Compound-compound interaction analysis of baicalin and berberine derivatives in aqueous solution.

Baicalin and berberine are biologically active constituents of the crude drugs Scutellaria root and Coptis rhizome/Phellodendron bark, respectively. Baicalin and berberine are reported to combine together as a 1:1 complex that forms yellow precipitates by electrostatic interaction in decoctions of Kampo formulae containing these crude drugs. However, the structural basis and mechanism for the precipitate formation of this compound-compound interaction in aqueous solution remains unclarified. Herein, we searched for berberine derivatives in the Coptis rhizome that interact with baicalin and identified the chemical structures involved in the precipitation formation. Precipitation assays showed that baicalin formed precipitates with berberine and coptisine but not with palmatine and epiberberine. Thus, the 2,3-methylenedioxy structure may be crucial to the formation of the precipitates, and electrostatic interaction is necessary but is not sufficient. In this multicomponent system experiment, palmatine formed a dissociable complex with baicalin and may competitively inhibit the formation of berberine and coptisine precipitation with baicalin. Therefore, the precipitation formed by berberine and baicalin was considered to be caused by the aggregation of the berberine-baicalin complex, and the 2,3-methylenedioxy structure is likely crucial to the aggregation of the complex.

Comparison of Regulations for Arsenic and Heavy Metals in Herbal Medicines Using Pharmacopoeias of Nine Counties/Regions.

INTRODUCTION: Standardization is an import factor in ensuring the safety, efficacy, and quality of herbal medicines, and facilitates their international commerce. Heavy metal poisoning due to herbal medicines has been reported in many countries. Here, to better understand the current state of harmonization, we compared regulations for arsenic and heavy metals in herbal medicines across seven countries and two regions with two international standards. METHODS: We studied the monographs of herbal medicines of seven countries and two regions, as well as the WHO guidelines and ISO standards. We then compared the limits and test methods adopted for elemental impurities in herbal medicines listed in the monographs and standards among countries. RESULTS: The number of herbal medicines assessed amounted to over 2000. Limits and test methods adopted for elemental impurities in herbal medicines varied by country/region and organization. Although WHO recommends a uniform upper limit for lead and cadmium for all herbal medicines, some countries set unique upper limits for individual herbal medicines. ISO 18664:2015 lists only instrumental analysis methods, whereas Japan and India list only chemical methods. CONCLUSIONS: Many countries do not adhere to the WHO or ISO recommendations on elemental impurities in herbal medicines. These findings suggest the presence of differences in regulations for herbal medicines among countries/regions, likely rooted in cultural differences and policies aimed at maintaining the diversity of herbal medicines. Regulatory convergence by "loose harmonization" to internationally agreed standards appears a feasible option to maintain diversity and safety, and promote international trade in herbal medicines.

Genetic and Chemical Diversity of Commercial Japanese Valerian.

In order to investigate the relationship between the chemical composition of essential oils and haplotypes of the psbA-trnH intergenic spacer region of chloroplast DNA (psbA-trnH) in Valerianae Fauriei Radix (Japanese Valerian; JV), we analyzed the DNA sequence and GC-MS metabolome of JV from Japanese markets and of herbal specimens from related species. DNA analysis revealed that JV products from Japan consisted of three haplotypes, namely AH-1, -2 and -5 reported in our previous study. The GC-MS metabolome revealed five chemotypes (J1, J2, C, K and O), of which J1, J2 and C were detected in the JV products from Japan. Chemotypes J1 and J2, with kessyl glycol diacetate (KGD) as the main volatile component, were found in the products of Japanese origin whereas chemotype C, with 1-O-acetyl-2,10-bisaboladiene-1,6-diol (ABD), was found in the products of Chinese and Korean origin. The haplotypes were correlated with the chemotypes: haplotype AH-1 for chemotype J1, AH-2 for chemotype J2 and AH-5 for chemotype C, suggesting that the chemical diversity of JV is not attributed to the environmental factors rather to the genetic factors. Since KGD and ABD were reported to have sedative effects and nerve growth factor (NGF)-potentiating effects, respectively, understanding the chemotypes and selecting an appropriate one would be important for the application of JV. The psbA-trnH haplotypes could be useful DNA markers for the quality control and standardization of JV.

[Biologically Active Constituents of Natural Medicines -A Mixture Can Do More].

Natural medicines, including crude drugs and Kampo prescriptions, have a long history of clinical uses. An important characteristic of natural medicines is that they are multicomponent medicines. Kampo prescriptions, particularly, usually consist of several crude drugs that contain a large number of constituents. The therapeutic effects of a Kampo prescription result from the total effects of its constituents and not from the effect of a representative constituent with a strong pharmacological effect. In fact, only a few of these constituents with strong biological activity have been listed in the Japanese Pharmacopoeia as therapeutic agents. During my research career, I have observed various synergistic effects and interactions among the constituents of natural medicines. This article reviewed our researches on the biologically active constituents of natural medicines, including the analysis of the anti-inflammatory constituents of orengedokuto (a Kampo prescription). Understanding the role of each constituent with therapeutic effects in Kampo prescriptions forms a scientific basis of Kampo medicine. This will enable the better use and quality control of Kampo prescriptions. Moreover, this will aid the future development of a multicomponent mimic for a specific effect of a Kampo prescription using the appropriate mixture of active constituents in amounts found in the prescription. The above is my dream as a natural product chemist, and I believe that the mixture can do more than we anticipate!

Oxidation of methylophiopogonanone A on the surface of TLC plate.

Methylophiopogonanone A (MOPNA, 1) is a characteristic homoisoflavonoid, having two methyl groups on the A ring, isolated from Ophiopogon Root (enlarged part of the root of Ophiopogon japonicus Ker-Gawler, Liliaceae). Although MOPNA is chemically stable in various organic solvents, such as acetone, chloroform, methanol and dimethyl sulfoxide, it gave a spot of higher polarity in addition to the spot of MOPNA on the surface of TLC plate. The spot was isolated and the structure of the major compound was revealed to be a compound with an oxygen atom at C-6 of the A ring. This oxidation on the surface of TLC plate was observed for synthetic intermediates of MOPNA having two methyl groups on a phloroacetophenone-type ring, suggesting that the methyl groups enhanced susceptibility to air oxidation. The structure of the major oxidation product was similar to those of humulone and sufflomin A. Humulone has two prenyl units and sufflomin A has two C-glucosyl moieties instead of the two methyl groups, respectively. As dialkylated phloroacetophenone derivatives seem susceptible to oxidation, air oxidation might be involved in the formation of these compounds.

Saponin constituents of Achyranthes root.

Achyranthes root is a crude drug used as diuretic, tonic and remedy for blood stasis. Characteristic oleanolic acid saponins with a dicarboxylic acid moiety have been isolated as one of the representative constituents of this crude drug. This review focuses on the triterpene saponin constituents, especially those with a characteristic dicarboxylic acid moiety, of A. bidentata and A. fauriei. Several groups isolated the saponins and different names were given to one compound in some cases. The names of the compounds are sorted out and the stereochemistry of the dicarboxylic acid moieties are summarized. HPLC analysis of the composition of the saponin constituents and the effect of processing and extraction conditions on the composition are reviewed. Biological activities of the saponin constituents are also summarized.

Anti-trypanosomal screening of Salvadoran flora.

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi, and in Central America, it is considered one of the four most infectious diseases. This study aimed to screen the anti-trypanosomal activity of plant species from Salvadoran flora. Plants were selected through literature search for plants ethnobotanically used for antiparasitic and Chagas disease symptomatology, and reported in Museo de Historia Natural de El Salvador (MUHNES) database. T. cruzi was incubated for 72 h with 2 different concentrations of methanolic extracts of 38 species, among which four species, Piper jacquemontianum, Piper lacunosum, Trichilia havanensis, and Peperomia pseudopereskiifolia, showed the activity (≤ 52.0% viability) at 100 µg/mL. Separation of the methanolic extract of aerial parts from Piper jacquemontianum afforded a new flavanone (4) and four known compounds, 2,2-dimethyl-6-carboxymethoxychroman-4-one (1), 2,2-dimethyl-6-carboxychroman-4-one (2), cardamomin (3), and pinocembrin (5), among which cardamomin exhibited the highest anti-trypanosomal activity (IC50 = 66 µM). Detailed analyses of the spectral data revealed that the new compound 4, named as jaqueflavanone A, was a derivative of pinocembrin having a prenylated benzoate moiety at the 8-position of the A ring.

Solubility enhancement of berberine-baicalin complex by the constituents of Gardenia Fruit.

A Kampo prescription usually consists of several crude drugs and contains many kinds of compounds. Physicochemical interactions between the compounds may occur in the process of decoction, by which Kampo prescriptions are usually prepared for ingestion, and the interactions may change the extraction yields of the constituents. Berberine and baicalin have been reported to form precipitates. Orengedokuto, which consist of Coptis Rhizome, Gardenia Fruit, Phellodendron Bark and Scutellaria Root, has been a representative Kampo prescription used to treat inflammatory diseases. In our previous papers, we revealed that the precipitates formed in the decoction of orengedokuto without Gardenia Fruit mainly consists of berberine-baicalin complex and that Gardenia Fruit reduced the amount of the precipitates in orengedokuto decoction. In this report, through solubility-enhancement assay based on HPLC, we identified crocins as the constituents of Gardenia Fruits, which enhanced the solubility of berberine-baicalin complex. All-trans crocin-1 (1) and 13-cis crocin-1 (5) showed high activities among the isolated crocins, and the number of glucosyl groups in the molecule seemed correlated with the activity. As berberine and baicalin were reported as the anti-inflammatory constituents of Coptis Rhizome and Phellodendron Bark, and Scutellaria Root, respectively, Gardenia Fruit contributes anti-inflammatory activity of orengedokuto by increasing solubilities of anti-inflammatory constituents of the other component crude drugs in the prescription. Our result will add a scientific basis to the understanding of the effectiveness of orengedokuto as a whole.

Five new 2-(2-phenylethyl)chromone derivatives from agarwood.

Agarwood has been used as an incense and in traditional medicines as aphrodisiac, sedative, cardiotonic, and carminative. In this study, five new 2-(2-phenylethyl)chromones (2, 13-16) and eleven known compounds (1, 3-12) were isolated from the agarwood. The structures of the new compounds were determined by 1H-, 13C-, and two-dimensional NMR together with electronic circular dichroism (ECD) spectroscopy. All isolated compounds were evaluated for the phosphodiesterase (PDE) 3A and 5A1 inhibitory activity by the fluorescence polarization method. Dimeric 2-(2-phenylehyl)chromones (13, 14, 16) had potent inhibitory activity to PDE 5A1 with IC50 values of micro molar range (13: 4.2 µM, 14: 7.9 µM, 16: 4.3 µM), whereas they had weak activity to PDE 3A. In contrast, compound (15), which has a phenylpropionic acid moiety instead of the 2-(2-phenylethyl)chromone moiety in the dimers, showed moderate inhibition of both PDE 3A (IC50: 42.6 µM) and PDE 5A1 (IC50: 15.1 µM).

LC-MS analysis of saponins of Achyranthes root in the Japanese market.

LC-MS analyses of saponin fractions of Achyranthes roots in the Japanese market revealed that there were three patterns for the saponin fraction of their water extracts, i.e., the saponins with a sugar moiety at position 28 [achyranthosides B (3), C (4) and D (5)] were the major constituents, the saponins without sugar moiety at position 28 [betavulgarosides II (10) and IV (11)] were the major constituents, and mixtures of these saponins. In a decoction prepared from the sample which contained 10 and 11 as the major saponins, their amounts were largely decreased compared with those of the water extract. As large amounts of these saponins were found in the precipitates formed by heating of the water extract, these saponins were seemed to precipitate out under heating. When hot water was used for the extraction, 3, 4 and 5 were detected even from the samples whose water extract did not contain these saponins. This was attributed to inhibition of endogenous esterase which hydrolyzes the ester linkage at position 28. When saponins were extracted with reagent grade 1-butanol, in addition to the decrease of the amounts of highly polar saponins, oxidative decarboxylation of 3 and 10 occurred resulting in formation of achyranthoside E (6) and spinacoside D (12), respectively. As these changes were not observed with HPLC grade 1-butanol, which contain not more than 5 ppm of peroxide impurities, the change was attributable to the peroxide impurities contained in the reagent grade 1-butanol.

Preparation of menisdaurigenin and related compounds.

Menisdaurin (1), a cyano glucoside, was first isolated in 1978 from Menispermum dauricum (Menispermaceae) and named after the plant. It has been also isolated from several plant sources. The stereochemistry of the aglycone part was first reported as (Z,4R,6S)-enantiomer of (4,6-dihydroxy-2-cyclohexen-1-ylidene)acetonitrile based on the CD spectrum of menisdaurilide (2), the α,ß-unsaturated γ-lactone obtained by an acid hydrolysis of menisdaurin. Later, the absolute stereochemistry was revised as (Z,4S,6R) by X-ray crystal analysis of 1 isolated from Saniculiphyllum guangxiens. The aglycone part of menisdaurin (1) has not been obtained from 1, because an acid hydrolysis of 1 gave menisdaurilide (2), and enzymatic hydrolysis with emulsin did not give the aglycone. On the other hand, a compound named coculauril (3) was isolated from Cocculus lauriforius. This compound has the same planner structure corresponding to the aglycone of 1, but the stereochemistry was reported to be (E,4R,6S). Here, we confirmed the absolute stereochemistry of 1 by Mosher's method to be (Z,4S,6R), and prepared the aglycone of 1, i.e., menisdaurigenin (4) by an enzymatic hydrolysis of 1. We also revealed that 4 is a different compound from 3 and unstable in water and MeOH.

A novel derivative (GTN024) from a natural product, komaroviquinone, induced the apoptosis of high-risk myeloma cells via reactive oxygen production and ER stress.

New drugs have significantly improved the survival of patients with multiple myeloma (MM), but the prognosis of MM patients with high-risk cytogenetic changes such as t(4; 14), t(14; 16) or del17p remains very poor. A natural product, komaroviquinone (KQN), was originally isolated from the perennial semi-shrub Dracocephalum komarovi and has anti-protozoal activity against Trypanosoma cruzi, the organism causing Chagas' disease. Here we demonstrate that a novel KQN-derivative, GTN024, has an anti-MM effect both in vitro and in vivo. GTN024 induced the apoptosis of MM cell lines including those with high-risk cytogenetic changes. GTN024 produced reactive oxygen species (ROS) and increased phosphorylated eIF2α. The ROS production and subsequent endoplasmic reticulum (ER) stress are thought to play a key role in GTN024-induced apoptosis, as the apoptosis was completely abrogated by anti-oxidant treatment. In a mouse xenograft model, an intraperitoneal injection of 20 mg/kg of GTN024 significantly delayed tumor growth. Hematological toxicity and systemic toxicity as indicated by weight loss were not observed. These results suggest that the novel KQN-derivative GTN024 could become a candidate drug for treating high-risk MM.

Taxodione induces apoptosis in BCR-ABL-positive cells through ROS generation.

Chronic myeloid leukemia (CML) and acute lymphoblastic leukemia (ALL) are hematopoietic malignancies caused by the constitutive activation of BCR-ABL tyrosine kinase. Although direct BCR-ABL inhibitors, such as imatinib, were initially successful in the treatment of leukemia, many patients developed drug resistance over time due to the gatekeeper mutation of BCR-ABL T315I. In the present study, we found that taxodione, a quinone methide diterpene isolated from Taxodium distichum, significantly induced apoptosis in human myelogenous leukemia-derived K562 cells, which were transformed by BCR-ABL. Taxodione reduced the activities of mitochondrial respiratory chain (MRC) complexes III and V, which appeared to induce the production of reactive oxygen species (ROS). N-acetylcysteine (NAC), an antioxidant agent, canceled taxodione-induced ROS production, reductions in MRC activities, particularly complex V, and apoptotic cell death. Furthermore, in K562 cells treated with taxodione, BCR-ABL and its major signaling molecules, such as STAT5 and Akt were sequestered in mitochondrial fraction, and their localization changes decrease their abilities to stimulate cell proliferation, suggesting that these actions seem to be a mechanism how taxodione functions as an anti-tumor drug. Strikingly, NAC canceled these taxodione-caused anti-cancer effects. Taxodione induced apoptosis in transformed Ba/F3 cells induced not only by BCR-ABL, but also T315I-mutated BCR-ABL through the generation of ROS. Collectively, the present results suggest that in the treatment of leukemia, taxodione has potential as a compound with high efficacy to overcome BCR-ABL T315I mutation-mediated resistance in leukemia cells.

Quantitative analysis of the anti-inflammatory activity of orengedokuto II: berberine is responsible for the inhibition of NO production.

Orengedokuto is a Kampo formula that has been used for removing "heat" and "poison" to treat inflammation, hypertension, gastrointestinal disorders, and liver and cerebrovascular diseases. We report here our analysis of the anti-inflammatory effect of the component crude drugs of orengedokuto and their constituents using the inhibition of nitric oxide (NO) production in the murine macrophage-like cell line J774.1. An initial comparison of NO production inhibitory activities of the extracts of the component crude drugs and their combinations revealed that the activity could be attributed to Phellodendron Bark and Coptis Rhizome. Berberine (1), the major constituent of these crude drugs, showed potent activity (IC50 4.73 ± 1.46 µM). Quantitative analysis of 1 in the extracts of all combinations of component crude drugs revealed that the amount of 1 in each extract of the combination of Scutellaria Root with either Phellodendron Bark and/or Coptis Rhizome was lower than that in the corresponding mixtures of the extracts of the individual crude drugs and that 1 was present in the precipitates formed during the decoction process. To the contrary, the differences in the amounts of 1 were smaller in the extracts containing Gardenia Fruit. These results indicated that the constituents of Scutellaria Root precipitated with 1 and that the constituents of Gardenia Fruit dissolved the precipitates. To identify the constituents affecting the solubility of 1, we fractionated the hot-water extracts of Scutellaria Root based on solubility tests of 1 to give baicalin (2), wogonin (3) and oroxyloside (4), which formed precipitates with 1.

Three new 5,6,7,8-tetrahydroxy-5,6,7,8-tetrahydrochromone derivatives enantiomeric to agarotetrol from agarwood.

Agarwood (jinkoh in Japanese) is a resinous wood from Aquilaria species of the family Thymelaeaceae and has been used as incense and in traditional medicines. Characteristic chromone derivatives such as agarotetrol have been isolated from agarwood. In previous study, we isolated two new 2-(2-phenylethyl)chromones together with six known compounds from MeOH extract of agarwood. Further chemical investigation of the MeOH extract led to isolation of eighteen 2-(2-phenylethyl)chromones, including three new 5,6,7,8-tetrahydroxy-5,6,7,8-tetrahydrochromones with stereochemistry enantiomeric to agarotetrol-type, viz. (5R,6S,7S,8R)-2-[2-(3'-hydroxy-4'-methoxyphenyl)ethyl]-5,6,7,8-tetrahydroxy-5,6,7,8-tetrahydrochromone (2), (5R,6S,7S,8R)-2-[2-(4'-methoxyphenyl)ethyl]-5,6,7,8-tetrahydroxy-5,6,7,8-tetrahydrochromone (6), and (5R,6S,7S,8R)-2-[2-(4'-hydroxy-3'- methoxyphenyl)ethyl]-5,6,7,8-tetrahydroxy-5,6,7,8-tetrahydrochromone (13). The absolute configurations of the new compounds were determined by exciton chirality method. All isolated compounds were tested for their phosphodiesterase (PDE) 3A inhibitory activity by fluorescence polarization method. Compounds 8, 12-15, 21-24 showed moderate PDE 3A inhibitory activity.

Synergistic effect of baicalein, wogonin and oroxylin A mixture: multistep inhibition of the NF-κB signalling pathway contributes to an anti-inflammatory effect of Scutellaria root flavonoids.

Scutellaria root, the root of Scutellaria baicalensis Georgi, is a crude drug used for inflammatory diseases. In our previous report, the combination of flavonoids contained in Scutellaria root have been found to inhibit PGE2 production more strongly than individual flavonoids. Here, to investigate the mechanism of the synergistic effect, we examined the effects of an equimolar mixture (F-mix) of baicalein (1), wogonin (2) and oroxylin A (3) on the production of PGE2 in LPS-treated J774.1 cells. Although 1 and 3 inhibited COX-2 activity, the F-mix showed no synergistic effect on COX-2 inhibition. Therefore, we investigated the steps leading to the activation of COX-2 protein. Compounds 1-3 and F-mix inhibited the expression of COX-2 protein. However, only 2 inhibited the expression of COX-2 mRNA among the flavonoids, and the F-mix showed no synergistic effect. Only 1 inhibited NF-κB translocation into the nucleus, and the F-mix showed no synergistic effect. Although 2 did not affect NF-κB translocation, it strongly inhibited NF-κB-dependent transcriptional activity, and the F-mix inhibited the activity slightly more than 2. Compounds 1-3 also inhibited NO production, and the F-mix showed a synergistic effect. However, the effects of each flavonoid on the expression of iNOS mRNA were not consistent with those on COX-2 mRNA. Because the flavonoids inhibit different steps in the production of PGE2 and NO, and their mixture did not show apparent synergistic effects in each step, we conclude that the synergistic effect of the flavonoid mixture reflects the total effect of the flavonoids inhibiting different steps in the NF-κB signalling pathway.

Synthesis and Antigenicity against Human Sera of a Biotin-Labeled Oligosaccharide Portion of a Glycosphingolipid from the Parasite Echinococcus multilocularis.

Synthesis of a biotinylated analog of the carbohydrate portion of a glycosphingolipid from the parasite Echinococcus multilocularis has been achieved. We synthesized ß-D-Galp-(1→6)-ß-D-Galp-(1→6)-[α-L-Fucp-(1→3)]-ß-D-Galp-(1→R: biotin probe) (1) and compared the antigenicity by an enzyme linked immunosorbent assay (ELISA) with biotinylated trisaccharide α-D-Galp-(1→4)-ß-D-Galp-(1→3)-α-D-Galp-(1→R: biotin probe) (F), which has been shown to have significant antigenicity. Both of the oligosaccharides reacted with sera of alveolar echinococcosis (AE) patients, but showed different reactivity. Among the 60 sera of AE patients, more sera reacted with the linear sequence Galα1→4Galß1→3GalNAcα1→R of oligosaccharide (F) than for branched compound 1. Some sera showed high specificity to one of the compound, indicating that the antibodies in the sera of AE patients differ in their specificity to recognize carbohydrate sequences of glycosphingolipids. Our results demonstrate that both of the biotinylated oligosaccharides 1 and F have good serodiagnostic potential and are complementary to detect infections caused by the parasite Echinococcus multilocularis.

Two new lignans and melanogenesis inhibitors from Schisandra nigra.

An acetone extract from the stems of Schisandra nigra MAX. (Schisandraceae) exhibited significant inhibition of 3-isobutyl-1-methylxanthine (IBMX)-stimulated melanogenesis in murine B16 melanoma F10 cells. Fractionation and purification of the extract led to the isolation of two new tetrahydrofuran-type lignans, (+)-5-methoxyzuonin A (2) and kadlongirin C (3), along with eight known compounds (1, 4-10). The structures of the new compounds were determined by spectroscopic analyses. Of the isolated compounds (1, 3 -10), (+)-zuonin A (1) showed remarkable inhibition of melanogenesis at concentrations without cytotoxicity in B16 melanoma F10 cells. (+)-Zuonin A (1) did not inhibit tyrosinase; however, Western blot analysis revealed that it decreased protein levels of tyrosinase and tyrosinase-related proteins (TRP)-1 and TRP-2 without changing phosphorylation level of cAMP response element-binding protein.