A novel spiro - pyrrolizidine[2 ' -{[3,5-bis(benzyloxy)phenyl]carbonyl}-1 ' -(4-ethoxyphenyl)-1,1 ' ,2,2 ' ,5 ' ,6 ' ,7 ' 7 ' a-octahy- drospiro[indole-3,3 ' -pyrrolizine]-2-one (compound 1 ) was synthesized via 1,3-dipolar cycloaddition of by refluxing 1-(3,5-bis(benzyloxy)phenyl)-3-(4-ethoxyphenyl)prop-2-en-1-one with isatin and L-proline . The structure was successfully elucidated by determination of single-crystal structures. The spiro-pyrrolizidine ( 1 ) crystallized in the triclinic centrosymmetric space group P1. The compound 1 exhibits significant anticancer activity on MDA-MB 231 and HCT-116 cell lines with an IC 50 values of 61.07 +/- 0.98 mu M and 62.5 +/- 70 mu M respectively.