Linaria arcusangeli contains a new bisiridoid, named arcusangeloside,
besides the known antirrhinoside, linarioside, antirrhide, linaride an
d 5-glucosylantirrhinoside. The new bisiridoid is formed from a non-gl
ycosidic cyclopentanoid which esterified the iridoid glucoside 5-deoxy
antirrhinoside, also isolated as a free compound from the plant extrac
t. L. flava subsp. sardoa contains the new bisiridoid, 5-deoxyantirrhi
noside, antirrhinoside, linarioside and antirrhide.