2007 - Flávia Oliveira Resende
MSc. Thesis
Author: Flávia Oliveira Resende
Postgraduate Program in Pharmaceutical Sciences - State University of Maringá
Area of Knowledge: Pharmacognosy
Date of Defense: April 03, 2007
Advisor: Prof. Dr. João Carlos Palazzo de Mello
Examination Board: Prof. Dr. Diógenes Aparício Garcia Cortez
Prof. Dr. Wagner Luiz Ramos Barbosa
Title: Trichilia catigua: pharmacognostic, phytochemical, and biological evaluation in vitro
Abstract: Trichilia catigua A. Juss. (Meliaceae), popularly known as “catuaba”, is a plant native from South and Central America and widely distributed in Brazil. Its barks are mainly used as stimulants, and they have a high concentration of tannins. An ethyl-acetate (FAE) and an aqueous (FA) fraction were obtained from the crude extract (EB) of the “catuaba” bark. The aim of this study was to evaluate the chemical composition and the antioxidant activity of the crude extract and fractions and to establish standards for quality control of the barks. The quality control was carried out based on pharmacopeia tests, granulometric analysis, loss on drying (PD), determination of extractives (TE), total polyphenolics content (PT) and total tannins content (TT). The results found for the drug were mean diameter=0.56 mm, PD=9.93%±0.14 (CV%=1.46), TE=19.16%±0.78 (CV%=4.10), PT=10.51±0.17 (CV%=1.62) and TT=6.95±0.11 (CV%=1.57). Besides, the tannins content was also evaluated in EB, FAE and FA, giving values of 38.89±1.14 (CV%=2.93); 69.36±0.49 (CV%=0.70) and 33.80%±0.30 (CV%=0.89), respectively. FAE was fractionated by column chromatography (SEPHADEX® LH-20) and 32 subfractions were obtained. The following compounds were isolated and identified: epicatechin, procyanidins B2 and B4, cinchonains Ia, Ib, IIb and IIc, apocynin E, and procyanidin C1. The antioxidant capacity in vitro of EB, FAE, FA and isolated compounds was evaluated using the DPPH• scavenging method and Fe3+-Fe2 reduction capacity. The values obtained by DPPH• method for the extracts were IC50 (µg.ml-1): EB= 5.44±0.18 (CV%=3.31); FAE=3.85±0.09 (2.35) and FA = 8.76±0.15 (CV%=1.68); for the isolated compounds the values were IC50 (µM): epicatechin= 10.12 ± 0.24 (CV%=2.43); PB2=7.95 ± 0.04 (CV%=0.51); cinchonain Ia=7.87 ± 0.05 (CV%=0,63); cinchonain Ib=7.67 ± 0.23 (CV%=2.98); cinchonain IIb=5.05 ± 0.05 (CV%=0.98); cinchonain IIc=5.15 ± 0.08 (CV%=1.61) and PC1=4.08 ± 0.01 (CV%=0.28). Concerning the reduction capacity, the extracts had higher activity than Trolox, but lower than vitamin C. All the isolated compounds were more effective than vitamin C and Trolox; procyanidin C1, cinchonain IIb and cinchonain IIc had the highest reduction capacities.
Keywords: Trichilia catigua, Condensed Tannins, Cinchonains, Antioxidant Capacity, DPPH, Reduction capacity.
Dissertation PDF: Flávia Oliveira Resende
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