Ten halogenated monoterpenes (2-6 and 8-12) related to the novel antitumor compound halomon (1) or to the carbocyclic analog 7 have been isolated from different geographic collections of the red alga, Portieria hornemannii. Structures were assigned to the basis of spectral analyses (primarily NMR and MS). The absolute configuration of isohalomon (2) was further established by X-ray crystallography. The compounds were comparatively evaluated alongside 1 and 7 in the U.S. National Cancer Institute's in vitro human tumor cell line screening panel. The results provide some interesting initial insights into the structure/activity relationships in this series.

Sixteen sesquiterpenoids and norsesquiterpenoids, six of them new, were isolated from the octocoral Lemnalia africana. Antileukemia activity (P-388) was found only in the known eremophilane derivative 15.

Lokysterolamine A and B are two steroidal alkaloids isolated from an undescribed species of the sponge genus Corticium, collected in Sulawesi, Indonesia. Compound A is N,N-dimethyl- and B is N-acetyl-4 beta-hydroxy-3-epi-plakinamine A.

&m~~cr.-Three new cytotoxic bromotyrosinederived secondary metabolites, aplysamines 3 [Z], 4 131, and 5 147, were isolated from the sponge Psammaplysillapu@urrca.Marine sponges ofthe order Vwongida are often characterized by a wide range of bioactive bromotyrosine constituents (1,2). The large number of biosynthetically related compounds is due to chemical variations occurring in the side chain andlor aromatic ring of the tyrosine moiety. We now report the structures and in vitro bioactivity of aplysamines 3 127,4 E31, and 5 {41, which are related to aplysamine 2 117.A CH,Cl,-iPrOH (1 : 1) extract of the sponge Psammaplysilla pu+pureu Carter (family Aplysinellidae), collected by scuba on the south shore of Maui, Hawaii, at -40 m (sample ID 12-DD-91)displayed antimicrobial activity and cytotoxicity against human epidermoid carcinoma Kl3 cells. Bioassay-guided fractionation of the extract resulted in the isolation of three new compounds 2-4.The hrfabms of the major metabolite, aplysamine 3 E21, indicated a molecular formula of C,,H,,Br3N3O,. The

New bastadins 16 [1] and 17 [2] and the previously reported bastadins 3 13], 5 [4], 6 [5], 8 [6], 9 [7], and 12 [8] were isolated from the sponge lanthella hasta collected in Indonesia.The bastadins are a series of predominantly macrocyclic sponge metabolites, which are biogenetically derivable from four tyrosines by oxidative phenolic coupling of two tyramine-tyrosine units (1-8). A recent collection of marine invertebrates in Indonesia provided a specimen of lanthella basta Pallas from which were isolated several known and two new bastadins.