Cytotoxicity and Chromatographic Fingerprinting of Euphorbia Species Used in Traditional Medicine.

Abstract

Chromatographic fingerprinting of plant species play an important role in species identification and standardization of plant based health products. Some of the Euphorbia species are used in folk medicine, yet majority of these exhibit various degrees of toxicity. It becomes a challenge to distinguish the toxic from the non-toxic species. The study aimed to evaluate cytotoxicity and to determine the method for fingerprinting the chemical constituents of the selected Euphorbia species to identify markers of toxicity. Hexane, DCM, ethyl acetate and methanol extracts of E. arabica, E. bupleurifolia, E. enopla, E. gorgonis, E. horrida indigenous and E. horrida var. were examined in mammalian vero cell line using MTT cell viability test assay. The presence of secondary metabolites and proteins were assessed in the plant extracts and thin layer chromatography was used to identify toxicity markers. The hexane and DCM extracts of E. arabica, E. bupleurifolia and the DCM extract of E. horrida var. exhibited the highest cell growth inhibition reaching IC50 at a concentration of 10 μg mL-1. Both polar and non-polar extracts of E. enopla exhibited cell growth inhibition with the hexane extract reaching IC50 at a concentration of 10 μg mL-1. Euphorbia gorgonis and E. horrida indigenous were not active against the vero cell line. Secondary metabolites were detected, however, proteins were not detected in all six Euphorbia species. The TLC profiles of toxic extracts revealed additional bands which were absent in non-toxic species. It is concluded that the TLC method developed in this study can be used as a quick screen method to possibly distinguish toxic from non-toxic species, as well as in identifying the studied species.