Ruta chalepensis seedlings were sown in the field in January 1999. Leaf materials were collected at vegetative stage (25th August 1999, plant height 60 cm, temp. min. 26.4 ℃, max. 35.6 ℃) and at budding stage (25th February 1999, plant height 115 cm, temp. min. 9.6 ℃, ma. 26.2 ℃). At flowering stage (2Sth March 2000, plant height 118 cm, temp. min. 14.3 ℃, max. 29.7 ℃), both leaves and flowers were collected; at fruiting stage (25th April 2000, plant height 119 cm, temp. min. 21.5 ℃, max. 39.1 ℃), leaves and fruits were again collected for oil isolation and analysis.

Analysis of the oils from R. chalepensis showed that the major constituents of oils were 2-undecanone, 2-nonanone, 2- nonyl-acetate and 2-dodecanone. 2-Undecanone was found to reach a maximum in the flower oil followed by fruit and leaf oils. The quantity of 2-undecanone was highest in the leaves when the plants were young and in the vegetative stage, and it gradually decreased when the plants started flowering and fruiting. 2-Nonanone, on the other hand, was at its maximum in the Leaf oil followed by flower and fruit oils. The quantity of 2-nonanone in the leaves gradually increased from the vegetative stage to the flowering stage and was highest during fruiting stage. The concentration of 2-nonyl acetate was observed to be highest in the leaves during the vegetative stage, while 2-dodecanone was at its maximum in the fruits. Lina-lool, an important aromatic compound, has been found to be highest in flowers. Gamma-Terpinene and 6-methyl-5-hepten-2-one were observed only in vegetative stage of the plants. During the flowering and fruiting stages they could not be detected. Pregeijerene was observed during flowering only, while geijerene was observed both during flowering and fruiting; however, this compound was found in leaves.