Variation in composition and yield of foliage oil of eucalyptus polybractea

Eucalyptus polybractea (blue mallee) is the essential oil rich species used in the commercial production of pharmaceutical-grade eucalyptus oil in australia. this species was grown at nuclear institute for agriculture and biology (niab),faisalabad,pakistan during 2004-08 to investigate the quantity and quality of its foliage oil. the oils were extracted by hydro-distillation method,from the leaves of four year aged ten e. polybractea plants. the data showed a significant intra-species variation in their oil contents (29.3 to 41.8 mg g-1 fresh weight of leaves). out of ten plants eight contained oil >30 mg g-1 fresh weight of leaves. the components of the extracted oils varied from 12-26 as detected by gc/fid on carbowax 20 m packed glass column. among all the oil components,1,8-cineole was the major compound (91.7-94.2 %),while the other identified compounds were α-pinene (0-1.2 %),β-pinene (0.4-2.3 %),limonene (0.2-1.3 %),p-cymene (1.23-2.75 %),and terpinene-4-ol (0.6-0.92 %). the extracted oils from all the eucalyptus polybractea plants contained high amount of 1,8-cineole (>90 %),therefore,classified as species of high quality medicinal oil.