19891-51-1 4H,9H-Furo(2',3',4':4,5)naphtho(2,1-c)pyran-4,9-dione, 1,2,3,3a,5a,6,10b,10c-oxtahydro-1,2,6-trihydroxy-3a,10b-dimethyl-7-(1-methylethyl)-, (1S-(1alpha,2alpha,3abeta,5abeta,6alpha,10balpha,10cbeta))-