Next Article in Journal
Casing Contribution to Proteolytic Changes and Biogenic Amines Content in the Production of an Artisanal Naturally Fermented Dry Sausage
Next Article in Special Issue
Procyanidin-Rich Extract from Grape Seeds as a Putative Tool against Helicobacter pylori
Previous Article in Journal
Perceived Risk of Fish Consumption in a Low Fish Consumption Country
Previous Article in Special Issue
Comparative Analysis of Physicochemical Characteristics, Nutritional and Functional Components and Antioxidant Capacity of Fifteen Kiwifruit (Actinidia) Cultivars—Comparative Analysis of Fifteen Kiwifruit (Actinidia) Cultivars
Open AccessArticle

Comparison of Phenolic Compounds, Carotenoids, Amino Acid Composition, In Vitro Antioxidant and Anti-Diabetic Activities in the Leaves of Seven Cowpea (Vigna unguiculata) Cultivars

1
Phytochemical Food Network Research Group, Department of Crop Sciences, Tshwane University of Technology, Pretoria West 0001, South Africa
2
ARC Industrial Transformation Training Centre for Uniquely Australian Foods, Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, QLD 4108, Australia
3
Department of Biomedical Sciences, Tshwane University of Technology, Arcadia, Pretoria 0001, South Africa
*
Author to whom correspondence should be addressed.
Foods 2020, 9(9), 1285; https://doi.org/10.3390/foods9091285
Received: 5 August 2020 / Revised: 4 September 2020 / Accepted: 5 September 2020 / Published: 12 September 2020
(This article belongs to the Special Issue Bioactive/Nutraceutical Compounds in Plant Foods)
Cowpea is a well-known nutrition rich African leafy vegetable that has potential to sustain food and nutrition insecurity in sub-Saharan Africa. Consumption of cowpea legumes is associated with reduced risk of type 2 diabetes mellitus. Therefore, the present study was designed to evaluate the (i) variation in phenolic metabolites in seven cowpea cultivars (VOP1, VOP2, VOP3, VOP4, VOP5, VOP7, and VOP8 using UHPLC coupled with high resolution Q-TOF-MS technique, (ii) in vitro antioxidant activity using ferric reducing/antioxidant capacity (FRAP) assay (iii) in vitro anti-diabetic effects and (iv) composition of carotenoids and amino acids of theses cowpea cultivars. The results of this study demonstrated that gentisic acid 5-O-glucoside, quercetin 3-(2G-xylosylrutinoside) and Quercetin 3-glucosyl-(1->2)-galactoside were highest in VOP1 VOP4 and VOP5, respectively. High inhibition (>50%) of α-glucosidase and α-amylase activities was shown by the leaf extracts (50 and 25 mg/mL) of VOP1 and VOP4. Cowpea cultivars VOP1 and VOP4 demonstrated the highest gene expression levels of regulation of glucose transporter GLUT4 in C2C12 skeletal muscle cells, similar to insulin. A positive correlation exited between the phenolic components and the inhibitory effect of antidiabetic enzymes and FRAP activity. Cytotoxic effect was not detected in vitro in any cowpea cultivar. Lutein (124.6 mg/100 g) and all-trans-beta-carotene (92.6 mg/100 g) levels were highest in VOP2 and VOP1, respectively. Cowpea cultivars VOP3 and VOP4 showed potential to fulfil the daily requirements of essential amino acids. Thus, based on this information, cowpea (leaves) genotypes/cultivars can be selected and propagated for the further development of supplementary foods or functional food ingredients. View Full-Text
Keywords: leafy vegetables; polyphenols; anti-diabetic enzymes; protocatechuic acid-O-glucoside; lutein; phenylalanine; antioxidant capacity; regulation of glucose transporter leafy vegetables; polyphenols; anti-diabetic enzymes; protocatechuic acid-O-glucoside; lutein; phenylalanine; antioxidant capacity; regulation of glucose transporter
Show Figures

Graphical abstract

MDPI and ACS Style

Moloto, M.R.; Phan, A.D.T.; Shai, J.L.; Sultanbawa, Y.; Sivakumar, D. Comparison of Phenolic Compounds, Carotenoids, Amino Acid Composition, In Vitro Antioxidant and Anti-Diabetic Activities in the Leaves of Seven Cowpea (Vigna unguiculata) Cultivars. Foods 2020, 9, 1285.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop