Quantitative analysis of vasicine and vasicinone in <i>Adhatoda vasica</i> (Nees.) using RP-HPLC: distribution and solvent extraction efficiency

<i>Adhatoda vasica</i> Nees (Acanthaceae), an ayurvedic shrub, is used widely in respiratory disorders. The pharmacologically most studied phytoconstituent in <i>A. vasica</i> is vasicine, a bitter quinazoline alkaloid present in leaves. A robust method was developed for the simultaneous quantification and analysis of two major alkaloids i.e. vasicine and vasicinone by RP-HPLC. This paper describes the distribution of these markers in different parts of the plant along with the best extraction method for their recovery. The highest abundance of vasicine was observed in the leaves (0.7332%), than in the stems and roots, whereas vasicinone was present only in the leaves (0.0436%). Methanol was identified as the most effective solvent for the extraction of vasicine in successive extraction (the herb was extracted sequentially with increasing solvent polarity) whereas 30% aq. Methanol is recommended for extraction of vasicinone in individual solvent extraction (the fresh herb was extracted separately with different solvents) method.