When isopropanol was used as an extraction solvent, the mean oil yields were 15.1%, 15% and 19.6% at seed to solvent ratios of 1/4, 1/6 and 1/8, respectively. We can also observe in Fig. 2(c) that isopropanol is a better solvent than ethanol at seed to solvent ratio of 1/8. Therefore, the optimal conditions that produced the greatest oil content used acetone as the solvent at a seed
to solvent ratio of 1/4 for 60 min. According to Moraes et al. (2009),the increase in the sonication time causes an increase in the mean temperature of the extraction process, which favours the extraction of the oil.