Seasonal variation in the composition of the essential oils from the leaves, thin branches and resin of Protium spruceanum (Benth.) Engl.

In a previous paper, we described the essential oils of Protium spruceanum obtained from different parts of the plant. In this paper, the essential oils obtained from the leaves, thin branches and resins were collected from October 1999 at 1 month intervals up to October 2000. At each sampling, the oil content was determined in a Clevenger‐type apparatus, and examined by GC–MS. The major component from the leaf, resin and thin branch oils was sabinene (leaves, January 81.4%; thin branches, January 79.8%; resin, October 1999, 61.3%), followed by β‐caryophyllene in the leaf oil. The maximum content of β‐caryophyllene from the leaf oil was 36.4% in February. The highest oil yields were observed from leaves (0.4%) sampled in April and from resin sampled in October 1999 (4.0%). Thin branch oil yields were in the range ≤0.1–0.2%.