SummaryThe biosynthesis of the benzo [clphenanthridine alkaloids was investigated in a cell suspension culture of Macleaya cordata (papaveraceae). Feeding experiments define the biosynthetic pathway (-)-7,8,13,13 a-tetrahydrocoptisine -+ (-)-cis-Nmethyl-7,8,13,13a-tetrahydrocoptisinium salt 15 + protopine (5) -+ sanguinarine (1) -+ chelirubine (3)+ macarpine (4).Sanguinarine (1) and chelerythrine (2) belong to the benzo [clphenanthridine alkaloids class [I]. These alkaloids occur widely in papaveraceous plants [2]. They have four oxygen functions at the positions 2, 3, 7 and 8. Besides 1 and 2, the alkaloids chelirubine (3), chelirutine, sanguirubine and sanguirutine bearing five oxygen functions at C(2), C(3), C(7), C(8) and C(10) have been isolated from several plants [3]. Macarpine (4) bearing six oxygen functions at C(2), C(3), C(7), C (8), C (10) and C (12) has been also found [4].Although biosynthetic studies on 0,-type alkaloids (sanguinarine and chelerythrine) have been described [5] [6], the biosynthetic route of the 05-and 0,-type alkaloids has been unexplored, presumably due to their poor existence in plants. We now report a biosynthetic investigation on chelirubine (3) and macarpine (4) by using the callus tissues of Macleaya cordata (papaveraceae). Moreover, the opportunity has been taken to investigate in detail the pathway of sanguinarine (1) and chelerythrine (2). A related experiment with the intact plants of Macleaya cordata is also described.The callus tissues of M . cordata were derived from the stem and the root tissue, respectively. Each callus grew to form a mixture of the white and the red-orange colored colonies. The white-type and the red-orange-type colonies were selected visually, and two types of the colonies were subcultured under the same conditions. After subculturing for one year, the alkaloidal fraction of each callus tissue was examined. The alkaloidal components found in our callus tissues always involved the same four alkaloids, sanguinarine (I), chelirubine (3), macarpine (4) and protopine (S), which were also found in the intact plants [7]. Berberine (6), chelerythrine (2) and allocryptopine (7) were not detected in our callus tissues. These results are different from those reported by Neumann et al. [8] or by Furuya et al. 191.

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New sulfur-containing alkaloids, 1 and 2 , were isolated from the bark of Cassipourtz guianensis and identified as l-methyl-2-(4'-hydroxy-1',2'-dithiolan-l'-oxo-3'-yl)-5-(4'-hydroxy-l", 2"-dithiolan-3"-yl)pyrrolidine and l-methyl-2,5-bis-~4'(4")-hydroxy-1 '( l"), 2 '( 2")-dithiolan-1 '( 1")-oxo-3 '( 3")-yl)pyrrolidine, respectively.The sulfur-containing pyrrolidine alkaloid, gerrardine (3), from the bark of Cassipoureu gewardii and Cassipoureu guianensis Aubl. (Rhizophoraceae) has already been reported in previous papers (1-3). In the present paper, the isolation and structural elucidation of two new minor alkaloids (1 and 2) from C. guianensis is described. Evidence for the structures was obtained by spectral studies and comparison with derivatives from an authentic sample of gerrardine (3). RESULTS AND DISCUSSIONThe dried bark of C. guianensis (2 kg) was extracted with petroleum ether and 80% MeOH. The concentrate from 80% MeOH was extracted with 2% aqueous citric acid and partitioned with C6H6. The aqueous extract was basified with 10% Na,C03 and extracted with CHCI,; the CHCI, extract was dried over anhydrous Na,S04, and the solvent was removed to give the crude alkaloids (4.5 g). First, a major component, gerrardine (3), in the crude alkaloidal extract was separated by chromatography on a silica gel column with C6H6-Et20-CHC1,-MeOH (10: 10:3:3). On further treatment with a second eluant, Me,O-EtOAc (1: l), the column furnished compound 1, which was crystallized from CHC1,-MeOH as colorless crystals. Continued elution with the same solvent system yielded compound 2 which was crystallized from CHCI3-MeOH as white needles.In order to elucidate the structures of both compounds, 1 and 2, a comparative study of spectral data among 1, 2, and a known compound, gerrardine (3), was carried out as follows. The molecular formulas C , ,H 1S03NS4 and C, ,H 1904NS4 were advanced for 1 and 2, respectively, on the basis of fdms. Their fdms gave (M+ +H) signals at m/z 342 and 358 whichareinaccordancewitheachformula(CllH1903NS4+H, C , ,H190,NS4+H) corresponding to mono-and di-oxidation products of gerrardine (C, ,H 1902NS4). It is assumed that 1 and 2 are biogenetically related to gerrardine (3) by differences in their oxidation levels. ' In their fdms, both 1 and 2 exhibited significant strong peaks at m/z 220, which are probably due to the l-methyl-5-(4-hydroxy-1,2-dithiolan-1-oxo-3-yl)dehydropyrrolidium cation (C,H *4N02S2) + formed from the cleavage shown in Figure 1. The ir spectra of 1 and 2 showed the presence of both hydroxyl groups C u max (KBr) 3400-3450 cm-'1 and sulfoxide groups (1035, 1045, 1050 cm-'), respectively. The uv spectrum of 1 showed absorptions characteristic of 1,2-dithiolane {A max (MeOH) 330 nm, log E 2.171 (4) and 1,2-dithiolan-oxide [A max (CHCI,) 247 nm, log E 3.573 (5,6), while the uv of 2 revealed only the absorption 'The possibility that the alkaloids 1 and 2 are artifacts of the isolation process was excluded by an experiment in which 0, was bubbled into a solution of 3 mg ofgerrardine (3) in ...

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