Seeds of P. ruderale were collected from wild plants found on the campus of the Federal University of Vicosa, Minas Gerais state (Brazil), in September 2000. The seeds were cultivated in a greenhouse during the period of February to May 2001; 60 days after sowing, the leaves and flowers were collected at regular intervals of 15 days for the oil isolation.

The oil content found for the leaves of P. ruderale varied during the period of 60 to 120 days, as follows: 13.8 mg/100 g of fresh material after 60 days; 7.5 mg/100 g (75 days); 23.1 mg/100 g (90 days); 10.6 mg/100 g (105 days); 12.5 mg/100 g (120 days). The first floral buds were collected after 105 days of sowing, and its oil content was 45.1 mg/100 g of fresh material. A significant decrease in the production of oil from the buds was observed after 120 days of sowing, when only 23.0 mg oil/100 g of fresh material was obtained. During the period of 90 days to 105 days, a significant decrease in leaf oil content was observed, at the same time the plants were flowering. This data suggests the plants were relocating their resources to produce more oil in the floral buds.