The plants were harvested at five different phenological stages (rosette, bolting, pre-flowering, flowering and post flowering). Leaves, stem, young inflorescence and mature inflorescence were separated manually, oven dried at 37 ◦C and weighed. Dried samples were kept in plastic bags at room temperature until analysis for artemisinin collected. This step was repeated thrice and finally pooled solvents were concentrated under reduced pressure. With minor modifications in the method as described by Bhandari et al. (2005) was used for artemisinin analysis. 2 l of extracted solutions were applied on silica coated TLC plates (Merck, Germany). TLC plates were air dried and developed in mobile phase, containing hexane:ethyl acetate (9:1, v/v). The densitometric determination of artemisinin was carried out after derivatization with anisaldehyde reagent at 540 nm in absorption-reflectance mode. Artemisinin was quantified with the help of standard curve prepared by HPTLC (CAMAG) using different concentrations of standard artemisinin. Artemisinin content was expressed as % on dry weight basis.