Antinoceptive and Anti-inflammatory Activities of the Ethanolic Extract, Fractions and Flavones Isolated from Mimosa tenuiflora (Willd.) Poir (Leguminosae).

The bark of Mimosa tenuiflora (Willd.) Poiret (Leguminosae family), popularly known as "jurema preta" in Brazil, is used by the population of Contendas of Sincorá (Bahia State, Brazil) for the treatment of coughs and wound healing. Thus, the aim of this study was to evaluate the antinociceptive and anti-inflammatory activities of the bark ethanol extract (EEMT) and solvent soluble fractions (hexane-H, DCM-D, EtOAc-E and BuOH-B) of the extract in vivo. Additionally, we synthesized 5,7-dihidroxy-4'-methoxyflavanone (isosakuranetin) and isolated the compound sakuranetin, and both compounds were also tested. The anti-inflammatory and antinociceptive assays performed were: writhing test; nociception induced by intraplantar formalin injection; leukocyte recruitment to the peritoneal cavity; evaluation of vascular permeability (Evans blue test); and evaluation of mechanical hypernociception (von Frey test). Production of TNF-α, IL-10, myeloperoxidase and the expression of ICAM-1 were also evaluated. Statistical analysis was performed by one-way ANOVA followed by the Bonferroni post-test (n = 8), with P < 0.05. The EEMT showed antinociceptive activities in writhing test (100-200 mg/kg), in the second phase of the formalin test (50-200 mg/kg), and in mechanical hypernociception (100 mg/kg). EEMT showed an anti-inflammatory effect by reducing neutrophil migration to the peritoneal cavity and in the plantar tissue detected by the reduction of myeloperoxidase activity (100 mg/kg), reduction of IL-10 levels and expression of ICAM-1 in the peritoneal exudate and the mesentery (100 mg/kg), respectively. The four soluble EEMT fractions showed good results in tests for antinociceptive (H, D, E, B) and anti-inflammation (H, D, E). Only sakuranetin showed reduction of the writhing and neutrophil migration (200 mg/kg). Thus, the EEMT and soluble fractions of M. tenuiflora bark demonstrated great antinociceptive and anti-inflammatory activities, as also sakuranetin. More studies should be conducted to elucidate the mechanism of action of this compound. To the best of our knowledge, this is the first report on the antinociceptive activity of the M. tenuiflora fractions and the bioactive isolated compound sakuranetin in vivo

Effect of the ethanolic extract of <i>M</i>. <i>tenuiflora</i> bark on Cg-induced TNF-α (A) and IL-10 (B) production in the peritoneal exudate.

<p>VH is the vehicle group (negative control). The ethanol extract of <i>M</i>. <i>tenuiflora</i> bark was tested at a dose of 100 mg/kg (s.c.). The results are presented as the mean ± S.D. (n = 8). Statistical significance was calculated by ANOVA followed by Bonferroni's test. *<i>P</i> < 0.05 compared to the vehicle-negative control treated group.</p

Effect of ethanolic extract of <i>M</i>. <i>tenuiflora</i> bark on vascular permeability using the Evans blue test.

<p>VH is the vehicle group (negative control). The ethanol extract of <i>M</i>. <i>tenuiflora</i> bark was tested at the 100 mg/kg (s.c.) dose. The results are presented as the mean ± S.D. (n = 8). Statistical significance was calculated by ANOVA followed by Bonferroni's test. *<i>P</i> < 0.05 compared to the vehicle-negative control treated group.</p

Effect of ethanolic extract of <i>M</i>. <i>tenuiflora</i> bark on the inhibition of Cg-induced hyperalgesia.

<p>VH is the vehicle group (negative control). The ethanol extract of <i>M</i>. <i>tenuiflora</i> bark was tested at a dose of 100 mg/kg (s.c.). The results are presented as the mean ± S.D. (n = 8). Statistical significance was calculated by ANOVA followed by Bonferroni's test. *<i>P</i> < 0.05 compared to the vehicle-negative control treated group.</p

Effect of pretreatment of the mice with 50, 100 or 200 mg/kg of the ethanolic extract of <i>M</i>. <i>tenuiflora</i> bark on writhing induced by acetic acid (0.6%).

<p>VH is the vehicle group (negative control) and I is the positive control employing indomethacin (10 mg/kg, i.p.). The extract ethanol of <i>M</i>. <i>tenuiflora</i> bark was tested at doses of 50, 100 or 200 mg/kg (s.c.). The results are presented as the means ± S.D. of writhing in mice (n = 8). Statistical significance was calculated by ANOVA followed by Bonferroni's test. *<i>P</i> < 0.05 compared to the vehicle-negative control treated group. # <i>P</i> > 0.05 compared to the indomethacin—positive control group.</p

Flavonoids from <i>Mimosa tenuiflora</i>.

<p>Flavonoids from <i>Mimosa tenuiflora</i>.</p

Effects of ethanolic extract of <i>M</i>. <i>tenuiflora</i> bark on the response to nociception induced by intraplantar formalin injection in mice during the neurogenic phase (3A) and inflammatory phase (3B).

<p>Morphine (M, 5 mg/kg, s.c.) and indomethacin (I, 10 mg/kg, i.p.) were the positive control group. VH is the vehicle group (negative control). The ethanolic extract of <i>M</i>. <i>tenuiflora</i> bark was tested at doses of 50, 100 or 200 mg/kg (s.c.). The results are presented as the mean ± S.D. (n = 8) of the number of flinches in the injected paw for a period of 30 min. Statistical significance was calculated by ANOVA followed by Bonferroni's test. *<i>P</i> < 0.05 compared to the vehicle-negative control treated group. # <i>P</i> > 0.05 compared to the indomethacin or morphine—positive control groups.</p

Effect of pretreatment of the mice with the hexane (H), DCM (D), ETOAc (E) and BuOH (B) (100 mg/kg) soluble fractions of the <i>M</i>. <i>tenuiflora</i> extract on acetic acid (0.6%)-induced writhing.

<p>VH is the vehicle group (negative control). The results are presented as the mean ± S.D. (n = 8). Statistical significance was calculated by ANOVA followed by Bonferroni's test. *<i>P</i> < 0.05 compared to the vehicle-negative control treated group.</p

Effect of the hexane (H) (200 mg/kg) and EtOAc (E) (50 mg/kg) <i>M</i>. <i>tenuiflora</i> bark extract fractions on neutrophil migration to the peritoneal cavity of mice after Cg administration.

<p>VH is the vehicle group (negative control). The results are presented as the mean ± S.D. (n = 8). Statistical significance was calculated by ANOVA followed by Bonferroni's test. *<i>P</i> < 0.05 compared to the vehicle-negative control treated group.</p

Effect of the hexane (H), DCM (D), EtOAc (E) and BuOH (B) (100 mg/kg) soluble fractions of <i>M</i>. <i>tenuiflora</i> bark in the Evans blue (A) and Von Frey tests (B).

<p>VH is the vehicle group (negative control). The results are presented as the mean ± S.D. (n = 8). Statistical significance was calculated by ANOVA followed by Bonferroni's test. *<i>P</i> < 0.05 compared to the vehicle-negative control treated group.</p