Antinociceptive Activity of Inula britannica L. and Patuletin: In vivo and Possible Mechanisms Studies

Zarei M, Mohammadi S, Komaki A
Journal of Ethnopharmacology, 2018


ETHNOPHARMACOLOGICAL RELEVANCE: INULA BRITANNICA: L. (IBL) is a predominant medicinal plant traditionally utilized in the treatments of arthritis and back pain in Iranian folk medicine.

AIM OF THE STUDY: The purpose of this research was to evaluate the analgesic effects of Inula britannica L. flower essential oil (IBLEO) and one of its major constituents, Patuletin (Pn), in male mice.

MATERIALS AND METHODS: In this study, we used pain assessment tests including acetic acid-induced writhing, tail flick, formalin, and glutamate-induced paw licking (GPL). For understanding the supposed analgesic mechanisms of IBLEO, opioid and L-Arginine/NO/cGMP/ KATP pathways were examined. A rotarod exam was performed to assess any possible effect of IBLEO on the motor activity of mice.

RESULTS: In the tail flick, writhing, GPL, and formalin tests, a dosage of 100mg/kg of IBLEO showed noteworthy analgesic effects (p < 0.05). In mice, pain decreased with the administration of Naloxone, an opioid non-selective antagonist, plus IBLEO (p < 0.001). However, administration of selective opioid antagonists (Naltrindole, Nor-binaltorphimine, and Naloxonazine) attenuated the antinociceptive effect of IBLEO (p < 0.001). Both Methylene blue and Glibenclamide blocked the antinociceptive effect of IBLEO (p < 0.05), but the administration of L-arginine or sodium nitroprusside fundamentally potentiated the antinociception induced by IBLEO in phase II of the formalin test (p < 0.05). Patuletin showed strong analgesic effects in all tests (p < 0.01).

CONCLUSION: The results of this examination showed that IBLEO and Patuletin have analgesic effects. The modulation of glutamatergic systems by opioid receptors could be involved, at least in part, in these effects. Our data also suggest the activation of the L-Arginine/NO/cGMP/KATP pathway in IBLEO antinociceptive effects.


Zarei M, Mohammadi S, Komaki A. Antinociceptive Activity of Inula britannica L. and Patuletin: In vivo and Possible Mechanisms Studies. J Ethnopharmacol. 2018 Mar 19. pii: S0378-8741(17)33902-8.

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