroscopic data and chemical methods.