Osteoarthritis is the most common joint disease worldwide. Some of the risk factors for the disease include age, obesity and a history of trauma. Patients often complain of pain, stiffness of the joints, morning stiffness and limited range of motion. For the treatment of every single patient with osteoarthritis there needs to be a separate individualist approach. Treatments include non-pharmacological methods (such as training sessions, exercise programs to maintain range of motion and muscle strength, use of assistive devices, weight management and nutritional supplements), pharmacological (such as topical and oral painkillers) and surgical procedures.
Menthol is one of the active ingredients of mint (Mentha spicata) and its counter-irritant and topical analgesic effects are well documented. When applied to the skin, mint essential oil or menthol stimulates the nerves which perceive cold, while simultaneously suppressing those for pain.
According to results of the studies conducted on animals, menthol produces antinociceptive effects by activating the endogenous opioid system or to some extent by having local anesthetic reactions without any anti-inflammatory effects. Moreover, mint essential oil subdues muscle contractions which occur as a result of serotonin and substance P release.
According to results of animal studies, celery essential oil has anti-inflammatory, anti-spasmodic and relaxant effects. Mint essential oil has anti-inflammatory and anti-spasmodic effects.
In a survey of the analgesic and anti-inflammatory effects of celery and mint essential oils and their mixture, examined by carrageenan test in rat and mice, significant local anti-inflammatory effects were attributed to these essences and their mixture. Mint essential oil and celery-mint essential oils mixture significantly suppress pain in the first phase of formalin test which is a neurogenic pain and is caused as a result of direct stimulation of nerves. Moreover, mint essential oil, celery essential oil and their mixture showed significant suppressive effects on the pain in the second phase of formalin test which is an inflammatory pain.
In a double-blind, placebo-controlled clinical trial, 102 patients with knee osteoarthritis were randomly divided into three groups of mint lotion, mint-celery lotion (C.M Barij Topical Lotion) and the other one with placebo lotion, each to be treated4 times a day topically. Further examinations were performed 1, 2, 3 and 4 weeks later after the first examination and the patients’ pain intensity during level walking, climbing stairs, descending stairs, sleeping, sitting down and ascending a slope were evaluated and data were analyzed using statistical tests.
According to results of this trial, 2 and 4 weeks after the start of the treatment, the effect of mint essential oil and C.M Barij Lotion on pain intensity reduction during level walking, showed significant difference to placebo (p<0.01). Additionally, C.M Barij Lotion showed relatively better effects on pain intensity during level walking and sitting down in comparison with mint lotion (although it was not statistically significant). Two weeks after the start of the treatment, in C.M Barij Topical Lotion group, pain intensity during sleeping reduced significantly in comparison with mint lotion and placebo groups (p<0.01).