Phytochemical Analysis and Chemobiological Standardization of Artemisia amygdalina

Abstract

This chapter deals with the bioactivity guided isolation of Artemisia amygdalina Decne. The hexane extracts of both shoot and root parts of Artemisia amygdalina Decne have displayed potent cytotoxic effects. Phytochemical analysis of these active extracts has led to the isolation of six cytotoxic constituents, viz., 7,22-ergostadien-3β-ol (1), ludartin (2), 5-hydroxy-6,7,3′,4′-tetramethoxyflavone (3) (from shoots) and trans-matricaria ester (4), diacetylenic spiroenol ether (5) and cis-matricaria ester (6) (from root) from this plant. The constituents have been identified using spectral and analytical techniques in the light of literature. Sulphorhodamine B cytotoxicity screening of the isolated constituents has been carried out against four human cancer cell lines including lung (A-549), leukemia (THP-1), prostate (PC-3), and colon (HCT-116) cell lines. Ludartin (2) exhibited the highest cytotoxicity with IC50 values of 7.4, 3.1, 7.5 and 6.9 µM against lung (A-549), leukemia (THP-1), prostate (PC-3), and colon (HCT-116) cancer cell lines, respectively. To test against in vitro skin cancer models [human dermal fibroblasts (CRL-1635)], all the isolates have been further subjected to 3-(4,5-dimethylthiazol-yl)-diphenyl tetrazolium bromide (MTT) cytotoxicity screening. Ludartin being highly cytotoxic has been evaluated against mouse melanoma (B16F10) and human epidermoid carcinoma (A-431) cells by MTT assay displaying IC50 values of 6.6 µM and 19.0 µM respectively. Finally a simple and reliable HPLC method has been developed (RP-HPLC-DAD) and validated for the simultaneous quantification of these cytotoxic constituents in A. amygdalina Decne. Excellent specificity and high linearity for all the standard calibration curves, having regression coefficients of the respective linear equations in the range of 0.9962 − 0.9999, has been observed. Relative recovery rates varied between 98.37 ± 0.90 and 105.15 ± 1.74 with relative standard deviation less than 4 %. Based on these results, the developed method features good quantification parameters, accuracy, and precision and can serve as effective quality control method for standardization of A. amygdalina Decne.