| Dipeptidyl peptidase IV (DPP-IV, CD26) is an important target for the treatment ofdiabetes in recent years. It has been showed that glucagon-like peptide-1, the substrate ofDPP-IV, have significant hypoglycemic effects. But in vivo, GLP-1is rapidly degraded byDPP-IV, the inactivation of GLP-1make it diffcult to play its hypoglycemic effect in diabetes.As a result, DPP-IV inhibitors have emerged as a promising drug to treat diabetes byextending half-life of GLP-1. So far, there are a numbers of inhibitors have been approvedand some have been taken part in Phase â…¢.Inonotus obliquus (Pers.:Fr.) Pil.(syn; Fuscoporia oblique (Pers.:Fr.) Aoshima) is arare fungus which can prevent and cure many diseases such as gastric cancer, intestinal cancer,heart disease and diabetes. Submerged culture was used to produce Inonotus obliquus due tothe scarce of fruiting bodies and difficulty in culture of this fungus. Previous researchesshowed that there existed components inhibiting DPP-IV in the fermentation products.In this paper, fementated product of Inonotus obliquus was obtained by submergedfermentation. Then, screening of DPP-IV inhibitory components from fementated productwas performed by separation and purification technology combined with evaluated model ofDPP-IV inhibitory activity. Using structural analysis technology, structure of activecompounds was identified. Mechanism of the interaction of the active compounds with theDPP-IV was studied by Molecular docking.The chief results were summarized as follows:(1) Fermentation at a scale of50L was performed, and the biomass rearch up tomaximum of8.6g/L on the nineth day. Mycelia powders (201.9g) and broth powders(117.91g) were obtained by liquid fermentation and10extracts from fementated productwere obtained by extracting by a variety of solvents. The evalution of activity showed thatchloroform extract of mycelium and methnol extract of btoth, which inhibited DPP-IV by38.1%and31.2%at200mg/L, may be the potential active component.(2)Separation and purification of two extracts were peformed by a variety of techniquessuch as silica gel column chromatography, sephadex LH-20column chromatograph,macroporous resin column chromatography and preparative HPLC. After purificating, theinhibitory rate repectively improved to47.1%and51.7%. At last, the active coponents andactive compounds were obtained.(3) Twenty compounds in the active sites were deduced using UPLC-Q-TOF-MS. Therewere eleven compounds of Alkaloids classes, five compounds of steroids and triterpenoidsand four compounds of others. To identify the potential inhibitors, we simulated theinteractions between the compounds and the enzyme by molecular docking. Compared with Sitagliptin, a approved inhibitor, compound5,8,9,14,15showed stronger interactions thatmeans these six compounds maybe the potential inhibitors. |
