محمدرضا مرشدلو

Background: Preharvest and postharvest conditions of medicinal plants strongly affect the quantity and quality oftheir secondary metabolites. Here, the effect of different harvesting times (5 am, 12 noon and 5 pm) and different dry-ing methods (shade at 25 °C, oven at 60 °C and microwave at 180 W) on essential oil content and components, totalphenol content and antioxidant activity of rosemary was monitored.Results: Harvesting time only had a significant effect on the essential oil content and components; however, allinvestigated traits were significantly affected by drying methods. The essential oil content of plants harvested at 5 amand 5 pm was higher than those harvested at 12 noon. The highest amount of essential oil was obtained from shade(0.85–1.12%) and oven (0.66–1.04%) dried plants, respectively. Total phenol and antioxidant activity of oven driedplants were significantly lower than shade and microwave-dried plants. The number, type and amount of essentialoil components were affected by harvesting time and drying method. α-Pinene, verbenone and camphor were themajor components of the essential oils. Oxygenated monoterpenes were the main group of essential oil compoundsin all treatments. The results of biplot and cluster analysis, based on the measured traits, placed the treatments inthree separate clusters; I: shade dried, II: oven-dried, and III: microwave-dried plants.Conclusion: Generally, to obtain the higher essential oil content, phenol and antioxidant activity, harvesting at 5 amand 5 pm and also shade drying are recommended; however, for reaching to essential oil with specific quality, differ-ent harvesting time and drying method could be used. (PDF) Essential oil content and components, antioxidant activity and total phenol content of rosemary (Rosmarinus officinalis L.) as affected by harvesting time and drying method. Available from: https://www.researchgate.net/publication/361851862_Essential_oil_content_and_components_antioxidant_activity_and_