The role of lecithin on topical anti-inflammatory activity of turmeric (Curcuma longa L.) ointment

Background: Turmeric (Curcuma longa L.) is widely used in traditional medicine. In Iranian folk medicine, turmeric and egg yolk mixture is used for inflammation due to dislocations and strains. Since lecithin (one of the component of egg yolk) is an absorption enhancer, it seems this phospholipid can increase turmeric absorption and its anti-inflammatory effect. Objective: In order to find the role of lecithin in the folklore formulation, anti-inflammatory effects of ointments containing turmeric extract and lecithin have been studied. Methods: Ointment base was prepared using bees wax, vaseline, liquid paraffin and eucerin. Then, hydroalcoholic turmeric extract (2.5 % and 5 %) with lecithin (5 % and 15 %) or without lecithin were added to the ointment base. Anti-inflammatory effect of the ointments was assessed in arthritis model in rat using complete Freund’s adjuvant. Ointments were used daily on the inflamed joints for 20 days. Finally, arthritis index, TNF-α concentration and histopathological changes of joints were determined. Results: The results showed that arthritis index has decreased in all groups but it was significant in groups of turmeric 2.5 % and turmeric 5 % with lecithin 15 %. TNF-α was decreased in all samples but reduction was more significant in group turmeric 2.5 %. Histopathological changes were significantly less in turmeric groups compared to ointment base group. Conclusion: It seems that local healers use egg yolk as a binder in formulation. In other words, turmeric 2.5 % ointment is preferable compared to other formulations.