Effects of Hangeshashinto on Growth of Oral Microorganisms

Recent advances in the treatment of oral ulcerative mucositis from clinical and basic perspectives

BACKGROUND

Oral ulcerative mucositis (OUM) is common in patients with cancer, particularly in those undergoing chemoradiation therapy. The effective management of OUM is crucial for continuous cancer care and patient well-being. Recent studies have advanced our understanding of the causes, leading to clinical trials toward novel treatments. This review focuses on the contemporary therapeutic landscape, and provides the latest insights into the mechanisms of mucosal healing and pain.

HIGHLIGHTS

Management strategies for OUM in patients with cancer include maintaining good oral hygiene, reducing mucosal irritation against radiation, and using various topical analgesic treatments, including herbal medicines. However, the current management practices have limitations that necessitate the development of more efficacious and novel treatments. Molecular research on transient receptor potential (TRP) channels in the oral mucosa is crucial for understanding the mechanisms of wound healing and pain in patients with OUM. Targeting TRPV3 and TRPV4 can enhance wound healing through re-epithelialization. The suppression of TRPV1, TRPA1, and TRPV4 may be effective in alleviating OUM-induced pain.

CONCLUSION

Research advancements have improved our understanding and potentially led to novel treatments that offer symptomatic relief. This progress highlights the importance of collaborations between clinical researchers and scientists in the development of innovative therapies.

Hangeshashinto Inhibits Porphyromonas gingivalis Pathogen-Associated Molecular Patterns-Mediated IL-6 and IL-8 Production through Toll-Like Receptors in CAL27 Cells

While previous reports have established the anti-inflammatory effects of hangeshashinto, the intracellular signal transduction pathways involved have yet to be elucidated. We aim to employ an experimental system using oral cancer cells to assess the impact of hangeshashinto on intracellular signal transduction pathways in response to stimulation by Porphyromonas gingivalis pathogen-associated molecular patterns (PAMP). Hangeshashinto demonstrated the ability to inhibit the production of interleukin (IL)-6 and IL-8 induced by P. gingivalis PAMP. Furthermore, hangeshashinto suppressed the activation of the IL-6 promoter stimulated by PAMP. Hangeshashinto, like Toll-like receptor (TLR) signaling inhibitors (resatorvid and C29) and an immunosuppressant (dexamethasone), exhibited the ability to suppress TLR-mediated activation of the transcription factor nuclear factor-κB (NF-κB) in response to PAMP stimulation. This study suggests that the anti-inflammatory effects of hangeshashinto may be attributed to the inhibition of TLR signal transduction pathways including NF-κB activation, thereby suppressing NF-κB-dependent gene expression.

Comparison between hangeshashinto and dexamethasone for IL-1α and β-defensin 1 production by human oral keratinocytes

OBJECTIVE

Human β-defensin 1 (hBD-1) is a antimicrobial peptide that is constantly secreted by oral tissues. Hangeshashinto (HST), a traditional Japanese medicine, has been reported to be effective against stomatitis. This study aimed to clarify the profile of HST by comparing the system of production of interleukin-1α (IL-1α) and hBD-1 in human oral mucosal epithelial cells with dexamethasone (DEX), a steroid used for the treatment of stomatitis.

METHODS

Human oral keratinocytes (HOK) were treated with HST, DEX, or HST components (baicalein, baicalin, berberine, and glycyrrhizin) for 24 h, and subsequently cultured for 24 h with or without Pam3CSK4 or lipopolysaccharide (LPS). The cell supernatants, total RNA, and intracellular proteins were collected, and changes in IL-1α and hBD-1 protein production and gene expression were evaluated using ELISA and RT-PCR. The phosphorylation of NF-kB and the cell proliferative ability of HOK were evaluated by western blotting and XTT assay, respectively.

RESULTS

DEX (0.01-10 μM) significantly suppressed IL-1α and hBD-1 production induced by either Pam3CSK4 or LPS, and also decreased cell growth. In contrast, HST inhibited Pam3CSK4- and LPS-induced IL-1α production at a concentration range of 12.5-100 μg/mL without affecting the cell proliferative capacity and hBD-1 production of HOK. Baicalein and baicalin, which are flavonoid ingredients of HST, showed anti-IL-1α production.

CONCLUSION

HST may be useful as a therapeutic agent for stomatitis and other inflammatory diseases of the oral cavity.

Preparation and pharmaceutical properties of Hangeshashinto oral ointment and its safety and efficacy in Syrian hamsters with 5-fluorouracil-induced oral mucositis

Chemotherapy-induced oral mucositis (COM) is a common adverse effect of cancer chemotherapy. Several clinical studies reported that repetitive use of mouthwashes containing 2.5-6.25% Hangeshashinto (HST), a Kampo formula, relieves COM, but the effect is insufficient. To solve this problem, we produced an oral ointment of 12% HST extract (considered quantitatively equivalent to 20% commercially available HST), which will increase the local concentrations of its active ingredients and prolong the contact time with COM. In this study, we evaluated the pharmaceutical properties (spreadability and stability) of HST oral ointment. In addition, its safety (oral mucosal irritation) and therapeutic effects on 5-fluorouracil-induced oral mucositis were evaluated in male Syrian hamsters. The HST ointment showed good spreadability and stability for more than 8 weeks at 4 °C. In the oral mucosal irritation test, topical application of HST ointment (0.2 g) three times per day for 14 days had no adverse effect on the oral mucosa of hamsters. In hamsters treated with 5-fluorouracil (60 mg/kg) twice, COM was induced by a submucosal injection of 5% acetic acid into the cheek pouch. When HST ointment (50 µg) was topically applied to the mucositis area once per day for 12 days, the area and macroscopic score of mucositis were significantly decreased, and the depth of the wound tended to be reduced compared with the lactose ointment-treated control animals. These findings suggest that HST oral ointment shows good properties in spreadability, stability, and safety, and elicits a therapeutic effect in an animal model of COM.

The Japanese Herbal Medicine Hangeshashinto Induces Oral Keratinocyte Migration by Mediating the Expression of CXCL12 Through the Activation of Extracellular Signal-Regulated Kinase

Several clinical studies have reported that Japanese herbal medicine Hangeshashinto (HST) has beneficial effects on chemotherapy-induced oral ulcerative mucositis (OUM). Our previous research demonstrated that HST improves chemotherapy-induced OUM through human oral keratinocyte (HOK) migration, which was suppressed by mitogen-activated protein kinase (MAPK) and C-X-C chemokine receptor 4 (CXCR4) inhibitors. However, the association between these molecules and HOK migration was unclear. Here, we examined the effects of HST on the expression of CXCR4/CXCR7 and C-X-C motif chemokine ligands 11 and 12 (CXCL11/CXCL12) in HOKs. Our results indicated that HST upregulated CXCL12, but not CXCR4, CXCR7, nor CXCL11 in HOKs. HST-induced expression of CXCL12 was significantly suppressed by an inhibitor of extracellular signal-regulated kinase (ERK), but not of p38 and c-Jun N-terminal kinase (JNK). In addition, HST induced phosphorylation of ERK in HOKs. These findings suggest that HST enhances HOK migration by upregulating CXCL12 via ERK.

The effects of herbal medicines on cancer therapy-induced oral mucositis: A literature review

Cancer therapy-induced oral mucositis (OM) is one of the most troublesome morbidities after radio-chemotherapy. Age, nutritional status, tumor type, oral hygiene, and treatment method are the determinants for OM incidence. In addition, oxygen-free radicals can act as a trigger for an inflammatory milieu that causes OM. Based on the debilitating nature of OM, finding a safe and inexpensive agent with anti-inflammatory, anti-microbial, and antioxidative properties can be valuable for this situation. Considering the harmful effects of some chemical agents, herbal medicine has been suggested as a potential alternative owing to unique properties such as safety, availability and low cost. Many studies have illustrated several pharmacological properties of herbal medicines in recent years, such as anti-inflammatory, anti-microbial, and antioxidative activities, which are essential factors in the palliation of cancer therapy-induced OM. This review aimed to evaluate herbal medicines' effects on cancer therapy-induced OM. According to this comprehensive review, it is concluded that medicinal plants and phytochemicals can be used as practical agents in the palliation of cancer therapy-induced OM without any serious side effects.

Japanese Herbal Medicine Ninjinyoeito Mediates Its Orexigenic Properties Partially by Activating Orexin 1 Receptors

Cancer cachexia is highly prevalent in patients with progressive cancer and is characterized by decreased food consumption, and body weight. Japanese herbal medicine Ninjinyoeito (NYT), composed of 12 herbal crude drugs, is prescribed in Asian countries to improve several symptoms such as anorexia and fatigue, which are commonly observed in patients with cancer cachexia. However, the action mechanisms of NYT in improving anorexia or fatigue in patients with cancer are not clear. Therefore, in the present study, we examined the effects of NYT on the activities of several G-protein-coupled receptors (GPCRs), which activate hyperphagia signaling in the central nervous system, using an in vitro assay with the CellKey™ system, which detects the activation of GPCRs as a change in intracellular impedance (ΔZ). NYT increased the ΔZ of human embryonic kidney 293 (HEK293) cells expressing orexin 1 receptor (OX1R) and those expressing neuropeptide Y1 receptor (NPY1R) in a dose-dependent manner. On the contrary, NYT did not significantly increase the ΔZ of HEK293A cells expressing growth hormone secretagogue receptor (GHSR) and those expressing NPY5R. The selective OX1R antagonist SB674042 significantly decreased the NYT-induced increase in ΔZ in OX1R-expressing cells. Contrarily, the selective NPY1R antagonist BIBO3340 failed to inhibit the NPY-induced increase in ΔZ in NPY1R-expressing cells. Additionally, we prepared modified NYT excluding each one of the 12 herbal crude drugs in NYT and investigated the effects on the activity of OX1R. Among the 12 modified NYT formulations, the one without citrus unshiu peel failed to activate OX1R. A screening of each of the 12 herbal crude drugs showed that citrus unshiu peel significantly activated OX1R, which was significantly suppressed by SB674042. These finding suggest that NYT and citrus unshiu peel could increase food intake via activation of orexigenic OX1R-expressing neurons in the hypothalamus. This study provides scientific evidence to support the potential of NYT for cancer patients with anorexia.

Effects of Topical Hangeshashinto (TJ-14) on Chemotherapy-Induced Oral Mucositis

Purpose

Hangeshashinto (TJ-14), a Kampo medicine comprising seven types of herbs, has been used in Japan to alleviate the side effects associated with anticancer drug treatments. However, the pharmacological effects of this medicine currently remain unclear. The present study aimed to demonstrate the efficacy of TJ-14 against anticancer drug-induced stomatitis, the pain associated with which may have a negative impact on mastication and swallowing.

Methods

Mucositis was induced in Sprague-Dawley rats by cancer chemotherapy. Changes in body weight, stomatitis grades, histopathological scores, and oral bacterial counts were examined among TJ-14-treated, saline-treated, and Control (no treatment) rats. In vitro studies, including cell proliferation and wound healing assays, using epidermal keratinocyte and fibroblast cell lines were conducted.

Results

The local application of TJ-14 exerted strong antibacterial effects and attenuated oral chemotherapy-induced stomatitis in rats. TJ-14 also increased the viability and invasion of epidermal keratinocytes and fibroblasts.

Conclusion

The present results demonstrated the potential of TJ-14 to attenuate chemotherapy-induced stomatitis.

The Japanese herbal medicine Hangeshashinto enhances oral keratinocyte migration to facilitate healing of chemotherapy-induced oral ulcerative mucositis

Chemotherapy often induces oral ulcerative mucositis (OUM) in patients with cancer, characterized by severe painful inflammation. Mouth-washing with the Japanese herbal medicine hangeshashinto (HST) ameliorates chemotherapy-induced OUM in patients with colorectal cancer. Previously, we demonstrated that HST decreased interleukin 1β-induced prostaglandin E2 production in human oral keratinocytes (HOKs) and OUM-induced mechanical or spontaneous pain in rats. However, HST effects on tissue repair functions in HOKs remain unclear. Here, we examined the effects of HST on scratch-induced wound healing in vitro and in vivo. In vitro, HST enhanced wound healing mainly through scratch-induced HOK migration. Screening of the seven constituent medicinal herbs and their major components revealed that Scutellaria root, processed ginger, and Glycyrrhiza components mainly induced the scratch-induced HOK migration. Pharmacokinetic analyses indicated that the active ingredient concentrations in rat plasma following oral HST administration were below the effective doses for HOK migration, suggesting direct effects of HST in OUM. Mitogen-activated protein kinase and C-X-C chemokine receptor 4 inhibitors significantly suppressed HST-induced HOK migration. Moreover, HST enhanced tissue repair in our OUM rat model. Thus, HST likely enhanced OUM tissue repair through oral keratinocyte migration upon MAPK and CXCR4 activation and may be useful in patients with cancer-associated OUM.

Efficacy and safety of hangeshashinto for treatment of GERD refractory to proton pump inhibitors : Usual dose proton pump inhibitors plus hangeshashinto versus double-dose proton pump inhibitors: randomized, multicenter open label exploratory study

BACKGROUND

Proton pump inhibitor (PPI)-refractory gastroesophageal reflux disease (GERD) leads to a clinical decline in the quality of life (QOL). Therefore, new treatment options are needed. We performed a multicenter, randomized, parallel-group exploratory trial to determine the efficacy of hangeshashinto (HST) in patients with PPI-refractory GERD.

METHODS

We enrolled 78 patients with PPI-refractory GERD for standard PPI regimens for at least 4 weeks and randomly assigned patients to receive either a combination of usual dose of rabeprazole (10 mg/day) + HST (7.5 g/day; HST group) or a double dose of rabeprazole (20 mg/day; double-dose PPI group). The primary end points were the extent of improvement in FSSG (Frequency Scale for the Symptoms of GERD) score and the change over time in FSSG score.

RESULTS

There was no significant difference in terms of the improvement degree of the FSSG score between the two groups. Although the total FSSG score and reflux syndrome score decreased significantly for both groups over time (p < 0.001), the acid-related dyspepsia (ARD) score decreased significantly in the HST group from 1 week after drug administration (p < 0.05), indicating an improvement in the condition earlier than in the double-dose PPI group. Moreover, in examinations concerning BMI and age, the HST group had a significantly higher improvement degree of ARD score in patients with BMI < 22 (p < 0.05) and aged < 65 years (p < 0.05) than the double-dose PPI group.

CONCLUSIONS

HST may be beneficial for patients with PPI-refractory GERD, particularly in non-obese and non-elderly patients with dyspepsia symptoms.

Evaluation of the effect of a toothpaste containing Pudilan extract on inhibiting plaques and reducing chronic gingivitis: A randomized, double-blinded, parallel controlled clinical trial

ETHNOPHARMACOLOGICAL RELEVANCE

Pudilan is a famous traditional Chinese medicine compound which contains several Chinese herbal ingredients, and has been wildly used to treat a variety of inflammatory diseases in China. Recently, it was reported that Pudilan extract had been used in the oral field, especially in the treatment of minor oral ulcers for its anti-inflammatory, pain relieving, antibacterial, clearing heat, and detoxifying effects.

AIM OF THE STUDY

To evaluate the effectiveness and safety of Pudilan extract-containing toothpaste in controlling plaques and reducing chronic gingivitis.

MATERIALS AND METHODS

A total of 120 patients with chronic gingivitis were randomized into an experiment group and a control group (n = 60 patients per group) based on a double-blinded method. Patients in the experiment group used a Pudilan extract-containing toothpaste, whereas patients in the control group used a Pudilan toothpaste simulator, which were identical as the toothpaste used by the experiment group, except for not containing the Pudilan extract. The Plaque Index (PI), Gingival Index (GI), Bleeding Index (BI), and Bleeding On Probing proportion (BOP%) were recorded at baseline, 4 weeks, 8 weeks and 12 weeks after using the toothpaste.

RESULTS

After using the toothpaste for 8 and 12 weeks, PI, BI, GI, and BOP% of the experiment group were significantly lower when compared to the control group (both p < 0.001). Moreover, after using the toothpaste for 4, 8, and 12 weeks, the decline of the PI and GI in the experiment group were significantly higher than the control group (p < 0.001, except 4weeks PI p = 0.011). After 12 weeks, the PI of the experiment group decreased 35.73% (p < 0.001) whereas the GI decreased 29.04% (p < 0.001). BI and BOP decline rates were statistically significant when compared to those of the control group at 8 and 12 weeks (both p < 0.001). Moreover, at 12 weeks, the BI of the experiment group decreased 34.33% (p < 0.001) and BOP% decreased 54.71% (p < 0.001).

CONCLUSION

Toothpaste with Pudilan extract demonstrated good effect on relieving symptoms of chronic gingivitis by inhibiting plaque formation, reducing gingival inflammation and the degree of bleeding, and the bleeding rate. Toothpaste containing Pudilan extract has prospective application potentials in the prevention and treatment of chronic gingivitis.

In Vitro Effect of the Traditional Medicine Hainosan (Painongsan) on Porphyromonas gingivalis

Background: Hainosan (Painongsan) is a traditional Japanese and Chinese medicine that is used to treat several purulent diseases, including gingivitis and periodontitis. This formulation contains three crude drug components: The dried immature fruit of Citrus aurantium (Aurantii Fructus Immaturus), the dried root of Paeonia lactiflora (Paeoniae Radix), and the dried root of Platycodon grandiflorum (Platycodi Radix). Here we evaluated the in vitro antibacterial effects of hainosan extract (HNS) and extracts of its three components against Porphyromonas gingivalis, one of the pathogenic bacteria that causes periodontitis. Methods: The antibacterial activities of HNS and its components were examined by counting the number of colony-forming units (CFUs) and through transmission electron microscopy. Results: We found that HNS had direct antibacterial activity against three P. gingivalis isolates (JCM12257, JCM8525, and JCM19600), with HNS-treated cells being significantly smaller than those of untreated bacteria. Extracts of Platycodi Radix and Paeoniae Radix significantly suppressed the growth of P. gingivalis in a dose-dependent manner, with Platycodi Radix extract having the greatest antibacterial effect. In addition, P. gingivalis that were treated with Platycodi Radix extract were significantly larger than those treated with Aurantii Fructus Immaturus or Paeoniae Radix extracts. Further analysis showed that platycodin D, which is one of the ingredients of Platycodi Radix, reduced bacterial growth. Conclusions: Platycodi Radix is the active component in Hainosan and may represent a useful agent for the treatment of P. gingivalis-induced gingivitis and periodontitis.

Pain mechanism of oral ulcerative mucositis and the therapeutic traditional herbal medicine hangeshashinto

BACKGROUND

Oral ulcerative mucositis causes severe pain during eating and speaking, resulting in poor quality of life for patients with cancer undergoing chemoradiotherapy. Recently, some basic and clinical studies demonstrated that hangeshashinto, a traditional Japanese herbal medicine, alleviated oral ulcerative mucositis-induced pain. Here, we review a recently revealed pain mechanism underlying oral ulcerative mucositis in a preclinical rat model and the pharmacological analgesic effect of hangeshashinto.

HIGHLIGHT

In a rat model of experimentally induced oral ulcerative mucositis, the mucosal surface of the ulcerative region is damaged, which increases oral bacterial loading in the mucosa and prostanoid production. Chemotherapeutic drugs exaggerate the pathological condition and cause severe pain. The pain-related TRP channels, TRPV1, TRPA1, and/or TRPV4, mediate spontaneous and mechanical pain in oral ulcerative mucositis models. Swab application of hangeshashinto had a prolonged localized analgesic effect on oral ulcerative mucositis, even in a chemotherapy-treated oral ulcer model. Two ingredients of hangeshashinto, gingerol and shogaol, strongly inhibit voltage-activated sodium channels (though they have agonistic effects on TRPV1 and TRPA1), which confers hyposensitivity to the oral mucosa. Their analgesic effects on oral ulcerative mucositis are accompanied by accelerated delivery of drugs (other saponin-containing herbal extracts) into the ulcerative region.

CONCLUSION

Elucidation of the pain mechanism of oral ulcerative mucositis and analgesic mechanism of hangeshashinto will allow identification of novel therapeutic approaches against oral ulcerative mucositis-induced pain in patients. The traditional Japanese herbal medicine hangeshashinto is a reliable drug with supporting scientific evidence.

Kampo (Traditional Japanese Herbal) Formulae for Treatment of Stomatitis and Oral Mucositis

Stomatitis is occasionally multiple, recurrent, and refractory. Currently, mucositis induced by chemotherapy and radiation therapy in patients with cancer has become a significant clinical problem. Effective treatments have not been established and the treatment of numerous cases remains a challenge for physicians. Traditional Japanese herbal medicines termed Kampo formulae (i.e., Hangeshashinto, Orengedokuto, Inchinkoto, Orento, Byakkokaninjinto, Juzentaihoto, Hochuekkito, and Shosaikoto) are used for treating various types of stomatitis and mucositis. Its use has been based on the Kampo medical theories—empirical rules established over thousands of years. However, recently, clinical and basic research studies investigating these formulae have been conducted to obtain scientific evidence. Clinical studies investigating efficacies of Shosaikoto and Orento for the treatment of cryptogenic stomatitis and acute aphthous stomatitis and those investigating the effects of Hangeshashinto, Orengedokuto, and Juzentaihoto on chemotherapy- or radiotherapy-induced mucositis have been conducted. The Kampo formulae comprise several crude drugs, whose mechanisms of action are gradually being clarified. Most of these drugs that are used for the treatment of stomatitis possess anti-inflammatory, analgesic, and antioxidative properties. In this review, we introduce the clinical applications and summarize the available evidence on the Kampo formulae for the treatment of stomatitis and oral mucositis.

A Review of Evidence for a Therapeutic Application of Traditional Japanese Kampo Medicine for Oral Diseases/Disorders

Kampo medicines prescribed by specialized medical practitioners and Japanese physicians have gradually reemerged in Japan as alternatives to Western medications. Kampo formulations are composed of several plant extracts and, as such, the broad variety of phytochemicals they contain likely act synergistically to provide their beneficial effects. Kampo medicines have traditionally been prescribed for a number of health conditions, including chronic hepatitis, bronchial asthma, anemia, etc. The aim of this article is to review the beneficial effects of Kampos with respect to oral health. Pertinent papers published between 1970 and 2017 were retrieved by searching in PubMed, ScienceDirect, Web of Science, and Scopus using key words followed by evaluation of the relevant articles. In vitro studies have identified a number of properties that give credence to the potential of Kampos for treating or preventing oral diseases/disorders. Given their anti-microbial and anti-inflammatory properties, they may be promising agents for controlling periodontal diseases, oral mucositis, xerostomia, and drug-induced gingival overgrowth. Since some oral diseases have a complex etiology that involves microbial pathogens and the host immune response, agents with dual functionality such as Kampo phytochemicals may offer a therapeutic advantage.

Selection and characterization of alanine racemase inhibitors against Aeromonas hydrophila

Background

Combining experimental and computational screening methods has been of keen interest in drug discovery. In the present study, we developed an efficient screening method that has been used to screen 2100 small-molecule compounds for alanine racemase Alr-2 inhibitors.

Results

We identified ten novel non-substrate Alr-2 inhibitors, of which patulin, homogentisic acid, and hydroquinone were active against Aeromonas hydrophila. The compounds were found to be capable of inhibiting Alr-2 to different extents with 50% inhibitory concentrations (IC₅₀) ranging from 6.6 to 17.7 μM. These compounds inhibited the growth of A. hydrophila with minimal inhibitory concentrations (MICs) ranging from 20 to 120 μg/ml. These compounds have no activity on horseradish peroxidase and d-amino acid oxidase at a concentration of 50 μM. The MTT assay revealed that homogentisic acid and hydroquinone have minimal cytotoxicity against mammalian cells. The kinetic studies indicated a competitive inhibition of homogentisic acid against Alr-2 with an inhibition constant (K_i) of 51.7 μM, while hydroquinone was a noncompetitive inhibitor with a K_i of 212 μM. Molecular docking studies suggested that homogentisic acid binds to the active site of racemase, while hydroquinone lies near the active center of alanine racemase.

Conclusions

Our findings suggested that combining experimental and computational methods could be used for an efficient, large-scale screening of alanine racemase inhibitors against A. hydrophila that could be applied in the development of new antibiotics against A. hydrophila.

Electronic supplementary material

The online version of this article (doi:10.1186/s12866-017-1010-x) contains supplementary material, which is available to authorized users.

Kampo Medicines for Infectious Diseases

Numerous Kampo medicines and Oriental herbs have been used for the treatment of infectious diseases for several reasons, such as genetic background, economical reasons, fewer adverse effects, and so on. This chapter describes Kampo medicines and related Oriental herbs that are effective or promising in the treatment of infectious diseases at the clinical level and/or in animal models. In addition, effective Kampo medicines tested in vitro in cultured-cell studies are also included in this chapter. Each section is categorized by infectious disease and according to the popularity of the Kampo medicine.

[6]-gingerol and [6]-shogaol, active ingredients of the traditional Japanese medicine hangeshashinto, relief oral ulcerative mucositis-induced pain via action on Na+ channels

The traditional Japanese herbal medicine hangeshashinto (HST) has beneficial effects for the treatment of oral ulcerative mucositis (OUM) in cancer patients. However, the ingredient-based mechanism that underlies its pain-relieving activity remains unknown. In the present study, to clarify the analgesic mechanism of HST on OUM-induced pain, we investigated putative HST ingredients showing antagonistic effects on Na⁺ channels in vitro and in vivo. A screen of 21 major ingredients using automated patch-clamp recordings in channel-expressing cells showed that [6]-gingerol and [6]-shogaol, two components of a Processed Ginger extract, considerably inhibited voltage-activated Na⁺ currents. These two ingredients inhibited the stimulant-induced release of substance P and action potential generation in cultured rat sensory neurons. A submucosal injection of a mixture of [6]-gingerol and [6]-shogaol increased the mechanical withdrawal threshold in healthy rats. In a rat OUM model, OUM-induced mechanical pain was alleviated 30min after the swab application of HST despite the absence of anti-bacterial and anti-inflammatory actions in the OUM area. A swab application of a mixture of [6]-gingerol and [6]-shogaol induced sufficient analgesia of OUM-induced mechanical or spontaneous pain when co-applied with a Ginseng extract containing abundant saponin. The Ginseng extract demonstrated an acceleration of substance permeability into the oral ulcer tissue without an analgesic effect. These findings suggest that Na⁺ channel blockage by gingerol/shogaol plays an essential role in HST-associated analgesia of OUM-induced pain. This pharmacological mechanism provides scientific evidence supporting the use of this herbal medicine in patients suffering from OUM-induced pain.

The traditional Japanese medicine hangeshashinto alleviates oral ulcer-induced pain in a rat model

OBJECTIVE

Recent studies have demonstrated that mouthwash made with the traditional Japanese medicine hangeshashinto exhibits anti-inflammatory action and alleviates oral mucositis scores, including pain complaints, in patients undergoing chemoradiotherapy. However, no study has demonstrated the mechanism underlying how hangeshashinto provides pain relief in oral ulcers.

DESIGN

The analgesic effects on pain-related behaviors following the topical application of hangeshashinto were evaluated in an oral ulcer rat model treated with acetic acid using recently developed methods. Indomethacin, the representative anti-inflammatory agent, was intraperitoneally administered. The tissue permeability of the oral mucosa was histologically evaluated after applying the fluorescent substance FluoroGold.

RESULTS

The topical application of hangeshashinto in ulcerative oral mucosa suppressed mechanical pain hypersensitivity over 60 min, without any effects on healthy mucosa. The same drug application also inhibited oral ulcer-induced spontaneous pain. Indomethacin administration failed to block the mechanical pain hypersensitivity, though it did largely block spontaneous pain. Topical anesthesia with lidocaine showed hyposensitivity to mechanical stimulation in healthy mucosa. In the ulcer regions in which the oral epithelial barrier was destroyed, deep parenchyma was stained with FluoroGold, in contrast to healthy oral mucosa, in which staining was limiting to the superficial site.

CONCLUSIONS

Hangeshashinto leads to long-lasting analgesic effects, specifically in the ulcer region by destroying the epithelial barrier. Hangeshashinto alleviates oral ulcer-induced pain in inflammation-dependent and/or independent manner.