Hydrolyzed Konjac Glucomannan Suppresses IgE Production in Mice B Cells

Abstract

Background: Oral administration of pulverized Konjac glucomannan (KGM) reduces increased plasma IgE and the amount of Ε-germline transcript (ΕGT) in the spleen, as well as preventing the development of dermatitis in mice. To elucidate the mechanism of action of pulverized KGM, we solubilized KGM and studied its effect on IgE in vitro and in vivo. Methods: Solubilized KGM was prepared by acid hydrolysis, and we analyzed the effective molecular size for the suppression of IgE production and ΕGT in vitro and the level of plasma IgE induced by immunization with ovalbumin in BALB/c mice. Results: The production of IgE and ΕGT in splenic cells, but not purified B cells, was inhibited by hydrolyzed KGM (KGM hydrolyzed with 0.25 N HCl; H-KGM) at the optimal size of between 10 and 500 kDa. However, no effect was observed when H-KGM was substituted with unhydrolyzed KGM in vitro. IgE production from purified B cells cocultured with purified monocytes, but not with purified T cells, was inhibited by H-KGM. The release of IFNγ in cultures of monocytes but in purified B cells with or without T cells was enhanced in the presence of H-KGM. Injection of mice with H-KGM also suppressed the production of plasma IgE and IgG1 but not IgG2a in vivo. Conclusion: KGM at an optimal size prevents germline class-switching and IgE production both in vitro and in vivo. H-KGM may be useful as a tool to study the mechanism of action of KGM and as a dietary supplement to prevent atopic diseases.

Pulverized konjac glucomannan ameliorates oxazolone-induced colitis in mice

“…Therefore, we prepared various particle sizes of low viscous and highly specific surface area of the KGM molecule that would be expected to possess the more effect of these well-known [11,12]. Soluble PKGM suppressed IgE production in splenocytes of mice in vitro [27]. Both the Th1 and Th2 cytokines play important roles in AD [28], and Th2-specific chemokines are overproduced in NC/Nga mice [29].…”

Preparation, composition analysis and antioxidant activities of konjac oligo-glucomannan

“…At the same time, KG also was applied to control rheology and structure of potato starch (Khanna & Tester, 2006;Silva, Birkenhake, Scholten, Sagis, & van der., 2013), cassava starch (Shanavas, Moorthy, Sajeev, Misra, & Sundazeem, 2010), and corn starch (Yoshimura, Takaya, & Nishinari, 1998), revealing that the behavior of KG is similar to a physical barrier to prevent amylopectin chain association (Khanna & Tester, 2006 Recent researches found that its degradation products with different molecular weight have particular biological functions, such as anti-tumor (Vuksan et al, 2000), immuno regulation (Onishi et al, 2005), and cytothesis (Yeh, Lin, & Chen, 2010). These findings promote researchers to pay more and more attention to the research and development of konjac degradation products (Suzuki et al, 2009). Presently, several strategies have been developed to obtain oligosaccharides by the depolymerization of Konjac Glucomannan (Courtois, 2009), such as acid degradation, oxidative degradation, radiation-induced degradation (Relleve et al, 2005), microwave-induced degradation (Zhou, Yao, & Wang, 2006), and physical methods (Pang et al, 2012).…”

Beneficial health characteristics of native and hydrolysed konjac (Amorphophallus konjac) glucomannan

“…For example, administration of pulverised konjac glucomannan can prevent the development of allergic rhinitis‐like symptoms and the increase of plasma IgE and IgG in mice . More recently, as mentioned above, a study by Suzuki et al concluded that consuming hydrolysed konjac glucomannan can help prevent atopic skin diseases by suppressing IgE production in mice. Furthermore, Onishi et al concluded that feeding pulverised konjac glucomannan to mice suppressed the development of scratching behaviour, substance ‘P’ expression with mastocytosis and skin inflammatory immune responses.…”

“…When consumed they may have systemic effects mediated via GALT, e.g. against certain forms of dermatitis . Figure models the overall role of hydrolysed glucomannans in beneficial (probiotic) and pathogenic gut bacteria.…”

“…The effects of konjac glucomannan hydrolysates in the gut can be seen in other parts of the body such as the skin or vagina . Suzuki et al concluded that consuming hydrolysed konjac glucomannan can help prevent atopic diseases by suppressing immunoglobulin (Ig)E production in mice.…”