Prenylindole alkaloids from Raputia praetermissa (Rutaceae) and their chemosystematic significance

Abstract

O extrato diclorometano do caule de Raputia praetermissa levou ao isolamento de quatro compostos novos, 4-desóxi-raputindol C (1), raputimonoindol A-B (2, 3) e hexadecanil 2-hidróxi-4-metóxi-cinnamato (5), juntamente com os alcalóides 5-(4-metóxi-metilfuran-2-il)-1H-indol (raputimonoindol C), furoquinolinos maculosidine, robustine, evolitrine e dictamnine. O estudo do extrato hexano levou ao isolamento de N-metil-4-metóxi-quinolin-2(1H)-ona, skimmianina, cicloartenona, sitosterol, stigmasterol e sitostenona. Os alcalóides antranílicos isolados indicam que o gênero possui afinidade química relevante com aqueles da tribo Cusparieae, mas difere de Neoraputia devido à ausência de alcalóides prenilindois neste último, cujas espécies foram anteriormente incluídas em Raputia.The dichloromethane extract from the stems of Raputia praetermissa afforded four new compounds, 4-deoxyraputindole C (1), raputimonoindole A-B (2, 3), and hexadecanyl 2-hydroxy-4-methoxy-cinnamate (5), besides the alkaloids 5-(4-methoxymethylfuran-2-yl)-1H-indole (raputimonoindole C), furoquinolines maculosidine, robustine, evolitrine and dictamnine. The hexane extract yielded N-methyl-4-methoxyquinolin-2(1H)-one, skimmianine, cycloartenone, sitosterol, stigmasterol and sitostenone. The anthranilate alkaloid content indicates that the genus is strongly related to those included in Cusparieae tribe, but differs from Neoraputia by the absence of prenylindole alkaloids in the late, whose species have previously been placed in Raputia. Previous investigations of Neoraputia reported the presence of eleven polymethoxylated flavonoids, six flavones, three 5,6-(2",2"-dimethylpyrano)flavones, one 6,7-(2",2"-dimethylpyrano)flavone and one flavanone from N. alba (Engler) Emmerich; 6,7 five polymethoxylated flavones and two flavanones, 2'-hydroxy-3,4,4',5,6'-pentamethoxychalcone, three 5',6'-(2",2"-dimethylpyrano)-polymethoxylated chalcones from N. magnifica var. magnifica (Engler) Emmerich; 8,9 ten polymethoxylated flavonoids, six flavones, three 6,7-(2",2"-dimethylpyrano) flavones and one 6-(3"-hydroxy,3"-methyl-trans-but-1"-enyl)flavone from N. paraensis. Keywords10,11 A reinvestigation of N. paraensis searching for alkaloids afforded flindersine, skimmianine, 8-methoxyflindersine and dictamnine.12 Rosas et al. 1347 Vol. 22, No. 7, 2011 C-glycosylflavones were also reported from N. paraensis, 13 which was cited as Raputia paraensis, but this species was transferred to Neoraputia by Emmerich. 1The first investigation about the chemistry of Raputia reported the presence of cyclopentyl bisindole alkaloids raputiindoles A-D from R. simulans Kllunki. 14 In this paper we report a phytochemical study on R. praetermissa Pirani & Kallunki, and the chemosystematic significance of isolated compounds is discussed in order to clarify the relationships between Raputia and Neoraputia. Results and DiscussionThe dichloromethane extract from the stems of Raputia praetermissa afforded four prenylindole alkaloids (1-4), a cinnamic acid derivative (5) (Figure 1 -5b), a...

Synthesis of Raputimonoindoles A–C and Congeners

“…Now, the ethyl allyl ether side product could be removed by flash chromatography on RP‐18 silica gel. The optical rotatory power of ent ‐raputimonoindole A ( ent ‐ 3 , [ α ] D 20 = +38.7, c = 0.52, MeOH) was found to be opposite to that of the natural product 3 ([ α ] D 25 = –41, c = 0.003, CHCl 3 ) …”

“…The biosynthesis of the raputindoles probably involves oxidative homo and heterodimerization of 5‐, 6‐, and 7‐prenylindole, as supported by the occurrence of 5‐ and 7‐prenylindole in the same species . The 5‐prenyl side chain can also be oxygenated and cyclized to form furan systems, as in the raputimonoindoles A–C and congeners from R. simulans and R. praetermissa , . Raputimonoindole A ( 3 ) exhibits an additional prenyl side chain installed at the furan‐derived moiety.…”

“…Raputindoles A–D were isolated from the stem bark and roots of the neotropical tree Raputia simulans Kallunki (Rutaceae) collected in Peru . The currently most significant biological activity of any of the Raputia indole alkaloids concerns cell cycle arrest induced by deoxyraputindole C ( 2 ) from R. praetermissa , which binds to cathepsin L (IC 50 1.7 µ m ) . The biosynthesis of the raputindoles probably involves oxidative homo and heterodimerization of 5‐, 6‐, and 7‐prenylindole, as supported by the occurrence of 5‐ and 7‐prenylindole in the same species .…”

Protective Effect of Pitao (Pitavia punctata (R. & P.) Molina) Polyphenols against the Red Blood Cells Lipoperoxidation and the In Vitro LDL Oxidation

“…In addition different furoquinoline alkaloids have also been isolated from other members of the Rutaceae family. Thus, Rosas et al, 2011 [ 25 ], reported the presence of the furoquinolines maculosidine, robustine, and evolitrine among others, from the Raputia praetermissa species. Also, from the Zanthoxylum buesgenii species, three known furoquinolines have been reported: maculine, kokusaginine, and teclearverdoornine [ 26 ].…”

Total Synthesis of (+)-Raputindole A: An Iridium-Catalyzed Cyclization Approach

“… 1 Deoxiraputindole C ( 5 ) is another member of this family, which was isolated in 2011 from Raputia praetermissa , collected in the Brazilian Amazon forest. 2 Structurally, this is a rare new class of indole alkaloid as it features unsubstituted N-1, C-2, and C-3 positions. 1 Other natural products containing the 1,2,3-unsubstituted pattern are trikentrin A 3 and the alkaloids from the herbindole family.…”