Contribuição ao estudo químico de plantas do Nordeste do Brasil: Cordia trichotoma Vell. e Cordia globosa Jack. (Kunth.)

Abstract

This work describes the phytochemical investigation of Cordia trichotoma Veil, and Cordia globosa (Jack.) Kunth. (Boraginaceae), popularly known in the Brazilian northeastern as "frei-jorge" and "moleque-duro", respectively. The essential oils of the two species were obtained by hydrodistillation and analyzed by GC-MS and GC-FID. A total of sixteen volatile components were identified in the oils of heartwood and sapwood of C. trichotoma. The sesquiterpenes were the predominant constituents in both oil samples. 8-Cadinene (11.9 and 9.7%), a-muurolol (25.1 and 13.4%) and guaia-3,10(14)-dien-11-ol (10.7 and 9.6%) were the main compounds. The leaf essential oils of C. globosa in two different ontogenetic stages (flowering and fructification) were also investigated and, a total of thirty-two terpenoids were identified. In both oils the main compounds were bicyclogermacrene (22.7 - 13.1%), 13- caryophyllene (11.9 - 11.6%) and 6-elemene (9.0 - 6.8%). The chemical studies of ethanol extracts from heartwood and sapwood of C. trichotoma resulted in the isolation and characterization of several compounds such as steroids, triterpenos, flavonoids, phenilpropanoids, sesquiterpenes and meroterpenoid benzoquinones with C16 skeleton. The isolated compounds were characterized as: a-cadinol, trichotomol, (+)-113,413,6atrihydroxyeudesmane, 1 f3,413,7a-trihydroxyeudesmane, 1 f3,4 f3,11-trihydroxy-oppositane, rel- 8a,11a-9a,11a-diepoxy-1,4-dihydroxy-2-metoxy-80-methy1-5,6,8,8a,9,10,10a-octahidroanthracen-10-one, oncocalyxone A, glaziovianol, oleanolic acid, oleanolyl acetate, the mixture of f3-sitosterol e stigmasterol and 3-(2',4',5'-trimethoxypheny1)-propionic acid. While the chemical investigation of extracts from flowers of C. trichotoma afforded the isolation and characterization of the 13-sitosterol and stigmasterol mixture, 4-hydroxy-benzoic acid, tiliroside, f3-sitosterol glucoside, alantoin and mannitol. The chemical studies of the hexane and ethanol extracts from roots of C. globosa lead to the isolation of steroids, triterpenes and quinones. The isolated secondary metabolites were P-sitosterol and stigmasterol mixture, oleanolic acid, oleanolyl acetate, microphyllaquinone, (1 aS*,lbS*,7aS*,8aS*)-4,5-dimethoxy-la,7a-dimethy1-1,1a,lb,2,7,7a,8,8ao ctahydro cyc lopro p a [3 ,4] cyc lop enta [1,2-b] naphtalene-3 ,6-d ione, f3-s ito sterol glucoside, sacarose and a mixture of cromenes. The compound ( 1 aS*, 1 bS*, 7aS*, 8aS*)-4, 5-dimethoxy- 1 a, 7a-dimethyl- 1 , la, 1 b,2,7, 7a, 8 , 8 a-o ctahydro cyclopropa [3 ,4] cyc lo penta [ 1 ,2-b]naphtalene-3 , 6- dione showed on TLC acetylcholinesterase inhibitory effect and potent cytotoxic activity. The oil of C. globosa in flowering stage showed larvicidal and antimicrobial activities. The molecular structures of compounds were established by IR, MS, 1D NMR 13C and DEPT) and 2D NMR (COSY, HMQC, HMBC, NOESY) and by comparison with published data.