Caryophyllene-type sesquiterpenoids and α-furanones from the plant endophytic fungus Pestalotiopsis theae.

Two new caryophyllene-type sesquiterpenoids, pestathenols A (1) and B (2) and one new α-furanone, pestatheranone A (6), along with five known compounds (3-5, 7 and 8) have been isolated from the crude extract of the plant endophytic fungus Pestalotiopsis theae. Their structures were unambiguously established by extensive spectroscopic analyses. The absolute configuration of the 5,6-diol moiety in 1 was assigned using Snatzke's method. Compounds 1 and 2 showed weak cytotoxicity against HeLa cell line.

Pestalotiones A-D: Four New Secondary Metabolites from the Plant Endophytic Fungus Pestalotiopsis Theae.

Two new xanthone derivatives, pestalotiones A (1) and B (2), one new diphenyl ketone riboside, pestalotione C (7), and one new diphenyl ether, pestalotione D (8), along with five known compounds isosulochrin dehydrate (3), 3,8-dihydroxy-6-methyl-9-oxo-9H-xanthene-1-carboxylate (4), isosulochrin (5), chloroisosulochrin (6), and pestalotether D (9), were isolated from the crude extract of the plant endophytic fungus Pestalotiopsis theae (N635). The structures of the new compounds were unambiguously deduced by HRESIMS and 1D/2D-NMR spectroscopic data. Compound 6 showed modest cytotoxicity against the HeLa cell line with an IC50 value of 35.2 µM. Compound 9 also showed cytotoxic to the HeLa and MCF-7 cell lines, with IC50 values of 60.8 and 22.6 µM, respectively. Additionally, compounds 1 and 2 exhibited antioxidant activity in scavenging DPPH radical with IC50 values of 54.2 and 59.2 µg/mL, respectively.

Chloropupukeananin and Pestalofone C Regulate Autophagy through AMPK and Glycolytic Pathway.

Chloropupukeananin (RN56-6) and Pestalofone C (RN56-49), isolated from the culture of the plant endophytic fungus Pestalotiopsis fici, have been shown cytotoxic, anti-HIV, and antimicrobial activities. However, the underlying mechanism of their regulatory roles in autophagy remains unknown. In the present study, we revealed that both compounds increased the formation of autophagosome and enhanced autophagic flux. While RN56-6 upregulated the expression of HK2, one of the key rate-limiting enzymes of glycolysis, the inhibition of glycolysis chemically attenuated RN56-6-induced autophagy. On the contrary, RN56-49 downregulated the expression of HK2, while the suppression of glycolysis promoted RN56-49-dependent autophagic flux. Moreover, the knockdown of AMPKß1, a scaffolding subunit of AMPK, decreased autophagy induced by these two compounds. Collectively, these findings revealed that RN56-6 and RN56-49 regulated autophagic process through AMPK and glycolytic pathway.

Diaporone A, a new antibacterial secondary metabolite from the plant endophytic fungus Diaporthe sp.

Diaporone A (1), one new dihydroisocoumarin derivative and four known α-dibenzopyrones, alternariol (2), 5'-hydroxyalternariol (3), alternariol 4,10-dimethyl ether (4), and alternariol 4-methyl ether (5) were isolated from the crude extract of the plant endophytic fungus Diaporthe sp. Their structures were determined on the basis of spectroscopic analysis, including 1D and 2D NMR techniques as well as HRESIMS and comparison with data from the literature. The absolute configuration of 1 was assigned by electronic circular dichroism (ECD) calculations. Compound 1 showed moderate antibacterial activity against Bacillus subtilis with the MIC value of 66.7 µM, and exhibited weak cytotoxicity against human cervical carcinoma (HeLa) cell line with IC50 value of 97.4 µM.

Theoretical study on the bactericidal nature of nanopatterned surfaces.

A natural biomaterial has been discovered with bactericidal activities, which is mainly attributed to its nanopatterned surface structure. The surface of Clanger cicada (Psaltoda claripennis) wings has been identified as a natural bactericidal material, which has lead to the emergence of research on the development of novel antibacterial surfaces. From the interactions between bacterial biofilms and nanopatterned surface structures, a new mechanical model is proposed that investigates the rupture of bacterial cells within the framework of the "stretching" theory. The effect of surface nanoroughness on the survival of bacterial cells is evaluated by determining the stretching ability of their cell walls. The results, calculated using Gram-positive and Gram-negative bacteria as examples, show a correlation between the stretching of the cell wall and the geometric parameters of the surface structures. The theoretical results indicate that for a given cell rigidity, the bactericidal nature of the surface is determined by the geometric parameters of the surface structures.