Phytochemiatry. 1977, Vol. 16, pp. 243-241, Pqunon SCREENING GEMMA&SANTE*, Rso, Printed in Eqhnd. OF THE GENUS CERCOSPORA FOR SECONDARY METABOLITES” zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONM ROMANOLoccf, Loror~zo C AMARDA$‘, LUCIO M~~LINI~$ and GIANLUCANASINI$ Isituto di Patologia Vegetalee, 7 Istituto di Biochimica Generale, Facolti di Agraria dell’Universit&,Milano, $ Istituto di Chiti= de1 Politecnico, 5 Milano, Italy zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA l (Reoisedreceived5 July 1976) Key Word Index-Cercospora; Deuteromycetes; cercosporin; cercosporin esters; 3-methoxy-2,5,7-trihydroxyl+naphthaquinone; c&4,6-dihydroxymellein. of 61 species of Cercosporu grown on a potato-agar medium showed the presence of the phytotoxin cercosporin in 24 of them, and of dothistromin in 8. Some strains of C. beticolu produce a yellow phytotoxin (CBT). The new metabolites cercosporin esters, ligustrone A, B, C, taiwapyrone, 3-methoxy-2,5,7-trihydroxy-1,4naphthaquinone, &4,6dihydroxymellein and ( - )-11-acetyldehydrocurvularirvularin were isolated besides the known cynodontin, ( - )-dehydrocurvularin, ( + )-me&sin and cis-3&4S4hydroxymellein. Abtract-Screening sodium methoxide in methanol. In particular the monoacetate monobenzoate (5) was obtained as a crystalline Among plant pathogens, the genus Cercospora (Deuteromy&es) [l] is well known, as it includes several species compound suitable for X-ray analysis, which is now in progress [ 143. responsible zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA for leafspot diseases of many plants, including All the other metabolites which have been isolated some of economic importance, such as sugar beet [2] are of polyketide origin. C. ligustrina produces the new and soya beans [3]. The possible phytotoxic role played chromones ligustrone A, B and C (6-8), whereas C. by secondary metabolites of Cercospora has been emphasized by Schl%ser [2]. However, the first report of the taiwanensis yields mellein (9), cis-3S-4S4hydroxymellein (lo), and taiwapyrone (11). The elucidation of these production of a phytotoxin by C. kikuchii is due to structures has been reported elsewhere [15,16]. From C. Kuyama and Tamura [4], who isolated cercosporin. The structure of cercosporin (1) was elucidated a few years cari cynodontin (1,4,5,8-tetrahydroxy-2-methylanthraquinone) was obtained, a known metabolite of some later [5], and its unusual stereochemical features clarified Helminthosporium sp. and of other fungi [ 173. The major [6,7]. Reports of the isolation of cercosporin from other metabolites of seven species are the two epimers dothC. species, namely C. beticola [8], C. huyii [9], C. peristromin (12) and 2-epidothistromin (13) [18]. It is sonatn [lo] and C. ricinella [ll] have also appeared. noteworthy that dothistromin has been recently isolated Recently, the biosynthesis of cercosporin has been studied from the fungus Dothistroma pini, and recognized as the [12], and its photodynamic and antibacterial activity phytotoxin responsible for the ‘pine blight’ disease [19]. demonstrated [ 133. A culture of C. smilacis showed also the presence of other Due to the interest of cercosporin as a phytotoxin, to anthraquinones, averufin and averythrin, which both are the possible synergism with other metabolites, and in the produced by Dothistroma pini. hope of finding new biologically active substances, we A new metabolite (14) was obtained from C. melonis. have undertaken the screening of a large number of The UV, NMR and MS data indicated that it was a Cercospora species for secondary metabolites. trihydroxymethoxy-1,4-naphthaquinone. The presence in the NMR spectrum of signals from two meta aromatic RESULTS AND DISCUSSION hydrogens, which were shifted to lower field by acetylation and were not decoupled by irradiation ofthe methoxy The results reported in Table 1 show that 23 of the 61 protons and of only one chelated OH, restricted the choice species of Cercospora examined produce cercosporin (l), to the two structures, 3-methoxy-2,5,7-trihydroxy-1,4which could so far be considered as a metabolite typical naphthaquinone (14) and 2-methoxy-3,5,7_trihydroxyof the genus. l+naphthaquinone (18). In order to distinguish between Besides cercosporin, Cercospora setariae produces four these two possibilities, the latter compound was preacetate and benzoate side chain esters (2-S). Their pared by selective demethylation of 2,3-dimethoxy-5,7structure and configuration was easily established from dihydroxy-l&naphthaquinone (17)with HCI in ethanol, NMR and MS, and by hydrolysis to cercosporin with [20-J, a reaction based on the different hydrolysis rates of the two methoxyls, the OH at C-3 being more acidic * Part 4 of a series on metabolites of Cercospora: for pre than that at C-2 in the parent tetrahydroxyquinone. As ceding papers see refs. [5], (151and [16]. the product (18) appeared different from the metabolite 9 Centro de1 C.N.R. per le Sostanze Organiche Naturali. INTRODUCllON 243 G. ASSANTEet zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLK al. 244 Table 1. Species of Cercospora examined Species for phytotoxins Metabolites Source* Cercosporin(l)t 1 2 3 4 5 ; 8 9 10 11 12 13 14 1.5 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercosporu Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora Cercospora aleuritidis althaeina ampelopsidis angolensis apii ariminiensis armoraciae astragali belly nchii bertoreae beticola beticola beticola beticola beticola beticola bizzozeriana bolleana calotropidis canescens cantuariensis cari carotae chenopodii cistinearum cladosporioides diazu dulcamarae erysimi exosporioides ferruginea festucae fusca italica kaki kikuchii kikuchii ligustrina magnoliae malvacearum malvicola medicaginis melonis mercurialis microsora musae nitotionae olivascens ory zae personata plantaginis plumbaginea psoruleae- bituminosae rautensis rhapisicola rosicola rubi salina scirpicola setariae smilacis taiwanensis unamunoi vaginae violae zebrina zonata CBS 281.62% CBS 248.67 CBS 249.67 CBS 149.53 CBS 119.25 CBS 137.56 CBS 250.67 CBS 537.71 CBS 150.49 CBS 538.71 CBS 152.52 CBS 121.31 IPV-F586$ IPV-F587$ IPV-F588$ IPV-F5735 CBS 540.7 1 CBS 541.71 CBS 129.30 CBS 153.55 CBS 112.24 CBS 148.52 CBS 101.65 CBS 126.29 CBS 257.67 CBS 159.48 CBS 138.28 CBS 544.7 1 CBS 545.71 CBS 751.70 CBS 546.71 CBS 143.51 CBS 106.14 CBS 130.32 CBS 128.39 CBS 128.27 CBS 135.28 CBS 148.59 CBS 541.63 CBS 126.26 CBS 548.7 1 CBS 108.22 CBS 161.60 CBS 551.71 CBS 552.71 CBS 143.36 CBS 131.32 CBS 253.67 CBS 145.37 CBS 220.3 1 CBS 252.67 CBS 553.71 CBS 554.71 CBS 555.71 CBS 282.66 CBS 138.35 CBS 256.35 CBS 141.60 CBS 104.40 CBS 494.71 CBS 556.71 CBS 139.35 CBS 156.62 CBS 140.34 CBS 151.49 CBS 129.39 CBS 557.71 * CBS = Centraal Bureau voor Schimmelcultures, Italy. t +, + + shows qualitatively the production prd E. Schliisser, Institut ftir Pflanzenkrankheiten tural work on other metabolites is in progress. Others ++ ++ ++ ++ ++ ++ ++ + + - CBT11 CBT CBT CBT CBT CBT ++ + ++ + ++ + ++ dothistromin (12) dothistromin (12) ++ ++ ligustrone A(6), B(7), C(8) + + ++ (14) dothistromin(l2) + + ++ + + + + dothistromin(l2)v dothistromin(l2) (19), (W, (22) (2). (3h (4)? Q dothistromin(l2J3), avertim and averythrin mellein(9), 4_hydroxymellein(lO) taiwapyrone(l1) n - Baarn, Netherlands. IPV = Istituto di Patologia Vegetale, Universita di Milano, of cercosporin. $ From Prof. V. D’Ambra. Universita di Padova, Italy. $ From der Universit%t, Bonn, Germany. (( CBT = Cercospora beticola toxin. T[ Struc- Secondary mctabolites of Cercospora 245 of C. zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA melonis on TLC, the structure (14) was attributed The extracts from a few strains of C. beticola and C. to this latter. bertoreae contain a yellow substance, that is named CBT (Cercospora beticola toxin) in Table 1. The presence of OH 0 this metabolite was previously reported by Schliisser, who named and partially characterized it, and studied R=H ; R’= H its phytotoxic and antibiotic activity [23]. We have R=COMe;R’=COMe : found CBT in the mycelia of some strains of C. beticola R=COhle;R’=H R=COPh ;R’=COPh isolated from infected sugarbeets, and also in that of the 5 R= COPh ; R’= COMe original strain of Dr. Schliisser, kindly provided by him. 3 6H “v-f” 6 19 R=H; R’=H R=H;R’=Ac R=Ac;R’aAc The macrolide dehydrocurvularin (19), a known metabolite of Cum&aria sp. [21] was isolated from C. scirpicola, together with a new compound (20). The structure of 19 was easily established by comparison of spectral data and optical rotation with those of the literature R 20 2 I Me H Me 6 R*H;8-9dehydro bH 9 R-H 16 R-OH II H 8 T”*“(“” Y 22 6 Although the substance is rather unstable, we have been able to obtain it in a reasonably pure state. Therefore the allegation of Balis and Payne [8] that it is a mixture of cercosporin and of fatty acids, is wrong. Structural work on CBT is in progress in our laboratories. The substance is also of interest, as it appears together with cercosporin in a few active strains, and preliminary experiments could suggest a possible synergism in the phytotoxic activity of both compounds. Further investigations on this particular subject are also in progress. I OH 0 OH bH EXPERIMENTAL zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA bH 13 I2 0 I4 R=H;R’=H I3 R=Ac; R’*Ac 19 R=Me;R’nH [22]. Spectral data for 20 and conversion of both 19 and 20 to the same diacetate (21) indicated that 20 must be a monoacetate of 19. The presence of a MeCO group and the lack of a chelated OH in the NMR spectrum of 20 led 0 OMe OR I7 19 R=Me R8H us to attribute to this compound the structure of 11-Oacetyldehydrocurvularin (20). A small amount of another metabolite was also obtained, the NMR and MS of which, compared with those of 9 and 10, indicated that it is the new cis+-dihydroxymellein (22). Mp’s are uncorrected UV spectra were measured in 95:/, &OH. NMR spectra were recorded at IOOMHz, chemical shiis are in pp. (S), from TMS as internal standard. Column chromatography and TLC were performed with Si gel. Unless otherwise indicated the purity of the products was checked by TLC, NMR and MS and deemed sufficient for the purposes of structural elucidation. M aterials and methods. The 61 species of Cmcospora which have been examined are reported in Table 1. Most of them were obtained from the Ccntraal Bureau voor Schimmelcultures, Baam, Holland. A survey of the differentfacton(culture medium, temperature, pH, light, addition of specific substances, etc.) influencing the growth led us to choose the following standard conditions for the cultures to be screened. The strains were cultivated on potato-agar medium, obtained by boiling 2OOg potatoes for 30 min, filtering, adding 20 g glucose and 13 g agar, zyxwvutsrqponm diluting to 1 I. and adjusting the pH to 6.5-6.8, in Roux flasks at 22-24”, containing 100 ml each of the culture medium. After a growth period of 15-20 days, the content of each flask was extracted twice with 100 ml EtOAc, and the extract dried on Na,SO, and evaporated in uacuo at 40”. The metabolites were isolated by PLC or column chromatography on Si gel. It was observed that all strains showed better production on media containing agar than in liquid media. For some species (6, 21, 24,27,40,42,65) the addition of 2 “,<of yeast and for others (11, 12, 13, 14, 15, 16, 36, 42, 47, 49) of a further loo/, of glucose to the standard medium increased the production of metabolites, whereas addition of biotin, thiamine or b-alanine [9] had no effect. Ferrous salts apparently induced a deeper pigmentation, but no svstematic investigation was carried out. I~ Ye G. ASSANTE et zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONML al. 246 Cercospora setariae. Extraction with EtOAc of 35 Roux flasks gave after evaporation of the solvent, 0.5 g of crude products; by PLC with C,H,-Et&formic acid (5050 :l) 5 meiabolites were obtained and identified as follows. Cercosuorin (1, 20mg). Zp’-diacetylcercosporin (2). 45 mg ofa red powder, mp 80-82”. (Found: C, 63.17; H, 4.50. C33H3,,0,2 requires: C, 64.07; H, 4.89%); MS 618; UV L.&m): 290, 297sh, 485, 600 and 640 (e327~,32400,21800,8~, 1iOOO);IR pdp’crn-‘: 174O(Ac), 1620 (conj. CO); CD (in EtOH, c 2.1 x lo-* g/lOOml): 246, 297, 320, 352 and 410 nm (As + 23.5, -43.5, -7.95, + 2.94, - 7.35); NMR (CD&): 6 0.55 (d, 2 Me; J = 6 Hz), 1.70 (2 AC), 3.73 and 3.0 (m, 2 -I-CH-0), I 2-CH,-m-O), 14.76 (2 chel. OH). 4.28 (2 OMe), 4.68 (m, 5.8 (s, O-Q&-O), 7.04 (s, 2 arom. H), Zdcety lcercosporin (3). 15 mg yield with mp 133-134”; MS 576; UV LX (nm): 253,291,2PPsh, +0,5POsh and 640 (E 15 500, 23000,23 300, 14 100, 5000,620O); IR vz>’ cm-’ .3450 (OH), 1740 (AC), 1620 (conj. CO); CD (in EtOH, c 0.9 x tom2 g/l00 ml): 240, 297, 352 and 410 nm (AZ + 23.6, -42.2, + 1.92, - 8); NMR (CDCI,); 6 0.56 and 0.64 (d, 2 Me), 1.66 (AC),2.80 - 3.80 (m, -CH,-a-0 I and 2 e,--AH-O), 4.24 and 4.22 (OMe), 4.64 (m, -CH,-&-OAc) 5.76 (s M2-0), 7.04 (s, 2 arom. H), 14.82 and 14.76 (2 Lhel. OI$ 2’,2”-Dibenzoylcercosporin(4). 5 mg of a red solid, mp 120-113 : (Found: C, 68.76; H, 4.60. C,,H,,O,, requires: C, 69.6: H. 4.62:/.); MS 742; UV LX (nmj-22% 2%,47j and 565 (E36700, 16300,118OO. 4300): IR v?Z! cm-‘: 1715 (GCOPhl. 1620 (coni. CO); CD (in EtOH;> 1.2i? lo-’ g/l00 61): 240,297,3li anh 410 nm (AE + 21, -24.2, - 6.95, - 3.62); NMR (CDCI,): 0.83 (d, 2 Me), 3.a3.86 (m, 2 -~z-CH-O), 4.32 (2 OMe), 5.0-5.2 (m, 2 -CH,--I;II-OCOPh), 5.62 (s, 0-m2-0), 6.80 (s, 2 arom. H), 7.0-7.40 (10 arom.), 14.70 (2 chel. OH). 2’-Acetyl?-benzoylcercosporin (5). 25 mg, red crystals mp 153-155”; (Found: C, 67.00; H, 4.74. CJSH32012 requires: C, 67.05; H, 4.75 “,/,);MS 680; UV Iz,, (nm). 223, 273, 380$, 480, 570 and 620 (E 41500,24400,4550, 18700,5850,4000); IR $$?p’ cm-’ : 174O(Ac),1720(OCOPh), 162O(conj. CO); CD(in EtOH, c 3.21 x 10m2g/100 ml): 240,298,320,360 and 410 mn (As + 16.2, -20, -4.86, +0.42, -3.82); NMR (CDCI,). 6 0.53 and 0.82 (d Me), 1.61 (AC), 2.92-3.88 (m, 2 -a2-JH-O), 4.28 and I 4.30 (OMe), 4.65 (m, CH,- L H-OAc), 5.07 (m, CH,-mGCOPh), 5.70 (d, w,-0; J 7 Hz), 6.85 and 7.06 (s, 2 aromatic protons), 7.16-7.50 (C,H,), 14.66 and 14.80 (2 chel. OH). Hy droly sis ofthe esters (Z- 5). To 5 mg(2-5 dissolved in MeOH, were added 10 mg MeONa, at room temp. for 1 day; all the products after acidification, gave (l), identified by TLC comparison. Cynodontin. A strain of Cercospora cari (5 flasks), gave, after PLC a few mg of cynodontin; it was identified by TLC and mp comparison with an authentic sample and by MS of the tetraacetate (Py and AczO), m/e: 454,412,370,328,286.257,229. Cercospora melonis. Isolation and idenHj?cation of metabolite 14. A strain of C. melonis was grown on potato-agar in the usual manner for 1 month. Myceha were crushed and extracted twice with EtOAc The less polar compound 14 was separated from the crude mixture by PLC in C,H,-Et@-formic acid (50/50/l). 2,5,7-nihvdroxv-3-methoxy-1,4-naphtha&none (14). Mp 255” (dec.); (Fouhd: C; 55.16; H, j.73. C1-,H,6, requiies: C, 35.94; H, 3.41 “,i); MS m/e (rel. int) : 236 (lOO),207 (8), 190 (20), 179 (lo), 165 (42), 137 (27), 121(34); UV d_ (nm): 225sh, 269.5,320,384 and 47Osh(8 12600, 15300, 6550,3140, 1200), basic EtOH 227, 291,374 and 580 (E 23 200,24400,5600, 1750); Ik fld; (cm-‘: 3360 (OH), 1650 (conj. CO) and 1615, NMR (DMSO): S 3.88 (OMe), 6.94 and 6.50 (d, 2 arom. m-H ; J 25 Hz), 12.2 (chel OH). 2,5,7-l?iacetoxy-3-methoxy-1,4-naphthquinone (15). 20 mg 14 in 0.2 ml of dry C,H,N and 0.4 ml Ac,O were left overnight at room temp. Dilution with H,O, extraction with Et,0 gave 15 as a yellow solid mp 145-147” (Et,O); IR v:t cm-’ : 1780 (AC), 168g(conj. CO), 16-Mand 1600, NMR (CDCI,): 6 2.43,2.38 and 2.33 (AC),4.15 (OMe), 7.80 and 7.21 (d, 2 arom. m-H). 5-Hydroxy-i3,7-~imethoxy-l,enaphrhaquino~e (is). 10 mg 14, dissolved in MeOH, were treated with an ethereal soln of CH,N, ; evap gave orange crystals of 16, mp 90-92” ; MS 264; UV I, (nm): 266,312,390 and 430sh (E 20000; 10700,3000,2940), NMR (acetone-d,): 6 4.08, 4.07 and 3.95 (OMe), 7.03 and 6.66 (4 2 arom. m-H), 12.13 (OH). Compound 17; NMR (aoetoneh,): 6 4.70 and 4.50 (OMe), j.03 ani 6.56 (d, arom. m-H), 12.10 (OH). Comnound 18; NMR (acetone-d,): 6 4.0 (OMe), 7.08 and 6.55 id, arok. m-H), i 1.64 (dH). The c&pound 18 is different from 14 as shown by the NMR spectrum of the mixture and by TLC in three solvents. Cercospora scirpicola. Identi&ztion of metabolites. A strain of C. scirpicola w&grown as u&l for 3 weeks ; the crude extract was separated by PLC in C,H,-Et,O-formic acid (50 : 50 : 1) as eluent ; 3 main products were obtained : the less polar one was dehydrocurmdarin (lP), mp 224”, identified by MS and NMR spectra. The more polar compound was Il-O-acetyldehydrocuroufarin (XI), mp 105-110”; [alif” - 31.7” (in MeOH, c 0.4); UV &,. (nm): 222, 232sh, 275 and 308 (E 10200, 8800, 5800, 4900); NMR (acetone-d,/DMSG-d,). 6 1.10 (d, Me; J 6Hz), 1 2 2.1 (6 aliphatic protons), 2.09 (AC),3.74 (4, Ar-=,-CO), ” 1 4.94 (m, protons). temp. for obtained O-a-Me), 6.2ti.48 (2 aromatic and 2 vinylic 5 mg of 20 were acetylated with Py and Ac,O at room 12 hr., to give the diacetate (21) identical to the product by acetylation of 19. The third compound was 4,6dihy droxy &ellein 122), white solid, mp 183-18?; (Found: m/e 210.0566 + 0.004. C,,H,,O, requires M. 210.0528). MS m/e. 210, 192, 177, 166, lZ%, l%‘, i21;*UV &,,‘(nm): 223ih, 267 and 302 (E 12600, 10700, 5800); IR v%‘l cm-‘: 1670 (CO), NMR (acetone+Q: S 1.45 (d, M e), 4.56 (H-4), 4.67 (H-3; J,, ., = 2, J s, M c6Hz), 6.33 and 6.49 (d, 2 arom. m-H ; J 2.5 Hz), 11.26 (chel. OH). Cercospora beticola toxin. (CBT) A strain of C. beticola (IPV-F 573), was grown as usual, Mycelia were extracted twice with EtOAc. Extracts were adsorbed on the top of a chromatographic column and eluted with a mixture of CHCl, and MeOH. CBT was obtained with CHCl-MeOH 9: 1. Yellow solid, mp > 3OO”(dec.);[a]:’ + 326”(in MeOH,cO.l6);UV,l_,(nm) 344,435 and 455sh; IR v,, cm-’ : 3450 (broad OH), 1730 (CO), 1610 (conj. CO), 1450; a hydrogenation product (Pd lo”,/, on BaS03 had M+ 640. Acknowledgments-We thank Prof. P. J. Scheuer (University of Hawaii) for a gift of 5,7-dihydroxy-l&naphthaquinone, Prof. F. Piozzi (University of Palermo) for a sample of cynodontin, Prof. P. Salvadori (University of I&a) for Cb measurements,. Prof. V. D’Ambra (University of Padova) and Prof. E. Schlbsser (University of Bonn) for-strains of Cercospora beticola. zyxwvutsrqponmlkjih REFERENCES 1. Chupp, C. (1956) A M onograph of the Genus Cercospora. Ithaca, N.Y. 2. Schl&ser, E. (1971) Phytoparh. M edit. 10, 154; and preccding papers. 3. Kikuchi, R. (1924) The Scientific Researches of the Alumni Association of the Utsunomiy a Agricultural College (Japan), Vol. I, 7-25. 4. Kuyama, S. and Tamura, T. (1957) J. Am. Chem. Sot. 79, 5725; Kuyama, S. (1962) J. Org. Chem. 27,936. 5. Lou&erg, R. J. J. Ch., Weiss, U., Salemink, C. A., Amone, A., Merlini, L. and Nasini, G. (1971) Chem. Commun. 1463. 6. Yamazaki, S. and Ogawa, T. (1972) Agr. Biol. Chem. 36, 1707. 241 Secondary metabolites of zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONML Cercospora 7. Locci, R., Merlini, L., Lou&erg, R. J. J. Ch. and Nasini, G. (1973) Abstracts XXZVZUPAC Congress, Hamburg, p. 222; and unpublished work from these laboratories. 8. Balis, C. and Payne, M. G. (1971) Phytopathol. 61, 1477. 9. Mumma, R. O., Lukezic, F. L. and Kelly, M. G. (1973) Phytochemistry 12,917. 10. Venkataramani, K. (1967) Phyfopathol. Z. 58,379. 11. Fajola, A. 0. (1973) Abstr. 2nd Znt. Congr. Plant Pathol. 0670, Minneapolis. 12. Okubo, A., Yamaraki, S. and Fuwa, K. (1975) Agr. Biol. them. 39 (5), 1173. 13. Yamazaki, S., Okubo, A., Akiyama, Y. and Fuwa, K. (1975) Agr. Biol. Chem. 39,287. 14. Andreetti, G. D. personal communication. 15. Amone, A., Camarda, L., Merlini, L. and Nasini, G. (1975) Gazr. Chim. Ital. 105, 1093. 16. Camarda, L., Merlini, L. and Nasini, G. (1976) Phytochemistry 15, 537. 17. Thomson, R. H. (1971) Naturally Occurring Quinones, p. 504. 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