Polyphenol fingerprinting and hypoglycemic attributes of optimized Cycas circinalis leaf extracts

Background: The Cycas circinalis(C. circinalis) leaves are used to treat diabetes mellitus in local medicinal system without any scientifically proved information on their medicinal potential and phytochemicals. In current study the total phenolic contents, total flavonoid contents, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and inhibitory effects on α-glucosidase and α-amylase were determined for optimized hydroethanolic leaf extracts. Secondary metabolites were identified using ultra-high performance liquid chromatography-quadrupole time of flight-mass spectrometry (UHPLC-QTOF-MS/MS). In vivo studies on diabetic albino mice were also carried out to evaluate the impact of most active extract on their blood glucose levels.

Results: The 60% ethanolic extract showed highest extract yield, total phenolic and flavonoid contents of 209.70 ± 0.20 g kg^-1 , 154.24 ± 3.28 mg gallic acid equivalent and 78.52 ± 1.65 mg rutin equivalent per gram dried extract, respectively and exhibited the maximum DPPH scavenging with IC₅₀ value of 59.68 ± 2.82 μg/mL. The IC₅₀ values inhibition of α-glucosidase (58.42 ± 2.22 μg/mL)and α-amylase (74.11 ± 1.70 μg/mL) were also significant for 60% ethanolic extract. The untargeted UHPLC-QTOF-MS/MS based metabolite profiling confirmed the presence of Iridoid glucoside, gibberllins A4, O-beta-D-glucosyl-4-hydroxy-cinnamate, 3-methoxy-2-phyenyl-4-H-furo (2,3-h) chromen-4-one, kaempferol, withaferin A, amentoflavone, quercitin-3-O-(6″-malonyl glucoside), ellagic acid and gallic acid. Plant extract at dose of 500 mg/kg body weight of reduced the blood glucose level to considerable extent and also improved lipid profile of diabetic mice after 28 days trial.

Conclusion: The findings revealed the medicinal potential of Cycas circinalis leaves to treat diabetes mellitus and provided the nutraceutical leads for functional food development. This article is protected by copyright. All rights reserved.

Keywords: Cycas revoluta; antidiabetic; diabetic mice; hypolipidemic; metabolite profiling.