Evaluation of the Analgesic Activity of Standardized Aqueous Extract of Terminalia chebula in Healthy Human Participants Using Hot Air Pain Model

Background: Pain affects millions of people worldwide, opioid analgesics have been used for chronic painful conditions. Due to their adverse effects, safer alternatives would be beneficial. Terminalia chebula, with proven analgesic action has been evaluated in the hot air pain model for its analgesic activity. Aim: To evaluate analgesic activity and safety of single oral dose of Terminalia chebula using hot air pain model in healthy human participants. Setting and Design: Randomized, Double blind, Placebo controlled, Cross over study. Materials and Methods: After taking written informed consent to IEC approved protocol, 12 healthy human participants were randomized to receive either single oral dose of two capsules of Terminalia chebula 500 mg each or identical placebo capsules in a double blinded manner. Thermal pain was assessed using hot air analgesiometer, to deliver thermal pain stimulus. Mean Pain Threshold time and Mean Pain Tolerance time measured in seconds at baseline and 180 minutes post drug. A washout period of two weeks was given for cross-over between the two treatments. Results: Terminalia chebula significantly increased mean pain threshold and tolerance time compared to baseline and placebo. Mean pain threshold time increased from 34.06 +/- 2.63 seconds to 41.00 +/- 2.99 seconds ( p<0.001) and mean pain tolerance time increased from 49.67 +/- 3.72 seconds to 57.30 +/- 3.07 seconds ( p<0.001). The increase in mean percentage change for pain threshold time is 20.42% ( p<0.001) and for pain tolerance time is 17.50% ( p<0.001). Conclusion: In the present study, Terminalia chebula significantly increased Pain Threshold time and Pain Tolerance time compared to Placebo. Study medications were well tolerated.