RESUMO
A phytochemical investigation on the aerial parts of Lindelofia stylosa has resulted in the isolation of seven phenyl propanoids. This includes three analogs of lithospermic acid, along with rosmarinic acid and its ester derivatives. Compound 1 was identified as a new natural product. These compounds were studied for their antioxidant properties.
Assuntos
Antioxidantes/química , Benzofuranos/química , Boraginaceae/química , Compostos Heterocíclicos de 4 ou mais Anéis/química , Antioxidantes/isolamento & purificação , Benzofuranos/isolamento & purificação , Compostos de Bifenilo , Fenômenos Químicos , Físico-Química , Cromatografia Líquida de Alta Pressão , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/isolamento & purificação , Compostos Heterocíclicos de 4 ou mais Anéis/isolamento & purificação , Quelantes de Ferro/química , Espectroscopia de Ressonância Magnética , Picratos/química , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Espectrofotometria Ultravioleta , Superóxidos/químicaRESUMO
Two xanthones, bangangxanthone A (1) [1,5,8-trihydroxy-6'-methyl-6'-(4-methylpent-3-enyl)- pyrano[2',3':3,4]xanthone] and B (2) [1,4,8-trihydroxy-2-prenylxanthone], along with two known xanthones, 1,5-dihydroxyxanthone, 2-hydroxy-1,7-dimethoxyxanthone and the pentacyclic triterpenoids, friedelin, oleanolic acid and lupeol were isolated from the chloroform extract of the stem bark of Garcinia polyantha. The structures of these compounds were assigned by spectroscopic analysis. Compounds 1-4 showed antioxidant DPPH radical scavenging activities.
Assuntos
Sequestradores de Radicais Livres/isolamento & purificação , Garcinia/química , Xantonas/isolamento & purificação , Compostos de Bifenilo/química , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/farmacologia , Hidrazinas/química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Picratos , Casca de Planta/química , Caules de Planta/química , Xantonas/química , Xantonas/farmacologiaRESUMO
Two new prenylated anthronoids, harunmadagascarins A and B, were isolated from the stem bark of Harungana madagascariensis along with six known compounds including two anthronoids: harunganol B and harungin anthrone, one benzophenone: methyl 3-formyl-2,4-dihydroxy-6-methyl benzoate and three pentacyclic triterpenes: friedelin, lupeol and betulinic acid. Harunmadagascarins A and B were characterized as 8,9-dihydroxy-4,4-bis-(3,3-dimethylallyl)-6-methyl-2,3-(2,2-dimethylpyrano)anthrone and 8,9-dihydroxy-4,4,5-tris-(3,3-dimethylallyl)-6-methyl-2,3-(2,2-dimethylpyrano)anthrone, respectively. The structures of these secondary metabolites were determined by spectroscopic means and comparison with the published data. Methyl 3-formyl-2,4-dihydroxy-6-methyl benzoate was isolated for the first time from a plant. Harunmadagascarins A and B, harunganol B and harungin anthrone exhibited significant antioxidant activity.
Assuntos
Antracenos/química , Antioxidantes/química , Clusiaceae/química , Casca de Planta/química , Sequestradores de Radicais Livres/química , Estrutura Molecular , Caules de Planta/químicaRESUMO
Fungal transformation of (E)-guggulsterone (= (17E)-pregna-4,17-diene-3,16-dione; 1) by Rhizopus stolonifer, Fusarium lini, Cunninghamella elegans, or Gibberella fujikuroi afforded ten hydroxylated metabolites (2-11; Scheme), which were fully characterized. Compounds 4-11 have not been described yet. Some of these novel hydroxylated metabolites, as well as acetylated derivatives thereof, exhibited significant antibacterial and radical-scavenging activities (Table 3).
