Determination of the content of rosmarinic acid by HPLC and analytical comparison of volatile constituents by GC-MS in different parts of Perilla frutescens (L.) Britt

Background: Perilla frutescens (L.) Britt. is not only an edible plant but also a traditional medicinal plant commonly used for treating common cold. It is widely cultivated in southern China. The anatomical parts of P. frutescens that are recorded as medicines in the Chinese material medica are: Perillae Caulis, Perillae Folium and Perillae Fructus, which are the dried stems, the dried leaves and the dried ripe fruits, respectively. Rosmarinic acid is one of major polyphenolic ingredients found in all three Perillae Caulis, Perillae Folium and Perillae Fructus. The characteristic volatile oil of P. frutescens is believed to be another essential composition of the herb, giving its wide range of use. Results: A simple, rapid and accurate HPLC-DAD method was set up, suitable for the assay of rosmarinic acid in Perillae Fructus, Perillae Folium and Perillae Caulis. 12 batches of Perillae Caulis, 12 batches of Perillae Folium and 13 batches of Perillae Fructus from 8 different regions of mainland China and Hong Kong herbal markets were collected for evaluating the quality of P. frutescens. Results showed that Perillae Folium typically had the highest content of rosmarinic acid. Certain macroscopic characteristics were related to the concentration of rosmarinic acid. The volatile components were identified and compared in Perillae Fructus, Perillae Folium and Perillae Caulis by gas chromatography-mass spectrometry (GC-MS). Extracts were prepared by steam distillation. Twelve, seventeen and nine compounds were identified and accounted for 69.71%, 50.54% and 81.73% of all identified peak areas in Perillae Caulis, Perillae Folium and Perillae Fructus respectively. The identified components were analyzed for comparison of Perillae Caulis, Perillae Folium and Perillae Fructus more effectively. Conclusions: This work provides a means by which samples of various parts of P. frutescens can be evaluated in terms of their pharmacologically active components. It should be of value in the efficient exploitation of P. frutescens plant material in clinical applications and drug development.