Search

Traditional Japanese medicines, i.e., Kampo medicines, consist of crude drugs (mostly plants) that have empirical pharmacological functions (' Yakuno ' in Japanese), such as clearing heat. Crude drugs with cold properties, such as Phellodendron bark, have the empirical function of clearing heat as they cool the body. Because we found that anti-inflammatory compounds were present in several crude drugs for clearing heat, it is speculated that the empirical function of clearing heat may be linked to anti-inflammatory activities. When 10 typical crude drugs were selected from 22 herbal crude drugs for clearing heat, we identified anti-inflammatory compounds in five crude drugs, including Phellodendron bark. In this study, the other crude drugs were extracted and partitioned with ethyl acetate (EtOAc) and n -butanol to obtain three crude fractions. All the EtOAc-soluble fractions, except that from Forsythia fruits, inhibited interleukin (IL)-1β-induced nitric oxide (NO) production in primary-cultured rat hepatocytes. Anti-inflammatory compounds were identified from these EtOAc-soluble fractions: baicalein from Scutellaria roots, (-)-nyasol from Anemarrhena rhizomes, and loniflavone from Lonicera leaves and stems. (+)-Phillygenin was purified from Forsythia fruits by removing cytotoxic oleanolic and betulinic acids. These compounds suppressed the production of NO and cytokines in hepatocytes. Anti-inflammatory compounds were not purified from the EtOAc-soluble fraction of Rehmannia roots because of their low abundance. Collectively, these findings indicate that anti-inflammatory compounds are present in all 10 crude drugs for clearing heat, confirming that these anti-inflammatory compounds in crude drugs provide the empirical functions for clearing heat. Other empirical functions of Kampo medicine can also be explained by modern pharmacological activities.

Two new monoterpene esters ( 1 and 2 ) and four known compounds ( 3 - 6 ) were isolated from the pericarps of Alpinia zerumbet . Their structures were elucidated by extensive spectroscopic analyses and their anti-inflammatory activity was evaluated by monitoring their inhibitory effects on the interleukin-1 β -induced production of nitric oxide in primary cultured rat hepatocytes. The new compound 1 and cardamonin 3 showed inhibitory activities with IC 50 values of 17.6 ± 1.1 and 10.2  ±  1.3 µM, respectively, which are comparable to that of the positive control N G -methyl-L-arginine acetate salt.

The roots of Polygonum multiflorum Thunberg (Polygonaceae) are used as a crude drug Kashu that is considered to improve blood deficiency based on a Kampo concept. Kashu has been included in Kampo formulas, such as Tokiinshi, which is used to treat eczema and dermatitis with itchiness by inhibiting inflammation and facilitating blood circulation in the skin. However, the effects of P. multiflorum roots on erythropoiesis are unclear. Previously, we isolated six phenolic constituents from an ethyl acetate (EtOAc)-soluble fraction of P. multiflorum root extract and identified them as (E)-2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucopyranoside [(E)-THSG], emodin, emodin-8-O-β-D-glucopyranoside, physcion, physcion-8-O-β-D-glucopyranoside, and catechin. To examine whether P. multiflorum roots facilitate erythropoiesis, the EtOAc-soluble fraction was orally administered to healthy ICR mice. When compared with mice fed a standard diet alone (Controls), the mice fed a diet including the EtOAc-soluble fraction exhibited significantly higher serum erythropoietin (Epo) levels. The renal Epo mRNA levels in EtOAc-soluble fraction-administered mice were significantly higher than those in the control mice. Then, we administered roxadustat, which is a drug to treat the patient suffering with renal anemia by specifically inhibiting hypoxia-inducible factor prolyl hydroxylases. Roxadustat slightly increased renal Epo mRNA levels in healthy mice. Administration of (E)-THSG, a major constituent, significantly increased serum Epo levels. It is likely that (E)-THSG may facilitate the process to convert inactive renal Epo-producing cells to active Epo-producing cells. Collectively, it is implied that (E)-THSG in the EtOAc-soluble fraction of P. multiflorum roots may primarily improve blood deficiency of Kampo concept by promoting erythropoiesis., (© 2023. The Author(s) under exclusive licence to The Japanese Society of Pharmacognosy.)

The roots of Peucedanum praeruptorum Dunn and Angelica decursiva Franchet et Savatier are designated Zenko , which is a crude drug defined by the Japanese Pharmacopoeia. This crude drug is used as an antitussive and an expectorant and is included in the Kampo formula Jinsoin , which improves cough, fever, and headache. Although the anti-inflammatory effects of this crude drug have been determined, the constituents responsible for this effect remain unknown. To investigate biologically active compounds, rat hepatocytes were used, which produce proinflammatory mediator nitric oxide (NO) in response to proinflammatory cytokine interleukin 1β (IL-1β). A methanol extract of P. praeruptorum roots, which suppressed IL-1β-induced NO production, was fractionated into three crude fractions (ethyl acetate (EtOAc)-soluble, n -butanol-soluble, and water-soluble fractions) based on hydrophobicity. The EtOAc-soluble fraction markedly inhibited NO production. After this fraction was purified, three biologically active compounds were identified as praeruptorins A, B, and E, the contents of which were high. A comparison of their activities indicated that praeruptorin B exhibited the highest potency to inhibit NO production by decreasing inducible NO synthase expression and suppressed the expression of mRNAs encoding proinflammatory cytokines. Collectively, the three praeruptorins may primarily contribute to the anti-inflammatory effects of P. praeruptorum roots., Competing Interests: Hiromu Ozaki and Airi Fujii performed the experiments as graduate students of the Graduate School of Life Sciences, Ritsumeikan University. Kaito Nakamura and Takanori Maesako performed this study as undergraduate students of the College of Life Sciences, Ritsumeikan University. The authors declare no conflicts of interest.

Many constituents of crude drugs in Japanese Kampo formulas are thought to function as pro-drugs, whose pharmacological activity is manifested after oral administration. Proteins and peptides in crude drugs may be digested and metabolized in the digestive tract and liver. However, few studies have reported the pharmacological activity of peptides in crude drugs. Here, we applied an analysis using LC-tandem mass spectrometry (LC-MS/MS) to identify the compounds derived from six crude drugs that are assumed to have anti-inflammatory effects. To simulate in vivo protease digestion, each water-soluble fraction of the crude drug extracts was treated with proteases, including endoproteinases and exopeptidases. Amines in the resultant digests were modified by 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate and analyzed using LC-MS/MS, which demonstrated the presence of four decarboxylated amino acids (primary amines). In the digest of the hydrophilic fraction of the fruit of Ziziphus jujuba Miller var. inermis Rehder (Taiso), isobutylamine, isoamylamine, and 2-methylbutylamine were identified, which may be derived from valinyl, leucinyl, and isoleucinyl residues, respectively. Additionally, tyramine possibly derived from tyrosyl residues was identified in the digests of all the crude drugs. In primary cultured rat hepatocytes treated with interleukin-1β, all these decarboxylated amino acids suppressed the production of nitric oxide, a proinflammatory mediator. Our approach, i.e., in vitro protease digestion and LC-MS/MS analysis, suggests that decarboxylated amino acids may be formed in vivo from peptides and may be responsible for the anti-inflammatory effect of crude drugs included in Kampo medicine.

PyroGlu-Leu is present in certain food protein hydrolysates and traditional Japanese fermented foods. Our previous study demonstrated that the oral administration of pyroGlu-Leu (0.1 mg/kg body weight) attenuates dysbiosis in mice with experimental colitis. The objective of this study was to elucidate why such a low dose of pyroGlu-Leu attenuates dysbiosis in different animal models. High fat diet extensively increased the ratio of Firmicutes/Bacteroidetes in feces of rats compared to control diet. Oral administration of pyroGlu-Leu (1 mg/kg body weight) significantly attenuated high fat diet-induced dysbiosis. By focusing on the production of intestinal antimicrobial peptides, we found that pyroGlu-Leu significantly increased the level of 4962 Da peptides, which identified as the propeptide of rattusin or defensin alpha 9, in ileum. We also observed increased tryptic fragment peptides from rattusin in the lumen. Here, we report that orally administered pyroGlu-Leu attenuates dysbiosis by increasing in the host antimicrobial peptide, rattusin., Competing Interests: Competing interestsThe authors declare no competing interests., (© The Author(s) 2019.)