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.     

Furo[3,2-h]isochroman, furo[3,2-h]isoquinoline, isochroman, phenol, pyranone, and pyrone derivatives from the sea fan-derived fungus Penicillium sp. PSU-F40

Nine new fungal metabolites, penicisochromans A-E, penicipyrone, penicipyranone, peniciphenol, and penicisoquinoline, were isolated from the sea fan-derived fungus Penicillium sp. PSU-F40 together with five known compounds. Their structures were determined by spectroscopic analysis. Their antibacterial activity against the standard Staphylococcus aureus ATCC 25923 and methicillin-resistant S. aureus was evaluated.     

A new pyrone derivative from the endophytic fungus Penicillium paxilli PSU-A71

One new pyrone derivative, named penicillone (1), together with paxilline, pyrenocines A (2) and B (3) were isolated from the endophytic fungus Penicillium paxilli PSU-A71. The structures were elucidated by spectroscopic methods. Pyrenocine B (3) mildly inhibited the growth of Microsporum gypseum SH-MU-4 with a MIC value of 32 microg/ml.     

Modiolin and phthalide derivatives from the endophytic fungus Microsphaeropsis arundinis PSU-G18

One new modiolin, microsphaerodiolin (1), and seven new phthalides, microsphaerophthalides A-G (2-8), together with 12 known compounds were isolated from the endophytic fungus Microsphaeropsis arundinis PSU-G18. Their structures were elucidated by spectroscopic methods. The new 3-oxygenated phthalides are rare natural products. The known 1-(2,5-dihydroxyphenyl)-2-buten-1-one exhibited significant antifungal activity against Microsporum gypseum SH-MU-4 with an MIC value of 8 μg/mL, moderate antimalarial activity with an IC₅₀ value of 9.63 μg/mL and strong radical scavenging potency with the IC₅₀ value of 0.018 mg/mL. The new compounds 2 and 6 showed moderately antifungal activity against M. gypseum SH-MU-4 and Cryptococcus neoformans, respectively, with equal MIC values of 64 μg/mL.     

Chlorinated chromone and diphenyl ether derivatives from the mangrove-derived fungus Pestalotiopsis sp. PSU-MA69

Four new diphenyl ethers, pestalotethers A–D (1–4), three new chromones, pestalochromones A–C (5–7), one new xanthone, pestaloxanthone (8), and one new butenolide, pestalolide (9), together with 11 known compounds were isolated from the mangrove-derived fungus Pestalotiopsis sp. PSU-MA69. Their structures were established by spectroscopic techniques. Compounds 1–3 and 5–7 are the rare chlorinated fungal metabolites of diphenyl ethers and chromones, respectively. Pestalolide (9) displayed weak antifungal activity against Candida albicans and Cryptococcus neoformans.     

Antispasmodic Effect of Asperidine B,a Pyrrolidine Derivative,through Inhibition of L-Type Ca2+ Channel in Rat Ileal Smooth Muscle

Antispasmodic agents are used for modulating gastrointestinal motility. Several compounds isolated from terrestrial plants have antispasmodic properties. This study aimed to explore the inhibitory effect of the pyrrolidine derivative, asperidine B, isolated from the soil-derived fungus Aspergillus sclerotiorum PSU-RSPG178, on spasmodic activity. Isolated rat ileum was set up in an organ bath. The contractile responses of asperidine B (0.3 to 30 µM) on potassium chloride and acetylcholine-induced contractions were recorded. To investigate its antispasmodic mechanism, CaCl₂, acetylcholine, Nω-nitro-l-arginine methyl ester (l-NAME), nifedipine, methylene blue and tetraethylammonium chloride (TEA) were tested in the absence or in the presence of asperidine B. Cumulative concentrations of asperidine B reduced the ileal contraction by ~37%. The calcium chloride and acetylcholine-induced ileal contraction was suppressed by asperidine B. The effects of asperidine B combined with nifedipine, atropine or TEA were similar to those treated with nifedipine, atropine or TEA, respectively. In contrast, in the presence of l-NAME and methylene blue, the antispasmodic effect of asperidine B was unaltered. These results suggest that the antispasmodic property of asperidine B is probably due to the blockage of the L-type Ca²⁺ channel and is associated with K⁺ channels and muscarinic receptor, possibly by affecting non-selective cation channels and/or releasing intracellular calcium.