Conclusion
In the extraction of C. asiatica using subcriticalwater, the extraction
yields of asiatic acid and asiaticoside increased with an increase
in temperature, while the extraction yields only slightly increased
with an increase in pressure. The optimum extraction conditions
of asiatic acid and asiaticoside were at 250 ◦C and 40MPa. Under
these conditions, 7.8mg/g of asiatic acid and 10.0 mg/g of asiaticoside
were extracted. The extraction yields of asiatic acid and
asiaticoside, using subcritical water at the optimum conditions,
were higher to those using the conventional liquid solvent extraction
withmethanol or ethanol at roomtemperature, while its values
were lower to those with methanol or ethanol at its boiling point
temperature. The extracted asiatic acid and asiaticoside precipitated
when the subcritical water containing the extracts were
depressurized and cooled to room temperature. This enables the
collection of asiatic acid and asiaticoside as particles using the simple
filtering process. The size of the particles containing asiatic acid
was larger than the size of the particles containing asiaticoside.
Thus, separation of asiatic acid and asiaticoside can be achieved
when choosing an appropriate size of filter.