Bipolarolides A–G (1–7), seven novel ophiobolin‐derived sesterterpenes with three new types of skeletons, were characterized from fungus Bipolaris sp. TJ403‐B1. Their structures were determined via spectroscopic analyses, X‐ray crystallography, and quantum chemical 13C NMR and electronic circular dichroism (ECD) calculations. Compounds 1 and 2 were uniquely defined by a multicyclic caged oxapentacyclo[9.3.0.01,6.05,9.18,12]pentadecane‐bridged system. Compounds 3 and 4 featured an unprecedented 5‐5‐5‐5‐fused core skeleton, while 3 also contained an unexpected C‐3–C‐14 oxygen bridge to construct the caged architecture. Compounds 5–7 form a new class of highly modified pentacyclic oxaspiro[4.4]nonane‐containing sesterterpene‐alkaloid hybrids. Their biosynthetic pathways and potential HMG‐CoA reductase inhibitory and antimicrobial activities are also discussed.

NW-G01 is a novel cyclic hexapeptide antibiotic produced by Streptomyces alboflavus 313. Its relative structure was established by HR-ESI-MS, IR, 1D and 2D NMR techniques, the absolute structure was determined using a combination of single-crystal X-ray diffraction and Marfey's method finally. The antibiotic consists of L-valine, (3S)-and (3R)-piperazic acids, N-methyl-Dalanine and (2S,3aR,8aS)-6-chloro-3a-hydroxy-1, 2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole-2-carboxylic acid.

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NW-G01, a novel cyclic hexadepsipeptide antibiotic, was isolated by macroporous resin and silica gel column chromatography and HPLC from the fermentation broth of strain no. 313. The producing strain was identified as Streptomyces alboflavus on the basis of the morphological characteristics, physiological property and 16S rDNA gene sequence analysis. NW-G01 exhibited strong antibacterial activity against Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, methicillin-resistant S. aureus, and their MIC values were 3.90, 3.90, 7.81 and 7.81 lg ml À1 , respectively.

Nine novel butenolide derivatives, including four pairs of enantiomers, named (±)-asperteretones A–D (1a/1b–4a/4b), and a racemate, named asperteretone E (5), were isolated and identified from the coral-associated fungus Aspergillus terreus. All the structures were established based on extensive spectroscopic analyses, including HRESIMS and NMR data. The chiral chromatography analyses allowed the separation of (±)-asperteretones A–D, whose absolute configurations were further confirmed by experimental and calculated electronic circular dichroism (ECD) analysis. Structurally, compounds 2–5 represented the first examples of prenylated γ-butenolides bearing 2-phenyl-3-benzyl-4H-furan-1-one motifs, and their crucial biogenetically related metabolite, compound 1, was uniquely defined by an unexpected cleavage of oxygen bridge between C-1 and C-4. Importantly, (±)-asperteretal D and (4S)-4-decarboxylflavipesolide C were revised to (±)-asperteretones B (2a/2b) and D (4), respectively. Additionally, compounds 1a/1b–4a/4b and 5 were evaluated for the α-glucosidase inhibitory activity, and all these compounds exhibited potent inhibitory potency against α-glucosidase, with IC50 values ranging from 15.7 ± 1.1 to 53.1 ± 1.4 μM, which was much lower than that of the positive control acarbose (IC50 = 154.7 ± 8.1 μM), endowing them as promising leading molecules for the discovery of new α-glucosidase inhibitors for type-2 diabetes mellitus treatment.

Our results suggest a putative association between SPARC and MMPs (especially MMP-9) in ameloblastoma to regulate tumor invasion.

A preliminary phytochemical investigation on the EtOAc extracts of the fungus Bipolaris sp. TJ403-B1 resulted in the identification of 12 ophiobolin-type phytotoxins (1−12), including nine new ones, termed bipolaricins A−I (1−9). The structures of 1−9 were elucidated via spectroscopic data (including HRESIMS and 1D and 2D NMR) and single-crystal X-ray diffraction (Cu Kα) analyses. All of the isolated compounds were tested in terms of HMG-CoA reductase inhibitory, anti-inflammatory, and cytotoxic activities. Compound 10 showed HMG-CoA reductase inhibitory activity (IC 50 = 8.4 ± 0.4 μM), and 2, 3, and 10−12 showed significant inhibitory potency against lipopolysaccharide (LPS)-induced nitric oxide production, with IC 50 values in the range of 5.1 ± 0.3 to 20 ± 1 μM. Further experiments showed that 10 could significantly inhibit the production of IL-1β, RANTES, MIP-1β, and TNF-α as well as enhance the release of IL-13 in macrophages through the inhibition of HO-1 induction as well as the NF-κB pathway. These findings provide a scientific rationale for an anti-inflammatory therapeutic and a template for a new HMG-CoA reductase inhibitor to produce a potential anti-hyperlipidemia agent.

Nine novel polyketide−terpenoid hybrids (1−9), characterized by a 1-alkylated-3,5-dihydroxyphenyl derivative coupled with a modified farnesyl pyrophosphate (FPP) unit, were isolated from a soil-derived fungus Bipolaris zeicola. Their structures were determined by comprehensive spectroscopic data, single-crystal X-ray diffraction analyses, and electronic circular dichroism calculations. Structurally, compounds 1, 2, 5, and 6 possess a rare thiazole moiety; compounds 3 and 4 are the first examples of meroterpenoids featuring an undescribed 6/6/6/6/5 pentacyclic system and bearing a tetrahydrofuran ring fused to a polyketide and a sesquiterpenoid subunit; compounds 7 and 8 possess a rare 2H-1,4-thiazin-3(4H)-one moiety; and compound 9 represents the first example of meroterpenoid having an unusual thiazol-2(3H)-one moiety. The bioactivity assays revealed that compounds 1, 2, 5, 6, and 9 exhibited a significant immunosuppressive effect against concanavalin A (ConA)-induced T lymphocyte proliferation with IC 50 values ranging from 5.6 to 8.8 μM, and compounds 1, 2, and 4 exhibited moderate cytotoxic activities with IC 50 values ranging from 18.4 to 29.4 μM.