Antioxidant effect of Stryphnodendron rotundifolium Martius extracts from Cariri-Ceará State (Brazil): potential involvement in its therapeutic use

Abstract

Stryphnodendron rotundifolium is a phytotherapic used in the northeast of Brazil for the treatment of inflammatory processes which normally are associated with oxidative stress. Consequently, we have tested the antioxidant properties of hydroalcoholic (HAB) and aqueous extracts (AB) from the bark and aqueous extract (AL) from the leaves of Stryphnodendron rotundifolium to determine a possible association between antioxidant activity and the popular use of this plant. Free radical scavenger properties were assessed by the quenching of 1',1'-diphenil-2-picrylhydrazyl (DPPH) and the calculated IC(50) were: HAB = 5.4 ± 0.7, AB = 12.0 ± 2.6, and AL = 46.3 ± 12.3 µg/mL. Total phenolic contents were: HAB = 102.7 ± 2.8, AB = 114.4 ± 14.6, and AL = 93.8 ± 9.1 µg/mg plant). HPLC/DAD analyses indicated that gallic acid, catechin, rutin and caffeic acid were the major components of the crude extracts of S. rotundifolium. Plant extracts inhibited Fe(II)-induced lipid peroxidation in brain homogenates. Iron chelation was also investigated and only HBA exhibited a weak activity. Taken together, the results suggest that S. rotundifolium could be considered an effective agent in the prevention of diseases associated with oxidative stress.

Figure 1

High performance liquid chromatography profile of S. rotundifolium: (A): hydroalcoholic bark extract; (B): aqueous leaves extract; (C): aqueous bark extract. Gallic acid (peak 1), catechin (peak 2), caffeic acid (peak 3) and rutin (peak 4).

Figure 2

Antioxidant properties of different extracts from S. rotundifolium Mart.: (A): hydroalcoholic bark extract; (B): aqueous leaves extract; (C): aqueous bark extract. Lipid peroxidation (TBARS production) in brain homogenates was determined either in the absence or in the presence of Fe²⁺ (10 µM). Values are expressed as mean ± SEM from 3 to 4 independent experiments performed in duplicate. *** p < 0.001 vs. Fe²⁺-induced TBARS; * p < 0.05 vs. Fe²⁺-induced TBARS; *** p < 0.001 vs. basal.

Figure 3

S. rotundifolium extracts did not inhibit Fenton’s reaction. (A) hydroalcoholic bark extract; (B) aqueous leaves extract; (C) aqueous bark extract on basal and Fe²⁺ (10 µM) + H₂O₂ (1 mM)-induced deoxyribose degradation. Deoxyribose was incubated for 20 min with or without H₂O₂ or Fe²⁺ + H₂O₂ in the presence or absence of extracts. Data are mean ± SEM. Values average from 3 to 4 independent experiments performed in duplicate.

Figure 4

DPPH radical scavenging activity by extracts from S. rotundifolium: (A) hydroalcoholic extract of bark; (B) aqueous extract of leaves; (C) aqueous extract of bark. The results are expressed as percentage of inhibition and ascorbic acid was used as a positive control. Data show means ± SEM values average from 3 to 4 independent experiments performed in triplicate. *** p < 0.001 vs. Control.

Figure 5

Effects of different extracts from S. rotundifolium on iron chelation: (A) hydroalcoholic bark; (B) aqueous leaves; (C) aqueous bark. Data show means ± SEM values average from 3 to 4 independent experiments performed in triplicate. *** p < 0.001 vs. Control; ** p < 0.01 vs. Control; * p < 0.05 vs. Control.