Involvement of the L-arginine-nitric oxide pathway in the antinociception caused by fruits of Prosopis strombulifera (Lam.) Benth

Ethnopharmacological relevance

Prosopis strombulifera (Lam.) Benth. is a rhizomatous shrub that grows in the north and central zone of Argentina. In folk medicine, the fruits of this plant have been used as an astringent, anti-inflammatory and odontalgic agent and anti-diarrheic.

Aim of the study

To investigate the antinociceptive effect of ethanol (EE), chloroform (CE) and ethyl acetate (EtOAcE) extracts of Prosopis strombulifera fruits and the involvement of the l-arginine-nitric oxide pathway in this effect.

Materials and methods

The antinociceptive effects of the EE, CE and EtOAcE of Prosopis strombulifera fruits were evaluated in vivo using the formalin-induced pain test in mice with aspirin and morphine as reference antinociceptive compounds. The participation of the l-arginine-nitric oxide pathway in the antinociceptive effect was investigated in the same animal model using l-arginine as a nitric oxide (NO) precursor. The in vitro inhibitory effect of the extracts on LPS-induced nitric oxide production and iNOS expression was investigated in a J774A.1 macrophage-derived cell line.

Results

CE (300 mg/kg), in contrast to EE and EtOAcE, caused significant inhibition (p < 0.05) of the in vivo nociceptive response. Moreover, CE (100–1000 mg/kg, p.o.) produced a dose-dependent inhibition of the neurogenic and the inflammatory phases of the formalin test with inhibition values (at 600 mg/kg) of 42 ± 7% and 62 ± 7%, respectively. CE inhibition was more potent in the inflammatory phase, with an ID₅₀ of 400.1 (252.2–634.8) mg/kg. The antinociception caused by CE (600 mg/kg, p.o.) was significantly attenuated (p < 0.05) by i.p. treatment of mice with l-arginine (600 mg/kg). In addition, CE (100 μg/mL) produced significant in vitro inhibition (p < 0.001) of LPS-induced NO production, which was not observed with EE and EtOAcE at the same concentration. The inhibition of NO production by CE (10–100 μg/mL) was dose-dependent, with an IC₅₀ of 39.8 (34.4–46.1) μg/mL, and CE significantly inhibited LPS-induced iNOS expression in J774A.1 cells.

Conclusions

This study supports, in part, the ethnomedical use of Prosopis strombulifera fruits by showing that its CE produces moderate antinociception in vivo. The findings also provide scientific information for understanding the molecular mechanism involved in the analgesic effect of this plant.     

Wound healing and anti-inflammatory activities of the Michauxia L'Hérit (Campanulaceae) species native to Turkey

Ethnopharmacological relevance

The leaves of Michauxia species are used for the treatment of wounds in Turkish traditional medicine. In the present study, wound healing, anti-inflammatory and antioxidant activities of the extracts obtained from the root and herb of 5 species of Michauxia collected in different parts of Turkey were evaluated.

Material and methods

In vivo incision and excision wound models were used in order to assess the wound healing effects of the methanolic extracts of the plants. Skin samples were also evaluated histopathologically. In vivo inhibitory effect of the extracts on acetic acid-induced increase in capillary permeability was studied for the assessment of anti-inflammatory activity. TBA (thiobarbituric acid) test, qualitative and quantitative DPPH (2,2-diphenyl-1-picrylhydrazyl) tests were used to evaluate the antioxidant activity.

Results

Noteworthy wound healing activity was observed for the ointment formulation prepared with 1% Michauxia nuda (root) and Michauxia tchihatchewii (herb) extracts. The results of histopathological evaluation supported the outcome of incision and excision wound models. Moreover, the Michauxia nuda (root) exerted remarkable anti-inflammatory effect. The highest antioxidant activity was observed with the ethyl acetate extract of Michauxia tchihatchewii herb.

Conclusion

The experimental study revealed that Michauxia displays remarkable wound healing and anti-inflammatory and antioxidant activities.