Fusarihexins A and B: Novel Cyclic Hexadepsipeptides from the Mangrove Endophytic Fungus Fusarium sp. R5 with Antifungal Activities.

Two novel cyclic hexadepsipeptides, fusarihexin A (1: ) and fusarihexin B (2: ), and two known compounds, cyclo-(L-Leu-L-Leu-D-Leu-L-Leu-L-Val) (3: ) and cyclo-(L-Leu-L-Leu-D-Leu-L-Leu-L-Ile) (4: ), were isolated from the marine mangrove endophytic fungus sp. R5. Their chemical structures were elucidated on the basis of spectroscopic data and Marfey's analysis. In an bioassay, fusarihexin A (1: ) remarkably inhibited three plant pathogenic fungi: (Penz.) Sacc., which causes anthracnose in many fruits and vegetables, (Berk. and M. A. Curtis) Arx, which causes crown rot and anthracnose in bananas, and Schlecht. f. sp. lycopersici (Sacc.) W. C. Snyder et H. N. Hansen, which causes Fusarium wilt and fruit rot in tomatoes. Fusarihexin B (2: ) strongly inhibited and . The compounds were more potent than carbendazim, which is widely used as an agricultural and horticultural fungicide worldwide.