Iridoids from Hymenodictyon floribundum

Abstract

Das cascas do tronco e das folhas do Hymenodictyon floribundum B. L. Rob foram isolados dois novos iridoides, floribundano A (1) e floribundano B (2), e três compostos conhecidos, lupenona (3), escopoletina (4) e 4,5-di-hidroblumenol A (5). As estruturas de todos os compostos foram estabelecidas com base nos seus dados espectroscópicos.Two new iridoids floribundane A (1) and floribundane B (2) and the known compounds lupenone (3), scopoletin (4) and 4,5-dihydroblumenol A (5) were isolated from trunk bark and leaves of Hymenodictyon floribundum B.L. Rob. The structures of all compounds were established from their spectroscopic data. Keywords: Hymenodictyon floribundum, monoterpenes, secoiridoids, nitrogen-containing iridoid, C-9 iridoid IntroductionThe Hymenodictyon genus comprises 22 species. Of these, 11 are endemic to Madagascar, 4 to Asia and 7 to Tropical Africa. 1 Hymenodictyon floribundum B.L. Rob. (Rubiaceae), endemic to Tropical Africa, is a small tree that grows in the mountains of the Huíla province and its traditional name is NDambi Yov`olwi, (omu)Lia-tyimeme. Its trunk bark is used in Angola folk medicine to treat fever. 2 A previous study has shown that the trunk bark of this tree contains scopoletin, hymeselsin, scopolin and 3-O-β-D-glucopyranosyl-β-sitosterol. 3 An exhaustive literature review revealed that, with the exception of an ongoing study examining the trunk bark and dried leaves of Hymendictyon floribundum (in the context of other medicinal plants of Angola), 4 other parts of the tree have not yet to be studied.In the aforementioned study, powdered trunk barks and dried leaves were extracted by maceration with methanol. The methanol extract was partitioned with hexane and chloroform. The hexane extract from trunk barks yielded lupenone (3) 5 and the chloroform extract yielded scopoletin (4). 6 The chloroform extract from dried leaves yielded floribundane A (1), 4,5-dihydroblumenol A (5) 7,8 and floribundane B (2). Results and DiscussionFloribundane A (1) was obtained as a colourless oil with [α] 2 D 0 = +25.31º. The HR-TOF-EI-MS showed a molecular ion peak at m/z 223.0843 [M] + (in agreement with the molecular formula C 11 H 13 NO 4 ) implying 6 degrees of unsaturation. The UV maximum at 234 nm and the IR absorptions at 1724, 1633 and 1268 cm -1 suggested the presence of the chromophore -OOCC=CHO. 9 The IR also showed the presence of a lactam ring: NH band (3403 cm -1 ), and the amide band I (1690 cm -1 ) with an absence of the amide II band. 10 The 1 H NMR spectrum of compound (1) ( 16 and rat intestinal bacteria. 17 Comparison with the published data of known iridoid alkaloids, such as (6) (Figure 1), and hemiacetal-secoiridoids 11,18 like (7) ( Figure 1) and compound (1) 11,18 showed that (1) it was neither a hemiacetal nor a nitrogen-containing iridoid (N-2) but that it was compatible with a C-1(N)O-2 substitution. This was also supported by the presence of the 1 H-1 H COSY correlation between H-1/NH, rather than the H-1/NH, H-3/NH correlations expected in the iridoid alkaloids, 17 ...

Naturally Occurring Iridoids and Secoiridoids. An Updated Review, Part 4

“…Valeriana jatamansi (Valerianaceae) 53) 119. Jatamanvaltrate 12.6, 6.6, H-6), 2.08 (dd, 12.6, 10.2, H-6), 4.83 (dd, 10.2, 6.6, H-7), 2.88 (d, 2.4, H-9), 4.28 (d, 12.6, H-10 57) 126. ; structure confirmed by X-ray study. Triosteum himalayanum (Caprifoliaceae), 58) T. pinnatifidum 59) 127.…”

Four New Iridoid Metabolites Have Been Isolated from the Stems of Neonauclea reticulata (Havil.) Merr. with Anti-Inflammatory Activities on LPS-Induced RAW264.7 Cells

“…Twenty compounds were isolated from the EtOAc fraction by silica gel column chromatography and normal-phase, semi-preparative, high-performance liquid chromatography (HPLC). Among these compounds, we isolated one new iridoid, which namely neonanin C ( 1 ) (neonanin A and B have been reported in our previous study [9]), one monocyclic iridoid ring-opened derivative namely neonanin D ( 2 ), two new bis-iridoid derivatives namely reticunin A ( 3 ), reticunin B ( 4 ) and sixteen known compounds, including strychnovoline ( 5 ) [15], siphonostegiol ( 6 ) [16], isoboonein ( 7 ) [17], floribundane B ( 8 ) [18], alyxialactone ( 9 ) [19], syringaresinol ( 10 ) [20], (+)-pinoresinol ( 11 ), (+)-medioresinol ( 12 ) [21], 4-methoxycatechol ( 13 ) [22], protocatechuic acid ( 14 ) [23], trans -caffeic acid ( 15 ) [24], syringic acid ( 16 ) [25], 3-hydroxy-1-(4-hydroxy 3,5-dimethoxyphenyl)-1-propanone ( 17 ) [26], ferulic acid ( 18 ) [27], protocatechuic acid methyl ester ( 19 ) [28], C-veratroylglycol ( 20 ) [29]. The structures of the new compounds were determined through spectral analyses, including IR, UV, 1D- and two-dimensional (2D)-NMR, as well as HR-ESI-MS data.…”

Molluscicidal Activity of Compounds Isolated from Euphorbia conspicua N. E. Br

“…Natural molluscicidal compounds isolated from a large number of plants have received much attention in hope that they might provide cheap, biodegradable and effective control agents in rural areas where schistosomiasis is endemic. 8,9 As part of our ongoing study of the plants of Angola, 2,10,11 we observed that Euphorbia conspicua latex exhibits strong molluscicidal activity 2 and may be a potential source of bioactive compounds. This work intended to isolate and describe the constituents of the active fractions and to evaluate their effects.…”