Ou-gon, an extract from Scutellaria baicalensis Georgi root, has been shown to exhibit pronounced antifungal activity. The present study aimed to identify antifungal components of Ou-gon and to determine their mechanism of action against pathogenic fungi. Antifungal activity was assessed by the microbroth dilution method using four common human pathogenic fungi, Trichophyton rubrum, Trichophyton mentagrophytes, Aspergillus fumigatus, and Candida albicans. Components of crude Ou-gon extract were separated by reversed-phase high-performance liquid chromatography. Active antifungal components were identified by liquid chromatography-electrospray ionization tandem mass spectrometry. Terminal deoxynucleotidyl transferase dUTP nick end-labelling assay, SYTOX® green uptake assay, determination of intracellular reactive oxygen species and mitochondrial membrane potential as well as microscopy (confocal laser microscopy, scanning and transmission electron microscopy) were used to probe the mode of action. Two components with potent antifungal activity, baicalein and wogonin, were identified in Ou-gon. Baicalein showed potent antifungal activity against the four fungi tested. Wogonin displayed antifungal activity against all four fungi except C. albicans. The components are considered to induce apoptosis-like programmed cell death via hyperproduction of reactive oxygen species. This study enhances our understanding of the antifungal activity of Kampo medicine, and may contribute to the development of new and safe antifungal therapeutics.

Kampo medicines consist of a variety of crude animal, plant, and mineral extracts that have long been used to relieve different symptoms, and are relatively safe. However, their mechanisms of actions have not been well investigated. We screened 61 commercially available Kampo medicines to determine if they contain constituents with antifungal activity against Trichophyton rubrum. The antifungal effect of the Kampo medicines was determined by measuring the mean absorbance of treated fungal culture media. Lower absorbance values suggested a higher inhibition of the growth rate of T. rubrum by the Kampo medicines. We found that seven of the evaluated formulations exhibited a comparable antifungal activity to that of fluconazole at 14 mg/mL. The seven active Kampo medicines were Saiko-keishi-kankyou-to, Saiko-ka-ryukotsu-borei-to, Saiko-keishi-to, Keishi-ka-ryukotsu-borei-to, Dai-saiko-to, Bohu-tsu-sho-san, and Otsu-ji-to. The seven Kampo medicines with antifungal activity contain 30 different crude extracts, and Ou-gon (Scutellaria root) is a supplement contained in six of the seven formulations. Therefore, Ou-gon was considered to play a major role in their antifungal effect. The antifungal assay of the Ou-gon water extract showed that it significantly inhibited the growth of T. rubrum at a concentration of 20 mg/mL. Future studies will focus on the isolation and identification of the antifungal components of the crude extracts of Ou-gon, which may be potentially useful, new, and safe antifungal drugs.

A 79-year-old Japanese woman had clinical and histopathological features of bullous pemphigoid, while direct immunofluorescence test revealed C3 and immunoglobulin G depositions in the lower cell surfaces of the epidermis in addition to those in the dermoepidermal junction. Chemiluminescent enzyme immunoassays were positive for desmoglein-1 and -3 antibodies in addition to anti-BP180 antibodies. In an immunoblotting study, antibodies against both 180-kDa bullous pemphigoid antigen and 130-kDa pemphigus vulgaris antigen were detected. Based on these results, bullous pemphigoid coexisting with anti-desmoglein autoantibodies was diagnosed in this case.

Bullous pemphigoid (BP) is an autoimmune disease characterized by the formation of blisters, in which autoantibodies mainly target type XVII collagen (ColXVII) expressed in basal keratinocytes. BP IgG is known to induce the internalization of ColXVII from the plasma membrane of keratinocytes through macropinocytosis. However, the cellular dynamics following ColXVII internalization have not been completely elucidated. BP IgG exerts a precise effect on cultured keratinocytes, and the morphological/functional changes in BP IgG-stimulated cells lead to the subepidermal blistering associated with BP pathogenesis. Based on the electron microscopy examination, BP IgG-stimulated cells exhibit alterations in the cell membrane structure and the accumulation of intracellular vesicles. These morphological changes in the BP IgG-stimulated cells are accompanied by dysfunctional mitochondria, increased production of reactive oxygen species, increased motility, and detachment. BP IgG triggers the cascade leading to metabolic impairments and stimulates cell migration in the treated keratinocytes. These cellular alterations are reversed by pharmacological inhibitors of Rac1 or the proteasome pathway, suggesting that Rac1 and proteasome activation are involved in the effects of BP IgG on cultured keratinocytes. Our study highlights the role of keratinocyte kinetics in the direct functions of IgG in patients with BP.

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