Abstract
Four spearmint, and two peppermint clonal lines, selected for enhanced rosmarinic acid content (50-120 mg g-1 rosmarinic acid DW), where up to 80% of the antioxidant activity was correlated to rosmarinic acid content, were examined to determine the effects of environmental and physiological conditions on the accumulation of rosmarinic acid in leaf tissues. Exposure to a short photoperiod of 12 hours in comparison to 16 hours reduced rosmarinic acid accumulation in two mint lines, but no significant difference was found between photoperiods of 14 and 16 hours. The physiological age of the plant strongly influenced the accumulation of rosmarinic acid with the highest levels recorded in the vegetative state, and a significant reduction in the concentration of rosmarinic acid in the leaves in both the bud initiation and flowering stages in the mint lines. Cold stress, impacted over a six week period had no effect on rosmarinic acid production. A field study of the commercial chemotype 700B indicated that soil type plays an essential role in the accumulation of rosmarinic acid in the leaf tissue, probably due to retention of moisture which favours rosmarinic acid production. For producers and extractors, taking these factors into account would significantly increase rosmarinic acid accumulation in commercially high rosmarinic acid mint and increase the quality control of plant extracts for the natural products industry.
Highlights
Mentha spicata L. and Mentha piperita L. are commonly produced as a crop for their essential oils for food products, cosmetics and pharmaceuticals
This study examines the changes in rosmarinic acid (RA) accumulation in different chemotypes of mint leaf tissue due to environmental effects
Spearmint contains numerous polyphenols and flavonoids, each contributing to the antioxidant activity of an aqueous ethanol extract
Summary
Mentha spicata L. (spearmint) and Mentha piperita L. (peppermint) are commonly produced as a crop for their essential oils for food products, cosmetics and pharmaceuticals. The stability of enriched chemotypes becomes a significant factor in delivering a high quality product with increased nutraceutical value Environmental factors such as photoperiod [5], water availability [6, 7], temperature [6], pest and disease incidence [8,9,10] are key to mint production due to the perennial nature of the crop. These factors have a direct impact on biochemical pathways, affecting the metabolism of secondary products. This study examines the changes in RA accumulation in different chemotypes of mint leaf tissue due to environmental effects (photoperiod, cold stress, soil type, year to year differences) and the effect of physiological status of the plant in indoor tests or field trials
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
