title: Elucidation of hypoglycemic action and toxicity studies of insulin-like protein from Costus igneus.
abstract: We have reported earlier, an orally active insulin-like protein (ILP) from Costus igneus having potent hypoglycemic property in STZ-induced diabetic Swiss mice. The blood glucose level was reduced significantly within two hours after feeding ILP orally in an oral glucose tolerance test. The present study elucidates the mechanism underlying the hypoglycemic action of ILP. Mechanism of action of ILP was studied in differentiated L6 myotubes. 2-NBDG uptake stimulated by ILP was studied in differentiated L6 myotubes under normoglycemic, hyperglycemic and induced insulin resistant conditions. ILP treatment significantly increased 2-NBDG uptake in differentiated L6 myotubes. The levels of insulin signaling molecules IRS-1 and GLUT-4 were assessed in ILP treated L6 myotubes by immunoblot analysis of cytoplasmic and plasma membrane fractions respectively. Immunoblot analysis revealed an increase in cytoplasmic IRS-1 with a concomitant increase in GLUT-4 translocation to the plasma membrane in a time dependent manner. Toxicity studies of ILP were performed on normal as well as diabetic Swiss albino mice. ILP did not show any toxicity in the acute and sub-chronic toxicity studies in normal as well as diabetic Swiss albino mice. Mass spectrometry was carried out to identify ILP. MALDI TOF/TOF MS analysis of ILP revealed sequence homology with the predicted protein from Physcomitrella patens. Our study reveals that ILP acts via insulin signaling pathway and can be used as oral insulin mimetic.
authors: Bioprospecting Group, Agharkar Research Institute, Pune 411 004, India.
authors: Manasi R
authors: MR
authors: Hardikar
authors: Bioprospecting Group, Agharkar Research Institute, Pune 411 004, India.
authors: Mokshada E
authors: ME
authors: Varma
authors: Department of Botany, Savitribai Phule Pune University, Pune 411 007, India.
authors: Anjali A
authors: AA
authors: Kulkarni
authors: Bioprospecting Group, Agharkar Research Institute, Pune 411 004, India.
authors: Prasad P
authors: PP
authors: Kulkarni
authors: Bioprospecting Group, Agharkar Research Institute, Pune 411 004, India. Electronic address: bimbajoshi@aripune.org.
authors: Bimba N
authors: BN
authors: Joshi
mesh_terms: D009327:4-Chloro-7-nitrobenzofurazan / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D029770:Costus / Q000737:chemistry*; D003847:Deoxyglucose / Q000031:analogs & derivatives / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000188:drug therapy*; D004195:Disease Models, Animal; D005951:Glucose Tolerance Test; D007004:Hypoglycemic Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D051379:Mice; D018482:Muscle, Skeletal / Q000187:drug effects; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin; D014409:Tumor Necrosis Factor-alpha; D003847:Deoxyglucose; D009327:4-Chloro-7-nitrobenzofurazan; C098340:2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose
keywords: Antidiabetic plants; Costaceae; Costus igneus; Diabetes mellitus; Insulin mimetics; Insulin signaling; Insulin-like protein