Indene derivatives and uses thereof

A compound of formula (I):

• wherein:
• R1 and R2, independently of each other, are hydrogen, hydroxyl, alkyl, alkoxy, methoxy-acetate, phosphate, valine, Gly-Ser, —OC(O)CH2OC(O)CH3, —OC(O)CH2OCH3, —OCH2C(O)C(CH3)3, —OCH2C(O)NH2 or —OCH2C(O)OH;
• or R1 and R2, together with the carbon atoms to which they are attached, form a 5 to 6-membered ring with one or two ring carbons replaced independently by oxygen or nitrogen;
• R3 is hydrogen, hydroxyl, halogen, cyano, —COOH, —C(O)NH2, —C(O)CH2CH3, —C(O)-alkoxy, alkyl, alkoxy, halo-lower alkyl, carboxyl, amide, ester or nitrile;
• and
• R4 is alkyl or alkenyl, said alkyl or alkenyl optionally mono or bi-substituted independently with hydrogen, halogen, hydroxyl, —OCH2-phenyl, cycloalkyl, —OCH2-halophenyl or —OCH2-phenylhaloalkyl,
• or a pharmaceutically acceptable salt thereof.