• Bulletin of the Korean Chemical Society
• /
• v.30 no.3
• /
• pp.742-744
• /
• 2009

• Bulletin of the Korean Chemical Society
• /
• v.30 no.5
• /
• pp.1218-1220
• /
• 2009

• Journal of the Korean Magnetic Resonance Society
• /
• v.25 no.2
• /
• pp.24-32
• /
• 2021

Two new sesterterpenes, including a known sesterterpene, were isolated from the marine sponge Haliclona sp. collected in the Gageo island, Korea. One of the new sesterterpenes (1) was an unusual compound possessing a spiroketal moiety and the other (2) represented a four ring-fused skeleton. The planar structure of compound 1 was identical to gombaspiroketals A and B isolated from the marine sponge Clathria gombawuiensis, but the configuration for the two chiral centers was different each other. On the other hand, the skeletal structure of compound 2 was similar to that of phorone A isolated from Phorbas sp. and a compound from C. gombawuiensis, except for one configuration at C-8. However, in comparing the ¹H and ¹³C NMR spectral data, the proton and carbon chemical shifts for the three compounds were almost consistent. The NOESY spectrum revealed that the C-8 configuration of 2 was reversed to that of the two reported compounds. The configuration for compound 2 was supported by quantum mechanical calculation for the carbon chemical shifts and DP4+ probability for the protons and carbons of 2.

• Journal of the Korean Magnetic Resonance Society
• /
• v.19 no.1
• /
• pp.23-28
• /
• 2015

Four spiroketal sestertepenoids (1 ~ 4) were isolated from the marine sponge Haliclona species. Their planar structures were completely determined from a combination of extensive 1D and 2D NMR experiments, and also the relative stereochemistry on the chiral centers were established by the ROESY experiment. Compounds 1 ~ 3 were determined as the same planar structures with different stereochemistry on the chiral centers C-11 and C-13. Of these, 1 was identified as a new stereoisomer. Four compounds showed the inhibition effect of nitric oxide (NO) production in LPS-stimulated RAW 264.7 cells (0.7~2.0 g/ml).

• Archives of Pharmacal Research
• /
• v.24 no.1
• /
• pp.44-50
• /
• 2001

To search for cytotoxic components from Allium victoriallis , MTT assays on each extract and an isolated component, gitogenin 3-O-lycotetroside, were performed against cancer cell lines. Cytotoxicities of most extract were shown to be comparatively weak, though $IC_50$ values of $CHCl_3$fraction was found to be <31.3-368.4 $\mu\textrm{g}/ml$. From the incubated methanol extract at $36^{\circ}C, eleven kinds of organosulfuric flavours were predictable by CG-MS performance. The most abundant peak was revealed to be 2-vinyl-4H-1,3-dithiin(1) by its mass spectrum. Further, this extract showed significant cytotoxicities toward cancer cell lies. Silica gel column chromatography of the n-butanol fraction led to the isolation of gitogenin 3-O-lycotetroside (3) along with astragalin (4) and kaempferol 3, 4'-di-O-$\beta$-D-glycoside (5). This steroidal saponin exhibited significant cytotoxic activities ($IC_50$, 6.51-36.5 $\mu\textrm{g}/ml$) over several cancer cell lines. When compound 3 was incubated for 24 h with human intestinal bacteria, a major metabolite was produced and then isolated by silica gel column chromatography. By examining parent and prominent ion peak in FAB-MS spectrum of the metabolite, the structure was speculated not to be any of prosapogenins of 3, suggesting that spiroketal ring were labile to the bacterial reaction. These suggest that disulfides produced secondarily are the antitumor principles.