RESUMEN
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.
Asunto(s)
Antracenos/química , Antioxidantes/química , Clusiaceae/química , Corteza de la Planta/química , Depuradores de Radicales Libres/química , Estructura Molecular , Tallos de la Planta/químicaRESUMEN
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.
Asunto(s)
Depuradores de Radicales Libres/aislamiento & purificación , Garcinia/química , Xantonas/aislamiento & purificación , Compuestos de Bifenilo/química , Depuradores de Radicales Libres/química , Depuradores de Radicales Libres/farmacología , Hidrazinas/química , Espectroscopía de Resonancia Magnética , Estructura Molecular , Picratos , Corteza de la Planta/química , Tallos de la Planta/química , Xantonas/química , Xantonas/farmacologíaRESUMEN
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).
Asunto(s)
Antibacterianos/química , Antibacterianos/farmacología , Depuradores de Radicales Libres/química , Depuradores de Radicales Libres/farmacología , Hongos/metabolismo , Pregnenodionas/química , Antibacterianos/metabolismo , Bacterias/efectos de los fármacos , Depuradores de Radicales Libres/metabolismo , Estructura Molecular , Pregnenodionas/metabolismoRESUMEN
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.