A comparative study of Soxhlet extraction and hydrodistillation for the extraction of volatile compounds from leaves of Citrus x aurantium L. planted in Damascus

Background: Citrus x aurantium L. leaves are known to contain volatile oil, the composition of which varies depending on several factors, including the country of origin, climate, and extraction method. The components of the volatile oil extracted from bitter orange leaves have not received much attention in the literature. Therefore, this study aimed to compare two methods for extracting volatile compounds from bitter orange leaves (hydrodistillation and extraction with a Soxhlet extractor). Materials and methods: Leaves were collected from several areas in the city of Damascus, and a comparison was made between the two methods for extracting volatile compounds by determining the chemical composition using a gas chromatograph connected to a mass spectrometer (GC-MS). Results: Hydrodistillation resulted in a volatile oil with a pale yellow color, with a yield of approximately 0.5%, in which 27 compounds were identified. As for extraction with a Soxhlet extractor, an extract of a dark green color was obtained, with a yield of approximately 40%, in which 33 compounds were identified. It was noted that the most abundant compound in both methods was linalyl acetate, at a percentage of 49.79% in the volatile oil sample, and at a percentage of 56.01% in the extract sample. The monoterpene compounds also achieved the highest availability percentage in both methods, at 97.16% in the volatile oil sample, and at 59.77% in the extract sample. Conclusions: We conclude that it is possible to extract the linalyl acetate compound using both methods (hydrodistillation and extraction with a Soxhlet extractor), but to obtain volatile compounds isolated from other compounds, the method of hydrodistillation is the best.