Chemical constituents of Cochlospermum regium (Schrank) Pilg. root and its antioxidant, antidiabetic, antiglycation, and anticholinesterase effects in Wistar rats

Abstract

The main physiological consequence of diabetes mellitus is chronic hyperglycemia. This condition is related to the formation of free radicals including advanced glycation end products (AGES) and to an increase in inflammatory processes. Cochlospermum regium (Schrank) Pilg., part of the Bixaceae family, is a cerrado plant known for its anti-inflammatory effects. The objectives of this study were to analyze the constituent compounds of C. regium roots and to evaluate the antioxidant, antiglycation, antidiabetic, and anticholinergic effects of its hydromethanolic extract through in vitro and in vivo experimental models. The presence of phenols, flavonoids, condensed tannins, and flavonols was analyzed by liquid chromatography - photodiode array (LC/PDA) analysis. Whereas antioxidant activity was investigated via DPPH, ABTS, β-carotene/linoleic acid, and malondialdehyde colorimetric assays. Inhibition of AGEs was examined via a bovine serum albumin system whose glycosylating agent was glucose. Antidiabetic potential was examined in normoglycemic Wistar rats that received glucose overload, in alloxan-induced diabetic rats, and in rats that received a hyperglycemic diet. Disaccharidase inhibition was assessed using in vitro and in vivo methods, as was acetylcholinesterase (AChE) inhibition in brain structures. The hydromethanolic extract (CRHE) possessed a high concentration of phenolic compounds and showed antioxidant effects. The LC-DAD results revealed that CRHE contained a high concentration of phenolic acids and the majority was gallic acid. Treatment with CRHE caused significant inhibition of AGE formation. The oral glucose tolerance test (OGTT) in normoglycemic animals showed a reduction in blood glucose levels after treatment with 100 mg/kg CHRE, accompanied by an increase in hepatic glycogen content. There was also a significant reduction in the fasting glucose levels of alloxan-induced diabetic animals after 7 days of treatment with daily doses of 100 mg/kg. After 14 weeks of hyperglycemic diet, the last four or which were combined with 100 mg/kg CRHE treatment, there was a decrease in blood triglyceride levels. There was also a statistically significant decrease in the enzymatic activity of maltase, lactase and sucrase. The results demonstrate that oral administration of 30 and 100 mg/kg CRHE inhibited AChE activity in different brain structures. Thus, the extract of C. regium showed promising antioxidant, antiglycation, and antidiabetic effects that may be related to its high phenolic content.