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Thirty sterols (1-30) were isolated from bioactive fractions of a marine sponge Topsentia sp., of which 16 were new (1, 2, 8, 10-14, 16, 17, 19, 21, 24, 25, 27, and 30). They were characterized as sterols with 10 different side chains and as having various functionalities including 5alpha,8alpha-epidioxy (1-9), 5alpha,6alpha-epoxy-7-ol (10-15), 5,8-dien-7-one (24-28), 5-en-3beta-ol (29), and 1(10-->6)abeo-5,7,9-triene-3alpha,11alpha-diol (30) units and included polyoxygenated sterols (16-23). One of the key features of these new sterols is the presence of the (24R,25R,27R)-26,27-cyclo-24,27-dimethylcholestane side chain, whose absolute stereochemistry was defined by an acid-catalyzed ring-opening method and by comparison with the four synthetic isomers of known absolute stereochemistry. The occurrence of several known fungal sterols and relevant new sterols in this sponge suggested their possible origin from symbiotic fungi. Selected compounds were tested against a panel of five human solid tumor cell lines and displayed moderate to marginal cytotoxicity.

Six new phenylethanoid glucosides, ternstrosides A-F (1-6), a new kaempferol derivative (7), and eight known compounds were isolated from the fresh leaves of Ternstroemia japonica. The structures were elucidated by 1D and 2D NMR spectroscopic analyses. Compounds 1-7 showed potent antioxidative activity in three different tests, with IC50 values in the range 3.26-6.50 microM in the hydroxyl radical (*OH) inhibitory activity test, 33.29-82.21 microM in the total ROS (reactive oxygen species) inhibitory activity test, and 1.14-13.53 microM in the peroxynitrite (ONOO-) scavenging activity test.

By a bioactivity-guided fractionation, seven new oxylipins, topsentolides A(1)-C(2) (1-7), were isolated from the MeOH extract of a marine sponge Topsentia sp. Detailed NMR and MS analyses established the planar structures of these structurally related oxylipins, which are proposed to be biosynthesized by lipoxygenation followed by cyclization of unsaturated fatty acids. Acetonide derivatives and MTPA esters were prepared to elucidate the stereochemistry of topsentolides B(1) (3), B(2) (4), and C(2) (7). All compounds were tested against a panel of five human solid tumor cell lines and displayed moderate cytotoxicity.

Four new (1, 2, 4, and 5) and 14 known (3 and 6-18) polyoxygenated sterols have been isolated from the MeOH extract of the marine sponge Homaxinella sp. by bioactivity-guided fractionation. The planar structures of the sterols were established by 1D and 2D NMR and MS spectroscopic analysis. 5,6:8,9-Diepoxy sterols (1-3) were isolated from a marine organism for the first time. The isolated sterols were tested against a panel of five human solid tumor cell lines and exhibited varying degrees of cytotoxicity.

Three new bisindole alkaloids of the hamacanthin class (1-3) and one new bisindole alkaloid of the topsentin class (6) were isolated along with known bisindole alkaloids (4, 5, 7-11) from the MeOH extract of a marine sponge Spongosorites sp. by bioactivity-guided fractionation. The planar structures were established on the basis of NMR, MS, and IR spectroscopic analyses. Configurations of compounds 1-4 were derived from 1H NMR data and optical rotation. Compounds 1, 4, 5, and 11 showed moderate to significant cytotoxicity against five human tumor cell lines, and compounds 1-5 showed weak antibacterial activity against clinically isolated methicillin-resistant strains.

A bioactivity-guided fractionation of a marine sponge Homaxinella sp. has led to the isolation of three new (1-3) highly degraded sterols and four new 6-O-alkylated (6-9) sterols, along with known sterol derivatives. The degraded sterols (1-5) belong to the class incisterols, previously isolated from the marine sponge Dictyonella incisa. Mainly NMR and MS spectroscopic analyses established the gross structures of the new compounds. The relationship between the stereoisomerism of the side chain and HPLC retention time has also been discussed. The compounds were tested against a panel of five human solid tumor cell lines, and especially the degraded sterols (1-4) displayed significant cytotoxicity.

Twelve new (1-7, 9-13) polyhydroxysterols and two new saponins (14 and 15) were isolated from the starfish Certonardoa semiregularis by activity-guided fractionation. Compounds 1-7 are rare examples of 15-keto steroids from starfish. The side chain of compound 11 was also unprecedented in nature. The structures were determined by combined spectroscopic methods and chemical derivatization. These compounds were evaluated for cytotoxicity against a small panel of human solid tumor cell lines, and most of them exhibited considerable activity. One of the 15-keto sterols (6) displayed the highest potency, which is comparable to that of doxorubicin.

Three new (1-3) and seven known (4-10) cytotoxic furanosesterterpenes were isolated from a marine sponge Psammocinia sp. by bioactivity-guided fractionation. The structures were established on the basis of NMR and MS analyses. The geometry and absolute configuration were determined on the basis of optical rotation, NMR, and CD data. These compounds were evaluated for cytotoxicity against a small panel of five human tumor cell lines, and most of the compounds showed toxicity to SK-MEL-2. The mixture of compounds 7 and 8 displayed significant inhibition of DNA replication and moderate antioxidant profile.

Eleven new polyhydroxysterols (1-11) and eight new saponins (12-19) were isolated from the brine shrimp active fraction of the starfish Certonardoa semiregularis. The structures were determined on the basis of spectral analysis and chemical derivatization. The structural variations of these compounds are due to the hydroxylation pattern of the sterol nucleus, the functionalization of the side chain, or the nature and location of the saccharide moiety. These compounds displayed considerable cytotoxicity against a small panel of human solid tumor cell lines.

Three new butenolides (1-3), a new cyclopentenone derivative (4), and a known alcohol (5) were isolated from a marine sponge Homaxinella sp. by bioactivity-guided fractionation. The planar structures were established on the basis of NMR and MS analyses. The stereochemistry of the butenolides and cyclopentenone derivative was defined on the basis of optical rotation and CD spectroscopy. The compounds were tested for cytotoxicity against a panel of five human solid tumor cell lines and displayed marginal to significant activity.

New norsesterterpenoids (3 and 4), a sesterterpenoid (6), pyrroloterpenoids (7-10), and a stereoisomer of kurospongin (5) were isolated, along with known furanosesterterpenes (11-15), from two marine sponges of the genus Sarcotragus. The gross structures were established on the basis of NMR and MS analysis. The stereochemistry was defined by combined use of NMR and CD spectroscopy. The compounds were evaluated for cytotoxicity against five human tumor cell lines and were found to exhibit marginal to moderate activity.

Three new bromotyrosine derivatives (4-6) were isolated from an association of two sponges, Jaspis wondoensis and Poecillastra wondoensis, along with the previously described (E,E)-psammaplin A (1), (E,Z)-psammaplin A (2), psammaplin D (3), bisaprasin (7), and (3-bromo-4-hydroxyphenyl)acetonitrile (8). The structures of the new compounds were established on the basis of NMR and MS spectroscopic analysis. The compounds 1, 3, and 5-7 displayed significant cytotoxicity against human lung (A549), ovarian (SK-OV-3), skin (SK-MEL-2), CNS (XF498), and colon (HCT15) cancer cell lines. Compounds 3-7 were further evaluated for antibacterial activity against methicillin- or ofloxacin-resistant Staphylococcus strains. Compound 4 exhibited more potent antibacterial activity than meropenem against several strains.

Three new triterpenoidal monodesmosides (1-3) and three new triterpenoidal bisdesmosides (4-6), together with two known saponins (7 and 8), were isolated from the fresh fruits of Ternstroemia japonica. The structures of 1-6 (ternstroemiasides A-F) were elucidated on the basis of spectral analysis and chemical degradation.

Two new lysophosphatidylcholines (1, 2) and four new monoglycerides (5-8) were isolated from the marine sponge Stelletta sp. by bioactivity-guided fractionation. The planar structures of the new compounds were established on the basis of NMR and MS analyses. The stereochemistry was defined by comparison of the optical rotation. The compounds were evaluated for cytotoxicity against a small panel of five human tumor cell lines.

Thirteen new polyhydroxysterols (1-5, 7-12, 14, 15) and two known polyhydroxysterols (6, 13) were isolated from the brine shrimp active fraction of the starfish Certonardoa semiregularis. The structures were determined on the basis of spectral analysis and chemical derivatization. These compounds displayed considerable cytotoxicity against a small panel of human solid tumor cell lines. These compounds were also evaluated for antibacterial activity against 20 clinically isolated strains. Most of the compounds showed weak antibacterial activity against Streptococcus pyogenes 308A, Pseudomonas aeruginosa 1771, and Pseudomonas aeruginosa 1771M.

Four new acetylenic acids were isolated from the marine sponge Stelletta sp. by bioactivity-guided fractionation. The planar structures were established on the basis of NMR and MS analysis. The stereochemistry was defined by combined use of CD spectroscopy and a chiral anisotropic reagent, phenylglycine methyl ester (PGME). The compounds were evaluated for cytotoxicity against a small panel of five human tumor cell lines and exhibited marginal to moderate cytotoxicity.

Ten new saponins designated as certonardosides A-J (1-5, 7-11) and the known halityloside D (6) were isolated from the brine shrimp active fraction of the MeOH extract of the starfish Certonardoa semiregularis. The structures were determined on the basis of spectral analysis and chemical manipulation. The compounds were evaluated for antiviral activity against HIV, HSV, CoxB, EMCV, and VSV and displayed insignificant activity within the range of noncytotoxic concentrations.

Reexamination of the configuration of sarcotins A-C, first isolated from the marine sponge Sarcotragus sp., revealed that the proposed stereochemistry of the tetronic acid moiety needs to be revised as shown in 1-3. Additional new pyrrolosesterterpenes (5-11), furanosesterpene derivatives (4, 12-14, 19), and furanoterpenoids, including two trinorsesterterpenes (15, 16) and two diterpenes (17, 18), were isolated from the same sponge by bioactivity-guided fractionation. The planar structures were established on the basis of NMR and MS analysis. The stereochemistry was defined by combined use of NMR, CD spectroscopy, and chemical degradation. The compounds were evaluated for cytotoxicity against five human tumor cell lines and were found to exhibit moderate to significant activity.

Two new sphingosine 4-sulfates (1 and 2) have been isolated from the sponge Spirastrella abata as cytotoxic constituents. The gross structures of 1 and 2 were determined by spectroscopic analysis, and their stereochemistry was established by chemical conversion. The compounds exhibited significant cytotoxicity against a small panel of five human tumor cell lines.

New polyacetylenic alcohols (1-5) have been isolated as cytotoxic principles from the marine sponge Petrosia sp. The compounds were particularly cytotoxic against a human melanoma cell line (SK-MEL-2). The gross structures were established on the basis of NMR and MS data, and the absolute configuration was determined by the modified Mosher's method.

Five new (1-3, 5, and 7) and two known (4, 6) furanosesterterpene tetronic acids were isolated from the marine sponge Sarcotragus sp. by bioactivity-guided fractionation. These compounds showed cytotoxicity against a panel of five human tumor cell lines. The gross structures were established on the basis of NMR and MS analyses. The compounds showed interesting variations of geometry and absolute configuration.

Ten new (1, 4-6, 9-14) and four known (2, 3, 7, 8) diacetylenes have been isolated from a brine shrimp active fraction of the methanolic extract of the stony coral Montipora sp. The structures were determined by combined spectroscopic methods. The compounds exhibited significant cytotoxicity against a small panel of human solid tumor cell lines. Montiporyne A (15), a previously reported congener, was also found to induce apoptosis in human colon tumor cell.

A new pyridinium alkaloid, montipyridine (1), has been isolated from the stony coral Montipora sp. The structure was established from spectroscopic data.

A known (1) and four new (2--5) lyso-PAF (platelet activating factor) derivatives were isolated from the sponge Spirastrella abata. Two of them are unprecedented in having a methoxy group at C-2'. The structures have been determined by combined spectroscopic methods. Their inhibitory effect on the biosynthesis of cholesterol and cytotoxicity against human solid tumor cell lines are reported.

Ten new polyacetylenic alcohols (1-6, 8-11), along with a known compound, petrocortyne C (7), were isolated from the marine sponge Petrosia sp. The gross structures were established based on NMR and MS data, and the absolute configuration was determined by the modified Mosher's method. These compounds displayed considerable cytotoxicity against a small panel of human solid tumor cell lines. Compounds 1-11 were further evaluated for in vitro inhibitory activity on DNA replication.

Six new acetylenic compounds (1-6) with cytotoxic activities against human solid tumor cell lines (SK-OV-3, SK-MEL-2, XF498, and HCT15) have been isolated from the stony coral Montipora sp. Structures of the compounds 1-6 were elucidated based on analysis of the NMR and MS data.

A series of phospholipids, including previously undescribed compounds 4-7, were isolated by a bioactivity-guided fractionation from the marine sponge Spirastrella abata as inhibitors of cholesterol biosynthesis in human liver cells. These compounds were identified as lyso-PAF analogues (1-5) and lysophosphatidylcholines (6, 7) based on NMR and MS analyses. Compounds 1-7 specifically blocked the conversion of lanosterol into cholesterol in the Chang liver cell.

New polyacetylenic alcohols with a C(45) carbon skeleton (2) and with an enone moiety in the alkyl chain (C(46), 1) were isolated from the marine sponge Petrosia sp. The gross structures of 1 and 2 were established by spectral methods, and the absolute stereochemistry was determined by the modified Mosher's method. Compounds 1 and 2 displayed considerable cytotoxicity against a small panel of human solid tumor cell lines. Significant inhibitions on DNA replication by 1 and 2 were also observed which could be explanative of their cytotoxicity.

A bioactive cyclitol derivative (1) was isolated from the marine sponge Petrosia sp. The chemical structure of 1 was determined as (2S)-1-O-(2',3',4',5'-tetrahydroxycyclopentyl)-3-O-(10' '-methylhexadecyl)glycerol. Compound 1 inhibited DNA replication in vitro at the level of initiation.

Three C46 (1-3) and three C30 (4-6) polyacetylenic alcohols with cytotoxic activity against a small panel of human solid-tumor cell lines have been isolated from the marine sponge Petrosia sp. Although compound 1 was identified as the stereoisomer of petrocortyne A, the structures of compounds 2-5 have not been previously reported and were established by spectral methods. Compound 6 was identified as the known compound petrosiacetylene D. The stereochemistry of compounds 1-5 was determined by the modified Mosher's method.