Sheng-Tao Fang

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, 4β-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.

A new minor diketopiperazine from the sponge-derived fungus Simplicillium sp. YZ-11

Chemical investigation of the cultures of a sponge-derived fungus Simplicillium sp. YZ-11 led to the isolation of a new minor diketopiperazine alkaloid cyclo-(2-hydroxy-Pro-Gly) (1) and a natural lactone (S)-dihydro-5-[(S)- hydroxyphenylmethyl]-2(3H)-furanone (2), together with five known ergostane-type sterols (3–7). Their structures were established based on extensive spectroscopic methods (1H and 13C NMR, 1H-1H COSY, HSQC and HMBC) and optical rotation analysis.

Cyathane diterpenoids from fruiting bodies of Phellodon niger

Four new cyathane-type diterpenoids, nigernins C-F (1–4), together with four known compounds, were isolated from the fruiting bodies of the basidiomycete Phellodon niger. The structures of these new compounds were established on the basis of spectroscopic analysis, including 1D and 2D NMR experiments. In addition, nigernin F (4) with an unusual 3,4-seco cyathane diterpenoid skeleton was found to occur in nature for the first time. It was suggested to be as an oxidation product of C-3-C-4 bond cleavage of nigernin E (3).

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.

Chemical constituents and their bioactivities from the fruits of Vitex negundo var. cannabifolia

Abstract Phytochemical investigation of the fruits of Vitex negundo var. cannabifolia led to the isolation of 22 compounds (1–22). Their structures were elucidated mainly by spectroscopic analysis and comparison with the literature data. Among them, compounds 1 and 2 were two new artificial lignans. Primary bioassay showed that the polymethoxyflavones 9–12 displayed moderate-to-weak cytotoxicity against human HepG2 and rat C6 cell lines, while the triterpenoids 13–17 exhibited significant brine shrimp lethality with LC50values of 7.5–29.4 μM.

Tricholumin A, a Highly Transformed Ergosterol Derivative from the Alga-Endophytic Fungus Trichoderma asperellum

Tricholumin A (1) with an unprecedented carbon skeleton was isolated from the fungus Trichoderma asperellum cf44-2, an endophyte from the marine brown alga Sargassum sp. Its structure and relative configuration were identified by extensive 1D/2D NMR and mass spectrometric data, and the absolute configuration was assigned by X-ray diffraction and ECD calculations. Compound 1 represents a highly transformed ergosterol derivative, and it exhibited inhibition of some pathogenic microbes and marine phytoplankton species.

Two new tricycloalternarene esters from an alga-epiphytic isolate of Alternaria alternata

Abstract Two new tricycloalternarene-type meroterpenes, 17-O-methyltricycloalternarene D (1) and methyl nortricycloalternarate (4), and two known congeners, TCA D (2) and TCA 1b (3), were isolated from the culture of a marine red alga-epiphytic fungal strain (k21-1) of Alternaria alternata. The planar structures and relative configurations of these two new compounds were unequivocally identified by a combination of 1D/2D NMR, UV, IR, and mass spectra and by comparison with literature data, and the absolute configurations were assigned by analysis of ECD spectra. Compounds 1–4 were evaluated for growth inhibition of four marine plankton species, but they appeared weak or moderate to inhibit them.

Two new isomeric tricycloalternarenes from the marine alga-epiphytic fungus Alternaria alternata k23-3

Tricycloalternarenes (TCAs) and their possible precursors, bicycloalternarenes, represent a large class of fungal‐derived meroterpenes, which are regarded as the products through hybrid mevalonate and shikimate pathways. Totally, more than 70 members have been isolated and identified so far, with TCAs accounting for over 70%. Most of the TCAs feature a ring system that is constructed by the fusion of a cyclohex‐2‐enonyl group and a cyclopentenyl/cyclopentyl group via a methylene group and an oxygen atom, and they have been obtained from some species of the genera Alternaria, Aspergillus, Guignardia, Pycnoporus, Septoria, and Ulocladium. In our ongoing investigation towards the chemical diversity and biological activity of secondary metabolites from marine algicolous fungi, a marine red alga‐epiphytic strain (k23‐3) of Alternaria alternata was examined. As a result, two new 15‐hydroxytricycloalternarenes (1 and 2) along with a known one, TCA 11a (3), were isolated and identified (Figure 1). Details of the isolation, structure elucidation, and bioactivity of these compounds are described in this paper.

Hymerhabdrin A, a novel diterpenoid with antifouling activity from the intertidal sponge Hymerhabdia sp.

Hymerhabdrin A (1), a diterpenoid possessing a novel 6/6/5 fused-ring skeleton, together with four known sterols were isolated from an intertidal marine sponge Hymerhabdia sp. Their structures were elucidated by extensive spectroscopic methods, and the relative and absolute configurations of 1 were determined by NOESY analysis and electronic circular dichrosim calculations, respectively. Hymerhabdrin A (1) exhibited significant antifouling activity against Balanus amphitrite larval with LC50 (lethal concentration 50) value of 3.6 μg ml−1.