The present invention concerns the use of compounds for preventing and/or treating diabetes, for modulating glucose, insulin, and/or triglyceride levels； for reducing blood glucose level； for maintaining or increasing insulin level； for increasing insulin secretion； increasing insulin sensitivity； or decreasing insulin resistance in a subject. These novel uses have been found for compounds represented by Formula I and pharmaceutically acceptable salts. wherein A is C5 alkyl, C6 alkyl, C5 alkenyl, C6 alkenyl, C(0)-(CH2)n-CH3 or CH(OH)-(CH2)n-CH3 wherein n is 3 or 4； R1 is H, F or OH； R2 is C5 alkyl, C6 alkyl, C5 alkenyl, C6 alkenyl, C(0)-(CH2)n-CH3 or CH(OH)-(CH2)n-CH3 wherein n is 3 or 4； R3 is H, F, OH or CH2Ph； R4 is H, F or OH； Q is 1) (CH2)mC(O)OH wherein m is 1 or 2, 2) CH(CH3)C(O)OH, 3) C(CH3)2 C(O)OH, 4) CH(F)- C(O)OH, 5) CF2- C(O)OH, or 6) C(O)- C(O)OH.
