From the culture of the endophytic fungus Fusarium sp. isolated from the roots of Mentha longifolia L. (Labiatae) growing in Saudi Arabia, a new cyclodepsipeptide, namely fusaripeptide A (1), along with three known compounds adenosine (2), 2[(2-hydroxypropionyl)amino]benzamide (3), and cyclopentanol (4), have been isolated. Their structures were determined, using extensive 1D and 2D NMR and HRESI and GC mass spectral data. That is the first report for the isolation of compound 4 from natural source. In addition, compounds 2 and 3 are reported here for the first time from Fusarium sp. The absolute configuration of the amino acid residues of 1 was assigned by chiral GCMS and Marfey's analysis after acid hydrolysis. Fusaripeptide A differs from the reported ones from Fusarium sp. in the length of fatty acidic alkyl chain. Compound 1 was evaluated for its antifungal, anti-malarial, and cytotoxic activities. It exhibited potent antifungal activity toward C. albicans, C. glabrata, C. krusei, and A. fumigates with IC50 values of 0.11, 0.24, 0.19, and 0.14 μM, respectively. Furthermore, it had significant anti-malarial activity toward P. falciparum (D6 clone) with IC50 value of 0.34 μM. However, it showed cytotoxic activity toward the tested cell lines.
Keywords: Fusarium sp.; anti-malarial; antifungal; cyclodepsipeptide; cytotoxic; fusaripeptide A.