Extraction Optimization, Structural Characterization, and Antioxidant Activities of Polysaccharides from Cassia Seed (Cassia obtusifolia).

Ding-Tao Wu,Su-Qing Li,Ping Wang,Xian-Rong Xiang,Wen Qin,Qiao-Hong Han,Wen Liu,Ye Ding,Li Zhao,Qing Zhang

doi:10.3390/molecules24152817

Ding-Tao Wu, Su-Qing Li + Show 8 more

Open Access

https://doi.org/10.3390/molecules24152817

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Abstract

In order to explore Cassia seed polysaccharides (CSPs) as natural antioxidants for application in the functional-food industry, microwave-assisted extraction (MAE) was optimized for the extraction of CSPs by using a response surface methodology. Furthermore, the chemical structures and antioxidant activities of CSPs extracted by MAE and hot water extraction were investigated and compared. The maximum extraction yield of CSPs extracted by MAE (8.02 ± 0.19%) was obtained at the optimized extraction parameters as follows: microwave power (415 W), extraction time (7.0 min), and ratio of water to raw material (51 mL/g). Additionally, the contents of the uronic acids, molecular weight, ratio of constituent monosaccharides, intrinsic viscosities, and degrees of esterification of CSPs were significantly affected by the MAE method. Moreover, CSPs exhibited remarkable 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) ABTS, 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl DPPH, nitric oxide, and hydroxyl radical scavenging activities as well as reducing power. The high antioxidant activities observed in CSPs extracted by MAE could be partially attributed to its low molecular weights and high content of unmethylated galacturonic acid. Results indicate that the MAE method could be an efficient technique for the extraction of CSPs with high antioxidant activity, and CSPs could be further explored as functional food ingredients.

Highlights

Oxidative stress is usually caused by reactive oxygen species (ROSs) produced during physiologic events [1]
Microwave-assisted extraction (MAE) method could be an efficient technique for the extraction of Cassia seed polysaccharides (CSPs) with high antioxidant activity, and CSPs could be further explored as functional food ingredients
The optimal extraction conditions of MAE for the extraction of CSPs were obtained by using the response surface methodology

Summary

Introduction

Oxidative stress is usually caused by reactive oxygen species (ROSs) produced during physiologic events [1]. It is well known that some of these ROSs play positive roles in vivo [2]. An excessive amount of ROSs can damage cellular components such as lipids, proteins, and DNA when the innate defense in the human body is not enough for severe oxidative stress, a variety of diseases will happen including cancer, aging, and other diseases [3,4,5]. Antioxidants play important roles in the protection of living organisms [6]. Many antioxidants have been found to be very important in reducing oxidation damage in recent years, but many synthetic antioxidants have toxicological reports [7]. The search for low toxicity or nontoxic natural antioxidants from plants such as plant derived polysaccharides has become a research hotspot [8]

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