The fact for increase in importance of natural plant based
material is that plant resources are renewable and if cultivated
or harvested in a sustainable manner, they can provide a
6 constant supply of raw materials . However, substances from
plant origin also pose several potential challenges such as
being synthesized in small quantities and in mixtures that are
structurally complex, which may differ according to the
location of the plants as well as other variables such as the
season. This may result in a slow and expensive isolation and
purification process. Another issue that has become increasingly important is that of intellectual property rights