8-methoxygriseorhodin C

(2R*,3'R*)-3,4-Dihydro-3,3',4',9',10-pentahydroxy-4,7'-dimethoxy-7-methylspiro[benzo[1,2-b:5,4-c']dipyran-2(9H),2'(3'H)-naphtho[2,3-b]furan]-5',8',9-trione