Two new compounds, deacetylisowortmins A and B, isolated from an endophytic Fungus, Talaromyces wortmannii LGT-4

Research advances in the structures and biological activities of secondary metabolites from Talaromyces

The genus Talaromyces belongs to the phylum Ascomycota of the kingdom Fungi. Studies have shown that Talaromyces species yield many kinds of secondary metabolites, including esters, terpenes, steroids, alkaloids, polyketides, and anthraquinones, some of which have biological activities such as anti-inflammatory, bacteriostatic, and antitumor activities. The chemical constituents of fungi belonging to the genus Talaromyces that have been studied by researchers over the past several years, as well as their biological activities, are reviewed here to provide a reference for the development of high-value natural products and innovative uses of these resources.

Antifungal activity, identification and biosynthetic potential analysis of fungi against Rhizoctonia cerealis

Purpose

Wheat sheath blight mainly infected by Rhizoctonia cerealis is one of the soil-borne fungal diseases of wheat worldwide and prevalent in major wheat growing areas in China at present. This study aimed to evaluate the antifungal activity of 163 endophytic fungi on R. cerealis. Antifungal strains were identified and their biosynthetic potential was analysed.

Methods

The antifungal activity of the strains was evaluated via dual-culture antagonism assay. The antifungal strains were identified on the basis of morphological characteristics and internal transcribed spacer gene sequencing. The polyketide synthases (PKSs) and nonribosomal peptide synthetase (NRPS) genes in antifungal strains were detected via specific amplification of chromosomal DNA.

Result

Twelve out of 163 fungal strains, including seven strains with matrix competition and five strains with antibiosis, were obtained. The twelve antifungal strains belonged to four genera: Alternaria, Ascochyta, Botryosphaeria, and Talaromyces. The inhibition rate of the seven strains with matrix competition was greater than 50%, with that of Botryosphaeria dothidea S2-33 being the highest at 84.6%. The inhibition zone of Talaromyces assiutensis R-03 amongst the five strains with antibiosis was the widest at up to 7 mm. Among the twelve antifungal strains, the strain S2-16 contained all the genes tested, five B. dothidea strains contained PKS-II and NRPS genes, two Alternaria alternata strains only contained PKS-II gene and the remaining four strains did not contain any.

Conclusion

Results demonstrated twelve potential strains for the biocontrol of wheat sheath blight. In particular, T. assiutensis R-03 was determined as a promising agent. The active substances secreted by antifungal strains may be produced by other biosynthetic pathways.

A norbisabolane and an arabitol benzoate from Talaromyces marneffei, an endophytic fungus of Epilobium angustifolium

A norbisabolane and an arabitol benzoate, Talaromarnine A (1), Talaromarnine B (2), together with eight known compounds were obtained from cultures of Talaromyces marneffei, an endophytic fungus of Epilobium angustifolium. Their structures were elucidated by IR, MS, 1D and 2D NMR spectra, and their absolute configuration was determined by single-crystal X-ray diffraction and molecular computation. These compounds were tested for monoamine oxidase, acetylcholinesterase and PI3K inhibitory activity, but no compounds exhibited significant activities.

Recent progress in the synthesis of the furanosteroid family of natural products

This review focuses on an overview of recent advances in the synthesis of furanosteroids and illustrates their applications in medicinal chemistry over the period of 2005–present.

Two New Diphenylketones and a New Xanthone from Talaromyces islandicus EN-501, an Endophytic Fungus Derived from the Marine Red Alga Laurencia okamurai

Two new diphenylketones (1 and 2), a new xanthone (3), and a known xanthone analogue (4) were isolated and identified from Talaromyces islandicus EN-501, an endophytic fungus obtained from the fresh collected marine red alga Laurencia okamurai. Their structures were elucidated on the basis of NMR spectroscopic and X-ray crystallographic analysis. The joint isolation of benzophenones and xanthones from the same fungal strain supports the biogenesis of xanthones via a benzophenone intermediate. It is worth mentioning that xanthones 3 and 4 have a methyl group at C-6 and C-2, respectively, which is uncommon compared with typical xanthones usually having a methyl group at C-8. Compounds 1–4 exhibited potent antioxidative activities against DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonate) radicals with IC₅₀ values ranging from 0.58 to 6.92 μg/mL, which are stronger than that of the positive controls BHT (butylated hydroxytoluene) and ascorbic acid. Compounds 1, 3, and 4 also showed inhibitory activities against several pathogenic bacteria.