Isolation, Structural Characterization and Antidiabetic Activity of New Diketopiperazine Alkaloids from Mangrove Endophytic Fungus <i>Aspergillus</i> sp. 16-5c
Geting Ye,
Cuiying Huang,
Jialin Li,
Tao Chen,
Jing Tang,
Wenbin Liu,
Yuhua Long
Affiliations
Geting Ye
Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, School of Chemistry, South China Normal University, Guangzhou 510006, China
Cuiying Huang
Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, School of Chemistry, South China Normal University, Guangzhou 510006, China
Jialin Li
Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, School of Chemistry, South China Normal University, Guangzhou 510006, China
Tao Chen
Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, School of Chemistry, South China Normal University, Guangzhou 510006, China
Jing Tang
Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, School of Chemistry, South China Normal University, Guangzhou 510006, China
Wenbin Liu
Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, School of Chemistry, South China Normal University, Guangzhou 510006, China
Yuhua Long
Guangzhou Key Laboratory of Analytical Chemistry for Biomedicine, School of Chemistry, South China Normal University, Guangzhou 510006, China
Six new DIKETOPIPERAZINE alkaloids aspergiamides A–F (1–6), together with ten known alkaloids (7–16), were isolated from the mangrove endophytic fungus Aspergillus sp. 16-5c. The structures of the new compounds were elucidated based on 1D/2D NMR spectroscopic and HR-ESIMS data analyses. The absolute configurations of aspergiamides A-F were established based on the experimental and calculated ECD data. All the compounds were evaluated for the antidiabetic activity against α-glucosidase and PTP1B enzyme. The bioassay results disclosed compounds 1 and 9 exhibited significant α-glucosidase inhibitory with IC50 values of 18.2 and 7.6 μM, respectively; compounds 3, 10, 11, and 15 exhibited moderate α-glucosidase inhibition with IC50 values ranging from 40.7 to 83.9 μM; while no compounds showed obvious PTP1B enzyme inhibition activity.
