Comparative Study on Seed Characteristics, Antioxidant Activity, and Total Phenolic and Flavonoid Contents in Accessions of Sorghum bicolor (L.) Moench.

Bimal-Kumar Ghimire,Ji-Won Seo,Chang-Yeon Yu,Seung-Hyun Kim,Ill-Min Chung

doi:10.3390/molecules26133964

Abstract

Sorghum is a major cereal food worldwide, and is considered a potential source of minerals and bioactive compounds. Its wide adaptive range may cause variations in its agronomic traits, antioxidant properties, and phytochemical content. This extensive study investigated variations in seed characteristics, antioxidant properties, and total phenolic (TPC) and flavonoid contents (TFC) of sorghum collected from different ecological regions of 15 countries. The antioxidant potential of the seed extracts of various sorghum accessions was determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis 3-ethylbenzothiazoline-6-sulfonate (ABTS) radical scavenging assays. Significant variations in TPC were observed among the sorghum accessions. All 78 sorghum accessions used in this study exhibited significant variations in TFC, with the lowest and highest amount observed in accessions C465 and J542, respectively. DPPH scavenging potential of the seed extracts for all the accessions ranged from 11.91 ± 4.83 to 1343.90 ± 81.02 µg mL−1. The ABTS assay results were similar to those of DPPH but showed some differences in the accessions. Pearson’s correlation analysis revealed a wide variation range in the correlation between antioxidant activity and TPC, as well as TFC, among the sorghum accessions. A wide diversity range was also recorded for the seed characteristics (1000-seed weight and seed germination rate). A dendrogram generated from UPGMA clustering, based on seed traits, antioxidant activity, TPC, and TFC was highly dispersed for these accessions. Variations among the accessions may provide useful information regarding the phytoconstituents, antioxidant properties, and phytochemical contents of sorghum and aid in designing breeding programs to obtain sorghum with improved agronomic traits and bioactive properties.

Highlights

Sorghum (Sorghum bicolor L.) Moench, belonging to the Poaceae family and inhabiting arid and semi-arid tropical regions, is one of the most important crops worldwide
Along axis 2 of the Principal Component Analysis (PCA) analysis, four Indian accessions (I339, I340, I351, I353, and I-353), Japanese accession (J540 and J541), USA accessions (U311 and U308), Korean accessions (K665 and K675) and Botswana accessions (B533, B34 and B536) were primarily characterized by high antioxidant properties (DPPH and azinobis 3-ethylbenzothiazoline-6-sulfonate (ABTS)), indicating that accessions in this group have Molecules 2021, 26, x FOR PEER REVIEWclosely related genotypes. These results suggest that the antioxidant activity, total phenolic (TPC), a9nodf 20 Total Flavonoid Content (TFC) profiles of sorghum accessions could be used as potential biomarkers for studying its biodiversity
This study is the first to report the seed characteristics, antioxidant activity, and polyphenol contents of 78 sorghum accessions collected from 15 countries

Summary

Introduction

Sorghum (Sorghum bicolor L.) Moench, belonging to the Poaceae family and inhabiting arid and semi-arid tropical regions, is one of the most important crops worldwide. Owing to its wide range of adaptability and ease of growth, sorghum is largely produced in Asian and African countries, and is a good alternative source of animal feed and human food [3,12]. It contains various nutrients and bioactive compounds [13,14], such as phenolic acids (ferulic, tannic, and p-coumaric acids), flavonoids (luteolin, apigenin, catechin gallate, and epigallocatechin [15,16]), tannins [3,17], and lipids [18]. There is an increased interest in identifying the active ingredients in plants that can act as natural antioxidants and contribute to food preservation without damaging human health and the environment [26]

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