Sanaz Mahdipour, Samaneh Teimouri, Omid Reza Tamtaji, Mojgan Mohammadifar, Mohsen Taghizadeh, Sayyed Alireza Talaei,
Volume 20, Issue 2 (5-2017)
Abstract
Background: Neuropathic pain is a chronic pain that affects on the patient’s quality of life. Use of herbal instead of synthetic drugs recently has been increased due to side effects of synthetic drugs and herbal effective components. Flavonoids are herbal compounds that have analgesic and anti-inflammatory effects. Because Allium cepa L. has a great amount of flavonoids, this study has been designed to evaluate analgesic effects of alcoholic extract of Allium cepa L. on neuropathic pain behavior in chronic constriction injury model in rats.
Materials and Methods: In this experimental study, neuropathic pain induced by chronic constriction injury (CCI model) in Rats. Animals were randomly divided into 4 groups (n=10 for each): Sham, CCI model, receiving red onion hydroalcoholic extract at a dose of 100 mg/kg and a group receiving gabapentin (100 mg/kg). Red onion extract and gabapentin were administered by gavage for 21 days. Using thermal hyperalgesia, mechanical and thermal allodynia tests, the analgesic effects of extract have been measured.
Results: Findings of this study revealed that CCI surgery on rats induced hyperalgesia, mechanical and thermal allodynia. Daily intakes of alcoholic extract of red onion and gabapentin significantly increase the paw withdrawal latency; increase the threshold to mechanical allodynia and decrease in response to acetone.
Conclusion: Oral use of alcoholic extract of Allium cepa L. reduces neuropathic pain behavior in CCI model in rats.
Mojgan Mohammadifar, Fereshteh Bahmani, Alireza Abed, Gholamali Hamidi, Mohammad Hossein Aarabi, Sayyed Alireza Talaei,
Volume 28, Issue 4 (10-2025)
Abstract
Introduction: The analgesic effects of rosemary and peppermint essential oils have been shown in many studies. Low solubility of essential oils in water and low bioavailability limit their consumption, and nanoparticles can help solve these limitations. This study aimed to investigate the analgesic effect of a nanoemulsion containing rosemary and peppermint essential oils in a rat model of neuropathic pain.
Methods: Forty male rats were assigned to four groups: control (CON), neuropathic pain received normal saline (NPS), nanoemulsion (NPN), or gabapentin (NPG). Neuropathic pain was induced using the CCI model. Animals received a nanoemulsion containing 10% rosemary extract and peppermint essential oil via gavage for 21 days. Behavioral tests (Thermal Hyperalgesia, Thermal Allodynia, and Mechanical Allodynia) were done on days 1, 4, 7, 14, and 21 of the study. Biochemical tests were also done on the sciatic nerve of animals at the end of the study.
Results: The NPS rats had a significantly increased pain threshold compared to the control group (P < 0.001). Furthermore, the analgesic potential of nanoemulsion containing rosemary and peppermint essential oils was seen in allodynia and hyperalgesia tests. Biochemical analyses showed that CCI reduced total antioxidant capacity, superoxide dismutase, and glutathione peroxidase activity, and also increased MDA levels in the rats' sciatic nerve (P < 0.001 for all comparisons). Administering nanoemulsion containing rosemary and peppermint essential oils reversed all the above-mentioned changes in the biochemical parameters (P < 0.001).
Conclusions: Our findings revealed that treating rats with a nanoemulsion containing rosemary and peppermint essential oils can reduce neuropathic pain symptoms by balancing their sciatic nerve's oxidant and antioxidant systems.
