Qiu-Fen Hu

Antiviral and Cytotoxic Isocoumarin Derivatives from an Endophytic Fungus Aspergillus oryzae.

Oryzaeins A-D (1-4), four new isocoumarin derivatives, along with five known ones (5-9) were isolated from solid cultures of an endophytic fungus Aspergillus oryzae. Their structures were elucidated by detailed spectroscopic analysis and by comparison with reported data of related derivatives. Among them, compounds 1 and 2 represent the first examples of isocoumarins possessing an unusual 2-oxopropyl group and a rare 3-hydroxypropyl group. Compounds 1 and 2 displayed moderate anti-tobacco mosaic virus activities with inhibition rates of 28.4% and 30.6%, respectively, at the concentration of 20 µM. The new compounds showed moderate inhibitory activities against several human tumor cell lines with IC50 values in the range of 2.8-8.8 µM. Supporting information available online at http://www.thieme-connect.de/products.

Biomimetic Synthesis of Macahydantoins A and B from Lepidium meyenii, and Structure Revision of Macahydantoin B as a Class of Thiohydantoin with a 4-Methyl-hexahydropyrrolo[1,2-c]imidazole Skeleton

Phytochemical investigation on Lepidium meyenii led to the discovery of macahydantoin C (3), a new thiohydantoin with a 1,3-diazabicyclo[3.3.1]nonane core, the spectral properties of which indicate a potential structural misassignment of its previously reported analogue, macahydantoin B (2a). To probe this hypothesis, a concise, scalable, and biomimetic synthesis of the originally proposed 2a and its revised structure (2b) was efficiently accomplished using the modified Edman degradation as the key step from commercially available materials in 65% (three steps) and 52% (three steps) overall yields, respectively. These synthetic endeavors undoubtedly reassigned the structure of macahydantoin B as an unreported type of thiohydantoin featuring a 4-methyl-hexahydropyrrolo[1,2-c]imidazole scaffold.

Butyrolactones from the Endophytic Fungus Aspergillus versicolor and their Anti-Tobacco Mosaic Virus Activity

New butyrolactones aspernolides C and D, along with two known butyrolactones (A and B) were isolated from the culture of the endophytic fungus Aspergillus versicolor. Their structures were elucidated on the basis of extensive spectroscopic analysis, including 1D and 2D nuclear magnetic ressonance techniques, and electronic circular dichroism. The butyrolactones aspernolides C and D were tested for their anti-tobacco mosaic virus activity. The results showed that butyrolactones aspernolides C and D exhibited moderate anti-tobacco mosaic virus activity with IC50 values of 64.2 and 88.6 μM, respectively.

Xanthones from the Fermentation Products of the Endophytic Fungus of Phomopsis amygdali

Two new xanthones, 3-methoxy-1,4,8-trihydroxy-5-(1′,3′,4′-trihydroxybutan-2′-yl)-xanthone (1), 8-methoxy-1,3,4-trihydroxy-5-(1′,3′,4′-trihydroxybutan-2′-yl)-xanthone (2), and three known xanthones (3–5) were isolated from the fermentation products of a Phomopsis fungus. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1–5 were tested for their cytotoxicity against five human tumor cell lines (NB4, A549, SHSY5Y, PC3, and MCF7). Compound 1 showed cytotoxicity against A549 with IC50 values of 3.6 μM. Compound 2 showed cytotoxicity against SHSY5Y cells with IC50 value of 4.2 μM. The other compounds also showed potential cytotoxicity for some tested cell lines with IC50 values between 5.4–8.8 μM.

Anti-Tobacco Mosaic Virus Chromones from the Twigs of Cassia fistula

Two new chromones, fistulachromones A and B (1 and 2), together with three known chromones (3–5), were isolated from the twigs of Cassia fistula. Their structures were determined by means of HR-ESI-MS and extensive 1D and 2D NMR spectroscopic studies. Compounds 1 and 2 were tested for their anti-tobacco mosaic virus (anti-TMV) activities. Compounds 1 and 2 showed high anti-TMV activities with inhibition rates of 27.5 and 30.8%, respectively. These rates are close to that of positive control.

Anthraquinones from the Barks of Cassia alata and their Anti-Tobacco Mosaic Virus Activity

Two new anthraquinones, alataquinones A and B (1 and 2), together with two known anthraquinones (3 and 4), were isolated from the barks of Cassia alata. Their structures were determined by means of HR-ESI-MS and extensive 1D and 2D NMR spectroscopic studies. Compounds 1–4 were tested for their anti-tobacco mosaic virus (anti-TMV) activity. The results showed that compounds 1–4 exhibited moderate anti-TMV activity with inhibition rates in the range of 22.8–26.4%.

Anti-Tobacco Mosaic Virus Isocoumarins from the Leaves of Nicotiana tabacum

Two new isocoumarins, tabaisocoumarins D and E (1 and 2), together with two known isocoumarins (3 and 4), were isolated from the leaves of Nicotiana tabacum. The structures of 1–4 were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1–4 were also tested for their anti-tobacco mosaic virus (anti-TMV) activities. Compounds 1–4 exhibited anti-TMV activities with inhibition rates in the range of 11.2–17.5%.

Two New Isoquinoline Alkaloids from the Barks of Cassia fistula and Their Anti-Tobacco Mosaic Virus Activity

Two new isoquinoline alkaloids, fistulaquinolines A and B (1 and 2), were isolated from the barks of Cassia fistula. Their structures were determined by means of HR-ESI-MS and extensive 1D and 2D NMR spectroscopic studies. Compounds 1 and 2 were tested for their anti-tobacco mosaic virus (anti-TMV) activity. The results showed that the two compounds showed weak anti-TMV activity with inhibition rates of 18.9 and 22.6%.

Dihydroxanthenones from the Fermentation Product of the Endophytic Fungus Gliomastix murorum

Two new dihydroxanthones, muroxanthenones D and E (1 and 2), were isolated from the fermentation products of the endophytic fungus Gliomastix murorum. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1 and 2 were tested for their anti-tobacco mosaic virus (anti-TMV) activity, and they exhibited activity with inhibition rates of 16.4 and 15.3%, respectively.

CHALCONES FROM Desmodium podocarpum AND THEIR CYTOTOXICITY

Two new chalcones, 2′,4-hydroxy-3,4′-dimethoxychalcone (1) and 2′,3-hydroxy-4,4′-dimethoxychalcone (2), together with four known chalcones (3–6), were isolated from the whole plant of Desmodium podocarpum. All of their structures were determined by spectroscopic methods including 1D and 2D NMR. Compounds1and2were evaluated for their cytotoxicity using five tumor cell lines. Compound1exhibited cytotoxicity against SHSY5Y and PC3 cells with IC50values of 3.8 and 3.6 μM, and compound2exhibited cytotoxicity against A549 cells with IC50value of 3.5 μM, respectively.