Skullcap (Scutellaria Baicalensis) Hexane Fraction Inhibits the Permeation of Ovalbumin and Regulates Th1/2 Immune Responses

Abstract

Skullcap (Scutellaria baicalensis) is well known for its anti-inflammatory and anti-allergic effects. In our previous study, we found that skullcap could inhibit allergen permeation and regulate Th1/2 immune balance. To reveal the key fractions and components of skullcap, we fractionated skullcap extract into five fractions: hexane, chloroform, ethyl acetate, butanol, and water fraction. Among these fractions, the hexane fraction significantly suppressed the production of Th2-mediated cytokines (Interleukin (IL)-4, 5, 10 and 13) and increased Th1-mediated cytokines (Interferon (IFN)-γ and IL-12). Furthermore, the hexane fraction inhibited the permeation of ovalbumin (OVA), used as an allergen, across the intestinal epithelial cell monolayer. To confirm the active compounds in the hexane fraction, fatty acids were analyzed. Linoleic acid (LA, C18:2 (>59.7%)) was identified as the most important fatty acid in the skullcap hexane fraction. LA significantly suppressed IL-4 production and increased IFN-γ secretion, as well as inhibiting OVA permeation. Thus, LA significantly diminished the permeation of allergen by enhancing intestinal barrier function and regulated allergic responses to maintain Th1/Th2 immune balance.

Lamiaceae: An Insight on Their Anti-Allergic Potential and Its Mechanisms of Action

“…Results revealed that baicalein (47) was able to increase Treg cells population through induction of CD4 + FOXP 3 + T cell differentiation without causing any cytotoxicity at concentrations smaller than 10 µmol/L (Bae et al, 2016). In light of a study by Jung et al (2017), linoleic acid (50) in hexane fraction from ethanol extract of S. baicalensis roots was reported to cause a significant suppression (P < 0.05) in the production of pro-allergic cytokines (IL-4, IL-5, IL-10 and IL-13) and enhancement of secretion of T H 1 cytokines (IFN-γ (P < 0.05) and IL-12 (P < 0.01)). The fact that a fatty acid from a plant can contribute anti-allergic effect through restoration of T H 1/T H 2 balance is a new discovery (Jung et al, 2017).…”

“…In light of a study by Jung et al (2017), linoleic acid (50) in hexane fraction from ethanol extract of S. baicalensis roots was reported to cause a significant suppression (P < 0.05) in the production of pro-allergic cytokines (IL-4, IL-5, IL-10 and IL-13) and enhancement of secretion of T H 1 cytokines (IFN-γ (P < 0.05) and IL-12 (P < 0.01)). The fact that a fatty acid from a plant can contribute anti-allergic effect through restoration of T H 1/T H 2 balance is a new discovery (Jung et al, 2017). A similar outcome was noted in a food allergy murine model conducted by Shin et al (2014b) with S. baicalensis ethanol extract.…”

Traditional Medicinal Plants Conferring Protection Against Ovalbumin-Induced Asthma in Experimental Animals: A Review

“… Skullcap 70% Ethanol Polyphenolic compounds (baicalin, baicalein and wogonin) Treatment for allergic, inflammation and viral infections. Jung et al; 57 Li-Weber; 131 Zhang et al 132 S. ternatum Ophioglossaceae It is a common herb and is mainly found in China. Whole plant 70% Ethanol Not identified Deemed to have anti-toxic effects in the body.…”

“…In a study, n-hexane fraction of 70% Scutellaria baicalensis ( S. baicalensis ) ethanolic extract has significantly suppressed the production of Th2-mediated cytokines and increased Th1-mediated cytokines against OVA-induced animals. 57 The 70% aqueous ethanolic extract of Sceptridium ternatum ( S. ternatum ) treatment significantly reduced AHR, raised the ratio of Th1/Th2 and reduced Cyslt1 mRNA level in a dose-dependent manner. 58 Moreover, high-dose of S. ternatum had similar efficacy as the investigated standard drug (Montelukast) in a mouse asthma model and therefore is a good potential anti-asthmatic agent.…”

“… – ↓ Th2-related cytokines (IL-4, 5, 10 and 13) and ↑ Th1-mediated cytokines (IFN-γ and IL-12), ↑ IFN-γ. Jung et al 57 S. ternatum 1.935 g/kg, 9.675 g/kg and 19.350 g/kg**, P.O., 10 days Balb/c mice OVA (0.08%, 0.1 mL) mixed with equal volume of Inject Al(OH) 3 (Day 1 and 14, i.p.). On days 24–26, aerosolised with 10 mL of 1% OVA for 20 min daily via nebuliser.…”