Comparison of chemical composition of essential oils obtained by hydro-distillation and microwave-assisted extraction of Japanese mint (Mentha arvensis L.) grown in Vietnam

Abstract

The Japanese mint (Mentha arvensis L.) is known as a culinary and medicinal herb widely cultivated in several countries. The mint essential oil is considered as one main source of menthol. In this study, the Japanese mint collected from the Central Highlands of Lam Dong Province (Vietnam) was extracted the essential oil by hydro-distillation (HD) and microwave-assisted extraction (MAE). Different extraction parameters were investigated, involving mint leaf drying periods (30, 60, and 90 mins) at 50 °C, material to water ratios (1:4, 1:6, 1:8, and 1:10 for HD and 1:1, 1:1.5, 1:2, and 1:2.5 for MAE), extraction durations (60-180 for HD and 10-25 mins for MAE), and microwave energy (230, 380, 540, and 700 W) in order to discover the conditions with the highest yields for both HD and MAE. The GC-MS was used to determine the oil chemical constituents. For dried mint leaves (nearly 40 % moisture), the highest oil yield of 0.0832 mL g−1 (dried weight) was recorded, and the content of menthol was up to 70.60 % extracted by MAE whilst 0.0510 mL g−1 of yield (dried weight) and lower menthol (62.80 %) were obtained from HD. Besides, menthol, trans- and cis-menthone were found at relatively high concentrations for both HD and MAE (20.19-16.30 and 4.62-5.01 %, respectively). Compared to HD, MAE exhibited higher oil yields and menthol contents, but lower distillation time, resulting in more effective extraction performance of MAE.

Conventional vs. Microwave-Assisted Hydrodistillation: Influence on the Chemistry of Sea Fennel Essential Oil and Its By-Products

“…This can be explained by the higher dipole moment of the oxygenated compounds, which is why they interact more strongly with microwaves and are, therefore, more easily extracted than the monoterpene hydrocarbons with weak dipole moment [ 4 ]. Agreement with these observations was found in studies by Lucchesi et al [ 22 ] on basil, garden mint, and thyme; Ferhat et al [ 5 ] on citrus peel’s EO; Filly et al [ 6 ], Moradi et al [ 23 ], and Elyemni et al [ 4 ] on rosemary; and Bui Phuc et al [ 2 ] on mint EO. Cardoso-Ugarte et al [ 21 ] studied the influence of the method used and different extraction parameters on the chemistry of basil essential oil and reported a greater number of detected compounds in the oil obtained by MHD, as well as Ferhart et al [ 5 ] in the citrus peel oils obtained by MHD compared to HD and cold pressing.…”

“…Published studies have come to conflicting conclusions regarding the influence of the EO isolation method on the chemical profile of EO. While some of them report significant differences between samples, especially in terms of EO yield [ 2 , 5 ], others confirm that EOs are not significantly affected by the extraction method [ 4 , 21 ]. However, in general, a higher content of oxygenated compounds and a lower number of hydrocarbons are reported in EOs isolated by the MHD method.…”

“…), and (ii) modern, innovative techniques (e.g., microwave-assisted hydro-distillation (MHD), microwave hydro-diffusion and gravity, supercritical fluid extraction, etc.) [ 1 , 2 ].…”

“…This technique also minimizes the environmental impact because it is solvent-free and is characterized by lower CO 2 emissions. Therefore, the MHD technique is more suitable for laboratory-scale studies [ 2 , 3 , 4 , 5 , 6 ].…”

Efficient nanostructured materials to reduce nutrient leaching to overcome environmental contaminations

“…After the completion of dose application and growth of Mentha arvensis L., the healthy and matured plants were harvested and shade dried, prior to the extraction of essential oil 14 . The essential oil was extracted through Clevenger type hydrodistillation apparatus 15 .…”