A new lignan, 1, was isolated from Lepidozia vitrea, together with two known eudesmane terpenoids, 2 and 3, as well as 7,8-dihydroxycoumarin (4). Their structures were elucidated on the basis of extensive 1D-and 2D-NMR as well as MS analyses.
Introduction. -Lepidozia vitrea, a liverwort belonging to the family of Lepidoziaceae, is a rich source of sesquiterpenoids . Several sesquiterpenoids from the essential oil and ethyl ether extract of this plant have been reported [2]. In the course of our phytochemical investigations on antifungal constituents from liverworts [3], the new lignan derivative 1 was isolated from L. vitrea, together with three known compounds: 7a-hydroxyeudesm-3-en-6a-yl acetate (2), eudesm-3-ene-6a,7b-diol (3), and 7,8-dihydroxycoumarin (= 7,8-dihydroxy-1-benzopyran-2(2H)-one; 4). Herein, we report the isolation, structure elucidation, and characterization of these compounds.
Results and Discussion. -Compound 1, isolated from the EtOH extract of L. vitrea, was obtained as a colorless powder. Its molecular formula, C 48 H 48 O 26 , was derived by ESI-MS (M + at m/z 1040.012; calc. 1040.243). Five subunits were identified. The first one was an aryl-substituted 1,2-dihydro-6,7-dihydroxynaphthalene-2,3-dicarboxylate moiety, showing 18 signals in the 13 C-NMR spectrum (Table ), including two carboxylic C-atoms (d(C) 167.5, 170.5), 14 aromatic or olefinic resonances, and two aliphatic CH groups (d(C) 46.2, 49.6).
We were able to identify the parent structure 1a, which has been isolated before from Pellia epiphylla [4a], and named epiphyllic acid [4c]. The 1 H-NMR spectrum of the resonances belonging to its skeleton consisted of two coupled methine H-atoms [d(H) 3.83 (d, J = 2.4 Hz, 1 H), 4.40 (br. s, 1 H)], three signals of a 3,4-dihydroxyphenyl group [d(H) 6.35 (d, J = 7.8 Hz, 1 H), 6.36 (s, 1 H), 6.48 (d, J = 7.8 Hz, 1 H)], and three singlets at d(H) 6. 80, 7.04, and 7.54 (1 H each). These data were identical with those reported for epiphyllic acid proper.
One glucosyl (Glc) moiety was recognized, with an anomeric resonance at d(C) 103.9 in the 13 C-NMR spectrum, as well as five O-bearing aliphatic C-atoms at d(C) 62.2, 70.2, 74.8, 77.5, and 77.9. The anomeric H-atom resonated at d(H) 4.85 (d, J = 7.2 Hz, 1 H), which indicated b-configuration. Also, the anomeric Glc H-atom showed a 3 J correlation to C(7) of epiphyllic acid in the HMBC spectrum. Accordingly, the main skeleton of compound 1 consisted of a 7-O-glucosylated epiphyllic acid unit.