Three new triterpenes from the resinous bark of Protium kleinii and their antinociceptive activity

Abstract

Três triterpenos pentacíclicos inéditos foram isolados da resina de Protium kleinii. Suas estruturas, 3-oxo-11β,16β-diidróxi-urs-12-eno (1), 3-oxo-11β-hidróxi-urs-12-eno (2) e 3-oxo-11β-hidróxi-olean-12-eno (3), foram elucidadas por espectroscopia de RMN. A administração sistêmica destes compostos (10-100 mg kg -1 , i.p.) foi capaz de inibir tanto a primeira quanto a segunda fase da nocicepção induzida pela formalina em camundongos. Em adição, foram isolados os triterpenos conhecidos 3β,16β-dihidróxi-urs-12-eno (breina) (4) e uma mistura de α (5)-e β-amirina (6).Three novel pentacyclic triterpenes have been isolated from the resin of Protium kleinii and their structures elucidated by NMR spectroscopy as 3-oxo-11β,16β-dihydroxy-urs-12-ene (1), 3-oxo-11β-hydroxy-urs-12-ene (2) and 3-oxo-11β-hydroxy-olean-12-ene (3). The systemic administration of the above compounds (10-100 mg kg -1 , i.p.) was able to inhibited both first and second phase of the formalin-induced nociception in mice. The known triterpenes 3β,16β-dihydroxy-olean-12-ene (brein) (4) and a mixture of α (5)-and β-amyrin (6) were also found.

21β-Hydroxy-oleanane-type triterpenes from Hippocratea excelsa

“…Concerning the orientation of the hydroxyl group at C-11, several 11-hydroxy and methoxy D 12 oleane and ursane type triterpenes have been reported from different plant families, mainly from the Labiatae (De la Torre et al, 1990;Luis and Andrés, 1999;Bruno et al, 1987;Topcu et al, 2003;Taylor, 1967), Burseraceae (Lima et al, 2004;Lima et al, 2005) and Celastraceae (Muhammad et al, 2000;González et al, 1987;Kutney et al, 1992). In most cases, the orientation of the OH group has been proposed to be in the less hindered equatorial 11a-position, based mainly in the large axial-axial J 9,11 values (8-11 Hz).…”

Constituintes químicos e atividade antiedematogênica de Peltodon radicans (Lamiaceae)

“…O esqueleto de triterpenos pentacíclicos do tipo oleonano de 1 foi proposto pela análise dos dados de RMN e comparação com dados da literatura para 3β-OH-β-amirina. 58 O carbono metílico C-28 de 2 foi confirmado pela correlação HMBC do sinal em δ H 5,13 (m, H-18) com o sinal de carbono em δ C 28,1 (C-28). Análises por RMN indicaram o esqueleto de triterpenos pentacíclicos do tipo ursano para 2, estando de acordo com dados descritos na literatura para α-amirina.…”

Salacetal, an Oleanane-type Triterpene from Salacia longipes var. camerunensis

“…In fact, signals at δ C = 120.5 and 152.8 are characteristic of an olean-12-ene triterpenoid skeleton [7]. The NMR data of 1 were similar to those of 3-oxo-11β -hydroxyolean-12-ene (2) [8]. The differences were the disappearance of the 26-methyl and the 11-hydroxy groups in compound 1 and the appearance of a dioxymethine moiety and an additional double bond equivalent.…”

“…The additional double bond equivalent in compound 1 may be derived from the formation of an additional ring between the 11-hydroxy and the 26-CH 3 groups (δ C = 16.2) of compound 2. In fact, couplings were observed in the 1 Studies relative to the orientation of the oxygenated group at C-11 in several 11-hydroxy and -methoxy 12-oleane-and ursane-type triterpenes have been reported from different plant families (Labiatae [9 -13], Burseraceae [14,8] and Celastraceae [15 -17]). In most cases, the hydroxy group was in the less hindered equatorial 11α-position, based on the large axial-axial J 9,11 values (8 -11 Hz) of the coupling constant between H-9 and H-11.…”

“…In most cases, the hydroxy group was in the less hindered equatorial 11α-position, based on the large axial-axial J 9,11 values (8 -11 Hz) of the coupling constant between H-9 and H-11. Two 11β -hydroxy-oleane-type triterpenes, 3-oxo-11β -hydroxy-olean-12-ene (2) [8] and 11β ,21β -dihydroxy-olean-12-en-3-one [18], have also been reported. With respect to the B and C rings with the trans junction and chair conformation in oleanane triterpenes [19 -20], the value of the coupling constant (J 11 , 9 = 4.5 Hz) observed between H-11 and H-9 clearly indicated that the oxygen at C-11 is in the axial position (β -oriented) in compound 1 (Fig.…”