Constituents of Parabaena sagittata. Two New Tetrahydroprotoberberine Alkaloids

Abstract

The plant is a climber indigenous to northern Thailand and has been used by the hill tribes for medicinal purposes. Three of the components are known natural products: the cyclohexanepentol, (+ )-protoquercitol (1); the tetrahydroprotoberberine, (-)-tetrahydropalmatine (4); and the protoberberine, berberíne. The other two components are previously unreported tetrahydroprotoberberines and have been given the names (-)-0-methylthaicanine ( 2) and ( -)-thaicanine (3)• Their structures were assigned after detailed analysis of their 'Hand 13C-nmr spectra. Methylation of 3 was shown to yield 2; 2 and 3 are the first reported examples of protoberberines with substituents at the 4-position.Parabaena sagittata Miers (Menispermaceae) is a lofty climber indigenous to the northern part of Thailand and has been used by the hill tribes of this region for medicinal purposes (2). A decoction of stems and leaves affords a treatment for jaundice, indigestion, and painful intestinal disturbances. All parts of the plant may be used as a febrifuge and tonic. There have been no previous reports of any phytochemical or pharmacological studies on this species, but a recent tic screening of P. sagittata Mooney suggested the presence of magnoflorine in the petiole (3). In this report, we describe the structural elucidation of five components isolated from the leaves of P. sagittata Miers. Two of these components are alkaloids not previously reported.The colorless crystalline solid, 1, was isolated as described in the Experimental section and was found to be the cyclohexanepentol (+ )-protoquercitol (1) on the basis of the data reported below. Our 400 MHz 'H-nmr spectrum of this cyclitol was essentially the same as that previously reported at 220 MHz (4). The 13C-nmr spectrum of 1 was reported recently ( 5), but two of the six carbon resonances could not be assigned unambiguously. We have found that 1H-13C shift-correlated 2-D nmr spectroscopy (6,7)showed clearly that the multiplet at 3.59 ppm assigned to -1 (4) was associated with the 13C resonance at 68.9 ppm and that the doublet of doublets at 3.85 for H-5 was attached to the carbon resonating at 68.6. Thus, we have been able to assign all six resonances, and these are reported in the Experimental section. The isolation of ( + )-protoquercitol from the family Menispermaceae has been reported previously (8,9)•

Cytotoxic and Antimalarial Alkaloids from the Tubers of Stephania pierrei

“…For paper XXII, see Likhitwitayawuid et al (1). [1} (7,8), (-)-asimilobine-2-0^-D-glucoside [2}, (-)-anonaine [3} ( 9), (-)-isolaureline [4} (10), (-)-xylopine [5} (10), (-)-roemeroline [6} (11), (-)-dicentrine [7} (12)(13)(14), ( -)-nordicentrine [8}, ( -)-phanostenine [9} (15), cassythicine [10} (14,16), and magnoflorine [11} (17)(18)(19)(20); (b) the tetrahydroprotoberberines (-)-tetrahydropalmatine {12} (21-23), (-)-capaurine [13} (24-27), ( -)-thaicanine [14} (23), (-)-corydalmine [15} (25,26), ( -)-N-methyltetrahydropalmatine [16} (28), (-)-xylopinine [17} (22), and (-)-tetrahydrostephabine [18} (29); (c) the tetrahydrobenzylisoquinolines (+)reticuline [19} (30,31), (+)-codamine [20} (32,33), and (±)-oblongine [21} (34,35); (d) the hasubanan ( -)-delavaine [22} (36) and the morphinan (-)-salutaridine [23} (37,38). Compounds 2 and 8 are hitherto unknown alkaloids.…”

Tilitriandrin, ein neues Bisbenzylisochinolin-Alkaloid ausTiliacora triandra

“…Eight of them are known and identified as: heyneanine (1), ibogamine (2), coronaridine (3), voacanginge (4), voacanginge hydroxyindolenine (5), ibogaine (6), (+)-minovincinine (7), and voachalotin (8) (3) while the last one is a new compound, for which we propose the name ervayunine (9). The JR spectrum of ervayunine (9), m.p.…”

“…Bereits beim Einengen des Methanol-Extrakts von Tiliacora triandra flelen aus 2 kg Droge Ca. 4,5 g kristallines (+)-Protoquercitol (4) an, das auf Grund seiner physikalischen Daten, den Massen-und NMR-Spektren im Vergleich zu Literaturangaben (7,8) eindeutig identifiziert werden konnten.…”

Untitled

“…21 It belongs to the rare group of 2,3,4-trisubstituted tetrahydroprotoberberines; so far only three alkaloids of this type, including 4, have been identified. [21][22] The 13 C NMR data of 4 were obtained for first time in this study by interpretation of the HMQC and HMBC correlations.…”