A RAPD-Based Method for the Quality Control of Mediterranean Oregano and Its Contribution to Pharmacognostic Techniques

A pharmacognostic survey on 84 commercial samples of Mediterranean oregano, obtained from wholesale traders during years 2001-2007, pinpointed the presence of extraneous plant material in 90.5% of the samples. In 59% of them extraneous material of plant origin was above 20%. Two major groups of botanical foreign matter were identified: oregano-like flavored plants (Satureja montana L., Origanum majorana L.) and plants lacking a clearly detectable essential oil profile (Rubus sp., Cistus incanus L., Rhus coriaria L.), added as bulk extraneous material. A Random Amplified Polymorphic DNA (RAPD) method was developed in order to make the detection of the second group of adulterants easier and speed up pharmacognostic analysis of large batches of samples. Thirteen of 1%. The utilization of RAPDs as a reliable test to probe the authenticity of Mediterranean oregano or previously screen the presence of specific contaminants is proposed as a complementary approach to pharmacognostic and phytochemical screening