Profiling of Flavonoid and Antioxidant Activity of Fruit Tissues from 27 Chinese Local Citrus Cultivars.

Chen Chen,Tan Tan,Zhou Zhou,Wang Wang,Sundararajan Sundararajan,Hu Hu

doi:10.3390/plants9020196

Abstract

Flavonoid profile and antioxidant activity of citrus peels, pulps, and juices from 27 local citrus cultivars in China were investigated. Flavonoid composition and content were determined using UPLC-PDA. Total phenolic content (TPC) and total flavonoid content (TFC) were measured using a Folin–Ciocalteau reagent and Al(NO3)-NaNO2 complexometry, respectively. The antioxidant capacities of the extracts were evaluated by DPPH, ABTS and FRAP method, respectively. Citrus peel not only exhibited better antioxidant potential, but also presented more composition diversity and contained higher concentrations of flavonoids than pulp and juice. Different citrus species were characterized by their individual predominant flavonoids, contributing largely to the antioxidant activity, such as mandarin was characterized by hesperidin, nobiletin and tangeretin, while pummelo and papeda were characterized by naringin. The peel of Guihuadinanfeng (Citrus reticulata) had the highest TPC of 23.46 mg equivalent gallic acid/g DW (dry weight) and TFC of 21.37 mg equivalent rutin/g DW. Shiyueju (C. reticulata) peel showed the highest antioxidant capacity based on the antioxidant potency composite (APC) analysis. Overall, mandarin (C. reticulata) fruits peel contained more TPC and TFC, exhibiting higher antioxidant capacities than other species, and were good natural sources of flavonoids and antioxidants.

Highlights

Citrus fruits, which are widely cultivated worldwide, are important commercial crops [1]
As for peel, Guihuadinanfeng (NF) and Baiju (BJ) had significantly higher Total phenolic content (TPC) than other cultivars tested, and these two cultivars belong to mandarin (C. reticulata)
Different species were characterized by their individual dominant flavonoids, cultivars from mandarin contained significantly higher flavonoid, exhibited higher antioxidant capacities than cultivars from other species tested

Summary

Introduction

Citrus fruits, which are widely cultivated worldwide, are important commercial crops [1]. Citrus fruits are well-accepted by consumers owing to their pleasant flavors and abundant phytochemicals, such as vitamins A and C, mineral elements, carotenoids, and phenolics [2,3]. Citrus fruits have been suggested to be a good source of dietary antioxidants and their role in the prevention and treatment of various diseases were widely studied [4]. The major phenolic compounds found in citrus are flavonoids, which are considered to be one of the most important sources of bioactive compounds [5,6]. Flavonoids affect the quality of fruits in terms of appearance, taste and nutritional value [8], and effectively regulate many human diseases by mediating antioxidant, inflammatory, and Plants 2020, 9, 196; doi:10.3390/plants9020196 www.mdpi.com/journal/plants

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Discussion

Conclusion