Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
interest [ˈɪntrɪst] n
interest (in) интере́с (к +dat) (COMM) (in company) до́ля#; (:sum of money) проце́нты mpl
vt интересова́ть (impf)
compound/simple interest сло́жные/просты́е проце́нты mpl
it is in our interests (to our advantage) э́то в на́ших интере́сах
British interests in the Middle East брита́нские интере́сы на Бли́жним Восто́ке
his main interest is history его́ основно́й интере́с - э́то исто́рия
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.