Isolation and structures of avicins D and G: in vitro tumor-inhibitory saponins derived from Acacia victoriae.

Two new saponins named avicins D (1) and G (2) were isolated from the seed pods of the desert legume plant Acacia victoriae. The structures, elucidated by 1D and 2D NMR studies and by chemical means, were characterized as acacic acid-bearing oligosaccharides at C-3 and C-28 with a side chain linked to C-21 comprised of two monoterpene carboxylic acids and a quinovose moiety. Both compounds exhibited potent cytotoxicity (apoptosis) against human T-cell leukemia (Jurkat cells) in vitro.

Triterpenoid saponins from Acacia victoriae (Bentham) decrease tumor cell proliferation and induce apoptosis.

This report describes the isolation and partial purification of novel triterpenoid saponins [Fraction 35 (F035)] and two pure biologically active derivatives (termed avicins D and G) from Acacia victoriae, an Australian desert tree of the Leguminosae family. F035 and the avicins markedly inhibited the growth of several tumor cell lines with minimum growth inhibition in human foreskin fibroblasts, mouse fibroblasts, and immortalized breast epithelial cells at similar concentrations. F035 and the avicins induced cell cycle (G1) arrest of the human MDA-MB-453 breast cancer cell line and apoptosis of the Jurkat (T-cell leukemia) and the MDA-MB-435 breast cancer cell line.

Avicins: triterpenoid saponins from Acacia victoriae (Bentham) induce apoptosis by mitochondrial perturbation.

Anticancer agents target various subcellular components and trigger apoptosis in chemosensitive cells. We have recently reported the tumor cell growth inhibitory properties of a mixture of triterpenoid saponins obtained from an Australian desert tree (Leguminosae) Acacia victoriae (Bentham). Here we report the purification of this mixture into two biologically pure components called avicins that contain an acacic acid core with two acyclic monoterpene units connected by a quinovose sugar.

Metabolites from an Antarctic sponge-associated bacterium, Pseudomonas aeruginosa.

In an ongoing survey of the bioactive potential of microorganisms associated with marine invertebrates, the culture media of a sponge-associated bacterial strain of Pseudomonas aeruginosa was found to contain metabolites which inhibit the growth of several Gram-positive microorganisms. A series of diketopiperazines (1-6) including a new natural product (6) and two known phenazine alkaloid antibiotics (7 and 8) were isolated from the culture broth of this bacterium.

Homarine as a feeding deterrent in common shallow-water antarctic lamellarian gastropodMarseniopsis mollis: A rare example of chemical defense in a marine prosobranch.

The common bright yellow antarctic lamellarian gastropodMarseniopsis mollis was examined for the presence of defensive chemistry. Proton nuclear magnetic resonance (NMR) spectroscopy indicated that a major component of ethanolic extracts purified by reversed-phase column chromatography was homarine. Further high-performance liquid chromatography (HPLC) analysis of the mantle, foot, and viscera verified the presence of homarine in all body tissues at concentrations ranging from 6 to 24 mg/g dry tissue.