Salicylaldehyde derivatives from a marine-derived fungus Eurotium sp. SCSIO F452.

Two pairs of new salicylaldehyde derivative enantiomers, salicylaldehydiums A and B (1 and 2), along with five known analogues were isolated and identified from a marine-derived fungus Eurotium sp. SCSIO F452. Their structures and absolute configuration were determined by extensive spectroscopic analysis and electronic circular dichroism (ECD) calculations. All the new optical pure enantiomers [(+)-1, (-)-1, (+)-2, (-)-2] were evaluated for their cytotoxic and antioxidative activities. Compound (-)-1 exhibited weak cytotoxic activity.

Anti-inflammatory prenylbenzaldehyde derivatives isolated from Eurotium cristatum.

Two undescribed prenylbenzaldehyde derivatives, cristaldehydes A and B, and an undescribed quinone derivative, cristaquinone A, along with seven known compounds were isolated from the fungus Eurotium cristatum. The structures of undescribed compounds were determined by spectroscopic analysis including NMR, HR-ESIMS, and single-crystal X-ray diffraction. This is the first report of identification of a dibenzannulated 6,6-spiroketal derivative, cristaldehyde B, in a natural product. Cytotoxic and anti-inflammatory activities of all compounds were evaluated. Cristaldehyde A and cristaquinone A along with five known compounds showed significant anti-inflammatory activities with IC50 values in the range from 0.37 to 14.50 µM.

Isolation, Stereochemical Study, and Antioxidant Activity of Benzofuranone Derivatives from a Mangrove-derived Fungus Eurotium rubrum MA-150.

Enantiomers of a 2-benzofuran-1(3H)-one derivative [(-)- and (+)-] and four known analogs () were isolated and identified from the culture extract of Eurotium rubrum MA-150, a fungus obtained from the mangrove-derived rizospheric soil. Their structures were established by detailed interpretation of nuclear magnetic resonance (NMR) data and the structure of (±)- was confirmed by single-crystal X-ray diffraction analysis. The absolute configuration of the enantiomers (-)- and (+)- was determined by means of online high-performance liquid chromatography - electronic circular dichroism (HPLC-ECD) measurements and time-dependent Density Functional Theory - electronic circular dichroism (TDDFT-ECD) calculations. Compounds (±)- as well as and exhibited potent DPPH radical scavenging activities with IC50 values of 1.23, 2.26, and 3.99 µg/mL, respectively. Chirality 28:581-584, 2016. © 2016 Wiley Periodicals, Inc.

Three pairs of variecolortide enantiomers from Eurotium sp. with caspase-3 inhibitory activity.

7-O-methylvariecolortide A (1), variecolortide B (2), and variecolortide C (3), the rare variecolortides existing in racemic manner, were isolated from an endolichenic fungal strain Eurotium sp. (No. 17-11-8-1). With the chiral HPLC technology, (-)-(S)-7-O-methylvariecolortide A (1a), (+)-(R)-7-O-methylvariecolortide A (1b), (-)-(S)-variecolortide B (2a), (+)-(R)-variecolortide B (2b), (-)-(S)-variecolortide C (3a), and (+)-(R)-variecolortide C (3b) were successfully separated and obtained. Their absolute configurations were firstly assigned by ECD experiment and ECD calculation. According to the relation of isolated compounds, a plausible biosynthetic pathway for variecolortides was proposed. In caspase-3 enzymatic assay, compounds 1-3 showed inhibitory activity, with IC50 values of 1.7, 0.8 and 15.7 µM, respectively.

Anti-leishmanial activities of extracts and isolated compounds from Drechslera rostrata and Eurotium tonpholium.

The fungal extract of Drechslera rostrata and Eurotium tonpholium showed a significant anti-leishmanial activity against Leishmania major; IC50 was 28.8 and 28.2 µg/mL, respectively. Seven compounds, five from D. rostrata (H1-H5) and two from E. tonpholium (H6 and H7), were isolated and identified using different spectroscopic analysis including (1) HNMR, (13) CNMR, Hetero-nuclear multiple bond connectivity (HMBC), Hetero-nuclear Multiple Quantum Correlation (HMQC), and EI-MS. The isolated compounds are: di-2-ethylhexyl phthalate (1), (22E)-5α,8α-epidioxyergosta-6,22-diene-3ß-ol (2),1,3,8-trihydroxy-6-methyl-nthraquinone (3), aloe-emodine 8-O-glucopyranoside(4), 2R, 3R,4R,5R hexane 1, 2, 3, 4, 5, 6 hexole (Mannitol) (5), 1,8-dihydroxy-3-methoxy-6-methyl-anthraquinone (6) and 1, 4, 5-trihydroxy-7-methoxy-2-methyl-anthraquinone (7). However, compounds (1) and (6) showed activity against L. major with IC50 of 3.2 and 10.38 µg/mL, respectively. On the other hand, oral administration of the two extracts (100 mg/kg) and compounds 1 and 6 (50 mg/kg) showed very good activity when compared with the anti-leishmanial drug Pentostam (125 mg/kg). Interestingly, the complete heeling activity of the extracts and compounds (1) and (6) was obtained after 13-17 days of treatment, while complete healing activity of Pentostam was obtained after 28 days. No alteration on liver and kidney functions was recorded on animals treated with the two extracts for 15 consecutive days.

7-O-Methylvariecolortide A, a new spirocyclic diketopiperazine alkaloid from a marine mangrove derived endophytic fungus, Eurotium rubrum.

A new spirocyclic diketopiperazine alkaloid, namely, 7-O-methylvariecolortide A (1), together with recently reported known compounds variecolortides A-C (2-4), were isolated and identified from the liquid fermentation cultures of Eurotium rubrum, an endophytic fungus that was isolated from the inner tissue of the stems of the mangrove plant Hibiscus tiliaceus. The structures of these compounds were determined by extensive analyses of their spectroscopic data.