Flavonoides e terpenoides de Croton muscicarpa (Euphorbiaceae)

Abstract

Recebido em 17/8/12; aceito em 26/11/12; publicado na web em 6/3/13 FLAVONOIDS AND TERPENOIDS FROM Croton muscicarpa (Euphorbiaceae). A new sesquiterpene and twelve known compounds comprising eight flavonoids and four terpenoids, were isolated from the leaves, stems, roots and exudate of Croton muscicarpa Müll. Arg.. Their structures were identified as the terpenoids 6α-methoxy-cyperene, dammaradienol, squalene, acetyl aleuritolic acid and spathulenol, and as the flavonoids retusin, 3,7,4'-trimethoxy kaempferol, ombuine, pachipodol, kaempferol, casticin, 5-hydroxy-3,6,7,4'-tetramethoxyflavone and artemetin. All isolated compounds were characterized based on IR, MS, 1 H and 13 C NMR, including 2D analyses (COSY, HSQC, HMBC, NOESY) and comparison with data from the literature.

Chemical composition, antioxidant and topical anti-inflammatory activities of Croton cordiifolius Baill. (Euphorbiaceae)

“…The presence of triterpenes and steroids in C. cordiifolius agrees with the findings for C. muscicarpa leaves, stem, and roots, from which were isolated 6α-methoxy-cyperene, dammaradienol, squalene, acetyl aleuritolic acid and spathulenol (Barreto et al, 2013); C. regelianus leaves and stem, from which were found the bisnorditerpene rel-(5b,8a,10a)-8-hydroxy-13-methylpodocarpa-9(11),13-diene-3,12-dione and the guaiane sesquiterpene rel-(1R,4S,6R,7S,8aR)-decahydro-1-(hydroxymethyl)-4,9,9-trimethyl-4,7-(epoxymethano)azulen-6-ol (Torres et al, 2010); and C. sellowii leaves and stem, from which were isolated sitosterol, stigmasterol, cycloart-25-ene-3β,24β-diol, cycloart-25-ene-3β,24α-diol and betulonic acid (PalmeiraJúnior et al, 2006).…”

Reassignments and Corroborations of Oxo‐Bridged Natural Products Directed by OSE and DU8+ NMR Computation

“…[31] This idea would be in line with the reported structure for hugonianene B(31) [32] (i.e., same skeleton), but compounds matching the experimental SSCC of 29 proved difficult to identify.M any variations on structure were explored, albeit with no success.T hese included alternative ring systems,f or example,t he oxidation product (33)o f gurjunene (32), [33] aw ell known ring system that shares the gem-dimethyl group and seven-membered ring in common with hugonianene A. [34] Thus,on comparison with the reported NMR spectra, hugonianene A (29)i sr evised to 34.H owever,o nc omparison of the optical rotation data provided for 29 ( a ½ 20 D ¼À158 8)w ith that of 34, isolated from Croton muscicarpa ( a ½ 20 D ¼ + 248 8), [34] the absolute stereochemistry of 34 is assigned as the opposite enantiomer (i.e., as shown in Figure 4). Given that an umber of carbon signals reported for 29 did not support multiple oxygenation (i.e., insufficient number of downfield resonances), the molecular formula was revised to C 16 H 26 O( ad ecrease from two oxygens to one).…”

“…An additional search of the literature revealed that this compound was known. [34] Thus,on comparison with the reported NMR spectra, hugonianene A (29)i sr evised to 34.H owever,o nc omparison of the optical rotation data provided for 29 ( a ½ 20 D ¼À158 8)w ith that of 34, isolated from Croton muscicarpa ( a ½ 20 D ¼ + 248 8), [34] the absolute stereochemistry of 34 is assigned as the opposite enantiomer (i.e., as shown in Figure 4). Furthermore,h ugonianene B( 31)i st hen tentatively reassigned as 35 based on the comparison of experimental and calculated NMR data (see the Supporting Information and Figure 4).…”

Phytosterols isolated from endophytic fungus Colletotrichum gloeosporioides(Melanconiaceae)

“…In the 13 C NMR spectrum showed six signs related to olefinic carbons (δ C 135.1; 134.9; 131.2; 124.4; 124.3; 124.2) signals for six methylene carbons (δ C 39.7 2x ; 29.7; 28.3; 26.7 and 26.6) and four signals related to methyl carbons (δ C 25.7; 17.7; 16.0; 15.9). A comparison of the NMR data of the compound 4 with the literature enabled us to identify as squalene (Barreto et al 2013). …”