title: Phenylphenalenone-type Phytoalexins from Unripe Buñgulan Banana Fruit.
abstract: Fourteen phenylphenalenone-type phytoalexins (1-14), including three new compounds, were isolated from the peel of unripe Musa acuminata [AAA] cv. Buñgulan fruit which had been injured and then inoculated with conidia of Colletotrichum musae. These new phytoalexins were identified as (+)-cis-2,3-dihydro-2,3-dihydroxy-4-(4'-hydroxyphenyl)phenalen-1-one (12), 9-(3',4'-dimethoxyphenyl)-2-methoxyphenalen-1-one (13) and 9-(4'-hydroxyphenyl)-2-methoxyphenalen-1-one (14). The ratios of the relative intensities of the [M](+)/[M-H](+) ions or [M-H2O](+)/[M-H2O-H](+) ions in the EI mass spectra were applied to discriminate between 4- and 9-phenylphenalenones. An antifungal test on the phytoalexins showed that a phenolic hydroxyl group was essential for the activity.
authors.affiliation: a Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University.|b CREST, Japan Science and Technology Corporation (JST).
authors.forename: T
authors.initials: T
authors.lastname: Kamo
authors.affiliation: a Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University.
authors.forename: N
authors.initials: N
authors.lastname: Kato
authors.affiliation: a Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University.|b CREST, Japan Science and Technology Corporation (JST).
authors.forename: N
authors.initials: N
authors.lastname: Hirai
authors.affiliation: c Division of Environmental Science and Technology, Graduate School of Agriculture, Kyoto University.
authors.forename: M
authors.initials: M
authors.lastname: Tsuda
authors.affiliation: d Osaka Co-operative Wholesale Society.
authors.forename: D
authors.initials: D
authors.lastname: Fujioka
authors.affiliation: a Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University.
authors.forename: H
authors.initials: H
authors.lastname: Ohigashi
keywords: 1,8-naphthalenedicarboxylic acid; Musa acuminata; banana; phenylphenalenone; phytoalexin