Polyketides with different post-modifications from desert endophytic fungus Paraphoma sp.

Three new polyketides 4,6,8-trihydroxy-5-methyl-3,4-dihydronaphthalen-1(2H)-one (1), 5,7-dihydroxy-3-(1-hydroxyethyl)-3,4-dimethylisobenzofuran-1(3H)-one (2) and 1-(4-hydroxy-6-methoxy-1,7-dimethyl-3-oxo-1,3-dihydroisobenzofuran-1-yl) ethyl acetate (3) together with seven known analogues (4-10) were isolated from desert endophytic fungus Paraphoma sp. The structures of these compounds were elucidated by analysis of NMR data. The absolute configuration of (1-3) was established on the basis of CD experiments. The possible biosynthetic pathway of compounds (1-10) was suggested, which implied that these secondary metabolites might be originated from polyketide biosynthesis with different post-modification reactions. Compounds 2, and 5-8 were evaluated for bioactivities against plant pathogen A. solani, whereas none of them displayed any biological effects. In addition, compounds 1, 2 and 5-10 were also tested for cytotoxic activities against three human cancer cell lines (HepG2 cells, MCF-7 cells and Hela cells) without biological effects.

Diarylheptanoids from Alpinia officinarum.

A new diarylheptanoid, along with five known diarylheptanoids, was isolated from the rhizomes of Alpinia officinarum (Zingiberaceae). The structure of the new compound was determined to be trans,trans-1(3'-methoxy-4'-hydroxyphenyl)-7-phenyl-5-ol-4,6-dien-3-heptanone on the basis of spectral and chemical evidence.

Two new triterpene saponins from Lysimachia capillipes.

Two new saponins, capilliposide G (1) and capilliposide H (2), were isolated from the whole plants of Lysimachia capillipes. Their structures were determined by 1D and 2D NMR, MS technique and chemical methods.

A new cerebroside from Uvaria tonkinensis var. subglabra.

A new cerebroside, subglain A (1), together with five known compounds (2-6) have been isolated from the stems of Uvaria tonkinensis var. subglabra. The structure of 1 has been determined to be 1-O-beta-D-glucopyranosyl-(2S,3S,4R,8Z,2'R)-2-[N-(2'-hydroxytetracosanyl)-N-(1'',2''-dihydroxyethyl)-amide]-8-tetradecene-1,3,4-triol by spectroscopic evidence. The known compounds were identified as schisandriside (2), erythritol (3), beta-D-glucopyranose (4), kaempferol-3,7-O-alpha-L-dirhamnoside (5), and (+)-lyoniresinol (6).

A steroidal saponin from the seeds of Allium tuberosum.

A steroidal saponin, named tuberoside, together with seven known compounds, were isolated from the seeds of Allium tuberosum Rottl. ex Spreng. Its structure was established by spectroscopic data, hydrolysis, and comparison with spectral data of known compounds to be (2alpha, 3beta, 5alpha, 25S)-2,3,27-trihydroxyspirostane 3-O-alpha-L-rhamnopyranoyl-(1-->2)-O-[alpha-L-rhamnopyranoyl-(1-->4)]-beta-D-glucopyranoside.

[Studies on the steroidal alkaloids from Sarcococca vagans].

The root of Sarcococca vagans Stapt (Buxaceae) is well-known Chinese folk drug called as "Jie Gu Mu", distributed in southern of China. They are used in treatment of traumatic injury. Four new steroidal alkaloids, named sarcovagine A, B, C and D, were isolated from the root of Sarcococca vagans. Their structures were established on the basis of spectral evidence.

[Studies on the chemical constituents from roots of Agastache rugosa].

Eleven compounds were isolated from roots of Agastache rugosa and eight of them were identified as maslinic acid (I), oleanolic acid (II), 3-O-acetyl oleanolic aldehyde (III), acacetin (IV), tilianin (V), agastachoside (VI), daucosterol (VII) and beta-sitosterol (VIII). Compound IX is a new diterpenoid and its structure was proposed to be 19(4----3)abeo-11,14-dihydroxy-12-methoxy-abieta-8,11,13,15- tetraen-7-one based on spectral data, named dehydroagastol. The studies on X and XI are in progress.