Two new unsaturated fatty acids from the mangrove rhizosphere soil-derived fungus Penicillium javanicum HK1-22.

• Two new unsaturated fatty acids (1 – 2) were isolated from the fungus P. javanicum HK1-22. • The relative configuration of 1 was assigned by NOE spectra of the acetonide derivative (1a). • Compound 5 showed significant antifungal activities against four strains of crop pathogens. Two new unsaturated fatty acids, 6 R ,8 R -dihydroxy-9 Z ,12 Z -octadecadienoic acid (1) and methyl-6 R ,8 R -dihydroxy-9 Z ,12 Z -octadecadienoate (2), and two known 9 Z ,12 Z -octadecadienoic acid analogues (3 , 4) together with a known sesquiterpenoid (5) were isolated from the mangrove rhizosphere soil-derived fungus Penicillium javanicum HK1-22. An acetonide derivative (1a) from 1 was also prepared. The relative configuration of 1 was determined by analysis of the 1D and 2D NOE spectra of 1a. The absolute configuration of 1 was assigned on the basis of biogenetic considerations. The antifungal activity of the high yield compound 5 was evaluated against four strains of crop pathogens and it showed significant antifungal activities against all the tested strains. [ABSTRACT FROM AUTHOR]