ABSTRACT
Eighteen polycyclic polyprenylated acylphloroglucinols were isolated from the whole plant of Hypericum scabrum Linn., including six new compounds (1-6). Their structures were elucidated by comprehensive spectroscopic analyses. The evaluation of their cytotoxic activities was carried out against SMMC-7721 and MGC-803 cell lines. We found that most tested compounds exhibited moderate cytotoxic activities against SMMC-7721 cell line except for 11 and 12, while compounds 1, 5-7, 13 and 16 also showed cytotoxic activities on MGC-803 cells. Besides, Bacillus subtilis, MRSA and MDPRA were also used to test inhibitory activity of these compounds. Our results showed that only compounds 12 and 13 presented weak inhibitory activity against Bacillus subtilis, while compounds 7, 13 and 14 also inhibited MRSA weakly.
Subject(s)
Hypericum , Cell Line , Hypericum/chemistry , Molecular Structure , Phloroglucinol/chemistry , Phloroglucinol/pharmacologyABSTRACT
Five new phenylspirodrimanes, stachybomycins A - E (1-5), together with four known compounds (6-9), were isolated from the marine-derived fungus Stachybotrys sp. SCSIO 40434. Their structures were elucidated by comprehensive spectroscopic analyses of NMR and HRESIMS. The absolute configuration of 1 was confirmed by single crystal X-ray diffraction analysis. Compounds 5 and 7 showed moderate antibacterial activities against Micrococcus luteus, Staphylococcus aureus and methicillin resistant Staphylococcus aureus with minimal inhibition concentration (MIC) values of 8, 16 and 16 µg mL-1, respectively.
Subject(s)
Anti-Bacterial Agents/pharmacology , Biological Products/pharmacology , Stachybotrys/chemistry , Anti-Bacterial Agents/isolation & purification , Aquatic Organisms/chemistry , Biological Products/isolation & purification , China , Methicillin-Resistant Staphylococcus aureus/drug effects , Micrococcus luteus/drug effects , Molecular Structure , Pacific Ocean , Staphylococcus aureus/drug effectsABSTRACT
Trichoderma harzianum is a widely used biocontrol agent in agriculture. Obtaining a full inventory of the small molecules that can be biosynthesized from the encoded biosynthetic gene clusters (BGCs) is therefore useful for understanding associated plant-microbe and microbe-microbe interactions. Here we heterologously reconstituted a polyketide synthase-nonribosomal peptide synthetase (PKS-NRPS) encoding gene cluster from T. harzianum t-22 in Aspergillus nidulans A1145. Six new tetronate natural products trihazone A-F (1-6) were isolated and elucidated by HRESIMS and 1D and 2D NMR data. Three of the products contain an exocyclic olefin, which is derived from the oxidative decarboxylation of an α-ketoglutarate-dependent dioxygenase ThnC as shown by biochemical assays.
