Four lathyrane diterpenoids from the seeds of Euphorbia lathyris.

Four new diterpenoids, including three secolathyrane diterpenoids (1-3) and one lathyrane diterpenoid (4), together with seven known diterpenoids, were obtained in the shelled seeds of Euphorbia lathyris. In particular, 1-3 possess a rare split ring structure, and currently only one compound with the same skeleton has been identified in E. lathyris. Compound 4 furnishes an unprecedented oxygen bridge structure. The structures were identified using various spectral techniques, including NMR, HR-ESI-MS, single-crystal X-ray diffraction and calculated electronic circular dichroism (ECD). The biosynthetic pathway of 1-4 was inferred. Furthermore, the cytotoxic activities of all compounds (1-11) were measured on three human tumor cells. New compounds 2 and 3 showed moderate cytotoxic activities against U937 cells with IC50 values of 22.18 and 25.41 µM, respectively.

Suaeglaucin A, a new coumaronochromone from Suaeda glauca.

A new isoflavane, suaeglaucin A (1), which was isolated from the herb of Suaeda glauca (Bunge) Bunge, was elucidated as 5,6,8-trimethoxy-7- hydroxycoumaronochromone based on its MS and 1D and 2D NMR spectroscopic data. The structure of compound 1 was confirmed by X-ray crystallographic analysis. Five known compounds (2-6) were also isolated. All compounds were isolated for the first time from Chenopodiaceae. We found that compounds 2 and 4 possessed moderate antioxidant activity.

New cytotoxic diarylheptanoids from the rhizomes of Alpinia officinarum Hance.

Two new dimeric diarylheptanoids, named Alpinin C (1) and D (2), a new natural product of diarylheptanoid (3) along with three known diarylheptanoids (4-6) were isolated from the rhizomes of Alpinia officinarum Hance. Their structures were elucidated based on extensive spectroscopic analyses (1D and 2D NMR, HRTOFMS, IR). The isolated compounds were evaluated for their cytotoxicity against human tumor cell lines HepG2, MCF-7, T98G and B16-F10. Compound 1 showed selective cytotoxicity against cell lines of MCF-7 and T98G, while compound 6 showed significant cytotoxicity to the all tested tumor cell lines with IC50 in the range from 8.46 to 22.68 µmol/L.

A new quinoline alkaloid from the roots of Dictamnus angustifolius.

AIM: To investigate the quinoline alkaloids from the roots of Dictamnus angustifolius G.Don ex Sweet (Rutaceae). METHOD: The quinoline alkaloids were isolated by various column chromatographic methods and their structures were elucidated on the basis of spectral analysis. RESULTS: A new quinoline alkaloid, 5-methoxylrobustine (1), along with five known quinoline alkaloids were obtained, and their structures were identified as dictamnine (2), robustine (3), isopteleine (4), γ-fagarine (5), and skimmianine (6). Cytotoxicity testing of these alkaloids showed that all of them had weak cytotoxic activities against human breast cancer cells (MCF7). CONCLUSION: Compound 1 is a new quinoline alkaloid. Alkaloid 3 showed stronger anti-proliferation effect than the other alkaloids.

A new dimeric diarylheptanoid from the rhizomes of Alpinia officinarum.

AIM: To study the chemical constituents of the rhizomes of Alpinia officinarum Hance. METHOD: Compounds were isolated by repeated column chromatography, and their structures were elucidated on the basis of spectral analysis. The cytotoxic activities of these compounds were evaluated with the T98G and B16F10 cell lines by the MTT assay. RESULTS: A dimeric diarylheptanoid, named alpinin B (1), along with three known diarylheptanoids were obtained, and their structures were identified as alpinin B (1), 1, 7-diphenyl-3,5-heptanedione (2), (4E)-1, 7-diphenylhept-4-en-3-one (3) and (4E)-7- (4-hydroxyphenyl)-1-phenylhept-4-en-3-one (4). CONCLUSION: Compound 1 is a new dimeric diarylheptanoid. The biosynthetic pathway of 1 was speculated to originate from a Michael reaction between compounds 2 and 3. Compound 3 showed cytotoxicity against the human glioblastoma T98G cell line with IC50 of 27 µmol·L(-1).

Caesappin A and B, two novel protosappanins from Caesalpinia sappan L.

Two novel protosappanins, named Caesappin A (1) and B (2), along with three known protosappanins were isolated from Caesalpinia sappan L. Caesappin A is a new type protosappanin with a seven-membered ring fusing an acetal-type section. Compound 4 was isolated from the genus Caesalpinia for the first time. The structures were elucidated on the basis of spectral analysis and the absolute configuration was determined by the ECD experiment coupled with calculated ECD spectra. Their cytotoxic activities were evaluated using MTT assay.

Triticuside A, a dietary flavonoid, inhibits proliferation of human breast cancer cells via inducing apoptosis.

In this study we demonstrated that Triticuside A, one of the flavonoid compounds isolated from wheat bran, induced apoptosis and inhibited proliferation of human breast cancer cells. Triticuside A inhibited the proliferation of human breast cancer cells (MCF-7 and MDA-MB-231) in a dose-dependent manner but barely showed cytotoxicity to the normal human fibroblasts. Triticuside A-induced apoptosis was accompanied by a significant decrease of Mcl-1 and Bcl-2 proteins and by an increase of cleavage of caspases-3, -7, -9, and PARP. Triticuside A also suppressed the level of phospho-Akt and its downstream targets, mTOR and P70 S6 kinase. LY294002, a specific inhibitor of PI3K, significantly enhanced the Triticuside A-induced apoptosis. Moreover LY294002 not only downregulated the level of phospho-Akt but also enhanced the inhibition of Mcl-1 expression when combined with Triticuside A. Our results demonstrate for the first time the specific apoptogenic activity of Triticuside A in tumor cells and involvement of the mitochondrial apoptosis pathway and Akt/mTOR signaling pathway. Thus, Triticuside A may be a potentially useful wheat bran component that can be used for prevention or treatment of breast cancer.

Two new nortriterpenoid saponins from Salicornia bigelovii Torr. and their cytotoxic activity.

Investigation of characteristic constituents of Salicornia bigelovii Torr. led to isolation of two new 30-nortriterpenoid glycosides, Bigelovii A (1), Bigelovii B (2), together with two known 30-nortriterpenoid glycosides 3-4 and three known oleanane-type triterpenoid glycosides 5-7. The structures of new compounds were elucidated by extensive 1D and 2D NMR, and MS spectroscopic analysis, and chemical evidences. All compounds were isolated for the first time from Chenopodiaceae. Thus compounds 1-4 were evaluated for their cytotoxicity and compouds 1, 3 showed moderate activity against four cell lines, HL-60 (promyelocytic leukemia), MCF-7 (breast carcinoma), HepG2 (liver carcinoma) and A549 (lung carcinoma), with IC(50) values of 6.18, 78.08, 13.64 and >100µM for 1; 31.87, >100, ~100, >100µM for 3, respectively.