An antibacterial biphenyl derivative from Garcinia bancana MIQ

From the methanol extract of the twigs and leaves of Garcinia bancana MIQ., one new biphenyl derivative (1), was isolated and characterized along with nine known compounds; garcinol, isogarcinol, (-)-mellein, 8-hydroxy-6-methoxy-3-n-pentylisocoumarin, blumenol C O-beta-D-glucoside, quercetin 3-O-alpha-L-rhamnoside, kaemferol 3-O-alpha-L-rhamnoside, lupeol and stigmasterol. Their structures were determined by analysis of 1D and 2D NMR data and comparison of spectral data and physical data with those previously reported. The antibacterial activity against methicillin-resistant Staphylococcus aureus was evaluated. Garcinol showed the lowest minimum inhibition concentration (MIC) at 16 microg/ml while compound 1 exhibited weaker activity with MIC value of 64 microg/ml.     

Antibacterial caged-tetraprenylated xanthones from the fruits of Garcinia hanburyi

A new caged-tetraprenylated xanthone, hanburinone (1), was isolated from the fresh fruits of Garcinia hanburyi together with four known caged-tetraprenylated xanthones; isomoreollin B (2), morellin (3), moreollic acid (4) and morellic acid (5). Their structures were elucidated by analysis of spectroscopic data and comparison of the NMR data with those reported previously. Compounds 4 and 5 showed moderately antibacterial activity against methicillin-resistant Staphylococcus aureus with a MIC value of 25 microg/ml.     

Polyketide anthraquinone,diphenyl ether,and xanthone derivatives from the soil fungus Penicillium sp. PSU-RSPG99

Three new polyketides including one new diphenyl ether, penicillither (1), one new anthraquinone, penicilliquinone (2), and one new xanthone, penicillixanthone (3), together with twelve known compounds were isolated from the soil fungus Penicillium sp. PSU-RSPG99. Their structures were identified by spectroscopic evidence. In addition, the position of a chlorine atom in 1 was confirmed by the plausible biosynthetic pathway from the isolated chlorobenzophenone. Known GKK1032B displayed mild antimycobacterial and moderate cytotoxic (against human oral carcinoma, KB, human breast cancer, MCF-7, and noncancerous Vero cell lines) activities.     

Cytotoxic arylbenzofuran and stilbene derivatives from the twigs of Artocarpus heterophyllus

Four new natural products, including three arylbenzofurans named heterophyllenes A-C (1–3), and one stilbene named heterophyllene D (4), together with twenty-one known compounds were isolated from the twigs of Artocarpus heterophyllus and their structures elucidated by spectroscopic methods, mainly 1D and 2D NMR spectroscopy. The cytotoxic activity of selected compounds against KB, MCF-7 and NCI-H187 cell lines was evaluated. Heterophyllene C (3) exhibited cytotoxicity against the MCF-7 cell line with an IC₅₀ value of 12.56 μM. Additionally, the known compounds norartocarpin and artocarpin showed cytotoxic activity against MCF-7 and KB cell lines with IC₅₀ values of 10.04 and 13.57 μM, respectively. Both compounds also displayed cytotoxicity against the NCI-H187 cell line with values of 14.78 and 14.21 μM, respectively.     

Copper-catalyzed domino reaction of carbodiimides and benzoic acid derivatives for the synthesis of quinazolinediones

Quinazolinediones were obtained from 2-iodobenzoic acids and carbodiimide derivatives under mild reaction conditions via a copper-catalyzed domino reaction. The absence of an external base was essential to avoid the generation of amide by-products. Both alkyl- and aryl-substituted carbodiimides gave the corresponding quinazolinediones. However, the use of aryl-substituted carbodiimides resulted in low yields due to an undesired elimination process.     

Metabolites from the xylariaceous fungus PSU-A80

One hypoxylonol, xylarenol (1), one hexadienoic acid, xylarenoic acid (2), and one tetralone, xylarenone (3), were isolated from the xylariaceous fungus PSU-A80 together with ten known compounds. The structures were established by analysis of spectroscopic data. 8-Methoxy-1-naphthol, one of the known metabolites, displayed good radical scavenging potency with an IC(50) value of 30 microg/ml.     

Depsides and depsidones from the soil-derived fungus Aspergillus unguis PSU-RSPG204

Three new depsides, aspergisides A-C, and one new depsidone, aspergisidone, were isolated from the soil-derived fungus Aspergillus unguis PSU-RSPG204 together with one phthalide derivative and 11 depsidones including emeguisin A, aspersidone and folipastatin. The structures were determined by spectroscopic evidence. Aspersidone and emeguisin A showed remarkably antibacterial activity against Staphylococcus aureus and methicillin-resistance S. aureus with equal MIC values of 0.5?μg/mL. Emeguisin A, which displayed the highest activity with 87.06% inhibition of human colon carcinoma (HCT-116) cell viability, decreased numbers of live cells/numbers of dead cells in a dose-dependent manner with the IC₅₀ values of 34.8–84.7?μM in a 3D culture model depending on durations of incubation. In addition, folipastatin dose-dependently inhibited forskolin-stimulated chloride secretion in human intestinal epithelial (T84) cells with an IC₅₀ value of 0.5?μM. These depsidones were considered to be inactive against noncancerous Vero Cells with the IC₅₀ values of >10?μM.     

Eudesmane sesquiterpenes from the aquatic fungus Beltrania rhombica

From the ethyl acetate extract of the culture broth of Beltrania rhombica, two new eudesmane sesquiterpenes, named rhombidiol (1) and rhombitriol (2), were isolated and characterized along with five enantiomers of known sesquiterpenes: (-)-beta-eudesmol, (-)-pterocarpol, (-)-chrysanthemol, (-)-longilobol and (-)-5beta-hydroxy-beta-eudesmol. Their structures were determined by analysis of 1D and 2D NMR data and comparison of spectral data and physical data with those previously reported.     

Cytotoxic metabolites from the wood-decayed fungus Xylaria sp. BCC 9653

Chemical investigation of the wood-decayed fungus Xylaria sp. BCC 9653 has led to the isolation of a new methyl aminobenzoate (1) together with eleven known compounds. The structures were established by analysis of spectroscopic data. Cytochalasin D (2), one of the known metabolites, exhibited potent cytotoxicity against African green monkey kidney fibroblast (Vero) cells with an IC(50) value of 0.19 microM.