Phytochemical Analysis and Antimicrobial Activity of Euphorbia milii

Antimicrobial activities of Euphorbia milii (Euphorbiaceae) extract and its sub-fractions against Gram-negative, Gram-positive bacteria, unicellular yeast and two filamentous fungi were evaluated and the minimum inhibitory concentrations were determined. The ethyl acetate fraction (EAf) exhibited the most significant antimicrobial activity against five tested pathogenic microbes. For the first time, liquid chromatography-electrospray ionization-time-of-flight mass spectrometry analysis (LC-ESI-TOF-MS) of EAf was used to identify its chemical composition. LC-MS/MS analysis allowed the tentative identification of 22 compounds. Quercitrin, luteolin, quercetin, kaempferol-3-glucuronide and naringenin were the major constituents. The chemical composition of un-saponified and saponified from n-hexane fraction was analysed by gas chromatography/mass spectrometry (GC-MS). The oxygenated compounds represent the major constituent in both fractions (56.48 and 61.97%, respectively). Terpenes represented by 30.94% in un-saponified fraction while fatty acids and esters constituted by 18.91% in the saponified fraction. Quantification of the total phenolics and flavonoids of the methanolic extract and its successive fractions were determined. The highest percent of the total phenolic was observed for methanolic extract while total flavonoids were recorded for n-butanol and ethyl acetate.