Chen-Chen Zhu

New triterpene saponins from the root of Ilex pubescens.

Two new triterpene glycosides named ilexpublesnin A (1) and ilexpublesnin B (2) were isolated from the root of Ilex pubescens. Their structures were determined as 3-O-(β-D-xylopyranosyl)-28-O-(β-D-glucopyranosyl)-3β, 19α-dihydroxyurs-23-oxo-12-en-28-oic acid (1) and 28-O-(β-D-xylopyranosyl-(2→1)-β-D-glucopyranosyl)-3β, 19α-dihydroxyurs-23-oxo-12-en-28-oic acid (2) on the basis of chemical and spectroscopic methods.

Diterpenoid alkaloids and flavonoids from Delphinium trichophorum.

Five hetisane-type C20-diterpenoid alkaloids, trichodelphinines A-E, one delnudine-type C20-diterpenoid alkaloid, trichodelphinine F and three known flavonoids, quercetin, quercetin 3-O-β-D-glucopyranoside, and quercetin 3-O-β-D-glucopyranoside-7-O-α-L-arabinopyranoside, were isolated from whole plants of Delphinium trichophorum Franch. Their structures were elucidated on the basis of extensive spectroscopic analysis, including HSQC, HMBC, (1)H-(1)H COSY, NOESY and X-ray crystallographic analysis, and from chemical evidence. The cytotoxic activities of the diterpenoid alkaloids were evaluated using the MTT method, and the IC50 values of their cytotoxicity against A549 cancer cells ranged from 12.03 to 52.79 μM.

Investigation on the differences of four flavonoids with similar structure binding to human serum albumin

Flavonoids are structurally diverse and the most ubiquitous groups of polyphenols distributed in the various plants, which possess intensive biological activities. In this study, the interaction mechanisms between four flavonoids containing one glucose unit with similar molecular weight isolated from the Tibetan medicinal herb Pyrethrum tatsienense, namely, apigenin-7-O-β-D-glucoside(1), luteolin-7-O-β-D-glucoside(2), quercetin-7-O-β-D-glucoside(3), quercetin-3-O-β-D-glycoside(4), and human serum albumin(HSA), were investigated by fluorescence, UV–vis absorbance, circular dichroism, and molecular modeling. The effects of biological metal ions Mg2+, Zn2+, and Cu2+ on the binding affinity between flavonoids and HSA were further examined. Structure–activity relationships of four flavonoids binding to HSA were discussed in depth and some meaningful conclusions have been drawn by the experiment data and theoretical simulation. In addition, an interesting phenomenon was observed that the microenvironment of the binding site I in HSA has hardly changed in the presence of 4 differentiating from the other three flavonoids on the basis of conformation investigations.

Two new acetylated flavan glycosides from rhizomes of the fern Abacopteris penangiana

Two new acetylated flavan glycosides (2S,4R)-4,5,7-trihydroxy-4′-methoxy-6,8-dimethylflavan-5-O-β-D-6-acetylglucopyranoside-7-O-β-D-glucopyranoside (1) and (2S,4R)-5,7-dihydroxy-4,4′-dimethoxy-6,8-dimethylflavan-5-O-β-D-6-acetylglucopyranoside-7-O-β-D-glucopyranoside (2) were isolated from the rhizomes of Abacopteris penangiana. Their structures were elucidated on the basis of spectroscopic methods including IR, HR-ESI-MS, 1D and 2D NMR, and chemical evidences.

A novel anthocyanidin glycoside from the rhizomes of Abacopteris penangiana

A novel anthocyanidin glycoside, abacopterin J (1), together with the known eruberin B (2) and eruberin C (3) was isolated from the fern Abacopteris penangiana (Hook.) Ching. The structure of the new compound 1 was elucidated on the basis of extensive spectroscopic analysis, including HSQC, HMBC, ((1))H-((1))H COSY and ROESY, and chemical evidence. Abacopterin J is the first example of an anthocyanidin glycoside isolated from natural sources, which is comprised of a flavan and an anthocyanidin moiety.

Investigation of the interaction between two phenylethanoid glycosides and bovine serum albumin by spectroscopic methods

Two phenylethanoid glycosides, acteoside and forsythoside B, were first isolated from the traditional Chinese herb Callicarpa peii H.T. Chang. The interaction between the two phenylethanoid glycosides and bovine serum albumin (BSA) was investigated by fluorescence, UV–vis absorbance and circular dichroism (CD). The results showed that the quenching mechanism in the drug–BSA binary systems was a combination of static quenching and non-radiative energy transfer. Displacement experiments confirmed that the drug bound to the site I of BSA. UV–vis and CD measurements indicated that the binding of the drug to BSA induced conformational changes in BSA.

A new triterpenoid glycoside from the roots of Ilex asprella

AIM To study the chemical constituents of the roots of Ilex asprella Champ. ex Benth. METHODS Compounds were isolated by silica gel, ODS, and Sephadex LH-20 column chromatography, and their structures were elucidated on the basis of physicochemical properties and spectroscopic analysis. RESULTS Four triterpenoid glycosides were isolated and identified as (3β)-19-hydroxy-28-oxours-12-en-3-yl β-D-glucopyranosiduronic acid n-butyl ester (1), ilexasoside A (2), monepaloside F (3), and ilexoside A (4). CONCLUSION Compound 1 is a new triterpenoid glycoside, and compounds 3 and 4 were isolated from this plant for the first time.

Two new abietane diterpenoids from the caulis and leaves of Callicarpa kochiana.

Previous studies revealed that diterpenoids from Callicarpa genus were mainly of clerodane-type and phyllocladane-type, and abietane-type diterpenoids were seldom reported. In this paper, we reported two new abietane diterpenoids, kochianic acid A (1) and kochianic acid B (2), together with two known abietane-type diterpenoids, pedunculatic acid B (3) and 7α, 15-dihydroxydehydroabietic acid (4), which were all isolated from Callicarpa kochiana. The structures of the new compounds 1 and 2 were elucidated on the basis of extensive spectroscopic analysis, including HSQC, HMBC, (1)H-(1)H COSY, ROESY and finally confirmed by single-crystal X-ray diffraction.

Cytotoxic diterpenoids from Rabdosia lophanthoides var. gerardianus

Two new abietane diterpenoids, Gerardianin B (1) and Gerardianin C (2), one new lignan glycoside, Gerardianin D (3) and one new lupane-type triterpenoid, Gerardianol A (4), together with seven known abietane diterpenoids were isolated from the aerial parts of Rabdosia lophanthoides var. gerardianus. Their structures were determined by 1D and 2D NMR spectroscopic data. The cytotoxic activities of the nine diterpenoids were evaluated on human cancer cell lines. Compounds 6-11 exhibited significant cytotoxic activities against HepG2 cell lines with IC50 from 4.68 to 9.43μM and HCF-8 cell lines with IC50 from 9.12 to 13.53μM.

Gerardianin A, a new abietane diterpenoid from Isodon lophanthoides var. gerardianus

A new abietane diterpenoid, gerardianin A (1), along with a known compound 6,7-dehydroroyleanone (2), has been isolated from the aerial parts of Isodon lophanthoides var. gerardianus [Bentham] H. Hara. The structure of 1 was determined on the basis of spectroscopic methods and X-ray single-crystal diffraction analysis.