Isolation and structural characterization of a non-competitive α-glucosidase inhibitory polysaccharide from the seeds of Litchi chinensis Sonn

Jianjun Wu; Yongbin Xu; Xinya Liu; Miaomiao Chen; Bo Zhu; Huijun Wang; Songshan Shi; Luping Qin; Shunchun Wang

doi:10.1016/j.ijbiomac.2019.11.170

Isolation and structural characterization of a non-competitive α-glucosidase inhibitory polysaccharide from the seeds of Litchi chinensis Sonn

Int J Biol Macromol. 2020 Jul 1:154:1105-1115. doi: 10.1016/j.ijbiomac.2019.11.170. Epub 2019 Nov 21.

Authors

Jianjun Wu¹, Yongbin Xu², Xinya Liu³, Miaomiao Chen², Bo Zhu⁴, Huijun Wang², Songshan Shi², Luping Qin⁵, Shunchun Wang⁶

Affiliations

¹ The MOE Key Laboratory for Standardization of Chinese Medicines and the SATCM Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China; College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou 310053, China.
² The MOE Key Laboratory for Standardization of Chinese Medicines and the SATCM Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
³ Chengdu University of Traditional Chinese Medicine, Chengdu 610075, China.
⁴ College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou 310053, China.
⁵ College of Pharmaceutical Sciences, Zhejiang Chinese Medical University, Hangzhou 310053, China. Electronic address: lpqin@zcmu.edu.cn.
⁶ The MOE Key Laboratory for Standardization of Chinese Medicines and the SATCM Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China. Electronic address: shunchunwang@126.com.

PMID: 31760014
DOI: 10.1016/j.ijbiomac.2019.11.170

Abstract

In this study, a novel homogeneous polysaccharide (LSP-W-4, M_W = 6.70 kDa) was isolated and purified from the seeds of Litchi chinensis Sonn. Monosaccharide composition analysis indicated that LSP-W-4 is a heteropolysaccharide consisting of arabinose, mannose, glucose and galactose in a molar ratio of 6.33:3.88:10.35:1.00. A detailed structural analysis revealed that LSP-W-4 has a backbone consisting of 1,4-α-Glcp and 1,4-β-Manp, as well as four branched chains including of T-α-Galp, T-α-Araf, α-Araf-(1 → 5)-α-Araf-(1 → and α-Araf-(1 → 5)-α-Araf-(1 → 5)-α-Araf-(1 → attached to O6 of 1,4-β-Manp and 1,4-α-Glcp. LSP-W-4 exhibited significant inhibitory activity both against yeast (Saccharomyces cerevisiae) and mammalian (rat-intestinal acetone powder) α-glucosidase, with IC₅₀ values of 75.24 μM and 66.97 μM, respectively, with both such inhibitory activities being more powerful than those of acarbose. A kinetic analysis revealed that LSP-W-4 inhibited the activities of both yeast and mammalian α-glucosidase in a typical non-competitive manner, with K_M values of 0.43 mmol/L and 0.53 mmol/L, respectively.

Keywords: Litchi chinensis Sonn seeds; Polysaccharide; α-Glucosidase inhibitor.

MeSH terms

Animals
Glycoside Hydrolase Inhibitors* / chemistry
Glycoside Hydrolase Inhibitors* / isolation & purification
Glycoside Hydrolase Inhibitors* / pharmacology
Kinetics
Litchi / chemistry*
Phytochemicals / chemistry
Phytochemicals / isolation & purification
Phytochemicals / pharmacology
Plant Extracts / chemistry*
Polysaccharides* / chemistry
Polysaccharides* / isolation & purification
Polysaccharides* / pharmacology
Rats
Saccharomyces cerevisiae / drug effects
Seeds / chemistry*
alpha-Glucosidases / metabolism

Substances

Glycoside Hydrolase Inhibitors
Phytochemicals
Plant Extracts
Polysaccharides
alpha-Glucosidases