Relationship between oversulfation and conformation of low and high molecular weight fucoidans and evaluation of their in vitro anticancer activity.

Myoung Lae Cho,Sang Guan You,Boo-Yong Lee

doi:10.3390/molecules16010291

Myoung Lae Cho, Sang Guan You + Show 1 more

Open Access

https://doi.org/10.3390/molecules16010291

Copy DOI

Abstract

Low and high molecular weight fucoidans (F5-30K and F>30K) were chemically modified through the addition of sulfate groups, and the effect of oversulfation on the in vitro anticancer activity was investigated. After the addition of sulfate groups, a considerable increase of 35.5 to 56.8% was observed in the sulfate content of the F5-30K fraction, while the sulfate content of the F>30K fraction increased to a lesser extent (from 31.7 to 41.2%). Significant differences in anticancer activity were observed between the oversulfated F5–30K and F>30K fractions, with activities of 37.3–68.0% and 20.6–35.8%, respectively. This variation in the anticancer activity of oversulfated fucoidan derivatives was likely due to differences in their sulfate content. The results suggest that the molecular conformation of these molecules is closely related to the extent of sulfation in the fucan backbones and that the sulfates are preferably substituted when the fucoidan polymers are in a loose molecular conformation.

Highlights

Fucoidan, a sulfated-fucan, is commonly found in brown seaweed [1] and marine invertebrates, in echinoderms such as sea cucumbers and sea urchins [2]
In a study of fucoidan hydrolysates, partially hydrolyzed fucoidans (Mw = 490 kDa) showed significantly improved anticancer activity compared to the native polymers (Mw = 5,100 kDa), and the effect was mostly seen when fucoidans were hydrolyzed under mild conditions [3]
The sulfate contents of two native fucoidan fractions and their oversulfated derivatives are shown in. These changes in sulfate content were supported by evidence from the IR spectra (Figure 1)

Summary

Introduction

A sulfated-fucan, is commonly found in brown seaweed [1] and marine invertebrates, in echinoderms such as sea cucumbers and sea urchins [2]. Fucoidans have been extensively studied due to their diverse anticoagulant, antiviral and anticancer properties These biological activities have been reported to be closely related to their molecular weight and sulfate content. Desulfated fucoidans with sulfate contents of less than 20%, on the other hand, show drastic decreases in both anticoagulant and anticancer activities [6] These studies suggest that the biological activities of fucoidans are significantly influenced by sulfate content and could be improved by the modification of this feature. 5.6 kDa, respectively), were chemically modified by the addition of sulfate groups, and the effect of the molecular conformation on the extent of sulfation and the in vitro anticancer activity of oversulfated fucoidan derivatives was investigated

Results and Discussion

Experimental

Proximate composition and in vitro anticancer activity

Conclusions