A Herbal Composition of Scutellaria baicalensis and Eleutherococcus senticosus Shows Potent Anti-Inflammatory Effects in an Ex Vivo Human Mucosal Tissue Model

Abstract

Background. Patients seek an effective alternative to pharmacotherapy including herbal treatment options for allergic rhinitis and rhinosinusitis. Material and Methods. Nasal mucosal tissue was obtained from 12 patients, fragmented, preincubated with tissue culture medium, S. baicalensis and/or E. senticosus and/or vitamin C (each compound 0.2 μg/mL and 2 μg/mL) for 1 hour at 37°C/5% CO2, and stimulated with anti-IgE for 30 minutes and 6 hours to imitate the allergic early and late phases. Furthermore, Staphylococcus aureus superantigen B (SEB) stimulation for 6 hours was used to imitate T-cell activation. Results. The combination of S. baicalensis and E. senticosus had a more potent suppressive effect on the release of PGD2, histamine, and IL-5 than S. baicalensis alone. The combination also resulted in a significant inhibition of SEB-induced cytokines comparable or superior to an established topical corticosteroid, fluticasone propionate. Vitamin C increased ciliary beat frequency, but had no anti-inflammatory effects. Discussion. The combination of S. baicalensis and E. senticosus may be able to significantly block allergic early-and late-phase mediators and substantially suppress the release of proinflammatory, and Th1-, Th2-, and Th17-derived cytokines.

Figure 1

Mast cell-related mediators: Prostaglandin D2 (a) and histamine (b). Anti-IgE resulted in a significant increase in prostaglandin D2 (PGD2) and histamine release within 30 minutes after tissue exposure in nasal polyp mucosal tissue. In comparison to tissue culture medium, S. baicalensis, but not E. senticosus (data not shown), significantly reduced the release of de novo synthesized PGD2 at a concentration of 2 μg/mL (high) in nasal polyps. The combination of S. baicalensis and E. senticosus, however, had a more potent effect on the release of PGD2 in nasal polyp tissue and reached significance already at a low concentration of 0,2 μg/mL of each compound after anti-IgE stimulation (a). The combination of S. baicalensis and E. senticosus had a similarly strong suppressive effect at a low concentration of 0.2 μg/mL to reduce the release of histamine (b).

Figure 2

Anti-IgE-induced cytokine release. Anti-IgE stimulation of nasal polyps resulted in an increase in IL-5 within 6 hours. The combination of S. baicalensis and E. senticosus, but no single component, resulted in a significant inhibition of IL-5 release at a concentration of 2 μg/mL of each compound.

Figure 3

T-cell activation-related release of cytokines. (a) SEB resulted in a significant release of IL-1, TNF-α, IFN-γ, IL-2, IL-5, and IL-17 from nasal polyp tissue, indicating the stimulation of all prominent T helper cell populations. Although single components demonstrated suppressive activity, this suppression remained insignificant; only the combination of S. baicalensis and E. senticosus at a concentration of 2 μg/mL of each compound resulted in a significant, nearly complete suppression of the release of IFN, IL-5, IL-1β and TNF-α 6 h after SEB stimulation, and a partial suppression for IL-17 and IL-2. (b) The suppressive activity of the combination was superior to that of an established topical corticosteroid, fluticasone propionate (FP), for IFN-γ, IL-1β, TNF-α, and IL-17 and equivalent for IL-5 and IL-2.