Penicianstinoids F-K, six undescribed meroterpenoids from the marine algicolous fungus Penicillium sp. RR-DL-1-7.

Six previously undescribed meroterpenoids, penicianstinoids F-K (1-6), together with four known analogues, dehydroaustinol (7), dehydroaustin (8), penicianstinoid A (9), and furanoaustinol (10), were isolated from the cultures of the algicolous fungus Penicillium sp. RR-DL-1-7, derived from the red alga Rhodomela confervoides. Their structures and relative configuration were established by detailed spectroscopic analysis of NMR and HR-MS experiments, and the absolute configurations were assigned by X-ray diffraction and ECD spectral analysis. None of the isolates showed obvious growth inhibitory effects against five plankton and four bacteria species tested.

Myrochromanol analogues and trichothecene derivatives from the shellfish-derived fungus Albifimbriaverrucaria.

Eight myrochromanol analogues, including three pairs of epimers at C-2 with the myrochromanol scaffold and two examples of myrochromanol with sugar moiety linked at C-4, together with twelve trichothecene derivatives were isolated from the cultures of a shellfish-derived fungus Albifimbria verrucaria CD1-4. Among them, eight compounds named 2-epi-myrochromanol, ent-myrochromanol B, 4-epi-myrochromanol B, 2-epi-myrochromanol A, myrochromanosides A and B, 6',7'-erythro-(2'E,4'Z)-trichoverrol B, 3R,8S-dihyroxyroridin H were previously undescribed fungal metabolites. Their planar structures and relative configurations were established by 1D and 2D NMR, and HR-MS data analysis, and their absolute configurations were determined using the modified Mosher's method and electronic circular dichrosim calculations. Almost all isolates were evaluated for growth rate inhibition of three marine harmful microalgae Chattonella marina, Heterosigma akashiwo, and Prorocentrum donghaiense, and lethal activity to one marine zooplankton, Artemia salina. Myrochromanosides A and B exhibited obvious inhibitory against three tested microalgae with IC50 values in the range of 9.2-108.9 µM. 8α-Hydroxyroridin H, roridin A and verrucarin A exhibited significant inhibition against P. donghaiense with IC50 values of 6.1, 5.8, and 6.0 µM and toxicity against brine shrimp larvae with LC50 values of 1.4, 2.8, and 0.26 µM, respectively.

Alterbutenolide, a new butenolide derivative from a sponge-derived fungus Alternaria alternata I-YLW6-1.

Alterbutenolide (1), a new butenolide derivative with a long-chain aliphatic acid substitution, together with seven known phenolic compounds i.e. alternariol (2), asperigillol B (3), p-hydroxyphenylacetic acid (4), p-hydroxyphenylethyl alcohol (5), methyl p-hydroxyphenyl acetate (6), 2-(4-hydroxyphenyl)ethyl acetate (7), and 5,6-dihydro-4-methyl-2H-pyran-2-one (8), was isolated from the cultures of a sponge-derived fungus Alternaria alternata I-YLW6-1. The structure of 1 was established on the basis of HR-MS, 1D and 2D NMR, as well as by comparison of the optical rotation data with the literature reported. Compounds 2 and 3 showed significant to moderate inhibitory activities against three harmful microalgae with IC50 values from 3.0 to 36.2 µg/mL, whereas compound 1 only displayed moderate inhibition against Chattonella marina with IC50 value of 34.6 µg/mL. Meanwhile, compounds 3 and 4 showed weak toxicity against brine shrimp larvae with LC50 values >100 µg/mL.

A new lanostane-type triterpenoid from the marine shellfish symbiotic fungus Ceriporia lacerata CD7-5.

One new lanostane-type triterpenoid, 3ß-acetoxy-7,11-dioxolanosta-8,24-dien-21-oic acid (1), together with six known analogues (2-7), were isolated from the cultures of a marine fungus Ceriporia lacerata CD7-5, which was derived from the shellfish Ostrea denselamellosa. Their structures were determined by detailed analysis of spectroscopic data and comparison with the literature reported. The biological activities of these lanostane triterpenoids against marine-derived microalgae, zooplankton, and pathogenic bacteria were also evaluated in this study.

Terpenoids from the Marine-Derived Fungus Aspergillus sp. RR-YLW-12, Associated with the Red Alga Rhodomela confervoides.

Two new meroterpenoids, aspermeroterpenes D and E (1 and 2), two new ophiobolin-type sesterterpenoids, the C-18 epimers of 18,19-dihydro-18-methoxy-19-hydroxyophiobolin P (6 and 7), and two new drimane-type sesquiterpenoids, 3S-hydroxystrobilactone A (8) and 6-epi-strobilactone A (9), along with 11 known terpenoids (3-5 and 10-17) were isolated from the cultures of the algicolous fungus Aspergillus sp. RR-YLW-12, derived from the red alga Rhodomela confervoides. The structures and relative configurations of new compounds were established by detailed spectroscopic analysis of NMR and HRMS experiments, and the absolute configurations were assigned by X-ray diffraction experiments and comparison of their experimental and calculated ECD spectra. Compound 1 features a rare 6/6/6/6/5 pentacyclic system with a meroterpenoid skeleton, and the structure of terretonin E (3) was revised in this study. Compound 4 showed significant inhibitory activities against three microalgae, Prorocentrum donghaiense, Heterosigma akashiwo, and Chattonella marina, with IC50 values of 10.5, 5.2, and 3.1 µg/mL, respectively.

Seven chromanoid norbisabolane derivatives from the marine-alga-endophytic fungus Trichoderma asperellum A-YMD-9-2.

An examination of the endophytic fungus Trichoderma asperellum A-YMD-9-2 obtained from the marine red alga Gracilaria verrucosa led to the isolation of seven new chromanoid norbisabolane derivatives, trichobisabolins I-L (1-4) and trichaspsides C-E (5-7). Their structures and relative configurations were established on the basis of spectroscopic techniques, mainly including 1D/2D NMR and MS, and the absolute configuration of 1 was assigned by X-ray crystallographic analysis using Cu Kα radiation. All of these isolates feature a 1,9-epoxy ring system, and 5-7 represent the second occurrence of norbisabolane aminoglycosides. Compounds 1-7 exhibited potent inhibition of several marine phytoplankton species.

Cyclonerane Derivatives from the Algicolous Endophytic Fungus Trichoderma asperellum A-YMD-9-2.

Seven previously unreported cyclonerane derivatives, namely, 3,7,11-trihydroxycycloneran-10-one, cycloneran-3,7,10,11-tetraol, cycloneran-3,7,11-triol, 11,12,15-trinorcycloneran-3,7,10-triol, 7,10S-epoxycycloneran-3,15-diol, 7,10R-epoxycycloneran-3,15-diol, and (10Z)-15-acetoxy-10-cycloneren-3,7-diol, were isolated in addition to the known (10Z)-cyclonerotriol, (10E)-cyclonerotriol, catenioblin C, and chokol E from the culture of Trichoderma asperellum A-YMD-9-2, an endophytic fungus obtained from the marine red alga Gracilaria verrucosa. The structures of previously unreported compounds were established by spectroscopic techniques, including 1D/2D NMR, MS, and IR. The isolation of these new cyclonerane derivatives greatly adds to the structural diversity of unusual cyclonerane sesquiterpenes, and several isolates exhibit potent inhibition against some marine phytoplankton species.

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.

Diterpenes and Sesquiterpenes from the Marine Algicolous Fungus Trichoderma harzianum X-5.

Six new terpenes, including one harziane diterpene, 3 R-hydroxy-9 R,10 R-dihydroharzianone (1), one proharziane diterpene, 11 R-methoxy-5,9,13-proharzitrien-3-ol (2), three cyclonerane sesquiterpenes, 11-methoxy-9-cycloneren-3,7-diol (3), 10-cycloneren-3,5,7-triol (4), and methyl 3,7-dihydroxy-15-cycloneranate (5), and one acorane sesquiterpene, 8-acoren-3,11-diol (6), were isolated from the culture of Trichoderma harzianum X-5, an endophytic fungus obtained from the marine brown alga Laminaria japonica. Their structures and relative configurations were established by analysis of 1D/2D NMR, HREIMS, and IR data, and the absolute configurations were assigned on the basis of ECD curves or biogenetic considerations. These terpenes possess four different carbon skeletons, and compound 2, with a rarely occurring bicyclic framework, represents a possible precursor of tetracyclic harzianes. Compounds 1-6 exhibited growth inhibition of some marine phytoplankton species.

Trichocarotins A-H and trichocadinin A, nine sesquiterpenes from the marine-alga-epiphytic fungus Trichoderma virens.

In addition to CAF-603, 14-hydroxy CAF-603 (trichocarane B), 7-ß-hydroxy CAF-603, and trichocarane A, eight new carotane sesquiterpenes, trichocarotins A-H, and one new cadinane sesquiterpene, trichocadinin A, were isolated from the culture of Trichoderma virens Y13-3, obtained from the surface of a marine red alga. Their structures and relative configurations were unambiguously assigned by interpretation of 1D/2D NMR and MS data, and their absolute configurations were established by X-ray diffraction or ECD spectra aided by quantum chemical calculations. These compounds represent two rarely occurring sesquiterpene types from filamentous fungi, and six of them feature potent inhibition against some marine plankton species.