The Original articles Development of Massage Oil Containing Essential Oil from Zanthoxylum limonella Fruit and Pain Relief Effect on Calf Muscles in Healthy Volunteers

Abstract

Zanthoxylum limonella (Dennst.) Alston (ma-kwaen in Thai) is a local plant scattered all over northern Thailand. It is a member in the Rutaceae family. Its fruit is extensively used as a spice with hot flavor and pungent aroma in local food. Additionally, its fruit and pericarp are used as a Thai traditional household remedy for relieving muscle pain and spasm. Studies on major chemical compositions and biological activities in vitro and in vivo of essential oil from Z. limonella fruit have shown that the oil can inhibit inflammatory mediators and has anti-inflammatory effects. Therefore, this research aimed to develop a massage oil containing essential oil from Z. limonella fruit and evaluate its effectiveness via pain score on calf muscles. Subjects had induced pain on both calf muscles by standing heels raise. The study included two phases. Phase 1, developing ZLO: Z. limonella fruits (ZLF) were collected in Chiang Rai province, sun-dried, ground as coarse powder, and then distilled in water to obtain essential oil from fruits (EOF). The oil was analyzed for its chemical composition using the GC/MS method. Safflower oil (SFO) was found to be the best carrier oil selected from among coconut oil (CNO), safflower oil (SFO) and corn oil (CO) as it was most stable for preparing ZLO, which contained 3%, 6% and 9% of EOF. Phase 2, evaluating pain relief effect on both calf muscles in healthy volunteers: The three concentrations of ZLO were prepared for testing in three groups of subjects (20 persons per group, n = 60), respectively. In all subjects, pain was induced on both calf muscles and then ZLO was applied on the right side and carrier oil (placebo) on the left side every day (2 times a day, morning and evening) for 5 days. Results showed that terpinen-4-ol (19.87%), limonene (18.62%) and sabinene (17.31%) were major chemical compounds in EOF. After the subjects in groups 1, 2 and 3 had ZLO applied at 3%, 6% and 9% EOF concentrations, respectively, the mean pain score on the right calf was significantly lower than that on the left calf (p-value < 0.05); and the three concentrations of ZLO did not exhibit any significant difference in pain scores on the right calf. This research confirms the use of ZLO as ethnomedicine for relieving pain and the authors recommend using 3% concentration.