Polyphenolic Contents and Antioxidant Potential of Stem Bark Extracts from Jatropha curcas (Linn)

Osamuyimen O Igbinosa,Etinosa O Igbinosa,Isoken H Igbinosa,Anthony I Okoh,Olohirere E Uzunuigbe,Vincent N Chigor,Sunday O Oyedemi,Emmanuel E Odjadjare

doi:10.3390/ijms12052958

Abstract

We assessed the polyphenolic contents and antioxidant potential of the aqueous, ethanol and methanol stem bark extracts of Jatropha curcas. The total phenol, flavonoids, flavonols and proanthocyanidin contents of the extracts were evaluated to determine their effect on the antioxidant property of this plant, using standard phytochemical methods. The antioxidant and free radical scavenging activity of ethanol, methanol and aqueous extracts of the plant were also assessed against 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), ferric reducing, nitric oxide (NO), superoxide anion, (O2−) and hydrogen peroxide (H2O2) using spectroscopic methods and results were compared with that of butylated hydroxyl toluene (BHT) and ascorbic acid as standards. The concentrations of different classes of phenolic compounds were higher in methanol and ethanol extracts compared to aqueous extracts. There was correlation between total phenol, total flavonoids, total flavonol and total proanthocyanidins (r = 0.996, 0.978, 0.908, and 0.985) respectively. There was correlations between the amount of phenolic compounds and percentage inhibition of DPPH radicals scavenging activity of the extract (r = 0.98). Findings from the present study indicated that J. curcas is a potential source of natural antioxidants and may be a good candidate for pharmaceutical plant based products.

Highlights

Oxidative stress, the consequence of the imbalance between prooxidants and antioxidants in an organism, is considered to play a very important role in the pathogenesis of several degenerative diseases [1]
The aqueous extract showed the least concentration of phenol (10.92 ± 2.25 mg/g of tannic acid equivalent), flavonoids (6.28 ± 0.74 mg/g of quercetin equivalents), Flavonols (8.25 ± 0.17 mg/g of quercetin equivalent) and proanthocyanidins
The chemicals used in this study include 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), butylated hydroxytoluene (BHT), 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-4’,4’-disulfonic acid, hydrogen peroxide, ferrous chloride, potassium ferricyanide, catechin, ascorbic acid, tannic acid, quercetin, nicotinamide adenine dinucleotide (NADH), trichloracetic acid (TCA), phosphate buffer, sulfanilic acid, glacial acetic acid, naphthylethylenediamine dichloride, folin-ciocalteu reagent, sodium carbonate, vanillin, aluminum chloride, ascorbic acid and potassium acetate were obtained from Sigma (Sigma-Aldrich GmbH, Sternheim, Germany)

Summary

Introduction

The consequence of the imbalance between prooxidants and antioxidants in an organism, is considered to play a very important role in the pathogenesis of several degenerative diseases [1] These diseases include diabetes, aging, cancer, cardiovascular diseases, metabolic syndrome and atherosclerosis. Free radicals, such as hydroxyl, singlet oxygen, nitric oxide, hydrogen peroxide and superoxide radicals, are continuously generated in the cell, as a result of normal human metabolism. They can be harmful to the system if not properly regulated and may cause variety of pathological effect such as carcinogenesis, aging DNA damage and enzyme inactivation by attacking biological macromolecules. These compounds (phenolic substances) all share the same chemical patterns, with one or more phenolic groups for hydrogen proton donors and neutralize free radicals [4,5,6,7]

Methods

Results

Conclusion