The immunomodulatory activity of degradation products of Sesbania cannabina galactomannan with different molecular weights

Galactomannan (GM) is widely recognized as an immune enhancer; however, the underlying molecular mechanism is still unknown. Herein, four products with molecular weights in descending order, namely GM40, GM50, GM65, and GMOS, were separated from incomplete degradation products of Sesbania cannabina GM by ethanol precipitation, followed by their immunomodulatory activity. Through FTIR and XPS spectra, the amount of free hydroxyl groups was shown to decrease in the following order: GM > GM50 > GMOS > GM40 > GM65. Moreover, the immunomodulatory activity of different products decreased in abovementioned order. The TNF-alpha, IL-6 and TLR4 content in RAW 264.7 cells treated with different GM products in the presence or absence of TAK242 (TLR4 inhibitor) suggested that the immunomodulatory activity of GM and its degradation products is TLR4dependent. Overall, the preliminary relationship indicated here between the hydroxyl groups or the possible deeper structural changes of GM and the immunomodulatory activity need to be further investigated.

Automated summary

In this study, several different products with varying molecular weights were obtained from the degradation of Sesbania cannabina galactomannan (GM). The immunomodulatory activity of these products was investigated, and it was found that the activity depended on the hydroxyl groups and TLR4.