New ophiobolin sesterterpenoid and drimane sesquiterpenoids from a marine-alga-derived fungus Aspergillus sp.

Further investigation of secondary metabolites of a marine-alga-derived fungus Aspergillus sp. RR-YLW-12 led to isolate one new ophiobolin-type sesterterpenoid (1), four new drimane-type sesquiterpenoids (2-5) and one natural occurring compound (6), together with seven known compounds (7-13). Their structures and stereochemistry were elucidated by extensive spectroscopic analysis of NMR and HRMS experiments, and by comparison with the literature data. All isolates were evaluated for growth inhibition of five marine harmful microalgae. The new compounds exhibited significant to moderate inhibitory effects towards all tested microalgae species with IC50 values ranging from 5.8 to 54.5 µg/mL.

Trichobisabolins A-H, eight new bisabolane derivatives from the marine-alga-epiphytic fungus Trichoderma asperellum Y6-2.

Eight new bisabolane derivatives, trichobisabolins A-H, along with two known ones, (3R,6R,7R)-1,10-bisaboladien-3-ol (9) and (3R,6R,7S)-1,10-bisaboladien-3,6-diol (10) were isolated from the culture of Trichoderma asperellum Y6-2, obtained from the surface of the marine red alga Chondrus ocellatus. Their structures and relative configurations were identified by interpretation of 1D/2D NMR and MS data. Compounds 1-8 were assayed for inhibiting the growth of some marine-derived organisms, including four marine phytoplankton species, one marine zooplankton species, and five pathogenic bacteria. All of them exhibited inhibition against the marine phytoplanktons with IC50 values ranging from 2.1-78 µg/mL, compounds 4 and 8 showed weak lethality to the marine zooplankton, and none of them had inhibition against the five pathogenic bacteria.

Two new sesquiterpenoids from the marine-sediment-derived fungus Trichoderma harzianum P1-4.

Three cyclonerane sesquiterpenoids, including the known cyclonerodiol (1), together with its new derivatives, (10E)-12-acetoxy-10-cycloneren-3,7 -diol (2) and 12-acetoxycycloneran-3,7-diol (3) were isolated from the cultures of marine-sediment-derived fungus Trichoderma harzianum P1-4. The structures of the new compounds (2 and 3) were elucidated based on extensive spectroscopic methods (1D/2D NMR and HR-MS) and optical rotation analysis.

Two new flavonoid glycosides from the halophyte Limonium franchetii.

Two new flavonoid glycosides, named quercetin-3-O-(2″-O-tigloyl)-α-L-rhamnopyranoside (1) and quercetin-3-O-(3″-O-tigloyl)-α-L-rhamnopyranoside (2), together with 10 known flavonoids (3-12), were isolated from the whole plant of the halophyte Limonium franchetii. Their structures were elucidated on the basis of extensive spectroscopic analysis including 2D NMR and HR-EI-MS. In addition, primary bioassays showed that compound 1 had moderate cytotoxic activity against rat C6 glioma cell lines.

Flavonoids from the halophyte Apocynum venetum and their antifouling activities against marine biofilm-derived bacteria.

Eleven flavonoids were isolated from the leaves of the halophyte Apocynum venetum. Among them, the isolation of plumbocatechin A (1), 8-O-methylretusin (2) and kaempferol 3-O-(6″-O-acetyl)-ß-D-galactopyranoside (7) was reported for the first time from this plant. Their structures were identified by using spectral methods, including 2D NMR experiments, and confirmed by comparing with the literature data. In addition, the antifouling activities of these compounds against the marine fouling bacteria, Bacillus thuringiensis, Pseudoalteromonas elyakovii and Pseudomonas aeruginosa, have been evaluated in this article.

Ten new withanolides from Physalis peruviana.

Ten new withanolides, including four perulactone-type withanolides, perulactones E-H (1-4), three 28-hydroxy-withanolides, withaperuvins I-K (5-7), and three other withanolides, withaperuvins L-N (8-10), together with six known compounds (11-16) were isolated from the aerial parts of Physalis peruviana. The structures of these compounds were elucidated on the basis of extensive spectroscopic analyses (1D and 2D NMR, IR, HR-MS) and chemical methods.

A novel 1,10-seco withanolide from Physalis peruviana.

A novel 1,10-seco withanolide, 1,10-seco withaperuvin C (1), together with four known withanolides, 4 beta-hydroxywithanolide E (2), visconolide (3), withanolide F (4), and withaphysanolide (5), was isolated from the aerial parts of Physalis peruviana. The structures of compounds 1-5 were determined on the basis of spectroscopic methods including extensive 1D and 2D NMR analysis. In addition, the possible biogenetic relationships among these five withanolides are discussed.