“…Its pharmacological properties have being reviewed in literature [ 4 , 5 , 6 , 7 ]. Previous investigations have shown the occurrence in the species of several secondary metabolites [ 3 , 7 ], including quinonemethide triterpenes [ 8 , 9 , 10 ] and sesquiterpene pyridine alkaloids [ 11 , 12 ] with a wide spectrum of biological activities. Studies of the antioxidant activity of flavonoids and quinonemethide triterpenes using HPLC methods [ 13 , 14 , 15 ] and their biological activities [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ], have also been reported, but knowledge about byproducts other than those of plant origin is scarce.…”