A unique polysaccharide containing 3-O-methylarabinose and 3-O-methylgalactose from Tinospora sinensis

Shipra Nagar; Andreas Hensel; Petra Mischnick; Vineet Kumar

doi:10.1016/j.carbpol.2018.03.082

A unique polysaccharide containing 3-O-methylarabinose and 3-O-methylgalactose from Tinospora sinensis

Carbohydr Polym. 2018 Aug 1:193:326-335. doi: 10.1016/j.carbpol.2018.03.082. Epub 2018 Mar 27.

Authors

Shipra Nagar¹, Andreas Hensel², Petra Mischnick³, Vineet Kumar⁴

Affiliations

¹ Institute of Pharmaceutical Biology and Phytochemistry, University of Münster, D-48149, Münster, Germany; Institute for Food Chemistry, Technische Universität Braunschweig, Schleinitzstraße 20, D-38106, Braunschweig, Germany; Chemistry Division, Forest Research Institute, Dehradun, 248006, India. Electronic address: shhipranagar@gmail.com.
² Institute of Pharmaceutical Biology and Phytochemistry, University of Münster, D-48149, Münster, Germany. Electronic address: ahensel@uni-muenster.de.
³ Institute for Food Chemistry, Technische Universität Braunschweig, Schleinitzstraße 20, D-38106, Braunschweig, Germany. Electronic address: p.mischnick@tu-braunschweig.de.
⁴ Chemistry Division, Forest Research Institute, Dehradun, 248006, India. Electronic address: kumarv@icfre.org.

PMID: 29773388
DOI: 10.1016/j.carbpol.2018.03.082

Abstract

Tinospora sinensis (Lour.) Merrill is of great therapeutic significance in Indian traditional medicine. Crude polysaccharides were isolated from methanol pre-extracted stems of dried material by successive extractions with cold water, hot water and NaOH (0.25 mol/L) in 0.98, 0.55 and 0.70 % yields respectively. Cold water soluble polysaccharides (CWSP) were purified and fractionated by ion exchange chromatography on DEAE-Sephacel. Neutral polysaccharides were further fractionated on Sepharose CL6B to yield three fractions TW1, TW2, TW3. The study further focuses on structural elucidation of TW1. TW1 was obtained in 0.8 % yield relative to CWSP, with MW of 1.6 × 10⁵ Da. It was composed of 3-O-methyl-arabinose, 3-O-methyl-galactose and galactose in molar ratio of 1.0:6.3:0.9 respectively. Based on per-deuteromethylation, NMR and ESI-MS analyses, TW1 was composed of 1,4-linked 3-O-methyl-β-d-galactopyranose and β-d-galactopyranose backbone with branching at O-6 of 3-O-methyl-β-d-galactosyl residues by 1,5-linked 3-O-methyl-α-l-arabinofuranoside chains. 3-O-methyl-arabinose and 3-O-methyl-galactose have first ever been reported in any polysaccharide and Tinospora genus, respectively.

Keywords: 3-O-Me-arabinose; 3-O-Me-galactose; Arabinogalactan; Per-deuteromethylation; Tinospora sinensis.