Pursuing sesterterpene lactams in Australian Irciniidae sponges.

Chemical investigation of two Irciniidae sponges collected by hand (SCUBA) from Australian near shore waters, afforded six new examples of a rare class of sesterterpene lactam; ircinialactams B (1), G (2), H (5), and I (6), and 8-hydroxyircinialactams C (3) and G (4); together with the new biosynthetically related lactone, ircinialactone A (7). Also isolated were seven biosynthetically related known Irciniidae metabolites; ircinialactams A (8) and C (9), (7E,12E,20Z,18S)-variabilin (10), (7Z,12Z,20Z,18S)-variabilin (11), (7E,12Z,20Z,18S)-variabilin (12), (7Z,12E,20Z,18S)-variabilin (13) and irciniafuran A (14). The structure elucidation of 1-14 was achieved by detailed spectroscopic analysis, and consideration of a plausible biosynthetic relationship linking Irciniidae sesterterpene ß-furans, lactams and lactones.

Antioxidant and cytoprotective compounds from Berberis vulgaris (barberry).

Activity-guided fractionation of an EtOAc-soluble partition of the MeOH extract from the root bark of Berberis vulgaris L. (barberry), using a hydroxyl radical-scavenging assay, led to the isolation and identification of three phenolic compounds of a previously known structure, N-(p-trans-coumaroyl)tyramine, cannabisin G and (+/-)-lyoniresinol. Of these, cannabisin G and (+/-)-lyoniresinol exhibited antioxidant activity in this bioassay. Furthermore, it was found that cannabisin G showed cytoprotective activity in cultured MCF-7 cells modulated by hydrogen peroxide.

Potential anticancer activity of naturally occurring and semisynthetic derivatives of aculeatins A and B from Amomum aculeatum.

Activity-guided fractionation of hexanes- and CHCl 3-soluble extracts of Amomum aculeatum leaves, collected in Indonesia, led to the isolation of three new dioxadispiroketal-type ( 3- 5) and two new oxaspiroketal-type ( 6 and 7) derivatives. Nine semisynthetic derivatives ( 1a- 1h and 2a) of the parent compounds, aculeatins A ( 1) and B ( 2), were prepared. All isolates and semisynthetic compounds were tested against a small panel of human cell lines. Of these, aculeatin A ( 1; ED 50 0.2-1.0 microM) was found to be among the most cytotoxic of the compounds tested and was further evaluated in an in vivo hollow fiber assay; it was found to be active against MCF-7 (human breast cancer) cells implanted intraperitoneally at doses of 6.25, 12.5, 25, and 50 mg/kg. However, when 1 was tested using P388 lymphocytic leukemia and human A2780 ovarian carcinoma in vivo models, it was deemed to be inactive at the doses used.

New indole alkaloids from the roots of Ochrosia acuminata.

Two new indole alkaloids, polyneuridine-N-oxide (1) and 17-hydroxy-10-methoxy-yohimbane (2), together with seven known alkaloids were isolated from the roots of Ochrosia acuminata collected in Savu, Indonesia. 9-Methoxyellipticine (3) and ellipticine (4) were responsible for the antitumor activities of the extract. The structures of all compounds were elucidated using MS and NMR methods.

New indole alkaloids from the bark of Alstonia scholaris.

A new indole alkaloid, akuammiginone (1), and a new glycosidic indole alkaloid, echitamidine-N-oxide 19-O-beta-d-glucopyranoside (2), together with the five known alkaloids, echitaminic acid (3), echitamidine N-oxide (4), N(b)-demethylalstogustine N-oxide (5), akuammicine N-oxide (6), and N(b)-demethylalstogustine (7), were isolated from the trunk bark of Alstonia scholaris collected in Timor, Indonesia. The structures of all compounds were elucidated by spectroscopic methods. This is the first report of compounds 3-5and 7 in A. scholaris. Some NMR assignments of the known compounds were revised.

New alkaloids from Pandanus amaryllifolius.

Three new alkaloids, the two pyrrolidine type alkaloids (1 and 2) and 6E-pandanamine (3), together with five known alkaloids (4-8), were isolated from the leaves of Pandanus amaryllifolius collected in West Java, Indonesia. All the new alkaloids have two alpha-methyl alpha,beta-unsaturated gamma-lactone moieties, while compound 2 also has an additional seven-membered ring, which has not been encountered before in Pandanus alkaloids. Two different extraction methods, namely, a solvent partitioning extraction and acid-base treatment, were tested, giving secondary and tertiary amines, respectively. Spectroscopic and chemical studies showed that the tertiary amines isolated from the acid-base treatment were artifacts formed during the extraction process. This finding suggests that the use of conventional acid-base treatment in isolating Pandanus alkaloids should be reviewed since it can introduce artifacts.