Avaliação química e atividade antioxidante das cascas e triterpenóides obtidos de Cariniana domestica (Mart) Miers

Abstract

The Lecythidaceae family consists of about 230 species, classified in some 10 genera. The species Cariniana domestica (Mart) Miers is one of several Jequitibá species, the oldest and millenary trees from Brazil. The present work developed studies with the aim of characterize the species when concerning to chemical aspects, in order to contribute to the knowledge improvement about Lecythidadeae family. The barks of C. domestica were collected in Tangará da Serra-MS. Exsiccate was archived as voucher specimen in the herbarium of Department of Biology at UFSM (SMDB 11818). Plant material was dried, crushed and powdered. The powder was submitted to hidroalcoolic maceration (7:3, v/v) and concentrated under reduced pressure. The remained aqueous extract was partitioned to obtain the fractions FCH2Cl2, F-AcOEt e F-BuOH. Chromatographic procedures led to the isolation of phytosterols (β-sitosterol + stigmasterol) and pentacyclic triterpenes (lupeol + β- amyrin), which were identified by means of spectroscopic (1H-NMR and 13C-NMR) and chromatographic (GC/MS and HPLC) methods. Additionally, the antioxidant capacity was evaluated by measuring its scavenging ability on DPPH and also using TBARS assay. Contents of total polyphenolic and flavonoid were measured as well as a chromatographic profile searching for phenolic substances was determined.. From F-CH2Cl2, DPPH assay revealed high scavenging ability with IC50 values that ranged from 6.5 ± 0.81 to 19.5 ± 1.32 μg/mL. IC50 values obtained with TBARS assay ranged from 11.11 ± 0.85 to 44.5 ± 2.31 μg/mL. Polyphenolic contents varied from 54.6 ± 0.33 to 309.3 ± 2.73 mg/g. Total flavonoid and condensed tannin contents varied from 12.0 ± 0.12 to 14.18 ± 0.1 and 131 ± 0.03 to 149.7 ± 0.22, respectively. HPLC analysis revealed the presence of gallic, caffeic and chlorogenic acids, as well as the flavonoids rutin, quercetin and kaempferol. The carotenoids lycopene and β- carotene were identified in dichloromethane fraction. The results revealed that the species C. domestica achieves antioxidant properties and the compounds identified for the first time for this species can be related to its popular uses.