O=C(O[C@@H]1[C@@H]2O[C@]2(CO)[C@H]2[C@H](OC3OC(CO)C(O)C(O)C3O)OC=C[C@@H]12)c1ccc(O)c(O)c1
Molecules with a polar surface area of greater than 140 angstroms squared (Å2) tend to be poor at permeating cell membranes. What's the psa of this molecule?