Rhamnopterin is a derivative of L-biopterin , the oxidized form of tetrahydro-L-biopterin (BH₄), and D-biopterin .¹Dietary administration of rhamnopterin (0.5%) concurrently with the carcinogen 4-dimethylaminoazobenzene reduces the incidence of 4-dimethylaminoazobenzene-induced liver tumors in rats. Rhamnopterin has been used as an internal standard for the quantification of biopterin and neopterin in rat plasma by LC-MS.²

1.Sasaki, H., Nagase, S., Fujimaki, C., et al.Effect of polyhydroxy-alkylpterins on the development of liver cancers in the rat fed with 4-dimethylaminoazobenzeneGan.55297-304(1964) 2.Pickert, G., Lim, H.-Y., Weigert, A., et al.Inhibition of GTP cyclohydrolase attenuates tumor growth by reducing angiogenesis and M2-like polarization of tumor associated macrophagesInt. J. Cancer132(3)591-604(2013)