[Chemical constituents of Psidium guajava and their antitumor and antifungal activities].

Twenty-six compounds, including sixteen meroterpenoids(1-16), a triterpenoid(17), four terpenoid derivatives(18-21), and five aromatic compounds(22-26), were isolated from the leaves of Psidium guajava. Their structures were identified by spectroscopic analyses including NMR and MS. Compounds 21-26 were obtained from plants of Psidium for the first time. Based on the structure,(R)-2-ethylhexyl 2H-1,2,3-triazole-4-carboxylate(24 a), an α-glucosidase inhibitor recently isolated from Paramignya trimera, should be revised as compound 24. Meroterpenoids 1-16 were evaluated for their antitumor and antifungal activities. Meroterpenoids psiguajadial D(4), guapsidial A(5), 4,5-diepipsidial A(7), guadial A(14), and guadial B(15) showed cytotoxicities against five human tumor cell lines(HL-60, A-549, SMMC-7721, MCF-7, and SW-480), among which 5 was the most effective with an IC_(50) of 3.21-9.94 µmol·L~(-1).

Novel dibenzofuran and biphenyl phytoalexins from Sorbus pohuashanensis suspension cell and their antimicrobial activities.

Two novel sulfur-containing dibenzofurans, sorbusins A (1) and B (2), two unprecedented biphenyl glycosides, 2'-hydroxyaucuparin 2'-O-ɑ-L-rhamnoside (3) and noraucuparin 5-O-ɑ-L-rhamnoside (4), and four known analogues (5-8), were isolated from Sorbus pohuashanensis suspension cell induced by yeast extract. Their structures were elucidated based on spectroscopic analyses and quantum calculation of 13C NMR data. Structurally, compound 1 possessed a rare naturally occurring benzothiazole moiety and represents the first example of thiazole fused dibenzofuran. A plausible biosynthetic pathway for the sulfur-containing dibenzofurans is proposed. These dibenzofuran and biphenyl phytoalexins were evaluated for their antimicrobial activities against pathogenic fungi and drug-resistant bacteria. Compound 7 exhibited significant antibacterial activity against methicinllin-resistant Staphylococcus aureus with an MIC value of 3.13 µg/mL.

Three new hopane-type triterpenoids from the aerial part of Adiantum capillus-veneris and their antimicrobial activities.

Three new hopane-type triterpenoids (1-3), fern-7(8)-en-19α, 28-diol (1), pteron-14-ene-7α,19α,28-triol (2) and 3ß,4α,25-trihydroxyfilican (3), were isolated from the aerial parts of Adiantum capillus-veneris. Their structures were determined by NMR spectroscopic and mass spectrometric data. Compounds 2 and 3 exhibited remarkable antifungal activity against Helminthosporium maydis and Alternaria alternata with MIC values of 12.5-3.125 µg/mL, and compound 3 also against Verticillium dahliae Kleb with an MIC value of 3.125 µg/mL. In addition, compounds 1-3 also displayed weak antibacterial activity against Micrococcus lysodeikticus, Bacterium paratyphosum B and Pseudomonas aeruginosa with an MIC value of 100 µg/mL.

Three new phenanthrenes with antimicrobial activities from the aerial parts of Juncus effusus.

Three new phenanthrenes (1-3), designated as 2-methoxy-1,6-dimethyl-5-vinyl-9, 10-dihydrophenanthren-7-ol, 1,6-dimethyl-4,5-dihydropyrene-2,7-diol and 1-(3,7- dihydroxy-2,8-dimethyl-9,10-dihydrophenanthren-1-yl)ethanone, were isolated from the aerial parts of Juncus effusus. Their structures were determined by extensive spectroscopic experiments (NMR and MS) and comparing with those related known compounds. The antifungal and antibacterial activities of 1-3 were evaluated. Compound 1 showed remarkable antifungal activities against six agricultural pathogenic fungi (Rhizoctonia solani, Verticillium dahliae Kleb, Sclerotinia sclerotiorum, Gibberella saubinetii, Bipolaris zeicola, and Phytophthora parasitica) with minimum inhibitory concentration (MIC) values ranging from 3.125 to 12.5 µg/mL, and also displayed significant antibacterial activities against two human pathogenic bacteria (Bacterium paratyphosum B and Micrococcus lysodeikticus) with MIC values of 12.5 and 25 µg/mL, respectively.

New alkenylated tetrahydropyran derivatives from the marine sediment-derived fungus Westerdykella dispersa and their bioactivities.

Six new alkenylated tetrahydropyran derivatives belonged to polyketides, designated as (12R,13R)-dihydroxylanomycinol (1), (12S,13S)-dihydroxylanomycinol (2), (12R,13S)-dihydroxylanomycinol (3) and (12S,13R)-dihydroxylanomycinol (4), (12S,13R)-N-acetyl-dihydroxylanomycin (5) and (12S,13S)-N-acetyl-dihydroxylanomycin (6), together with one related known compound lanomycinol (7) were isolated from the liquid cultures of Westerdykella dispersa obtained from the marine sediments. Their structures and absolute configurations were determined on the basis of extensive analysis of NMR spectra combined with comparison of NMR data to those of known compound, and computational method via calculation of the electronic circular dichroism (ECD). The anti-agricultural pathogenic fungal and antibacterial activities of all isolated compounds were evaluated. Compounds 1-7 exhibited moderate antifungal activities selectively against tested fungal strains with minimum inhibitory concentration (MIC) values ranging from 12.5 to 50µg/mL, and weak antibacterial activities selectively against tested antibacterial strains with MIC value at 100µg/mL.