[Structure: see text]. Citrinadin A (2) is a pentacyclic indolinone alkaloid isolated from the cultured broth of a fungus, Penicillium citrinum, which was separated from a marine red alga. The absolute stereochemistry of the pentacyclic core in 2 and its new congener, citrinadin B (1), was elucidated by analysis of the ROESY spectrum for the chlorohydrin derivative (3) of 1 as well as comparison of the electronic circular dichroism (ECD) spectra for 1 and 2 with those of known spirooxiindole alkaloids. On the other hand, the absolute configuration at C-21 bearing an epoxide ring was assigned as S by comparison of the vibrational circular dichroism (VCD) spectra of 1 with those of model compounds 2S- and 2R-2,3-epoxy-3,3-dimethyl-1-phenylpropan-1-one (4a and 4b, respectively).

Five new monoterpene indole alkaloids, naucleamides A-E (1-5), were isolated from the bark and wood of Nauclea latifolia, and the structures and relative stereochemistry were elucidated from the spectroscopic data. Naucleamide E (5) is a unique monoterpene indole alkaloid possessing a pentacyclic ring system with an amino acetal bridge.

Three novel quaternary indole alkaloids with an unprecedented 1-azoniatricyclo[4.3.3.0(1,5)]undecane moiety, subincanadines A-C (1-3), as well as two new indole alkaloids with a 1-azabicyclo[5.2.2]undecane moiety, subincanadines D (4) and E (5), and a new indole alkaloid with a 1-azabicyclo[4.3.1]decane moiety, subincanadine F (6), have been isolated from the barks of Aspidosperma subincanum Mart, and the structures of 1-6 and the stereochemistry of 1-3 were elucidated by spectroscopic data and chemical means.

Taurospongin A (1), a novel acetylene-containing natural product consisting of a taurine and two fatty acid residues, has been isolated from the Okinawan marine sponge Hippospongia sp. and its structure elucidated by spectral data and chemical means. Taurospongin A (1) exhibited potent inhibitory activity against DNA polymerase β and HIV reverse transcriptase. The absolute configurations of taurospongin A (1) were established to be 3R, 7S, and 9R by synthesis of the MTPA ester of a degradation product of 1.