Biosci. Biotechnol. Biochem., 68 (7), 1608–1610, 2004 Note Fusicocca-3(16),10(14)-diene, and - and -Araneosenes, New Fusicoccin Biosynthesis-related Diterpene Hydrocarbons from Phomopsis amygdali y Takeshi SASSA,1;2; Hiromichi KENMOKU,2 Kayoko NAKAYAMA,1 and Nobuo KATO3 1Department of Bioresource Engineering, Faculty of Agriculture, Yamagata University, Wakaba-cho, Tsuruoka 997-8555, Japan 2Course of the Science of Bioresources, The United Graduate School of Agricultural Sciences, Iwate University (Yamagata University), Wakaba-cho, Tsuruoka 997-8555, Japan 3The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka, Ibaraki 567-0047, Japan Received March 8, 2004; Accepted April 10, 2004 Further isolation and examination of fusicoccane Fusicoccin A (FC A, Fig. 1),1) one of unique diterpene hydrocarbons biosynthetically related to fusicoccin glucosides produced by Phomopsis amygdali, shows not from Phomopsis amygdali allowed us to identify new only potent plant plasma membrane Hþ-ATPase-acti- fungal diterpene hydrocarbons of fusicoccadiene and vating activity,2) but also novel effects on amphibian araneosene. These were assigned as (þ)-fusicocca- embryogenesis.3) Its aglycon is a polyoxygenated de- 3(16),10(14)-diene, and (þ)- - and (þ)--araneosenes. rivative of fusicocca-1,10(14)-diene with a 5/8/5- These findings led to the experimental clarification of tricyclic skeleton.1) We have recently isolated a novel the structures of the biosynthetic hydrocarbon inter- (þ)-fusicocca-2,10(14)-diene (1, Fig. 1) from P. amyg- mediates presumed earlier. dali F6 as one of the important genuine hydrocarbon intermediates in the early stage of FC biosynthesis,4) and Key words: fusicoccadiene; araneosene; Phomopsis confirmed its structure by a total synthesis.4) In the amygdali; diterpene hydrocarbon; fungal course of isolating 1 from mycelia of the other FC- metabolite producing strains (Niigata 2 and 74) of P. amygdali,5) Fig. 1. Structures of Fusicoccin A, (þ)-Fusicocca-2,10(14)-diene (1), (þ)-Fusicocca-3(16),10(14)-diene (2), (þ)--Araneosene (3), and (þ)- - Araneosene (4), and Their Biosynthetic Relationships. 1 and 3, and 2 and 4 are respectively shown with filled and unfilled arrows in the fusicoccin biosynthesis from geranylgeranyl diphosphate (GGDP), together with the chemical isomerization of 2 to 1 and 20 shown with normal arrows. y To whom correspondence should be addressed. Fax: +81-235-28-2862; E-mail: [email protected] Fusicoccadiene and Araneosene from Phomopsis amygdali 1609 Fig. 2. Total Ion Chromatogram from the GC-MS Analysis of the n- Hexane-soluble Portion Obtained from the Mycelial Extract of a 7- Fig. 3. Observations of Differential NOEs in a C6D6 Solution of 2. 1 Day Culture of Phomopsis amygdali Niigata 2. H-NMR (C6D6, J(Hz)): 0.92 (d, 7, 17-H), 1.06 (s, 18-H), 1.56 Conditions for the GC-EIMS analysis: Aligent 6890N GC-5973N (ddd, 13,7,5, 12-H ), 1.60 (dd, 14.5,2.5, 1-H ), 1.88 (ddd, 13,8,8, MSD/Wiley 7n.1 database system; HP-1MS capillary column 12-H ), 1.96 (dd, 14.5,11.5, 1-H ), and 2.44 (br t, 9, 2-H). (0.25 mm  30 m), 60 C (2 min)–150 C (30 C/min)–180 C (10 C/min)–210 C(2C/min). 7, 15-H), 4.68 and 4.73 (each m, 16-H); C (CDCl3): 19.9 (br, C-17), 21.0 and 21.1 (C-19/20), 23.1 (br, C-9), we detected unknown hydrocarbons (2, 3 and 4) 27.0 (C-15), 27.3 (br, C-5), 27.7 (C-13), 28.2 (C-18), structurally related to 1 at tR 13.56 (1), 13.77 (2), 30.4 (C-4), 31.8 (br, C-8), 35.7 (C-12), 36.7 (br, C-7), 14.13 (3), and 17.30 (4) min by a GC-MS analysis 42.2 (C-1), 44.5 (br, C-6), 45.3 (C-2), 50.5 (C-11), 101.6 (Fig. 2). Compound 2 showed MS data similar to those (C-16), 138.7 (br, C-10), 140.5 (br, C-14), and 160.2 of 1,4) and 2 and 4 were detected as intense total ion (C-3). These observations and comparisons of its NMR chromatogram (TIC) peaks together with the strong peak data with those of 1 revealed 2 to be the 3(16)-double- of 1 in the course of fungal growth. These findings bond isomer of 1.The1H-NMR spectrum of 2 in acid- stimulated us to isolate and examine these hydrocarbons non-removed CDCl3 for a few hours at ambient temper- from the fungus. We report here the isolation and ature varied in a large part to that of 1; H (CDCl3, structural determination of (þ)-fusicocca-3(16),10(14)- J(Hz)): 0.86 (d, 7, 17-H), 0.92 and 0.98 (each d, 7, H- diene (2), and the identification of (þ)--araneosene (3) 19/20), 0.93 (s, 18-H), 1.63 (br s, H-16), 2.62 (septet, 7, and (þ)- -araneosene (4) from this fungus (Fig. 1). H-15), 1.95 and 2.30 (each d, 13, H-1), 2.48 (m, H-6).4) The n-hexane extract (2.1 g), including the basic and Furthermore, differential NOEs in a C6D6 solution of 2 neutral substances, was prepared in the usual way from at 50 C were observed as shown in Fig. 3, indicating mycelia obtained from the culture (48 Sakaguchi flasks) the cis configuration between -oriented 6-H and 2-H in of P. amygdali Niigata.5) This extract was carefully 2. Thus, the structure of 2 was assigned to be (þ)- separated by silica gel (Wakogel FC 40) flash chroma- fusicocca-3(16),10(14)-diene having the 2/6-cis config- tography, using n-hexane as the eluent, to give 9 uration (Figs. 1 and 3). A detailed NMR analysis of the fractions. Fractions 2, 3, 5 and 7 gave 1 (46 mg), 2 mixture of 1 and 2 in acid-non-removed CDCl3 just (12 mg, including a small amount of 1), 3 (colorless described revealed the presence of a new fusicoccadiene 0 0 solid, 1.2 mg), and 4 (colorless oil, 5 mg), respectively. (2 ) in the respective signal ratio of 3:1:1; 2 H (CDCl3, Fraction 3 was further purified by rechromatography J(Hz)): 0.88 (d, 7, 17-H), 0.94 and 1.00 (each d, 7, 19/ by a similar method to give 2 (colorless oil, 7 mg). 20-H), 1.03 (s, 18-H), 1.66 (br s, H-16), 2.70 (br septet, Compound 2 had ½ D þ19 (c 0.18, CHCl3), and 7, H-15), 5.30 (br s, H-4)). These characteristic NMR 0 molecular formula C20H32 based on its HR-EIMS signals suggested that 2 was fusicocca-3,10(14)-diene þ data (m=z (M ): calcd. for C20H32, 272.2486; found, as one of the endo-cyclic double-bond isomers of 2 272.2484). Its EIMS data [m=z (%): 272 (Mþ, 10), 257 (Fig. 1). Isomeric hydrocarbons 1 and 20 derivable from (12), 229 (45), 201 (4), 187 (6), 173 (11), 161 (14), 135 2 were newly prepared by an acid treatment with p- 4) 1 (100), 121 (85)] were similar to those of 1. Its H- and toluenesulfonic acid in C6D6/(CD3)2CO at 55 C for 13C-NMR signals were fully assigned by COSY, DEPT 10 hr; an olefinic proton at 5.37 as the diagnostic signal and HMBC methods by using a 600 MHz NMR showing the presence of 20 was observed in the NMR spectrometer; H (CDCl3, J(Hz)): 0.88 (d, 7.1, 17-H), spectrum. A GC-MS analysis of the reaction mixture 0.93 and 0.99 (each d, 7, 19/20-H), 1.10 (s, 18-H), 1.48 clearly indicated the presence of a deuterated mixture of 0 and 1.90 (each dd, 15, 2.0, 1-H , and 15, 11.5, 1-H ), 1 (tR 13.56 min) and 2 (tR 13.17 min) together with non- 1.53 and 1.81 (each ddd, 13, 7, 7, 12-H , and 13, 8.5, deuterated 2 (tR 13.77 min) in the respective ratio of 8.5, 12-H ), 2.17 (m, 6-H), 2.35 (m, 2-H), 2.69 (septet, 8:1:1. The MS data for 1 showed principally those of 1610 T. SASSA et al. [16-2H]-1; molecular ions m=z (rel. intensity): 273 (100, derivation of 20 from 2 suggested the presence of the [16-2H]-1), 274 (24) and 275 (3). The spectrum of 20 fusicocca-10(14)-en-3-yl cation as the final carbocation also showed that of [16-2H]-20; molecular ions m=z (rel. in the formation of intermediate 1, which is generated by intensity): 273 (100) and 274 (38). Non-deutrated 20 three consecutive 1,2-hydride shifts during the further newly prepared by an H2SO4/(CH3)2CO treatment of 2 cyclization of (þ)--araneosene to fusicoccadienes. The showed MS data similar to those of 2 (Fig. 1). A further results from this study clarify the biosynthetic route of 1 acid (H2SO4/(CD3)2CO) treatment of this hydrocarbon from GGDP in the early stage of FC biosynthesis as mixture at room temperature led to a decrease of the shown in Fig. 1. olefinic proton signal at 5.37 in the NMR spectrum. A GC-MS analysis of the reaction mixture gave a single Acknowledgments TIC peak showing the presence of a deuterated mixture of 1; its molecular ions were also observed at m=z (rel.