Four new glucosides from the aerial parts of Equisetum sylvaticum.

Two previously undescribed megastigmane glucosides, (3S)-3-hydroxy-4-oxo-7,8-dihydro-ß-ionone-3-O-ß-D-glucopyranoside (1), (3S)-3-hydroxy-4-oxo-ß-ionone-3-O-ß-D-glucopyranoside (2), an apocarotenoid glucoside named equiseoside A (3) and an unusual aromatic compound with a glucose-fused skeleton named equiseoside B (4), together with 35 known compounds (5-39) were isolated from the aerial parts of Equisetum sylvaticum. The structures of these compounds were elucidated by spectroscopic methods, including 1D and 2D NMR, IR, CD, and HR-MS.

Searching for constituents from plants in geographically characterized areas, Egypt, Madagascar, and Okinawa.

Secondary metabolites may not be produced under some conditions, and in most cases, their function and significance in the producing organisms is unknown. Conversely, there are some that are produced for readily understood reasons, for example, toxic substances as defensive substances against invaders, or volatile substances that attract other species of organisms. These secondary metabolites also contribute to our health. However, there has not been sufficient research to evaluate them from a pharmacological perspective, and much progress is expected in this area in the future. About 90% of the existing plants have not been studied for their chemical components and biological activities (Kazuki Saito in Bunshun shinsho 1119, pp. 119-126. ISBN 978-4-16-661119-5, 2017). On this basis, we have been searching for the constituents of unknown plants, and whose constituents have not been studied extensively. In this paper, the authors have reviewed some of their previous searching for constituents from plants in geographically characterized areas, Egypt, Madagascar, and Okinawa.

Anti-Oxidant and Anti-Inflammatory Substance Generated Newly in Paeoniae Radix Alba Extract Fermented with Plant-Derived Lactobacillus brevis 174A.

Fermentation of medicinal herbs can be a significant technique to obtain bioactive compounds. Paeoniae Radix (PR) used in the present study is a well-known herbal medicine that exhibits anti-inflammatory and immunomodulatory activity. The aim of this study is to explore the possibility that a bioactive compound is newly generated in PR extract by fermentation with a plant-derived lactic acid bacteria Lactobacillus brevis 174A. We determined the anti-inflammatory activities in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. The PR extract fermented with Lactobacillus brevis 174A markedly increased the total phenolic content, decreased intracellular ROS levels, inhibited the release of nitric oxide (NO). It also suppressed inflammatory cytokines IL-6, TNF-ɑ, while simultaneously downregulating the gene expressions of iNOS, IL-6, TNF-ɑ, and IL-1ß compared to the unfermented PR extract. Furthermore, the bioactive compound newly generated from the fermentation was identified as pyrogallol. It inhibits the inflammatory responses in a dose-dependent manner suggesting that fermentation of the herbal extract used as a medium together with the plant-derived lactic acid bacterial strain may be a practical strategy to produce medicines and supplements for healthcare.

Six New Phenylpropanoid Derivatives from Chemically Converted Extract of Alpinia galanga (L.) and Their Antiparasitic Activities.

Chemical conversion of the extract of natural resources is a very attractive way to expand the chemical space to discover bioactive compounds. In order to search for new medicines to treat parasitic diseases that cause high morbidity and mortality in affected countries in the world, the ethyl acetate extract from the rhizome of Alpinia galanga (L.) has been chemically converted by epoxidation using dioxirane generated in situ. The biological activity of chemically converted extract (CCE) of A. galanga (L.) significantly increased the activity against Leishmania major up to 82.6 ± 6.2 % at 25 µg/mL (whereas 2.7 ± 0.8% for the original extract). By bioassay-guided fractionation, new phenylpropanoids (1-6) and four known compounds, hydroquinone (7), 4-hydroxy(4-hydroxyphenyl)methoxy)benzaldehyde (8), isocoumarin cis 4-hydroxymelein (9), and (2S,3S,6R,7R,9S,10S)-humulene triepoxide (10) were isolated from CCE. The structures of isolated compounds were determined by spectroscopic analyses of 1D and 2D NMR, IR, and MS spectra. The most active compound was hydroquinone (7) with IC50 = 0.37 ± 1.37 µg/mL as a substantial active principle of CCE. In addition, the new phenylpropanoid 2 (IC50 = 27.8 ± 0.34 µg/mL) also showed significant activity against L. major compared to the positive control miltefosine (IC50 = 7.47 ± 0.3 µg/mL). The activities of the isolated compounds were also evaluated against Plasmodium falciparum, Trypanosoma brucei gambisense and Trypanosoma brucei rhodeisense. Interestingly, compound 2 was selectively active against trypanosomes with potent activity. To the best of our knowledge, this is the first report on the bioactive "unnatural" natural products from the crude extract of A. galanga (L.) by chemical conversion and on its activities against causal pathogens of leishmaniasis, trypanosomiasis, and malaria.

Ardisiatetrons A and B: tetronic acid derivatives and triterpenes from the leaves of Ardisia quinquegona and their biological activity.

From the leaves of Ardisia quinquegona, two alkylated tetronic acid derivatives, named ardisiatetrons A and B (1, 2), and four triterpenoids (3-6) were isolated together with one known compound (7) by a combination of various kinds of chromatography. The structure of new methyl migrated triterpene (3) was confirmed by X-ray crystallographic analysis. Compounds 2, 3, and 7 showed moderate anti-Leishmania activity and cytotoxicity towards A549 cells.

Isolation of Three New Diterpenes from Dodonaea viscosa.

An investigation into the methanol extracts obtained from the stems of Dodonaea viscosa led to the isolation of one nor-clerodane diterpene (1) and two labdane diterpenes (2, 3), as well as 17 known compounds (4-20). The structures of these compounds were elucidated based on chemical and spectral evidence. The stereochemical structure of the nor-clerodane diterpene was confirmed via its circular dichroism spectrum and calculated electronic circular dichroism spectrum. Isolated compounds were evaluated for their inhibitory effects on collagenase and tyrosinase. Since 5,7,4'-trihydroxy-3'-(4-hydroxy-3-methylbutyl)-5'-(3-methylbut-2-enyl)-3,6-dimethoxyflavone (9) showed collagenase inhibitory activity and scopoletin (12) had significant tyrosinase inhibitory activity, they were considered to be good candidates for cosmetic agents.

Symplocosins C-P: Fourteen Triterpene Saponins from the Leaves of Symplocos cochinchinensis var. philippinensis.

Extensive phytochemical work on the 1-BuOH-soluble fraction of a MeOH extract of the leaves of Symplocos cochinchinensis var. philippinensis resulted in the isolation of 14 new triterpenene saponins, along with four known ones. Their structures were elucidated by comparison of NMR spectroscopic data with related compounds reported in the literature. Three oleanane-type saponins, symplocosins K, M, and P, possessed glucuronic acid as a sugar component, and their carboxyl groups appeared as methyl esters. These are probably formed during extraction and isolation procedures. Symplocosin K (9) showed moderate cytotoxicity toward A549 cells. In addition, all isolated compounds did not show α-glucosidase inhibitory activity.

Zanthosides A-D: Four Aromatic Glucosides from the Leaves of Zanthoxylum ailanthoides.

From the leaves of Zanthoxylum ailanthoides, four new phenolic glucosides, termed zanthosides A-D (1-4), were isolated. Their structures were elucidated by means of spectroscopic evidence. Zanthoside A was enzymatically hydrolyzed and thus the aglycone obtained was found to be (1'S,2'R)-(-)-trans-decursidinol, isolated from Angelica decursiva.

Firmosides A and B: two new sucrose ferulates from the aerial parts of Silene firma and evaluation of radical scavenging activities.

Two new tri-ferulates of sucrose, firmosides A and B (1 and 2, respectively), together with 18 known compounds (3-20), were isolated from the aerial parts of Silene firma. The structures of the isolated compounds were elucidated by various spectroscopic methods, including 1D, 2D NMR, and high-resolution electro-spray ionization-mass spectrometry (HR-ESI-MS). All the isolated compounds were evaluated for their free radical scavenging activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. As a result, two new compounds (1, 2) and 11 demonstrated significant radical scavenging activity, implying the usefulness as antioxidant agents.

Lasianosides F-I: A New Iridoid and Three New Bis-Iridoid Glycosides from the Leaves of Lasianthus verticillatus (Lour.) Merr.

A series of iridoid glycosides were isolated from the leaves of Lasianthus verticillatus (Lour.) Merr., belonging to family Rubiaceae. A new iridoid glycoside, lasianoside F (1), and three new bis-iridoid glycosides, lasianosides G-I (2-4), together with four known compounds (5-8) were isolated. The structures were established by spectroscopic methods, including 1D and 2D NMR experiments (1H, 13C, DEPT, COSY, HSQC, HMBC, and NOESY) in combination with HR-ESI-MS and CD spectra.

Interleukin-8 Release Inhibitors Generated by Fermentation of Artemisia princeps Pampanini Herb Extract With Lactobacillus plantarum SN13T.

Some glycosides, which are detected in water extracts from medicinal plants, have been reported to be degraded into their aglycones by incubating with some microorganisms producing ß-glucosidase. We have shown that a plant-derived Lactobacillus plantarum SN13T harbors 11 open reading frames (ORFs) encoding the ß-glucosidase enzyme and can grow vigorously in several herbal water extracts. In this study, we observed that the water extract from Artemisia princeps Pampanini (AP) fermented with the SN13T strain strongly inhibited the release of interleukin (IL)-8 from the HuH-7 cells, when compared to that without fermentation. Furthermore, we demonstrated that the SN13T strain produced at least two bioactive compounds from some compounds contained in AP extract. In addition, we determined that the two compounds were catechol and seco-tanapartholide C, which dose-dependently inhibited the release of IL-8. Because some sesquiterpene lactones are useful in pharmaceuticals, seco-tanapartholide C may be useful as an anti-inflammatory agent. This study suggests that the fermentation of medicinal herbs with Lb. plantarum SN13T is a significant technique to obtain bioactive compounds having therapeutic potential.

Eudesmane-type sesquiterpene glycosides: sonneratiosides A-E and eudesmol ß-D-glucopyranoside from the leaves of Sonneratia alba.

Five eudesmane-type sesquiterpene glycosides, named sonneratiosides A-E (1-5), were isolated from the leaves of Sonneratia alba (Lythraceae). The aglycone of sonneratioside A was identified as cryptomeridiol also known as proximadiol. X-ray crystallographic analysis of sonneratioside A confirmed its structure and its absolute stereochemistry. Eudesmol ß-D-glucopyranoside (6) was also isolated from nature for the first time. The tyrosinase inhibitory activity was assayed for the new compounds together with seven known compounds. Among them, arbutin (12) showed the expected activity and luteolin 7-O-rutinoside (10) showed comparable activity to arbutin.

Lasianosides A-E: New Iridoid Glucosides from the Leaves of Lasianthus verticillatus (Lour.) Merr. and Their Antioxidant Activity.

The genus Lasianthus (Rubiaceae) consists of approximately 180 species, of which the greatest species diversity is found in tropical Asia. Some of the Lasianthus species have been used in folk medicine to treat tinnitus, arthritis, fever, and bleeding. Lasianthus verticillatus (Lour.) Merr. (Syn. Lasianthus trichophlebus auct. non Hemsl.) is a shrub, branchlets terete about 1.5-3 m in height. This paper studies the chemical composition of the leaves of L. verticillatus for the first time, which resulted in the isolation of five undescribed iridoid glucosides, lasianosides A-E (1-5), together with three known compounds (6-8). The undescribed structures of isolated compounds (1-5) were characterized by physical and spectroscopic data analyses, including one-dimensional (1D) and two-dimensional (2D) NMR, IR, UV, and high-resolution electrospray ionization mass spectra (HR-ESI-MS). Furthermore, the electronic circular dichroism data determined the absolute configurations of the new compounds. The free radical scavenging properties of isolated compounds was assessed by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, and their cytotoxicity was assessed toward human lung cancer cell line A549 by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Among the isolated compounds, 3 and 4 displayed potent radical scavenging activities with IC50 values of 30.2 ± 1.8 and 32.0 ± 1.2 µM, which were comparable to that of Trolox (29.2 ± 0.39 µM), respectively, while 5 possessed moderate activity with an IC50 value of 46.4 ± 2.3 µM. None of the isolated compounds exerted cytotoxicity against human cell line A549. As a result, lasianosides C, D, and E have the potential to be non-toxic safe antioxidant agents.

Phenolic compounds from the leaves of Breynia officinalis and their tyrosinase and melanogenesis inhibitory activities.

From the EtOAc-soluble fraction of a MeOH extract of the leaves of Breynia officinalis, five new compounds (1-5) along with 11 known compounds (6-16) were isolated. The structures of the new compounds were elucidated by spectroscopic methods and compounds 1-3 were found to be acylated hydroquinone apiofuranosylglucopyranosides, while compound 4 was an acylated hydroquinone glucopyranoside. Compound 5 was shown to be butyl p-coumarate and this seems to be its first isolation from a natural source. The tyrosinase inhibitory activity of all of the isolated compounds was assayed, and the activity was significant in p-coumarate derivatives. The most active compound, compound 3, also inhibited melanogenesis in an in vivo whole animal model, zebrafish.

Biological activity of Entada phaseoloides and Entada rheedei.

The aim of our study is to find functional compounds from natural resources. We focus on plants grown in tropical areas, especially Madagascar and Thailand, because they have unique flora and are expected to contain interesting compounds. We review the functional compounds of the seed kernels of Entada phaseoloides and E. rheedei and their biological activities such as anti-proliferation and melanogenesis inhibitory properties, etc.

Microtropins Q-W, ent-Labdane Glucosides: Microtropiosides G-I, Ursane-Type Triterpene Diglucoside and Flavonol Glycoside from the Leaves of Microtropis japonica.

Microtropins Q-W, (2S,3R)-2-ethyl-2,3-dihydroxybutyrate of various glucosides and glucose, as well as three ent-labdane diterpenoid glucosides, named microtropiosides G, H and I, an ursane-type triterpene diglucoside and a flavonoid glycoside were isolated from the MeOH extract of the leaves of Microtropis japonica. The structure of microtropioside A, also isolated from the branches of M. japonica, was elucidated spectroscopically in a previous experiment and was found to possess a rare seven-membered oxyrane ring. Its structure was confirmed by X-ray crystallographic analysis of its pentaacetate.

Chemical structures of constituents from the leaves of Polyscias balfouriana.

A new pyrrolidine derivative, (5S)-hydroxyethyl 2-oxopyrrolidine-5-carboxylate (1), a new flavonol glycoside, tamaraxetin 3,7-di-O-α-L-rhamnopyranoside (2), and a new triterpene saponin, polyscioside A methyl ester (3), along with six known compounds (4-9) were isolated from the leaves of Polyscias balfouriana. Their chemical structures were elucidated on the basis of extensive spectroscopic analysis.

Chodatiionosides A and B: two new megastigmane glycosides from Chorisia chodatii leaves.

Phytochemical investigation of Chorisia chodatii Hassl. leaves led to the isolation of an unusual rearranged megastigmane glycoside; chodatiionoside A (1) and another new megastigmane glycoside; chodatiionoside B (2), together with three known megastigmane glycosides (3-5) and one known flavonoid glycoside (6). Their structures were elucidated by spectroscopic methods including 1D and 2D NMR experiments (1H, 13C, DEPT, COSY, HSQC and HMBC) in combination with HR-ESI-MS, CD and modified Mosher's method. As a result, chodatiionoside A has been elucidated as a first example of an unusual rearranged form of megastigmane.

Dianthosaponins G-I, triterpene saponins, an anthranilic acid amide glucoside and a flavonoid glycoside from the aerial parts of Dianthus japonicus and their cytotoxicity.

Extensive isolation work on the 1-BuOH-soluble fraction of a MeOH extract of the aerial parts of Dianthus japonicus afforded three further triterpene glycosyl estsers, termed dianthosaponins G-I, an anthranilic acid amide glucoside and a C-glycosyl flavonoid along with one known triterpene saponin. Their structures were elucidated from spectroscopic evidence. The cytotoxicity of the isolated compounds toward A549 cells was evaluated.

Effects of Hepatoprotective Compounds from the Leaves of Lumnitzera racemosa on Acetaminophen-Induced Liver Damage in Vitro.

Phytochemical investigation of the n-BuOH fraction of the mangrove plant Lumnitzera racemosa WILLD. (Combretaceae) led to the isolation of one new flavonoid glycoside; myrcetin 3-O-methyl glucuronate (1), one new phenolic glycoside; lumniracemoside (2) and one new aliphatic alcohol glycoside; n-hexanol 1-O-rutinoside (3), in addition to seven known compounds (4-10). The structures of these compounds were determined by spectroscopic analyses (UV, IR, high resolution-electrospray ionization (HR-ESI)-MS, one- and two-dimensional (1D- and 2D)-NMR). Compound 7 showed the highest hepatoprotective activity against acetaminophen-induced hepatotoxicity using human HepG2 cells at protection % value of 34.2±3.1%, while compounds 1, 2, 3, 6, and 9 showed weak to moderate hepatoprotective activity (11.6-18.9%). Almost all of these compounds showed stronger 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity compared with the standard Trolox. These results suggest the usefulness of this plant extract and the isolated compounds as promising hepatoprotective agents.