From the MeOH extract of the Vietnamese sea cucumber Holothuria edulis, eight triterpene glycosides (1−8), including one new compound namely holothurin A5 (1), were isolated by using various chromatographic separations. Their structures were established by spectroscopic experiments including 1D, 2D NMR and HR-ESI-MS.Holothurin A5 (1) has a hydroperoxy group at C-25. To the best of our knowledge, this is the first report of this group in triterpene saponins obtained from sea cucumbers to date.In addition, the in vitro cytotoxicity against five human cancer cell lines (HepG2, KB, LNCaP, MCF7 and SK-Mel2) of all isolated compounds was also evaluated using SRB assays.

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Ten briarane-type diterpenoids (1−10), including one new stereoisomer 17-epijunceellolide B (1), were isolated from the MeOH extract of the Vietnamese gorgonian Junceella fragilis. Their structures were elucidated by spectroscopic experiments including 1D and 2D NMR, and HR-QTOF-MS. In addition, the in vitro cytotoxic activity against eight human cancer cell lines (LNCaP, HepG2, KB, MCF-7, SK-Mel2, HL-60, LU-1 and SW480) of all isolated compounds were evaluated by SRB assays.

Six pregnane steroids including one new compound namely 15β-hydroxypregna-4,20-dien-3-one (1), were isolated and structurally elucidated from the octocoral Carijoa riisei. The cytotoxic activity against a panel of eight human cancer cell lines of isolated compounds was also evaluated by SRB method. As the results, 18-acetoxypregna-1,4,20-trien-3-one (5) showed significant cytotoxicity against all the tested cell lines with the IC values from 22.29 ± 1.47 to 48.73 ± 3.93 μM, whereas 15β-acetoxypregna-1,4,20-trien-3-one (3) and 20R-acetoxypregna-1,4-dien-3-one (6) only exhibited weak effect on KB cell line with IC values of 93.62 ± 7.32 and 71.38 ± 5.45 μM, respectively.

Using various chromatographic separations, two new cembranoids, ehrenbergols F and G (1 and 2), along with three known analogs ehrenbergol D(3), (+)-isosarcophine (4) and sinulariol Z2 (5) were isolated from the soft coral Sarcophyton ehrenbergi. The structural elucidation was done by extensive analysis of the 1D and 2D NMR, HR-ESI-QTOF-MS as well as CD experiments.In addition, compounds 1 (IC50 of 38.38 ± 2.89 µM), 3 (IC50 of 37.14 ± 3.22 µM) and 4 (IC50 of 45.01 ± 2.49 µM) revealed moderate inhibitory activity on LPSinduced NO production in RAW264.7 cells, whereas 2 (IC50 of 73.32 ± 1.95 µM) and 5 (IC50 of 64.48 ± 4.93 µM) exhibited weak effect.