The rich bioactive compounds of medicinal rosemary, as well as their antioxidant activity has led to its wider application in the pharmaceutical, cosmetic and food industries. In the present work, seasonal variations of phenolic, flavonoid content and antioxidant activity were evaluated. This experiment was performed based on a complete randomised design with three replications. The total content of flavonoids and some phenolic compounds (caffeic acid and quercetin) increased when plants received sunlight for a longer period of time than the colder seasons. On the other hand, the highest antioxidant activity was observed in rosemary, which was accompanied by an increase in the important phenolic composition of rosmarinic acid in the cold season. Overall, this study can provide useful information about the best harvest period for rosemary to produce the desired compounds for use in the food, pharmaceutical and plant industries.
Keywords: Biological activities; harvest time; plant industries; rosmarinic acid.