Structurally diverse cucurbitane-type triterpenoids from the tubers of Hemsleya chinensis with cytotoxic activity.

Ten previously undescribed cucurbitane-type triterpenoids, namely hemslyencins A-F (1-6) and hemslyencosides A-D (7-10), together with twenty previously reported compounds (11-30), were isolated from the tubers of Hemsleya chinensis. Their structures were elucidated by unambiguous spectroscopic data (UV, IR, HR-ESI-MS, 1D and 2D NMR data). Hemslyencins A and B (1 and 2) possessing unique 9, 11-seco-ring system with a six-membered lactone moiety, were the first examples among of the cucurbitane-type triterpenoids, and hemslyencins C and D (3 and 4) and hemslyencoside D (10) are the infrequent pentacyclic cucurbitane triterpenes featuring a 6/6/6/5/6 fused system. The cytotoxic activities of all isolated compounds were evaluated against MCF-7, HCT-116, HeLa, and HepG2 cancer cells, and their structure-activity relationships (SARs) was discussed as well. Compounds 17, 25, and 26 showed significant cytotoxic effects with IC50 values ranging from 1.31 to 9.89 µM, among which compound 25 induced both apoptosis and cell cycle arrest at G2/M phase in a dose dependent manner against MCF-7 cells.

Five New C21 -Steroidal Sapogenins from the Acid Hydrolysate of Cynanchum otophyllum Roots.

Five new C21 -steroidal sapogenins (1-5) named cynotogenins J-N, were isolated from the acid hydrolysate of Cynanchum otophyllum roots. Their structures were established by extensive spectroscopic analysis (UV, IR, HR-ESI-MS, and NMR). Most notably, compounds 1-3 harboring a rare 5ß,6ß-epoxy group in the C21 -steroidal skeleton of Cynanchum plants. All compounds were evaluated for their cytotoxicities against multiple cancer cell lines, in which compounds 5 showed weak cytotoxicity against HepG2 cancer cells with IC50 values of 44.90 µM.

Design, Synthesis and Anticancer Activity of Novel Steroidal Derivatives with D-Ring Fused or Substituted N-Heterocyclic Systems.

A series of novel D-ring fused or substituted steroidal N-heterocycles were synthesized, and their chemical structures were characterized by spectroscopic analysis. The anticancer activity of these compounds against four human cancer cell lines (MCF-7, H1299, HeLa and HepG2) were evaluated and the structure-activity relationship (SAR) was also investigated. Compound 3c displayed significant inhibitory activity on the four cancer cells with IC50 values ranging from 3.88 to 10.05 µM. Overall, these studies indicated that construction of N-heterocyclic system with D-ring substituted containing a double bond at C-16 and C-17 or D-ring fused with [17,16-d]azolo[1,5-a]pyrimidine could be a promising strategy to improve antitumor activity for steroids deserved further investigation.

Enhanced anticancer efficiency of doxorubicin against human glioma by natural borneol through triggering ROS-mediated signal.

Doxorubicin (DOX) as a first-line chemotherapeutic drug has been widely used for therapy of human cancers. However, side effects and chemo-resistance severely blocked its clinic application. Herein, natural borneol (NB) as a novel monoterpenoid chemosensitizer was found to have the potential to increase the blood brain barrier (BBB) permeability and intracellular uptake of DOX in vitro, and synergistically enhanced DOX-induced cytotoxicity in human glioma cells. NB treatment significantly potentiated DOX-induced G2/M cell cycle arrest by triggering reactive oxygen species (ROS)-mediated DNA damage. NB also enhanced DOX-induced dysfunction of MAPKs and PI3 K/AKT pathways. Furthermore, U251 human glioma xenograft growth in vivo was also effectively inhibited by combined treatment of DOX with NB through induction of G2/M-phase arrest and antiangiogenesis. Taken together, our finding validated that NB could act as novel chemosensitizer to enhance DOX-induced anticancer efficacy, and strategy of using NB and DOX could be a high efficient way in therapy of human cancers.

Isolation of Flavonoids From Wild Aquilaria sinensis Leaves by an Improved Preparative High-Speed Counter-Current Chromatography Apparatus.

Four flavonoids including apigenin-7,4'-dimethylether, genkwanin, quercetin, and kaempferol were isolated in a preparative or semi-preparative scale from the leaves of wild Aquilaria sinensis using an improved preparative high-speed counter-current chromatography apparatus. The separations were performed with a two-phase solvent system composed of hexane-ethyl acetate, methanol-water at suitable volume ratios. The obtained fractions were analyzed by HPLC, and the identification of each target compound was carried out by ESI-MS and NMR. The yields of the above four target flavonoids were 4.7, 10.0, 11.0 and 4.4%, respectively. All these four flavonoids exhibited nitrite scavenging activities with the clearance rate of 12.40 ± 0.20%, 5.84 ± 0.03%, 28.10 ± 0.17% and 5.19 ± 0.11%, respectively. Quercetin was originally isolated from the Thymelaeaceae family, while kaempferol was isolated from the Aquilaria genus for the first time. In cytotoxicity test these two flavonoids exhibited moderate inhibitory activities against HepG2 cells with the IC50 values of 12.54 ± 1.37 and 38.63 ± 4.05 µM, respectively.

Xanthones from Swertia mussotii and their α-glycosidase inhibitory activities.

Two new xanthones, 1,8-dihydroxy-3-methoxyxanthone 7-O-[α-L-rhamnopyranosyl(1 → 2)-ß-D-glucopyranoside] (1) and 1,8- dihydroxy-3-methoxyxanthone 7-O-[α-L-rhamnopyranosyl(1 → 3)-α-L-rhamno-pyranosyl (1 → 2)-ß-D-xylopyranoside] (2), together with 26 known xanthones (3-28), were isolated from the aqueous ethanol extract of the traditional Chinese herb Swertia mussotii. Their structures were elucidated via spectroscopic analyses including 2D NMR. The inhibition of α-glucosidase by the isolated xanthones was evaluated by an in vitro high-throughput screening assay. Our results indicated that 1,3,5,8-tetrahydroxyxanthone is the best inhibitor with an IC50 value of 5.33 ± 0.09 µM, while the O-glycosylated xanthones were poor α-glycosidase inhibitors.

Antioxidant xanthones from Swertia mussotii, a high altitude plant.

Four new xanthones, 3,5,6,8-tetrahydroxyxanthone-1-C-ß-D-glucoside (1), 7-hydroxy-3,4,8-trimethoxyxanthone-1-O-(ß-D-glucoside) (2), 6-hydroxy-3,5-dimethoxyxanthone-1-O-(ß-D-glucoside) (3), 3,4,7,8-tetramethoxyxanthone-1-O-(ß-D-glucoside) (4), together with twenty-one known xanthones (5-25) were isolated from the ethanol aqueous extract of Swertia mussotii. Their structures were elucidated via spectroscopic analyses. Oxygen radical absorbance capacity of all the isolated xanthones was systematically evaluated by ORAC(FL) assay. Results disclose that all the tested xanthones display moderate to excellent antioxidant activity, where 1 is the most active compound and 13 is the least one. A preliminary structure-activity relationship is also discussed.