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Two new oxepine-containing diketopiperazine-type alkaloids, varioloids A and B (1 and 2, resp.), were isolated from the algal-derived fungus Paecilomyces variotii EN-291. The structures and absolute configurations were determined by detailed interpretation of 1D- and 2D-NMR spectroscopic data and by analysis of acidic hydrolysates. Compounds 1 and 2 exhibited potent activity against the plant-pathogenic fungus Fusarium graminearum with MIC values of 8 and 4 mu g/ml, respectively.

Three new prenylated indole alkaloids, including two -carbolines, penipalines A and B (1 and 2, resp.), and one indole carbaldehyde derivative, penipaline C (3), as well as two known indole derived analogs, 4 and 5, were isolated from the deep-sea-sediment derived fungus Penicillium paneum SD-44 cultured in a 500-l bioreactor. The structures of the new compounds were determined on the basis of 1D- and 2D-NMR spectroscopy, as well as by high-resolution mass spectrometry. The new compounds 2 and 3 showed potent cytotoxic activities against A-549 and HCT-116 cell lines.

Cultivation of the fungal strain Eurotium cristatum EN-220, an endophyte obtained from the marine alga Sargassum thunbergii, resulted in the isolation of one new anthraquinone glycoside, 3-O-(alpha-D-ribofuranosyl)questinol (1) and one new orsellinic acid ester, cristatumside A (2), together with three known aromatic glycosides, 3-O-(alpha-D-ribofuranosyl)questin (3), isotorachrysone 6-O-alpha-D-ribofuranoside (4), and asperflavin ribofuranoside (5), as well as three anthraquinone derivatives, asperflavin (6), eurorubrin (7), and (+)-variecolorquinone A (8). The structures of these compounds were determined by extensive analysis of their spectroscopic data, as well as by their comparison with those in the literature. Each of the isolated compounds was evaluated for its antimicrobial activity and brine shrimp lethality.

Two new 6,8(14),22-hexadehydro-5,9-epidioxy-3,15-dihydroxy sterols, nigerasterols A and B (1 and 2, resp.), together with two known cyclopentapeptides, malformins A1 and C (3 and 4, resp.), were identified in the culture extract of Aspergillus niger MA-132, an endophytic fungus isolated from a fresh healthy sample of the mangrove plant Avicennia marina. The structures and relative configurations of these compounds were established on the basis of extensive spectroscopic analyses. The absolute configuration of compound 1 was determined by application of a modified version of Mosher's method. Nigerasterols A and B (1 and 2, resp.) represent the first 5,9-epidioxy-sterol compounds of marine origin, and they displayed potent activity against tumor cell lines HL60 and A549 in a preliminary bioassay.

Two new triazoles, chrysotriazoles A and B (1 and 2, resp.), along with two known quinazolinones, 3 and 4, two known 2-(4-hydroxyphenyl)acetamides, 5 and 6, and two known N-(4-hydroxystyryl)formamides, 7 and 8, were isolated and identified from the culture extract of Penicillium chrysogenum EN-118, an endophytic fungus obtained from the marine brown alga Sargassum pallidium. The structures of the isolated compounds were elucidated by NMR-spectroscopic analysis, and that of compound 1 was confirmed by X-ray crystallographic analysis of its p-bromobenzoate derivative. Compounds 4, 5, and 7 showed moderate cytotoxicities against Du145, A-549, and HeLa cell lines.

Two new secoanthraquinone derivatives, wentiquinones A (1) and B (2), together with the eight known compounds 310, were isolated from the culture extracts of Aspergillus wentii EN-48, an endophytic fungus derived from an unidentified marine brown algal species of the genus Sargassum. The structures of these compounds were elucidated on the basis of extensive spectroscopic analysis.

Cultivation of the fungal strain Eurotium rubrum, an endophytic fungus that was isolated from the inner tissue of the semi-mangrove plant Hibiscus tiliaceus, resulted in the isolation of one new dioxopiperazine alkaloid, 12-demethyl-12-oxo-eurotechinulin B (1), and one new anthraquinone derivative, 9-dehydroxyeurotinone (2), together with ten known compounds including variecolorin J (3), eurotechinulin B (4), variecolorin G (5), alkaloid E-7 (6), cryptoechinuline G (7), isoechinulin B (8), 7-isopentenylcryptoechinuline D (9), 2-O-methyl-9-dehydroxyeurotinone (10), emodin (11), and emodic acid (12). The structures of the isolated compounds were determined by extensive analysis of their spectroscopic data as well as by comparison with literature reports. Some of the purified compounds were evaluated for antibacterial, antifungal, and cytotoxic activities.

Two new halogenated sesquiterpenes, (8 beta) 10 bromo-3-chloro-2,7-epoxychamigr-9-en-8-ol (1) and 2 bromo-3 chlorobisabola-7(14),11 diene 6,10 diol (3). and one new phytol derived diterpene, epoxyphytyl acetate (4), along with cis- and trans 1-methylcyclohexane-1,4-diol (5 and 6) which were isolated from a natural source for the first time but have been previously synthesized were isolated from the marine red alga Laurencia composita and characterized In addition, a known sesquiterpene, pacifenediol (2), and the known furanone derivative 7 were also identified Their structures were established by MAR and mass spectroscopic methods.

Four new halogenated sesquiterpenes, 10-bromo-3-chloro-2,7-epoxychamigr-9-en-8a-of (1), 2,10 beta-dibromochamigra-2,7-dien-9 alpha-ol (2), (9S)-2-bromo-3-chloro-6,9-epoxybisabola-7(14),10-diene (3), and (9R)-2-bromo-3-chloro-6,9-epoxybisabola-7(14),10-diene (4), were characterized from the marine red alga Laurencia saitoi. In addition, two known halosesquiterpenes, 2,10-dibromo-3-chlorochamigr-7-en-9 alpha-ol (5) and isolaurenisol (6), were also isolated and identified. Their structures were established on the basis of extensive analysis of spectroscopic data.

A new fungus-derived benzodiazepine analogue, 2-hydroxycircumdatin C (1), and a compound which has been isolated from a natural resource for the first time, but has been previously synthesized, namely (11aS)-2,3-dihydro-7-methoxy-1H-pyrrolo[2,1-c][1,4]benzodiazepine-5,11(10H,11aH)-dione (2), along with five structurally related known alkaloids (3-7), were isolated from Aspergillus ochraceus, an endophytic fungus derived from the marine brown alga Sargassum kjellmanianum. Their structures were established on the basis of spectroscopic methods. The absolute configuration of I was determined through CD evidence. Compound 1 displayed significant DPPH radical-scavenging activity with an IC(50) value of 9.9 mu M, which is 8.9-fold more potent than that of butylated hydroxytoluene (BHT), a well-known synthetic positive control.

Two new and one known squalenoid-derived triterpenoids. namely, laurenmariannol (1) and (21 alpha)-21-hydroxythyrsiferol (2). and the known thyrsiferol (3) were isolated and identified from the marine red alga Laurencia mariannensis, which was collected off the coast of Hainan and Weizhou Islands of China. The structures of these compounds were established by means of spectroscopic analyses, as well as by comparison with literature data. Compounds I and 2 displayed significant cytotoxic activity against P-388 tumor cells with IC(50) values of 0.6 and 6.6 mu g/ml, respectively.

Cultivation of the fungal strain Eurotium rubrum, an endophytic fungus that was isolated from the inner tissue of stems of the mangrove plant Hibiscus tiliaceus, resulted in the isolation of two new dioxopiperazine derivatives, namely, dehydrovariecolorin L (1) and dehydroechinulin (2), together with eight known dioxopiperazine compounds including variecolorin L (3), echinulin (4), isoechinulin A (5), dihydroxyisoechinulin A (6), preechinulin (7), neoechinulin A (8), neoechinulin E (9), and cryptoechinuline D (10). The structures of the isolated compounds were determined by extensive analysis of their spectroscopic data as well as by comparison with literature. Compounds 1, 2, 9, and 10 were investigated for their a,a-diphenyl-beta-picrylhydrazyl (DPPH) radical-scavenging activity. In addition, the new compounds, 1 and 2, were evaluated for their cytotoxic activity against the P-388, HL-60, and A549 cell lines.

Three new triterpenoids with the rarely occurring nigrum skeleton, namely (20E)-22-hydroxynigrum-20-en-3-one (1), 21 beta-hydroxynigrum-22(29)-en-3-one (2), and 21 alpha-hydroxynigrum-22(29)-en-3-one (3), were isolated from the mangrove plant Hibiscus tiliaceus. Additionally, five known triterpenoids including friedelin (4),12-oleanen-3 beta-ol (5), 3 beta-hydroxy-12-oleanen-28-oic acid (6),20(29)-lupen-3 beta,28-diol (7). and cucurbita-5,23-dien-3 beta,25-diol (8) were also isolated and identified. The latter structures were elucidated by a detailed NMR and MS analyses, as well as by comparison with reported literature data.

Two new brominated diterpenes, namely, laurendecumtriol (1) and 11-O-deacetylpinnaterpene C (2), one new polybromoindole, 2,3,4,6-tetrabromo-1-methyl-1H-indole (7), and six known natural products were isolated and identified from the marine red alga Laurencia decumbens. Their structures were elucidated on the basis of detailed spectroscopic and mass-spectrometric analysis as well as by comparison with literature data. Based on 2D-NMR experiments, the previously reported NMR data for pinnaterpene C (3) were reassigned.

Three new polybrominated 1H-indoles, compounds 1-3, and three new aristolane sesquiterpenes, compounds 4-6, were isolated from the marine red alga Laurencia similis, together with seven known natural products. Their structures were elucidated on the basis of detailed spectroscopic and mass-spectrometric analyses, as well as by comparison with literature data.

A new hydroperoxy-substituted cembranoid diterpene, 2-hydroperoxysarcophine (=(1aR*,4E,11E,14aR*)-2,3,6,7,10a,13,14,14a-octahydro-10a-hydroperoxy-1a,5,8,12-tetramethyloxireno[9,10]cyclote- tradeca[1,2-b]furan-9(1aH)-one; 1), was isolated from the marine soft coral Lobophytum crassum. Also isolated were two other cembranoid diterpenes, obtained for the first time from a natural source, i.e., 7 beta,8 beta-epoxy-4 alpha-hydroxycembra-1(15),2,11-trien-16,2-olide (2) and 7 beta,8 beta-epoxy-4 beta-hydroxycembra1(15),2,11-trien-16,2-olide (3), along with three further cembranoid derivatives, five sterols, and two open-chain metabolites. Their structures and relative configurations were elucidated on the basis of extensive spectroscopic analyses including 1D- and 2D-NMR, and HR-ESI-MS experiments.