Orally hypoglycemic activity of an insulin mimetic glycoprotein isolated from Cnidoscolus quercifolius Pohl. (Euphorbiaceae) seeds, Cq-IMP

• Published in: International journal of biological macromolecules 2020-09, Vol.159, p.886-895
• Main Authors: Moura, Luiz Francisco Wemmenson Gonçalves, da Silva Costa, Helen Paula, da Silva Neto, João Xavier, Dias, Lucas Pinheiro, Magalhães, Francisco Ernani Alves, van Tilburg, Maurício Fraga, Florean, Eridan Orlando Pereira Tramontina, de Oliveira, Jose Tadeu Abreu, Oliveira Bezerra de Sousa, Daniele de, Guedes, Maria Izabel Florindo
• Format: Article
• Language: English
• Subjects: Administration, Oral; alpha-Amylases - antagonists & inhibitors; alpha-Amylases - chemistry; Animals; Chromatography, Liquid; Diabetes mellitus; Euphorbiaceae - chemistry; Glucose Tolerance Test; Glycoproteins - administration & dosage; Glycoproteins - chemistry; Glycoproteins - isolation & purification; Hypoglycemic activity; Hypoglycemic Agents - administration & dosage; Hypoglycemic Agents - chemistry; Hypoglycemic Agents - isolation & purification; Insulin - chemistry; Mice; Molecular Mimicry; Molecular Structure; Molecular Weight; Plant insulin-mimetic protein; Plant Proteins - administration & dosage; Plant Proteins - chemistry; Plant Proteins - isolation & purification; Seeds - chemistry; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Spectrum Analysis
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2020.05.033

The genus Cnidoscolus (Euphorbiaceae) is widely distributed in tropical areas. In the Northeast of Brazil, the species C. quercifolius is endemic and has been used in traditional medicine. In this study, a novel protein was isolated from C. quercifolius seeds and characterized by its molecular weight, primary structure, isoelectric point (pI), and carbohydrate content. The hypoglycemic activity of this protein was investigated by in vitro assay with the RIN-5F glucose-responsive cell line and in vivo test using alloxan-induced diabetic mice models. In addition, safe use of the protein was also investigated by cytotoxicity, hemagglutinating, and immunogenicity assays. The protein which was named Cq-IMP (Cnidoscolus quercifolius – Insulin Mimetic Protein) showed a single 11.18 KDa glycopolypeptide chain (16.4% of carbohydrates, m/m), pI of 8.0 and N-terminal sequence (TKDPELKQcKKQQKKqQQYDDDDKK) with similarity around 46–62% to sucrose binding protein-like and vicilin-like protein that was confirmed by mass spectrometry tryptic peptides analysis. Besides that, Cq-IMP presented anti-insulin antibody cross-reactivity as hypoglycemic activity in both in vitro and in vivo models. Additionally, it did not present any toxicity by methods tested. In conclusion, Cq-IMP is an insulin-mimetic protein, with a potent hypoglycemic activity and no toxicity showing great potential for therapeutic applications and drug development. [Display omitted] •Isolation and characterization of an 11.18 kDa glycoprotein from Cnidoscolus quercifolius•In vitro and in vivo hypoglycemic activity and positive anti-insulin IgG cross-reactivity•No Vero cell cytotoxicity effect, allergenicity or hemolytic activity was detected.