Antidiabetic activity of Neolamarckia cadamba (Roxb.) Bosser flower extract in alloxan-induced diabetic rats

Abstract

Abstract Background Various parts i.e., stem bark, leaf, root and flower of Neolamarckia cadamba (Roxb.) Bosser has been extensively used by traditional practitioners to treat all types of diabetes. Our present study investigated the antidiabetic property of the extract from its flower and evaluated its traditional use for diabetes. Results Phenolic contents were found to be higher in the methanol soluble fraction (MESF) (228.16 ± 0.32 GAE/g of sample) while flavonoids were greater in quantity in the chloroform soluble fraction (CSF) (291 ± 5.99 QE/g of sample). The MESF showed the highest free radical scavenging and α-amylase inhibitory potential with IC50 value of 30.52 ± 2.40 and 6.26 ± 0.82 μg/mL respectively and both the values were promising when compared to the individual standards. Highest reduction of blood glucose level were observed when the N. cadamba flower extract (NCFE) were given (not in combination with metformin) orally for 2 weeks. NMCE at 500 mg/kg resulted 60.2% (p < 0.05) reduction of blood glucose in the diabetic group, comparable with the effect of standard metformin (68.4%). Gain in body weight were also observed in the test groups indicating an overall improvement of health in the diabetic rats. Conclusions The extract of Neolamarckia cadamba (Roxb.) flower is rich in phenolic and flavonoid compounds attributing to its potent in vitro antioxidant and α-amylase inhibitory potential. Oral administration of NCFE also resulted in a significant (p < 0.05) dose dependent reduction of blood glucose level in diabetic rats, while no synergistic activity was observed when it was given in combination with metformin. These findings imply the possible pharmacological mechanisms behind the antidiabetic property of NCFE could be: inhibition of α-amylase and delaying the absorption of glucose from the intestine, secondly possessing ‘metformin like’ activity such as increasing cellular uptake and glycolysis of glucose, reducing gluconeogenesis in the liver etc. This study also for the first time provides scientific evidence in favor of the traditional use N. cadamba flower against diabetes and demands future study in order to isolate and characterize the bioactive compounds responsible for such bioactivities.

Keywords

• Antidiabetic
• Antihyperglycemic
• Neolamarckia cadamba
• Kodom
• α-Amylase