This book discusses the isolation and structure elucidation of new P-coumaroyl flavonol glycosides from Centaurium spicatum arial parts which significantly increase both TNF-¿ and IL-1ß after 48 h of treatment (this level of increase of cytokines (300/200) activates the cytokines like vaccines towards invasion of microorganisms. Also the book discusses the isolation and structure elucidation of new ester of swertiamarin and secoxyloganic acid in addition to its known components secoiridoids swertiamarin and secoxyloganic acid. Structure elucidation of the new compounds was established on the basis of 1D and 2D NMR analyses including 1H-, 13C- NMR, DEPT-135 NMR, HMQC, HMBC and H- H HOHAHA experiments in addition to FAB+ and HRFAB+ Mass spectrometry. All tested secoiridoids have transaminases inhibition activity with different values for each compound (86%, 83%, 81%) for SGOT and (96%, 93%, 91%) for SGPT, respectively which means that the new ester compound has hepatoprotective activity over than its components.