Phenolic Profiles and Antioxidant Activity of Lotus Root Varieties.

Yang Yi,Li-Mei Wang,Ting Min,Jie Sun,Hong-Xun Wang,Jun Xie

doi:10.3390/molecules21070863

Abstract

Lotus root attracts increasing attention mainly because of its phenolic compounds known as natural antioxidants. Its thirteen varieties were systematically analyzed on the content, distribution, composition and antioxidant activity of phenolic compounds for a better understanding of this aquatic vegetable. The respective mean contents of total phenolics in their flesh, peel and nodes were 1.81, 4.30 and 7.35 mg gallic acid equivalents (GAE)/g fresh weight (FW), and those of total flavonoids were 3.35, 7.69 and 15.58 mg rutin equivalents/g FW. The phenolic composition determined by a high-performance liquid chromatography method varied significantly among varieties and parts. The phenolics of flesh were mainly composed of gallocatechin and catechin; those of peel and node were mainly composed of gallocatechin, gallic acid, catechin and epicatechin. The antioxidant activities of phenolic extracts in increasing order were flesh, peel and node; their mean concentrations for 50% inhibition of 2,2-diphenyl-1-picrylhydrazyl radical were 46.00, 26.43 and 21.72 µg GAE/mL, and their mean values representing ferric reducing antioxidant power were 75.91, 87.66 and 100.43 µg Trolox equivalents/100 µg GAE, respectively. “Zoumayang”, “Baheou”, “No. 5 elian” and “Guixi Fuou” were the hierarchically clustered varieties with relatively higher phenolic content and stronger antioxidant activity as compared with the others. Especially, their nodes and peels are promising sources of antioxidants for human nutrition.

Highlights

Lotus (Nelumbo nucifera Gaertn.), a well-known aquatic plant of family Nelumbonaceae, has been widely cultivated for food production, ornamental horticulture and traditional Asian medicine inChina, Korea, Japan and India [1,2]
Thirteen extensively cultivated varieties of lotus root were investigated on phenolic profiles and antioxidant activity for a better understanding on the high-value utilization of this aquatic vegetable in functional food industry
“Zoumayang”, “Baheou”, “No 5 elian” and “Guixi Fuou” possessed relatively higher phenolic content and stronger antioxidant activity compared with others

Summary

Introduction

Lotus (Nelumbo nucifera Gaertn.), a well-known aquatic plant of family Nelumbonaceae, has been widely cultivated for food production, ornamental horticulture and traditional Asian medicine inChina, Korea, Japan and India [1,2]. Some pharmacological potentials of the ethanol- and methanol-soluble extracts of lotus root, including antioxidant [2], immunomodulatory [8], antiobesity [2,7], hypoglycemic [9], psychopharmacological [10] and memory-improving activities [11], are proposed to be closely related to phenolic compounds. To our knowledge, these compounds in lotus root have attracted increasing attention mostly for the substrate of enzymatic browning [12,13,14], but not the bioactive components for human nutrition.

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