Five extraction methods (sonication, reflux, Soxhlet extraction, maceration and percolation) were compared and the yield of the 70% ethanolic extracts and Although, the
content of didehydrostemofoline in each extract was not significantly
different (0.471–0.538% w/w), sonication and reflux yielded
the extracts with the highest content (0.538 and 0.515% w/w).
Adding heat or ultrasonic energy during the extraction process can
decrease extracting time and promote higher yield of didehydrostemofoline.
This is because ultrasonication facilitates the swelling
and hydration of plant materials, resulting in enlargement of the
pores of the cell wall. This, thereby, improves the diffusion process
and enhances mass transfer (Vinatoru, 2001). Extraction efficiency
could also be improved by adding heat. Higher temperature in the
refluxing process induces higher solubility of analytes in solvent
and higher diffusion rate (Ong, 2004). Reflux promoted high yield
of crude extract (70.23% dry weight), required short extracting time
(2.5 h) and less amount of solvent (1:100 g:ml). It is also simpledidehydrostemofoline content in the extracts of S. collinsiae roots were shown in Table 2.