The essential oil components of fresh and dry aerial parts of Callistemon citrinus, monthly harvested from Iran during a year, were compared. The EO contents of dry plant samples were dramatically higher than the fresh materials. The dry sample collected in March with 1.10 ± 0.04% and fresh in August with 0.16 ± 0.01% (w/w), possessed the highest and lowest EO yields, respectively. From thirty-two identified aroma phytoconstituents, 1,8-cineole was the major compound with quantity variation of 60.01% in dry sample collected in January and 33.92% in fresh from August. In summer, the amount of α-pinene as the second predominant volatile terpenoid was raised, while dry sample in August (46.92%) was the richest. The present study explicitly demonstrates the impact of harvesting period on volatile oil contents of C. citrinus and the findings are considerable to obtain the favourite EO compositions for consuming in food and phyto-pharmaceutical industries.
Keywords: 1,8-cineole; Callistemon citrinus; Myrtaceae; chemotype; volatile oil; α-pinene.