Evaluation of Analgesic Properties of Piper Nigrum Essential Oil: a Randomized, Double-blind,Placebo-controlled Study

摘要

Objective: Essential oils are complex mixtures of chemical compounds, extracted from a wide range of plants. The volatile fraction of essential oils is responsible for their characteristic aroma and presents diverse biological properties that have been studied over the years. In Traditional Chinese Medicine, Piper nigrum is considered to be pungent and hot. Although its chemical constituents and respective pharmacological properties have been described by several authors, the volatile fraction is still underestimated as a therapeutic agent. The aim of this study was to evaluate the analgesic properties of the volatile fraction of Piper nigrum essential oil, in patients presenting different types of pain.Methods: Fifty-four patients presenting pain, were included in a randomized, double-blind, placebo-controlled study, over a 9-week period.The patients were randomly divided into two groups, and asked to inhale a vial containing Piper nigrum essential oil, or a vial containing a placebo（sesame oil）, for 15 minutes. A numerical pain scale was applied before and after the inhalation.Results: Results showed a statistically significant decrease in pain intensity in the patients that inhaled the black pepper essential oil, while the placebo group patients showed no significant change in pain intensity.Conclusion: Although the results are preliminary due to the limited sample size and short inhalation time, the volatile fraction of the Piper nigrum essential showed promising results in reducing pain. In the Chinese medicine perspective, these results support the use of black pepper in different types of pain, since it warms the center and disperses cold.