Inhibition of IgE-dependent mouse triphasic cutaneous reaction by a boiling water fraction separated from mycelium of Phellinus linteus

Abstract

Phellinus linteus, a mushroom, contains constituents that exhibit potent antitumor effects through activating immune cells. Recently, anti-inflammatory and anti-allergic properties of P. linteus extracts have also been implicated. In the present study, therefore, we separated the constituents of mycelium of P. linteus into five fractions-chloroform-soluble (CF), ethyl acetate-soluble (EA), methanol-soluble (AE), water-soluble (WA) and boiling water-soluble (BW) fractions-and examined their suppressive effects on the IgE-dependent mouse triphasic cutaneous reaction. The triphasic reaction was induced in the ear of BALB/c mice passively sensitized with anti-dinitrophenol IgE by painting with 2,4-dinitrofluorobenzene 24 h later. Ear swelling appeared triphasically with peak responses at 1 h, 24 h and 8 days after the challenge. ME, WA and BW given orally at a dose of 100 mg kg significantly inhibited the first and second phase ear swelling, and BW also inhibited the third phase response. CF only inhibited the second phase. The inhibition by BW was the most potent and almost dose-dependent at doses of 30-300 mg kg. BW also inhibited vascular permeability increase caused by passive cutaneous anaphylaxis and histamine, and ear swelling caused by tumor necrosis factor-alpha. In contrast, BW apparently potentiated the production of interleukin-4 and interferon-gamma from anti-CD3-stimulated mouse splenocytes. These results indicate that BW derived from mycelium of P. linteus contains some constituents with anti-allergic as well as immunopotentiating properties.

Figure 1

Fractionation of constituents of mycelium of P. linteus and the amount of each fraction obtained.

Figure 2

Effects of fractions prepared from mycelium of P. linteus and prednisolone on triphasic cutaneous reaction in the ear of BALB/c mice. Fractions and prednisolone were administered orally 1 and 2 h before challenge, respectively. EA was given at a dose of 50 mg kg⁻¹ because of the limited amount obtained. Each value represents the mean ± SEM for seven or eight mice. *P < 0.05, **P < 0.01.

Figure 3

Effects of fraction BW and prednisolone on triphasic cutaneous reaction in the ear of BALB/c mice BW and prednisolone were administered orally 1 and 2 h before challenge, respectively. Each value represents the mean ± SEM for seven or eight mice. *P < 0.05, **P < 0.01.

Figure 4

Effects of fraction BW and diphenhydramine on vascular permeability increase caused by PCA and histamine in male ddY mice. Vascular permeability increase was cause by PCA (A) and histamine injection (B) in the mouse ear. BW and diphenhydramine were administered orally 1 h and 30 min, respectively, before eliciting the reaction. Each value represents the mean ± SEM for three or seven mice. *P < 0.05, **P < 0.01.

Figure 5

Effects of fraction BW and prednisolone on ear swelling caused by TNF-α in male BALB/c mice BW and prednisolone were administered orally 1 h before TNF-α injection. Each value represents the mean ± SEM for seven mice. *P < 0.05, **P < 0.01.

Figure 6

Effects of fraction BW and prednisolone on cytokine production in mouse splenocytes. Splenocytes were incubated with anti-CD3 antibodies for 48 h in duplicate. After the incubation, cells were recovered and counted. IL-4 and IFN-γ in the supernatants were quantified by enzyme-linked immunosorbent assay. Each value represents the mean ± SEM for four mice.