Analgesic effects of crude extracts and fractions of Omani frankincense obtained from traditional medicinal plant Boswellia sacra on animal models

ABSTRACT

Objective: To investigate the analgesic effect of Boswellia sacra (B. sacra), which could support the Omani traditional uses of frankincense for muscle, stomach, and arthritis pain. Methods: The crude extract, the essential oils and various sub-fractions of the crude methanol extract (each 300 mg/kg of the body weight of the animal) obtained from the resin of B. sacra were administered orally, and were evaluated for their analgesic activities by using two well known models of pain in mice, viz. acetic acid induced writhing test and formalin induced pain test in mice. Results: Of 13 samples, almost all of them were effective at an orally administered dose of 300 mg/kg of the body weight. The acetic acid induced writhes were inhibited in all the three phases with comparable values to the standard drug aspirin (300 mg/kg of body weight) with inhibition of 67.6% in phase I, 66.8% in phase II, and 37.9% in phase III. At the same time, all the tested samples were found effective in both the early and the late phases of formalin test. In formalin test, most of the tested samples showed more inhibitory effects as compared to the standard drug aspirin (300 mg/kg of body weight), which showed 36.2% and 29.6% inhibition in early and late phases respectively. Among the tested samples, the most significant inhibition was produced by Shabi frankincense oil (57.5% in early phase, and 55.6% in late phase). Interestingly, the extracts showed comparable percentage of inhibition to the oil and found in the following order: 60% chloroform. /n-hexane sub-fraction (55.3% in early phase, and 66.7% in late phase), and 70% chloroform. /n-hexane sub-fraction (59.6% in early phase, and 63.0% in late phase). Conclusions: The present study provided the scientific justification about the analgesic properties of the essential oils, extract, and various sub-fractions obtained from the resin of B. sacra, thus validating its use in traditional folk medicines and other products; and hence supporting the development in the analgesic properties of bioactive natural substances.