Asplactones A-E(1-5),five unique diphenyl ether hybrids,along with two rare spiro-diphenyl ethers,aspviolaceols A(6)and B(7),were isolated and characterized from Aspergillus sp.F1-8A,an endophytic fungus associated wi...Asplactones A-E(1-5),five unique diphenyl ether hybrids,along with two rare spiro-diphenyl ethers,aspviolaceols A(6)and B(7),were isolated and characterized from Aspergillus sp.F1-8A,an endophytic fungus associated with the parotoid glands of Bufo gargarizans Cantor.Compounds 1-5 represent the first examples of diphenyl ether hybrids fused with unusual moieties,including conjugatedγ-butyrolactone and cyclopentenone.Compounds 6 and 7 are the first known natural spiro-diphenyl ethers,with 6 featuring an uncommon 6/6/6/6-membered carbon skeleton,and 7 possessing a distinct 6/6/6/6/6/6-membered diphenyl ether spiro-heterodimer carbon framework.Structural elucidation was performed using a combination of spectroscopic techniques,X-ray crystallography,and quantum-chemical calculations,and plausible biosynthetic pathways were proposed.Biologically,compounds 1,2,4,6,and 7 exhibited antioxidant activity comparable to or surpassing that of vitamin C in 1,1-diphenyl-2-picrylhydrazyl(DPPH)and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate)(ABTS),and ferric reducing power assays.They also significantly improved cell viability in H2O2-induced oxidative injury assays using A549 cells.展开更多
基金supported by the National Natural Science Foundation of China(No.82073721)Major Basic Research Project of the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.23KJA310003).
文摘Asplactones A-E(1-5),five unique diphenyl ether hybrids,along with two rare spiro-diphenyl ethers,aspviolaceols A(6)and B(7),were isolated and characterized from Aspergillus sp.F1-8A,an endophytic fungus associated with the parotoid glands of Bufo gargarizans Cantor.Compounds 1-5 represent the first examples of diphenyl ether hybrids fused with unusual moieties,including conjugatedγ-butyrolactone and cyclopentenone.Compounds 6 and 7 are the first known natural spiro-diphenyl ethers,with 6 featuring an uncommon 6/6/6/6-membered carbon skeleton,and 7 possessing a distinct 6/6/6/6/6/6-membered diphenyl ether spiro-heterodimer carbon framework.Structural elucidation was performed using a combination of spectroscopic techniques,X-ray crystallography,and quantum-chemical calculations,and plausible biosynthetic pathways were proposed.Biologically,compounds 1,2,4,6,and 7 exhibited antioxidant activity comparable to or surpassing that of vitamin C in 1,1-diphenyl-2-picrylhydrazyl(DPPH)and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate)(ABTS),and ferric reducing power assays.They also significantly improved cell viability in H2O2-induced oxidative injury assays using A549 cells.
