Screening and isolation of anti-nematodal metabolites against bursaphelenchus xylophilus produced by fungi and plant

Abstract

Several plants and fungi were tested in random screening of anti-nemato-dal metabolites against Bursaphelenchus xylophilus using an immersion test. Among 30 species of the terrestrial plants tested, Magnolia grandiflora, Michelia hedyos-perma, and Nerium indicum showed nematicidal activity. From leaf extracts of M. grandiflora, a new sesquiterpene, 4,5-epoxy-1(10)E, 11(13)-germacradien- 12, 6-olide (1), was isolated as a nemticidal principle against B. xylophilus with an ED50 value of 71.4 μg/mL. From 212 terrestrial fungi tested, 83 fungal strains were found to be pathogenic to the pine wood nematode, B. xylophilus. Surprisingly, 88 strains among 119 fresh water-derived fungi tested were found to have the ability to produce anti-nematodal substances against B. xylophilus. The degree of activity varied with the fungal isolate/species, extraction part, pH values of test solutions, length of exposure time, age of nematode, and media composition. From the nematicidal cultures of Gliocladium roseum YMF1.00133, Paraniesslia sp. YMF1.01400 and Pseudohalonectria adversaria YMF1.01019 and Caryospora carllicarpa YMF1.01026, several novel compounds, including gliocladines A-D (2-6), glioclatine (7), (2S, 2′R, 3R, 3′E, 4E, 8E)-1-O-(β-D- glucopyranosyl)-3-hydroxyl-2-[N-2′-hydroxyl-3 ′-eicosadecenoyl] amino-9-methyl-4,8-octadecadiene (8), 3, 5-dihydroxyaldehyde-4-hydroxyl-acetophenone (9), pseudohalonectrin A-B (10-11), caryospomycins A-C (12-14), were isolated and identified along with known compounds such as verticillin A (15), 11′-deoxyverticillin A (16), sch52900 (17), sch52901 (18), (2S, 2′R, 3R, 3 ′E, 4E, 8E)-1-O-(β-D-glucopyranosyl)-3-hydroxyl-2-[N- 2′-hydroxyl-3′-octadecenoyl] amino-9-methyl-4,8-octadecadiene (19), 1,3,6,8-tetrahydroxy-anthraquinone (20), inosine (21), and adenosine (22). All the above-mentioned compounds were examined for nematicidal activity against B. xylophilus. © 2008 Springer Science+Business Media B.V.