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Chemical investigations of the aerial parts of Tibetan folk medicine Delphinium chrysotrichum resulted in the isolation of two new diterpenoid alkaloids, delphatisine D (1) and chrysotrichumine A (2), together with ten known diterpenoid alkaloids (3-12) and 3β,6α-dihydroxysclareolida (13). Delphatisine D (1) is a rare atisine-type alkaloid from genus Delphinium and is the C-15 epimer of spiramine C which bears an internal carbinolamine ether linkage (N-C-O-C) between C-7 and C-20. Chrysotrichumine A (2) is a rare natural C 19 -diterpenoid alkaloid possessing a nitrone group between C-17 and C-19. Their structures were elucidated on the basis of extensive spectroscopic analysis. Compound 13 is a sesquiterpene first isolated from this genus. Compounds 1, 3-7 and 13 were investigated for cytotoxicity against human breast cancer cell lines of MCF-7 and MDA-MB-23, none of them presented significant activity except compound 7 which exhibited slight activity at 100 μM against MDA-MB-231, but did not reach the EC 50 ., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Chemical investigation of the MeOH extract from the gorgonian Pseudopterogorgia americana afforded two rare sterols, ameristerenol A (1) and B (2), both 9,11-secosterols possesses a seven-membered cyclic enol-ether in ring C, and ameristerol A (3) is the first example of a naturally occurring 9,11-secosterol containing a gorgosterol side chain with a C-24(28) double bond. Ameristerenol A (1) was converted to the sterol derivatives 4-6 to provide additional chemical diversity and comparison for biological screening. The structures of compounds 1-6, along with three related known analogues 7-9, were determined on the basis of extensive spectroscopic analysis and by comparison with literature data. Compound 6 exhibited slight cytotoxicity activity against human breast cancer cell line MDA-MB-231., (Copyright © 2017. Published by Elsevier Inc.)