Effects of saiboku-to on dual-phase bronchoconstriction in asthmatic guinea pigs

Baicalin suppresses type 2 immunity through breaking off the interplay between mast cell and airway epithelial cell

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional Japanese herbal medicine Shin'iseihaito was reported to ameliorate the airway type 2 inflammatory response in clinical and experimental studies. Airway type 2 inflammatory diseases, including bronchial asthma and eosinophilic chronic rhinosinusitis (ECRS), often coexist and interact with each other. However, it is still unclear how Shin'iseihaito exerts its pharmacological effects on cells involved in airway mucosa.

AIM OF THE STUDY

This study aims to examine the direct effect of baicalin, a representative bioactive compound of Shin'iseihaito, on type 2 immune responses in human airway epithelial cells and mast cells.

MATERIAL AND METHODS

We measured the plasma pharmacokinetics of flavonoids derived from Shin'iseihaito and investigated the effects of baicalin on type 2 immune responses in human airway epithelial cells and human mast cells.

RESULTS

Baicalin, wogonin, and wogonoside were detected in the plasma. The maximum plasma concentration of baicalin was highest at 1610 ng/ml (3.6 μM). In the normal human bronchial epithelial cells treated with baicalin, with or without stimulation by IFN-γ, the IL-33 expression was significantly downregulated. However, baicalin treatment did not affect the levels of thymic stromal lymphopoietin and IL-25. We noted that IL-33-dependent expression of tryptase mRNA in mast cells was significantly inhibited by baicalin. Also, the expression of IL-5 in mast cells enhanced by stimulation with TSLP plus IL-1β was significantly downregulated by baicalin treatment. Moreover, the enhancement of IL-13 expression in mast cells by IL-33 simulation was also significantly inhibited by baicalin.

CONCLUSIONS

Our results prove that by breaking off the vicious circle of mast cells and airway epithelial cells, baicalin may be an effective alternative therapeutic option for the treatment of type 2 inflammatory diseases, such as ECRS and comorbid asthma.

Protective effects of magnolol against oxidized LDL-induced apoptosis in endothelial cells

Magnolol, a compound extracted from the Chinese medicinal herb Magnolia officinalis, has several biological effects. However, its protective effects against endothelial injury remain unclear. In this study, we examined whether magnolol prevents oxidized low density lipoprotein (oxLDL)-induced vascular endothelial apoptosis. Incubation of oxLDL with magnolol (2.5-20 microM) inhibited copper-induced oxidative modification via diene formation, thiobarbituric acid reactive substances (TBARS) assay and electrophoretic mobility assay. Apoptotic cell death as characterized by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) stain. We measured the production of reactive oxygen species (ROS) by using the fluorescent probe 2',7'-dichlorofluorescein acetoxymethyl ester (DCF-AM), and observed the activity of antioxidant enzymes. Furthermore, several apoptotic signaling pathways which showed NF-kappaB activation, increased cytosolic calcium, alteration of mitochondrial membrane potential, cytochrome c release and activation of caspase 3 were also investigated. We demonstrated that magnolol prevented the copper-induced oxidative modification of LDL. Magnolol attenuated the oxLDL-induced ROS generation and subsequent NF-kappaB activation. Furthermore, intracellular calcium accumulation and subsequent mitochondrial membrane potential collapse, cytochome c release and activation of caspase 3 caused by oxLDL were also inhibited by magnolol. Our results suggest that magnolol may have clinical implications in the prevention of atherosclerotic vascular disease through decreasing the oxLDL-induced ROS production.

Pharmacology and toxicology of Bupleurum root-containing Kampo medicines in clinical use

Kampo (Japanese traditional herbal) medicines have been produced by combining multiple crude drugs, almost all of plant origin but with some of animal or mineral origin, and contain a great many substances. Their effect is a combination of the various interactions of the constituent substances, whether they are enhancing, synergistic or suppressive. Kampo medicine has an overall effect that is different from the combined effects of individual crude drugs, and several side effects such as anorexia, slight fever and nausea have been reported in the treatment of certain disorders and disease states with Kampo medicines. Among 210 medical formulations used in Japan, some relevant information on the clinical uses, pharmacology and toxicology of six manufactured Kampo medical formulations, Shosaikoto, Daisaikoto, Saikokeishito, Hochuekkito, Saibokuto and Saireito, containing Bupleurum root are reviewed. Studies of some potential interactions between Kampo medicine and western drugs are also considered.

Treatment of asthma patients with herbal medicine TJ-96: a randomized controlled trial

Alternative medicine use has increased at a remarkable pace all over the world in recent years. Although herbal medicine for the treatment of asthma is becoming the focus of public attention, randomized studies had not been performed, even in Eastern countries including Japan. This study was designed to investigate whether one of the Japanese government approved herbal complexes Saiboku-to (TJ-96) is effective for the treatment of atopic asthma, and to investigate whether this protective activity is associated with a reduction in eosinophilic inflammation. A double-blind, randomized, crossover design was used. Subjects received 2.5 g of TJ-96 or placebo orally 3 times daily for 4 weeks and then, after a washout period of at least 4 weeks, crossed over to receive the alternative treatment. We assessed the effects of pretreatment with TJ-96 on bronchoconstriction precipitated by inhalation of methacholine. Furthermore, eosinophil counts and measurement of eosinophilic cationic protein (ECP) were performed. After 4 weeks of treatment with TJ-96, values of PC20 -methacholine significantly improved in the treatment with TJ-96. Also, patients' symptoms, blood eosinophils, serum ECP, sputum eosinophils, and sputum ECP were significantly decreased. Our results suggest that TJ-96 has an antiinflammatory effect on bronchial eosinophilic infiltration. This study raises further interesting therapeutic possibilities and argues for further trials of new approaches to the treatment of asthma.

Effect of oral treatment of Perilla frutescens and its constituents on type-I allergy in mice

Perilla frutescens Britton (perilla, Labiatae) is a medicinal herb prescribed in Saiboku-to [Japanese letters: see text], which is a Kampo formula effective for allergic diseases such as bronchial asthma. The present study was conducted to evaluate the anti-allergic effect of orally administered perilla decoction and to identify the active constituents using mice ear-passive cutaneous anaphylaxis (PCA)-reaction, which is one of the animal models for type I allergy. Perilla decoction significantly suppressed PCA-reaction, and the inhibition % at the dose of 500 mg/kg was 43%. The perilla decoction contains 5.3% of luteolin 7-O-[beta-glucuronosyl(2-->1)beta-glucuronide], 1.6% of apigenin 7-O-[beta-glucuronosyl(2-->1)beta-glucuronide], 0.49% of scutellarin, and 2.5% of rosmarinic acid (weight of compound/dried weight of perilla decoction %), respectively. When these constituents were orally administered to mice at the dose equivalent to 500 mg/kg of perilla decoction, rosmarinic acid and apigenin 7-O-[beta-glucuronosyl(2-->1)beta-glucuronide] significantly suppressed PCA-reaction, and their inhibition % was 41% (p<0.01) and 32% (p<0.05), respectively. Since the inhibition % or perilla decoction and rosmarinic acid were nearly equal, the anti-allergic effect of perilla decoction depends primarily on rosmarinic acid. The standard Saiboku-to decoction contained 0.013% of rosmarinic acid, which was too low to exhibit anti-allergic activity in a daily dose of Saiboku-to in adults, suggesting that perilla would be prescribed in Saiboku-to to exhibit other pharmacological effects than its anti-allergic activity, such as a sedative.

Effects of an oriental herbal medicine, "Saiboku-to", and its constituent herbs on Compound 48/80-induced histamine release from peritoneal mast cells in rats

Effects of a traditional oriental herbal medicine, "Saiboku-to" and its constituent herbs on Compound 48/80-induced histamine release from peritoneal mast cells in rats were investigated. Saiboku-to inhibited Compound 48/80-induced degranulation of and histamine release from the mast cells, suggesting that Saiboku-to not only possesses anti-histamine release effect from mast cells, but also contains active herbs with this effect. Significant inhibitions were found in 4 of 10 constituent herbs of Saiboku-to: Magnoliae Cortex, Perillae Herba, Bupleuri Radix and Hoelen. In the dose-response curves of the four herbs, the logarithmic linearity was observed for each herb, and 50% inhibitory concentration, the IC50 values, were calculated to be 56.8 microg/ml for Magnoliae Cortex, 175.8 microl/ml for Perillae Herba, 356.6 microg/ml for Bupleuri Radix, and 595.8 microg/ml for Hoelen. One mg/ml of Saiboku-to showing 75% inhibition of Compound 48/80-induced histamine release level from mast cells contains 88.5 microg of Magnoliae Cortex (it was estimated from the dose-response curve that this dose inhibits 62.68% of the Compound 48/80-induced histamine release level), 58.8 microg of Perillae Herba (21% inhibition), 205.9 microg of Bupleuri Radix (35.24% inhibition), and 147.1 microg of Hoelen (11.15% inhibition). From these results, it is suggested that the anti-histamine release effect of Saiboku-to, which contains 10 herbs, may be due mainly to the effect of Magnoliae Cortex and the synergism of the 3 other herbs.

Anxiolytic-like effect of saiboku-to, an oriental herbal medicine, on histaminergics-induced anxiety in mice

Effect of saiboku-to, an oriental herbal medicine, on anxiety in mice was investigated using a light/dark test. Anxiogenic- and anxiolytic-like effects were evaluated on the basis of shortened and prolonged time spent in the light zone of the test. Subacute administration (once a day for 7 days) of saiboku-to (0.5-2.0 g/kg, p.o.) induced anxiolytic-like effect. To assess the effect of saiboku-to on brain histaminergic system in a state of anxiety, Compound 48/80 (1.0 microg/2 microl, i.c.v.), a non-neuronal mast cell histamine releaser, or thioperamide (10.0 mg/kg, i.p.), a neuronal histamine releaser possessing the inhibitory effect of histamine H(3) autoreceptors, induced decrease in the time spent in the light zone by co-injection with cimetidine (10.0 microg/2 microl, i.c.v.), a H(2) inhibitor, suggesting anxiety-like effect. These histaminergics-induced experimental anxieties were inhibited by pre-treatment with subacute administration of saiboku-to, as well as single treatment with diazepam. The results suggest that saiboku-to exhibits anxiolytic-like effect closely related to histaminergic system in the brain.

Effects of subacutely administered saiboku-to, an oriental herbal medicine, on pharmacodynamics and pharmacokinetics of diazepam in rodents

Subacute treatment with saiboku-to (2000 mg/kg, p.o., once a day) for 7 days induced an anxiolytic-like effect in rats. It did not, however, produce any other effects, such as sedative and hypnotic effects, anticonvulsive and muscle relaxant effects except for anxiolytic effect observed in diazepam-injected rats or mice. Diazepam (1.0 mg/kg, s.c.) induced anxiolytic-like effect was enhanced in saiboku-to treated rats as an additional effect of that induced by saiboku-to. To elucidate whether the enhancement of the anxiolytic-like effect following combined administration of diazepam and saiboku-to is due to the inhibition of hepatic drug-metabolizing enzymes, the pharmacokinetics of diazepam were further investigated in saiboku-to treated rats. The pharmacokinetic studies clearly demonstrated that subacute treatment with saiboku-to did not affect plasma concentration and protein binding rate of diazepam, and the activities of hepatic drug-metabolizing enzymes related to diazepam metabolism. These results, taken together, suggest that the enhancement of diazepam-induced anxiolytic-like effect observed in saiboku-to-treated rats is not due to an inhibition of diazepam metabolism.