Characterization of potent antidiabetic compounds from Costus pictus D. Don found in Assam, India using in vitro in vivo methods

Abstract

Objective: Costus pictus D. Don is a traditionally used plant in Naojan area of Golaghat district of Assam, India specifically for treating diabetes. Six compounds were isolated from standardized methanolic extract of the aerial parts (MECP). The prime objective was to select most potent antidiabetic compounds among the isolated compounds viz. F67, F12, F16, F3032, F37 & F48 by using in vitro and in vivo methods.

Methods: Isolated compounds were subjected to initial screening by in vitro α-amylase inhibition activity assay using iodine-starch and DNSA (3,5-dinitrosalicylic acid) methods. Compounds depicting promising in vitro activity were selected for in vivo Streptozotocin (STZ) induced antidiabetic screening activity. Then based on the in vivo results, most potent compounds were selected for instrumental characterization by Q-TOF ESI-MS, 1HNMR, 13CNMR & FTIR.

Results: Amongst the six compounds isolated from MECP, three compounds viz. F12, F16 & F48 showed potent in vitro activity. They were subsequently subjected to evaluation of the antidiabetic activity in vivo by oral administration, at dose of 10, 20 & 50 mg/kg body weight respectively, using Wister rat (120-150 g) and Glibenclamide (10mg/k body weight) as standard. Two compounds, F12 and F48 at dose of 50 mg/kg body weight, reversed STZ induced diabetic parameters (increased blood glucose level, altered plasma profile and histoarchitecture of the pancreatic and hepatic cells) with statistical significance (P<0.05), that was comparable with the standard. Hence, instrumental characterization by Q-TOF ESI-MS, 1HNMR, 13CNMR & FTIR of compounds F12 and F48 isolated from MECP was carried out which established their identity as (3,5,7-Trihydroxy-3’-hydroxy-4’-methoxy) flavanone or [3,5,7-Trihydroxy-2-(3’-hydroxy-4’-methoxy phenyl)-2,3-dihydrochromen-4-one] and 3,5,8-trihydroxy-7-methoxy-2-phenyl-2,3-dihydrochromen-4-one or [7-methoxy-3, 5, 8 trihydroxy flavanone] respectively.

Conclusion: The study culminated in elucidation of two flavanones as most potent compounds in exhibiting antidiabetic activities. The findings were thus successful in validating the traditional practices in Golaghat district of Assam, India, associated with the use of Costus pictus D. Don in the treatment of diabetes.