Quantitative HPTLC analysis of artemisinin in dried Artemisia annua L.: A practical approach

Artemisinin, an antimalarial substance, is obtained on a large scale from dried leaves of Artemisia annua L. To monitor the plant during growth, determine time of harvest, or evaluate the commercial value of plant material-all with respect to the artemisinin content-it is most important to have available a simple, rapid, and cost efficient, yet dependable quantitative method of analysis. In this paper, we propose a streamlined and practical approach, taking into account a critical review of several papers recently published on the subject, as well as experimental and validation data obtained in our laboratory. The resulting HPTLC method utilizes separation on silica gel 60 with cyclohexane, ethyl acetate, acetic acid (20: 10: 1) as mobile phase, derivatization with modified anisaldehyde reagent and highly specific densitometric evaluation of fluorescence at 520 urn with a cut-off filter at 540 nm. Over a wide concentration range of 20 ng absolute (0.05% in the dried plant material) up to a theoretical amount of 1,300 ng (3.25%), the method can be applied for screening the arternisinin content of 9 samples in an hour. Following a suitable dilution, a precise and accurate assay can be performed in the linear working range of 30- 100 ng absolute.