Background: Helianthus annuus L. (sunflower) is well known for its edible oil, sunflower seed has been used as folk remedy for several diseases including cancer. Materials and Methods: In this study, SUNCA, a standardized extract enriched with chlorogenic acid (CGA) from sunflower seed was investigated for in vitro antidiabetic activity using α-amylase and α-glucosidase enzyme inhibition assay. Further, for preventing obesity, we demonstrated anti-adipogenesis in 3T3-L1 cell culture system and on body weight gain and adiposity in rat fed high-fat diet (HFD). Results:SUNCA showed significant inhibitory activity toward digestive enzymes such as α-amylase and α-glucosidase. On the other hand, SUNCA significantly inhibits lipid accumulation during adipogenesis in a dose-dependent manner. The treatment with 100 μg/kg b.w of SUNCA apparently prevented the body weight gain and the increase of triglyceride and total cholesterol level in rat fed an HFD for 6 weeks. Further immunoblotting studies reveal that SUNCA significantly down-regulates the expression of transcription factors peroxisome proliferator-activated receptor gamma and CCAT/enhancer-binding protein alpha, both in adipocytes and adipose tissues. Conclusion: The findings reported here provide the therapeutic potential of SUNCA, a standardized extract from Helanthus annus L.