A new glucitol from an endophytic fungus Fusarium equiseti Salicorn 8

An endophytic fungus Salicorn 8 was isolated from Salicornia bigelovii Torr. and identified as Fusarium equiseti based on internal transcribed spacer gene (ITS) sequence analysis. A new glucitol, diglucotol (1), together with five known compounds, cerebroside C (2), Nb-acetyltryptamine (3), 3β,5α,9α-trihydroxy-(22E,24R)-ergosta-7,22-dien-6-one (4), cerevisterol (5) and ergosterol peroxide (6), was isolated from the culture of Salicorn 8. The chemical structures of these compounds were elucidated by extensive spectroscopic analysis and on the basis of their chemical reactivities. This work describes for the first time the isolation of these compounds from F. equiseti. Compound 1 exhibited weak antiproliferative activities toward MCF-7, MDA-MB-231 and Caco-2 cancer cells with EC50 values of 97.56, 92.35 and 99.39 μM, respectively, whereas compound 5 showed high levels of inhibitory activities against MCF-7, MDA-MB-231 and Caco-2 cancer cells with EC50 values of 32.4, 41.5 and 37.56 μM, respectively. Compound 6 exhibited less potent inhibitory activities than 5 against MCF-7, MDA-MB-231 and Caco-2 cancer cells with EC50 values of 64.5, 52.4 and 77.56 μM, respectively. All of the other compounds were found to be inactive.