Diurnal Effects on Mentha canadensis Oil Concentration and Composition at Two Different Harvests

Abstract

<jats:p>Japanese cornmint, also known as menthol mint (<jats:italic>Mentha canadensis</jats:italic> L. syn <jats:italic>M. arvensis</jats:italic> L.), is an essential oil crop cultivated in several countries in Asia and South America. The plant is currently the only commercially viable source for natural menthol as a result of the high concentration of menthol in the oil compared with other crops. The hypothesis of this study was that harvesting at regular intervals within a 24-hour period would have an effect on essential oil concentration and composition of Japanese cornmint grown at high altitude in northern Wyoming. Flowering plants were harvested every 2 hours on 7 to 8 Aug. and on 14 to 15 Aug. and the essential oil was extracted by steam distillation and analyzed by gas chromatography–mass spectroscopy (GC-MS). The effects of harvest date (Harvest 1 and Harvest 2) and harvest time (12 times within a 24-hour period) were significant on oil concentration and yield of menthol, but only harvest date was significant on the concentration of menthol in the oil. The interaction effect of harvest date and harvest time was significant on water content and on the concentrations of menthol and menthofuran in the oil and on the yield of limonene, menthol, and menthofuran. Overall, the oil concentration in grams per 100 g dried material for the two harvests (1.26 and 1.45, respectively), the concentration of menthol in the oil (67.2% and 72.9%, respectively), and menthol yield (1066 to 849 mg/100 g dried biomass) were higher in plants at Harvest 2 as compared with plants at Harvest 1. The oil concentration was higher in plants harvested at 1100 <jats:sc>hr</jats:sc> or at 1300 <jats:sc>hr</jats:sc> and lowest in the plants harvested at 1500 <jats:sc>hr</jats:sc>. Menthol yield was the highest in plants harvested at 1300 <jats:sc>hr</jats:sc> and lowest in the plants harvested at 0700 <jats:sc>hr</jats:sc>, 1900 <jats:sc>hr,</jats:sc> or at 0300 <jats:sc>hr</jats:sc>. This study demonstrated that harvesting time within a 24-hour period and harvest date (maturity of the crop) may affect essential oil concentration and composition of Japanese cornmint grown at high altitude in northern Wyoming.</jats:p>

Volatile Composition of Essential Oils from Different Aromatic Herbs Grown in Mediterranean Regions of Spain

“…According the previous studies, the harvest date and harvest time can affect the water content, the concentrations of menthol and menthofuran and the yield of limonene, menthol, and menthofuran in Mentha canadensis [ 25 , 26 ]. Besides, in Japanese mint ( Mentha arvensis L.) the content of menthol was not affected by the planting date or harvesting schedule but menthone signficantly decreased with the delay in harvesting [ 27 ].…”

Peppermint Essential Oil-Doped Hydroxyapatite Nanoparticles with Antimicrobial Properties

“…Aromatic herbs like peppermint, lavender, basil, oregano, and thyme have wide applications in the pharmaceutical or food industries due to their positive health effects [1,2,3,4]. The essential oils extracted from these aromatic plants are of great interest, especially due to their antifungal, antibacterial, and antioxidant properties [1].…”

“…The essential oils extracted from aromatic plants have the following bioactive components in their chemical composition: monoterpenes, monoterpenoids, and phenylpropanoids. Their concentrations in the extracted oils depend strongly on the soil, climatic, and geographical conditions [1,2,3,4] of the herbal culture growing.…”

Effects of Harvest Time and Hydrodistillation Time on Yield, Composition, and Antioxidant Activity of Mint Essential Oil

“…The influence of harvest time on the production of menthol and menthone in Mentha EOs has already been reported in the literature. According to Shiwakoti et al [29], a higher rate of light radiation tends to oxidize the chemical constituents of EO. The highest menthol content was observed in samples collected at 9 a.m., followed by 1 p.m. and 5 p.m. On the other hand, the highest menthone content was quantified in samples collected at 5 p.m., followed by 1 p.m. and 9 a.m. Based on these results, it can be inferred that greater solar radiation affects the activity of the limonene 3-hydroxylase enzyme, thereby decelerating the natural process of converting menthone into menthol, as described by Croteau [30].…”