Tetragalloylquinic acid, the major antiasthmatic principle of Galphimia glauca

In the search for antiasthmatic principles in plant drugs, a bioguided fractionation of an alcoholic extract of Calphimia glauca was performed using a plethysmographic in vivo model. Tetragalloylquinic acid (G1), which was found together with other compounds (gallic acid, methyl gallate, ellagic acid, and flavonoid acylglycosides), showed the highest activity against bronchial hyperreactivity and allergic reactions. Using mass and NMR spectroscopy in combination with energy calculations, the structure G1 was elucidated as tetra-O-galloylquinic acid. Depending on the solvent used, the quinic acid skeleton can occupy a fixed conformation or several interconverting ones on the NMR time scale.