Structurally diverse diterpenoids from the leaves of Croton mangelong and their anti-diabetic activity

Eighteen compounds including eleven previously undescribed diterpenes were isolated from the leaves of Croton mangelong. The structures were determined by HRESIMS, IR, NMR, X-ray diffraction and ECD spectroscopic analysis. All isolates were assayed for their anti-hyperglycemic activities in insulin resistance (IR) 3T3-L1 adipocytes, and compound 4 was tested for its anti-diabetic activity in vivo. Results suggested compound 4 could effectively reduce blood glucose level in diabetic SD rats in a dose of 30 mg/kg. Eleven undescribed diterpenes were isolated from the leaves of Croton mangelong. All isolates were assayed for their anti-hyperglycemic activities in insulin resistance (IR) 3T3-L1 adipocytes. Compound 4 was tested for its anti-diabetic activity in vivo. Results suggested 4 could effectively reduce blood glucose and blood lipids levels in diabetic SD rats with minimal liver damage in a dose of 30 mg/kg. [Display omitted] •Eleven undescribed diterpenes were isolated from the leaves of Croton mangelong.•The absolute configurations were ensured by X-ray crystallography or ECD calculation.•Compound 4 was evaluated in vivo for its hypoglycemic activity.