title: Characterization of cytochalasins from the endophytic Xylaria sp. and their biological functions.
abstract: Bioassay-guided fractionation of the fermentation extract of Xylaria sp. XC-16, an endophyte from Toona sinensis led to the isolation of two new cytochalasans cytochalasin Z27, 1, and cytochalasin Z28, 2, along with three known compounds seco-cytochalasin E, 3, and cytochalasin Z18, 4, and cytochalasin E, 5. The structures of 1 and 2 were elucidated by spectroscopic and electronic circular dichroism methods. Compound 5 was shown to be potently cytotoxic against brine shrimp (LC50 = 2.79 μM), comparable to that of the positive agent toosendanin (LC50 = 4.03 μM), and also exhibited potential phytotoxic effects on Lactuca sativa and Raphanus sativus L. seedlings, which are higher than that of the positive control glyphosate. Additionally, the fungicidal effect of 2 against the phytopathogen Gibberella saubinetti was better than that of hymexazol. This is the first report of the three types of cytochalasins present in genus Xylaria. A structure-phytotoxicity activity relationship is also discussed.
authors.affiliation: College of Science, Northwest A&F University , Yangling 712100, Shaanxi P. R. China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.forename: Jian
authors.initials: J
authors.lastname: Xiao
authors.forename: Qing-Qing
authors.initials: QQ
authors.lastname: Sun
authors.forename: Jian-Chun
authors.initials: JC
authors.lastname: Qin
authors.forename: Gennaro
authors.initials: G
authors.lastname: Pescitelli
authors.forename: Jin-Ming
authors.initials: JM
authors.lastname: Gao
mesh_terms: D000818:Animals; D001156:Artemia / Q000187:drug effects; D003572:Cytochalasins / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D060026:Endophytes / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D029582:Meliaceae / Q000382:microbiology*; D031224:Raphanus / Q000187:drug effects; D013098:Xylariales / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D003572:Cytochalasins
keywords: Xylaria sp.; absolute configuration; cytochalasins; natural products; phytotoxins; plant growth regulator; toxicity