Effect of KOB03, a polyherbal medicine, on ovalbumin-induced allergic rhinitis in guinea pigs

Endocannabinoid metabolism inhibition ameliorates ovalbumin-induced allergic airway inflammation and hyperreactivity in Guinea pigs

AIMS

Endocannabinoids are biologically active cannabinoid-related substances endogenously synthesized in many mammalian tissues. Mainly two enzymes carry out their degradation; Fatty Acid Amide Hydrolase (FAAH) and Monoacylglycerol Lipase (MAGL). Endocannabinoids are shown to affect the modulation of inflammatory processes and airway responsiveness. In the present study, we investigated the effects of FAAH and MAGL inhibitor treatments in experimental allergic airway inflammation in guinea pigs.

MATERIALS AND METHODS

Guinea pigs were sensitized and challenged by ovalbumin to induce an allergic asthma model. Then, the effects of FAAH inhibitor URB597, MAGL inhibitor JZL184, and dual (FAAH/MAGL) inhibitor JZL195 on airway inflammation and hyperreactivity were evaluated.

KEY FINDINGS

Ovalbumin challenge increased airway reactivity, IgE in serum, IL-4, and IL-13, and the percentage of eosinophils in bronchoalveolar lavage (BAL). In addition, inhibition of FAAH or MAGL enzymes leads to an increase in endocannabinoid levels. The selective inhibition of the FAAH enzyme prevented inflammation indicators such as cytokine production and inflammatory cell infiltration but had a negligible effect on airway hyperreactivity. However, the inhibition of the MAGL enzyme or dual inhibition of both FAAH and MAGL enzymes tent to moderate both pulmonary inflammation and airway hyperreactivity.

SIGNIFICANCE

We have previously demonstrated that modulation of endocannabinoid levels in the airways by FAAH or MAGL inhibition can be useful in preventing acute lung inflammation. The results of the present study further suggest that FAAH and MAGL inhibitor treatment can also be a promising strategy for bronchial hyperreactivity and airway inflammation in allergic asthma.

The Natural Products Targeting on Allergic Rhinitis: From Traditional Medicine to Modern Drug Discovery

More than 500 million people suffer from allergic rhinitis (AR) in the world. Current treatments include oral antihistamines and intranasal corticosteroids; however, they often cause side effects and are unsuitable for long-term exposure. Natural products could work as a feasible alternative, and this study aimed to review the efficacies and mechanisms of natural substances in AR therapies by examining previous literature. Fifty-seven studies were collected and classified into plants, fungi, and minerals decoction; clinical trials were organized separately. The majority of the natural products showed their efficacies by two mechanisms: anti-inflammation regulating diverse mediators and anti-oxidation controlling the activity of nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) pathway stimulated by reactive oxygen species (ROS). The main AR factors modified by natural products included interleukin (IL)-4, IL-5, IL-13, interferon-gamma (IFN-γ), tumor necrosis factor-α (TNF-α), cyclooxygenase 2 (COX-2), and phospho-ERK1/2 (p-ERK1/2). Although further studies are required to verify their efficacies and safeties, natural products can significantly contribute to the treatment of AR.

Comparative pharmacokinetics of a marker compound, baicalin in KOB extract after oral administration to normal and allergic-induced rats

KOB extracts are a polyherbal medicine had been prescribed for the treatment of hyperhydrosis and allergic diseases such as allergic asthma and rhinitis in oriental clinics. Therefore, the pharmacokinetic studies of the KOB extract administered orally to normal rats and rhinitis-induced rats to understand the correlation of the efficacy and plasma concentration of KOB in patients of allergic rhinitis in future were performed. The study was conducted according to administration for pure baicalin in normal rats, baicalin in KOB extract in normal rats and rhinitis-induced rats. Baicalin in rat plasma was analyzed and validated by HPLC analysis. The interday precision based on the standard deviation of replicates of quality control samples ranged from 3.6% to 7.9% with accuracy ranging from 92.9% to 101.2% for baicalin. Based on validated analysis, pharmacokinetic study was carried out. Pure baicalin in normal rats and baicalin in KOB extract in normal rats showed bimodal curves due to direct absorption and glucuronidation. The Tmax, Cmax and AUC of pure baicalin in normal rats or baicalin in KOB extract in normal rats were 12 h, 0.68 µg/ml and 9.85 µg h/ml, respectively, or 12 h, 0.46 µg/ml and 6.36 µg h/ml, respectively. The analytical method showed excellent sensitivity, precision and accuracy, being successfully employed in a pharmacokinetic study of polyherbal medicine, KOB extract. Allergic-induced condition did not affect the pharmacokinetics of KOB extracts, suggesting KOB extracts did not require dosage adjustment in subjects with allergic-induced diseases.