Anti-inflammatory, antimicrobial and acetylcholinesterase inhibitory activities of friedelanes from Maytenus robusta branches and isolation of further triterpenoids

摘要

Graphical abstractDisplay OmittedHighlights?Branches ofMaytenus robustawere investigated.?Three new pentacyclic triterpenoids (1–3) were isolated.?Their structures were established by spectroscopic data.?Anti-inflammatory, antimicrobial and acetylcholinesterase inhibitory activities were evaluated for triterpenoids fromMaytenus robusta.?Triterpenes5–8exhibited significantin vivoanti-inflammatory activity.The new pentacyclic triterpenoids friedel-1-en-3,16-dione (1), 1α,29-dihydroxyfriedelan-3-one (2) and 16β,28,29-trihydroxyfriedelan-3-one (3) were isolated fromMaytenus robustabranches in addition to the known, but new for this species, triterpenoid 12α,29-dihydroxyfriedelan-3-one (4). The structures and stereochemistry of the novel triterpenoids were established by IR, 1D/2D NMR and HR-APCIMS spectral data. In addition, the biological activity of compound2and the previously isolated friedelanes5–8(friedelan-3,16-dione, 29-hydroxyfriedelan-3-one, 29-hydroxyfriedelan-3,16-dione and 16β,29-dihydroxyfriedelan-3-one) was investigated. Compounds2and8were tested for their acetylcholinesterase properties and antimicrobial activity against the bacteriaStaphylococcus aureus,Pseudomonas aeruginosa,Listeria monocytogenes,Citrobacter freundii, and the fungusCandida albicans. Compound2was the most active compound for both assays, with values of 32.3% acetylcholinesterase inhibition, 42% activity against the fungusCandida albicansand 34% against the bacteriumPseudomonas aeruginosa. Compounds5–8were assayed for their antiedematogenic activity using the carrageenan-induced paw edema assay. At maximum inflammation after three hours, compounds6and8showed 42% and 57% activity, respectively. After four hours, compounds5and7showed activity of 71% and 75% compared to 79% of the control indomethacin.