Structure elucidation of a pectin from Dendrobium nobile Lindl. and its immunological activity

ABSTRACT

In this study, an RG-I pectin DNP-W6 was isolated from the stems of Dendrobium nobile Lindl. (Orchidaceae). It contained mannose, glucose, galactose, galacturonic acid and rhamnose in a molar ratio of 0.6: 1.0: 1.5: 1.1: 1.0. Its structural features were revealed by chemical, physical and spectral analysis. The results suggested that DNP-W6 possessed a backbone of a disaccharide of →4)-α-GalAp-(1→2)-α-Rhap-(1→, with approximate 50% substitution at O-4 of the rhamnopyranosyl residues. The side chains were neutral chains including galactosyl, mannosyl and glucosyl chains. The acetyl content was estimated to be 8.9%. The immunological results indicated that DNP-W6 and its derivatives exhibited different immunological activities in vitro, showing that the side chains and acetyl groups had an important effect on the expression of immunological activities.

KEYWORDS:

• Dendrobium nobile Lindl.
• pectin
• structure
• immunological activities

Disclosure statement

The authors declare no conflict of interest.

Additional information

Funding

This research was financially supported by the National Natural Science Foundation of China (grant number 31370371) and the Project for Science and Technology Research Plan of Anhui Province of China (grant number 15czz04087).