Quantification of Phenylbutanoids and Terpinen-4-ol in Zingiber montanum Oils: Comparison of Hydro-distillation and Deep-frying Extraction Methods and the Effect of Temperature

The aim of this study was to determine the quantities of (E)-1-(3,4-dimethoxyphenyl) butadiene (DMPBD), (E)-4-(3’,4’-dimethoxyphenyl) but-3-en-1-ol (compound D), and terpinen-4-ol in Zingiber montanum oils and to investigate the effect of temperature on the extraction efficiency of deep-frying method. Typically, Z. montanum oil is prepared by deep-frying with plant-fixed oil or by hydro-distillation. However, the quantities of compound D, DMPBD, and terpinen-4-ol in both types of oil have not been fully clarified. The results revealed that DMPBD and terpinen-4-ol were effectively extracted by hydro-distillation, while compound D, DMPBD, and terpinen-4-ol were found in the oil prepared by deep-frying with plant-fixed oil. Temperature was shown to have a significant impact on the quantities of active compounds in fried oil. The lowest amounts of compound D (0.75 ± 0.031 mg/mL), was quantified in the oil prepared by deep-frying at 200°C, while the highest amounts of compound D (0.90 ± 0.016 mg/mL) was observed in the oil prepared by deep-frying at 100°C. The highest amount of terpinene-4-ol (1.08 ± 0.004 mg/mL) and DMPBD (0.95 ± 0.045 mg/mL) were presented in hydro-distillation oil. Both Z. montanum oils show potential as ingredients for topical application, particularly in the treatment of muscle or skeletal inflammation. However, optimization of the preparation process needs to be considered.