The present invention relates to a compound of general formula (I) in which: —R1 and R2 are simultaneously or independently H, OH, OCH3 or a C1-C5 alkyl radical, —R3 and R4 are simultaneously CH3, —or R3 is H and R4 is CH3, CH2CH3 or an isopropyl radical or a phenyl radical, —R5 is a C4-C24 alkyl radical or a 3-phenylpropanyl or 2,2-diphenylethanyl radical.
