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Activation of human neutrophils by Esenbeckia leiocarpa: comparison between the crude hydroalcoholic extract (CHE) and an alkaloid (Alk) fraction.

de Liz R, Horst H, Pizzolatti MG, Fröde TS, Girard D - J Inflamm (Lond) (2012)

Bottom Line: Esenbeckia leiocarpa, a wide spread native Brazilian tree, was reported recently to possess anti-inflammatory effects in vivo, but the mechanisms involved are still not fully understood and its role in neutrophils is poorly documented.CHE inhibited intracellular reactive oxygen species (ROS) production but increased the extracellular superoxide (O2-) production, while Alk increased the former and also slightly increased O2- production.However, neither CHE nor Alk potentiated the effect of classical neutrophil agonists, namely the cytokines GM-CSF for phagocytosis and TNF-α for adhesion or N-formyl-methionyl-leucyl-phenylalanine (fMLP) for degranulation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratoire de recherche en inflammation et physiologie des granulocytes, Université du Québec, INRS-Institut Armand-Frappier, Laval, QC, Canada. denis.girard@iaf.inrs.ca.

ABSTRACT
Esenbeckia leiocarpa, a wide spread native Brazilian tree, was reported recently to possess anti-inflammatory effects in vivo, but the mechanisms involved are still not fully understood and its role in neutrophils is poorly documented. The aim of this study was to compare the effects of a crude hydroalcoholic extract (CHE) and an alkaloid-enriched (Alk) fraction obtained from Esenbeckia leiocarpa bark on human neutrophils by investigating the effect of each fraction alone or in a mixture with classical neutrophil agonists. CHE inhibited intracellular reactive oxygen species (ROS) production but increased the extracellular superoxide (O2-) production, while Alk increased the former and also slightly increased O2- production. We found that CHE and Alk also induced phagocytosis accompanied by Syk activation, adhesion and degranulation. However, neither CHE nor Alk potentiated the effect of classical neutrophil agonists, namely the cytokines GM-CSF for phagocytosis and TNF-α for adhesion or N-formyl-methionyl-leucyl-phenylalanine (fMLP) for degranulation. In addition, based on catalase treatment, CHE and Alk induced neutrophil apoptosis by a hydrogen peroxide (H2O2)-dependent mechanism. Since the elimination of apoptotic neutrophils by professional phagocytes is important for the resolution of inflammation, the ability of CHE and Alk to induce neutrophil apoptosis has to be considered as one possible mechanism associated with the anti-inflammatory activity of these fractions previously reported in vivo.

No MeSH data available.


Related in: MedlinePlus

Effect of CHE and Alk on superoxide production. PMNs were incubated in the presence (+) or absence (−) of PMA, CHE or Alk and O2.- production was determined after 5 min as described in Methods. Results are means ± SEM (n = 3). *, p < 0.05 vs Ctrl (no CHE, Alk or PMA); #, p < 0.05 vs PMA, by Student’s t-test.
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Figure 6: Effect of CHE and Alk on superoxide production. PMNs were incubated in the presence (+) or absence (−) of PMA, CHE or Alk and O2.- production was determined after 5 min as described in Methods. Results are means ± SEM (n = 3). *, p < 0.05 vs Ctrl (no CHE, Alk or PMA); #, p < 0.05 vs PMA, by Student’s t-test.

Mentions: Because treatment with catalase inhibited the capacity of CHE and Alk to induce apoptosis, and since catalase used in the experiments is not cell permeable and degraded therefore H2O2 present in the extracellular medium, we then decided to verify whether extracellular ROS production was also increased in response to CHE and Alk. We measured the classic response of O2- production, since O2- anions are rapidly transformed into H2O2 via the action of the enzyme superoxide dismutase (SOD). As illustrated in Figure 6, after only 5 min of treatment, CHE significantly increased the rapid production of O2-, whereas Alk did not, although a slight tendency towards increased production was noted. However, both CHE and Alk were found to significantly reduce the PMA-induced O2- production.


Activation of human neutrophils by Esenbeckia leiocarpa: comparison between the crude hydroalcoholic extract (CHE) and an alkaloid (Alk) fraction.

de Liz R, Horst H, Pizzolatti MG, Fröde TS, Girard D - J Inflamm (Lond) (2012)

Effect of CHE and Alk on superoxide production. PMNs were incubated in the presence (+) or absence (−) of PMA, CHE or Alk and O2.- production was determined after 5 min as described in Methods. Results are means ± SEM (n = 3). *, p < 0.05 vs Ctrl (no CHE, Alk or PMA); #, p < 0.05 vs PMA, by Student’s t-test.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 6: Effect of CHE and Alk on superoxide production. PMNs were incubated in the presence (+) or absence (−) of PMA, CHE or Alk and O2.- production was determined after 5 min as described in Methods. Results are means ± SEM (n = 3). *, p < 0.05 vs Ctrl (no CHE, Alk or PMA); #, p < 0.05 vs PMA, by Student’s t-test.
Mentions: Because treatment with catalase inhibited the capacity of CHE and Alk to induce apoptosis, and since catalase used in the experiments is not cell permeable and degraded therefore H2O2 present in the extracellular medium, we then decided to verify whether extracellular ROS production was also increased in response to CHE and Alk. We measured the classic response of O2- production, since O2- anions are rapidly transformed into H2O2 via the action of the enzyme superoxide dismutase (SOD). As illustrated in Figure 6, after only 5 min of treatment, CHE significantly increased the rapid production of O2-, whereas Alk did not, although a slight tendency towards increased production was noted. However, both CHE and Alk were found to significantly reduce the PMA-induced O2- production.

Bottom Line: Esenbeckia leiocarpa, a wide spread native Brazilian tree, was reported recently to possess anti-inflammatory effects in vivo, but the mechanisms involved are still not fully understood and its role in neutrophils is poorly documented.CHE inhibited intracellular reactive oxygen species (ROS) production but increased the extracellular superoxide (O2-) production, while Alk increased the former and also slightly increased O2- production.However, neither CHE nor Alk potentiated the effect of classical neutrophil agonists, namely the cytokines GM-CSF for phagocytosis and TNF-α for adhesion or N-formyl-methionyl-leucyl-phenylalanine (fMLP) for degranulation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Laboratoire de recherche en inflammation et physiologie des granulocytes, Université du Québec, INRS-Institut Armand-Frappier, Laval, QC, Canada. denis.girard@iaf.inrs.ca.

ABSTRACT
Esenbeckia leiocarpa, a wide spread native Brazilian tree, was reported recently to possess anti-inflammatory effects in vivo, but the mechanisms involved are still not fully understood and its role in neutrophils is poorly documented. The aim of this study was to compare the effects of a crude hydroalcoholic extract (CHE) and an alkaloid-enriched (Alk) fraction obtained from Esenbeckia leiocarpa bark on human neutrophils by investigating the effect of each fraction alone or in a mixture with classical neutrophil agonists. CHE inhibited intracellular reactive oxygen species (ROS) production but increased the extracellular superoxide (O2-) production, while Alk increased the former and also slightly increased O2- production. We found that CHE and Alk also induced phagocytosis accompanied by Syk activation, adhesion and degranulation. However, neither CHE nor Alk potentiated the effect of classical neutrophil agonists, namely the cytokines GM-CSF for phagocytosis and TNF-α for adhesion or N-formyl-methionyl-leucyl-phenylalanine (fMLP) for degranulation. In addition, based on catalase treatment, CHE and Alk induced neutrophil apoptosis by a hydrogen peroxide (H2O2)-dependent mechanism. Since the elimination of apoptotic neutrophils by professional phagocytes is important for the resolution of inflammation, the ability of CHE and Alk to induce neutrophil apoptosis has to be considered as one possible mechanism associated with the anti-inflammatory activity of these fractions previously reported in vivo.

No MeSH data available.


Related in: MedlinePlus