Colletotryptins A-F, new dimeric tryptophol derivatives from the endophytic fungus Colletotrichum sp. SC1355.

Seven new dimeric tryptophol-related alkaloids (1-4, 5a, 5b, and 6) were isolated from solid cultures of the endophytic fungus Colletotrichum sp. SC1355. The structures and absolute configurations of these compounds were determined by NMR spectroscopic analyses in combination with quantum chemical calculations of NMR (GIAO) shifts and ECD spectra. This is the first report of fungus-derived tryptophol dimers. In addition, the isolated compounds were evaluated for acetylcholinesterase (AchE) inhibitory activity.

A novel icariin type flavonoid from Epimedium pseudowushanense.

A novel icariin type flavonoid glycoside with a malonaldehydic acid intramolecular ester and two known flavonoid glycosides were isolated from Epimedium pseudowushanense. Their structures were elucidated on the basis of spectroscopic analysis and comparison of their data to the values reported in the literatures. The anti-inflammatory activities of these compounds icariin 3'''-O-malonaldehydic acid intramolecular 1'''', 2''' ester (1), icariin (2) and epimedin C (3) were tested. The results indicated that compounds 1, 2 and 3 showed maximal inhibitory ratio of 27.91, 44.80 and 46.61%, respectively in in vitro anti-inflammatory activity on LPS-induced TNF-α secretion in RAW264.7 cells. Compounds icariin (2) and epimedin C (3) were found to inhibit the secretion of TNF-α to a comparable degree as quercetin.

Anti-inflammatory neolignans from Epimedium pseudowushanese.

One new 8-O-4' neolignan has been isolated from Epimedium pseudowushanese B. L. Guo, together with nine other known neolignans. The structures of these neolignans were elucidated using spectroscopic and chemical techniques, and their anti-inflammatory activities were also evaluated. The results of these experiments revealed that compound 6 was the most potent of the 10 different compounds tested in the current study, with a maximal inhibitory ratio of 79% for its in vitro anti-inflammatory activity towards lipopolysaccharide-induced tumour necrosis factor alpha secretion in RAW264.7 cells. The other nine compounds exhibited only moderate inhibitory effects.

Bioactive Pentacyclic Triterpenoids from the Leaves of Cleistocalyx operculatus.

Thirteen new pentacyclic triterpenoids, cleistocalyxic acids A-K (1, 2, 4, 5, and 7-13) and cleistocalyxolides A (3) and B (6), and 15 known analogues (14-28), based on taraxastane, oleanane, ursane, multiflorane, and lupane skeletons, were isolated from the leaves of Cleistocalyx operculatus. The structures of 1-13 were elucidated by analysis of their spectroscopic data and ECD/TDDFT computations. Cleistocalyxolide A (3), presumed to be derived from the known taraxastane-type compound 14, has a rare rearranged triterpenoid backbone. Cleistocalyxic acid B (2) displayed cytotoxicity against HepG2, NCI-N87, and MCF-7 cancer cell lines with IC50 values ranging from 3.2 to 6.5 µM, and cleistocalyxic acid D (5) was active against HepG2 and NCI-N87 cells with values around 5.0 µM. The noncytotoxic cleistocalyxic acid E (7) inhibited production of IL-6 by 68.1% and TNF-α by 53.7% in LPS-induced RAW 264.7 macrophages at a concentration of 2 µM.

Anti-inflammatory cyclopeptides from exocarps of sugar-apples.

Two new cyclic peptides, fanlizhicyclopeptide A, cyclo(Pro(1)-Pro(2)-Tyr(3)-Leu(4)-Pro(5)-Gly(6)-Val(7)) (1), and fanlizhicyclopeptide B, cyclo(Pro(1)-Ile(2)-Tyr(3)-Ala(4)-Gly(5)) (2), were isolated along with six known kaurane diterpenoids and a known clovane sesquiterpene from the exocarps of sugar-apples, the fruit of Annona squamosa. Their structures were elucidated by ESI MS/MS experiments, 1D and 2D NMR data and chemical degradation. In the anti-inflammatory assay, both 1 and 2 showed in vitro inhibitory effects on the production of pro-inflammatory cytokines, TNF-α and IL-6, in LPS-stimulated RAW 264.7 macrophages.

Two new amides from Streptomyces michiganensis.

A new amide glycoside, 3-alpha-glucopyranosyloxy-N-methyl-3-phenylpropanamide (1), and a new cyclodipeptide, (3S,6S)-3,6-bis(4-acetamidobutyl)piperazine-2,5-dione (2), were isolated from the solid culture of Streptomycetes michiganensis strain SC0642. Their structures were elucidated by spectroscopic methods.

A new natural lactone from Dimocarpus longan Lour. seeds.

A new natural product named longanlactone was isolated from Dimocarpus longan Lour. seeds. Its structure was determined as 3-(2-acetyl-1H--pyrrol-1-yl)-5-(prop-2-yn-1-yl)dihydrofuran-2(3H)-one by spectroscopic methods and HRESIMS.

Resin glycosides from the aerial parts of Operculina turpethum.

Three glycosidic acids, turpethic acids A-C, and two intact resin glycosides, turpethosides A and B, all having a common pentasaccharide moiety and 12-hydroxy fatty acid aglycones of different chain lengths, were obtained from the aerial parts of Operculina turpethum. Their structures were elucidated by spectroscopic analyses and chemical correlations. The aglycones were characterized as 12-hydroxypentadecanoic acid in two compounds, 12-hydroxyhexadecanoic acid in two other components, and 12-hydroxyheptadecanoic acid in the fifth compound, which were all confirmed by synthesis. The absolute configurations of these aglycones were all established as S by Mosher's method. These compounds represent the first examples of resin glycosides with a monohydroxylated 12-hydroxy fatty acid as an aglycone, and one compound is the first described resin glycoside having a hydroxylated C(17) fatty acid as its aglycone.

Bioactive dammarane-type saponins from Operculina turpethum.

Four new dammarane-type saponins, operculinosides A-D (1-4), were isolated from the aerial parts of Operculina turpethum, of which 1 and 2 are the first two dammarane-type triterpenoids having an oxymethyl group at C-24. Their structures were determined by spectroscopic analysis and acid hydrolysis. The absolute configuration of operculinoside A (1) was confirmed by X-ray crystallography. Compounds 1 and 3 showed significant protective activities against d-galactosamine-induced toxicity in L-02 human hepatic cells.

A novel cyclopropyl-containing fatty acid glucoside from the seeds of Litchi chinensis.

3,12-Dihydroxy-cis-3,4-methylenedodecanoic acid 3-O-ß-d-glucopyranoside, trivially named litchioside C (1), the first cyclopropyl-containing fatty acid glycoside, was isolated along with three previously uncharacterized galactosylacylglycerols from the seeds of Litchi chinensis. Its structure was established on the basis of spectroscopic analysis including HRESIMS and 2D NMR spectra. Its antioxidant and antibacterial activities were evaluated and its biogenetic pathway was discussed.

The first cyclic phenolic acid glycoside dimer and new alpha-tetralone and triterpenoid glucosides from Gentiana loureirii.

Further chemical investigation of the whole plants of Gentiana loureirii led to the isolation and characterization of three new compounds, cyclic 4-O-beta-D-glucopyranosylcaffeic acid dimer (1), a new alpha-tetralone, 4-hydroxy-6-methyl-alpha-tetralone 4-O-beta-D-glucopyranoside (2), and 3beta,30-dihydroxy-12-ursen-28-oic acid 28-O-beta-D-glucopyranosyl ester (3), along with five known compounds. To the best of our knowledge, compound 1 is the first cyclic phenolic acid glycoside dimer.

A new coumarin from Sarcandra glabra.

Sarcandracoumarin (1), the first coumarin having a 1-phenylethyl substituent at the C-3 position, was isolated along with eleven known phenolic compounds from the water extract of Sarcandra glabra. Its structure was elucidated on the basis of spectroscopic data. Compound 1 exhibited moderate or weak cytotoxicity against several tumor cell lines.

Prenylflavonols from the leaves of Macaranga sampsonii.

Four novel prenylflavonols, macaranones A-D (1-4), were isolated from the leaves of Macaranga sampsonii. Their structures were elucidated on the basis of spectroscopic data. Macaranones C (3) and D (4) represent first two examples of flavonols having an unusual peltogynoid skeleton which is formed from a 2'-geranylflavonol by cyclization between 3-OH and C-1'' of the 2'-geranyl substituent of the flavonol. Compounds 1-4 were evaluated for the cytotoxicity against several human cancer cell lines.