Astraoleanosides E-P, oleanane-type triterpenoid saponins from the aerial parts of Astragalus membranaceus Bunge and their ß-glucuronidase inhibitory activity.

Historically, Astragalus membranaceus Bunge has been used as a beneficial medicinal plant, particularly in the Asian traditional medical systems, for the treatment of various human diseases such as stomach ulcers, diarrhea, and respiratory issues associated with phlegm. In this study, a phytochemical characterization of the aerial parts of A. membranaceusled to the isolation of 29 oleanane-type triterpenoid saponins, including 11 new compounds named astraoleanosides E-P (6-9, 13, 14, 18-22), as well as 18 known ones. The structures of these compounds were elucidated using nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry. Among them, astraoleanoside H (9) and cloversaponin III (15) demonstrated the most potent ß-glucuronidase inhibitory activities, with IC50 values of 21.20 ± 0.75 and 9.05 ± 0.47 µM, respectively, compared to the positive control d-saccharic acid 1,4-lactone (IC50 = 20.62 ± 1.61 µM). Enzyme kinetics studies were then conducted to investigate the type of inhibition exhibited by these active compounds. In addition, the binding mechanism, key interactions, binding stability, and dynamic behavior of protein-ligand complexes were investigated through in silico approaches, such as molecular docking and molecular dynamics simulations. These findings highlight the promising potential of triterpenoid saponins from A. membranaceus as lead compounds for ß-glucuronidase inhibitors, offering new possibilities for the development of therapeutic agents targeting various diseases where ß-glucuronidase plays a crucial role.

Acetylcholinesterase inhibition studies of alkaloid components from Crinum asiaticum var. sinicum: in vitro assessments by molecular docking and molecular dynamics simulations.

Alkaloids are among the most important and best-known secondary metabolites as sources of new drugs from medicinal plants and marine organisms. A phytochemical investigation of the whole plant of Crinum asiaticum var. sinicum resulted in the isolation of seven alkaloids (1-7), including one new dimeric compound, bis-(-)-8-demethylmaritidine (1). Their structures were elucidated using NMR and HR-ESI-MS. The absolute configuration of new compound 1 was established by circular dichroism spectroscopy. All isolated compounds were evaluated for their inhibitory effects on acetylcholinesterase (AChE) activity in vitro. Among them, compound 1 exhibited the most potent AChE inhibition. Moreover, molecular docking and molecular dynamics simulations were carried out for the most active compound to investigate their binding interactions and dynamics behavior of the AChE protein-ligand complex. Therefore, compound 1 may be a potential candidate for effectively treating Alzheimer's disease.

Effect of citric acid and heat treatment on the content of less-polar ginsenosides in flower buds of Panax ginseng.

Ginseng flower bud (GFB), as an inexpensive part of Panax ginseng, attracted significant attention as a beneficial functional food with medicinal potentials due to its high content of ginsenosides. A few studies focused on the utilization of heat treatment and citric acid treatment to process ginseng flowers, converting its polar ginsenosides into rare ginsenosides to improve its biological activities. Thus, in this study, we compared the changes of ginsenosides in GFB after citric acid and heat treatment by HPLC method. The results revealed that less-polar ginsenoside, Rg6 and F4, increased to 1.01 and 0.27% by heat treatment, respectively. Further, ginsenoside F2 increased to 1.13% with 1 M citric acid treatment. Furthermore, based on the combination of these two processing methods for the first time, the conversion rate of less-polar ginsenosides surged to 80%. The content of ginsenoside Rg3(s) and Rg5 increased to 1.509 and 1.871%, respectively, by simultaneous heat and citric acid treatment. Therefore, a processing approach that simultaneously performs heat and citric acid treatments has been proposed, and this considerably inexpensive and convenient processing method could be applied to the processing of GFBs and produce less-polar ginsenosides.

Inhibitory Effects of Cucurbitane-Type Triterpenoids from Momordica charantia Fruit on Lipopolysaccharide-Stimulated Pro-Inflammatory Cytokine Production in Bone Marrow-Derived Dendritic Cells.

The bitter melon, Momordica charantia L., was once an important food and medicinal herb. Various studies have focused on the potential treatment of stomach disease with M. charantia and on its anti-diabetic properties. However, very little is known about the specific compounds responsible for its anti-inflammatory activities. In addition, the in vitro inhibitory effect of M. charantia on pro-inflammatory cytokine production by lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells (BMDCs) has not been reported. Phytochemical investigation of M. charantia fruit led to the isolation of 15 compounds (1-15). Their chemical structures were elucidated spectroscopically (one- and two-dimensional nuclear magnetic resonance) and with electrospray ionization mass spectrometry. The anti-inflammatory effects of the isolated compounds were evaluated by measuring the production of the pro-inflammatory cytokines interleukin IL-6, IL-12 p40, and tumor necrosis factor α (TNF-α) in LPS-stimulated BMDCs. The cucurbitanes were potent inhibitors of the cytokines TNF-α, IL-6, and IL-12 p40, indicating promising anti-inflammatory effects. Based on these studies and in silico simulations, we determined that the ligand likely docked in the receptors. These results suggest that cucurbitanes from M. charantia are potential candidates for treating inflammatory diseases.

Inhibition of soluble epoxide hydrolase by phytochemical constituents of the root bark of Ulmus davidiana var. japonica.

A novel compound 1 and nine known compounds (2-10) were isolated by open column chromatography analysis of the root bark of Ulmus davidiana. Pure compounds (1-10) were tested in vitro to determine the inhibitory activity of the catalytic reaction of soluble epoxide hydrolase (sEH). Compounds 1, 2, 4, 6-8, and 10 had IC50 values ranging from 11.4 ± 2.3 to 36.9 ± 2.6 µM. We used molecular docking to simulate inhibitor binding of each compound and estimated the binding pose of the catalytic site of sEH. From this analysis, the compound 2 was revealed to be a potential inhibitor of sEH in vitro and in silico. Additionally, molecular dynamics (MD) study was performed to find detailed interaction signals of inhibitor 2 with enzyme. Finally, compound 2 is promising candidates for the development of a new sEH inhibitor from natural plants.

Anti-allergic Inflammatory Components from the Leaves of Piper crocatum Ruiz & Pav.

Piper crocatum Ruiz & Pav. (P. crocatum), a traditional medicinal plant, has been shown to possess various pharmacological activities, including anticancer activity, antioxidant activity, antibacterial activity, anti-hyperglycemic activity, anti-allergic inflammatory activity and others. To identify the potential anti-allergic inflammatory effective constituents of P. crocatum, 13 single compounds were isolated from the methanol extract of P. crocatum leaves, and their structures were identified by contrasting their NMR spectroscopic data and previously published papers. First, the anti-allergic inflammatory activities of these single compounds were examined by accessing immune function related biomarkers such as nitric oxide (NO) and ß-hexosaminidase. We found that the methanol extract and catechaldehyde (compound 1) potently suppressed NO production. Additionally, Western blot analysis showed that P. crocatum methanol extract and compound 1 suppressed the production of NO by reducing inducible nitric oxide synthase (iNOS) expression in lipopolysaccharide (LPS)-induced RAW264.7 macrophages. Consistent with these observations, P. crocatum methanol extract and compound 1 remarkably decreased ß-hexosaminidase release from RBL-2H3 cells stimulated with 2,4-dinitrophenylated bovine serum albumin (DNP-BSA)-specific immunoglobulin E (IgE) antibodies. Furthermore, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay indicated that P. crocatum methanol extract and compound 1 exhibited no cytotoxicity to RAW264.7 and RBL-2H3 cells. Based on these findings, compound 1 is suggested as an active anti-allergic inflammatory component of P. crocatum.

Chemical constituents of Vietnamese mangrove Hibiscus tiliaceus with antioxidant and alpha-glucosidase inhibitory activity.

Using various chromatographic techniques, a total of 15 compounds, including one novel megastigmane named tiliaceic acid A (1) and 14 known compounds, were isolated from the traditional medicinal Vietnamese mangrove Hibiscus tiliaceus. Their structures were confirmed based on spectroscopic experiments including, UV, 1 D- and 2 D-NMR, HR-ESI-MS, and ECD analysis. The antioxidant and α-glucosidase inhibitory activities of the isolated compounds from H. tiliaceus were evaluated for the first time. Compound 2 showed strong α-glucosidase inhibitory activity with an IC50 of 77.78 ± 1.00 µM compared with the positive control acarbose at 105.71 ± 2.29 µM.

The chemical constituents of ethanolic extract from Stauntonia hexaphylla leaves and their anti-inflammatory effects.

Stauntonia hexaphylla (Lardizabalaceae) is an important medicinal plant in Korea, Japan, and China. Its leaves are used to treat many diseases because of their analgesic, sedative, and diuretic effects; however, there are few reports on their chemical constituents and biological activities. This study divided an ethanol extract into dichloromethane (DCM), ethyl acetate (EtOAc), and water fractions. Bioassay-guided fractionation of the ethanol extracts led to the isolation of seven compounds (1-7). To our knowledge, this is the first report of 1-7 from S. hexaphylla. The anti-inflammatory effects were investigated by suppressing cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in Western blots. The ethanol extract (20 µg/mL), DCM fraction (20 µg/mL), and compound 1 (10 µM) decreased COX-2 and iNOS expression significantly in LPS-induced RAW264.7 cells. These results suggest that S. hexaphylla leaves and compound 1 are useful candidates for treating inflammatory and other diseases.

Isolation of bioactive components with soluble epoxide hydrolase inhibitory activity from Stachys sieboldii MiQ. by ultrasonic-assisted extraction optimized using response surface methodology.

Stachys sieboldii MiQ (SSM) is an important food and medicinal herb in Korea, used to improve memory of patients with senile dementia and cardiovascular diseases. However, little information on bioactive components from SSM or standardized extraction methods for these components is available. This study isolated and purified major components from SSM for the first time, and assessed their ability to inhibit soluble epoxide hydrolase (sEH). The results showed that acteoside is the most potent inhibitor of sEH, with an IC50 of 33.5 ± 0.5 µM. Additional active components, including harpagide, tryptophan, and 8-acetate-harpagide, along with acteoside, were tentatively identified using high-performance liquid chromatography photodiode array tandem mass spectrometry (HPLC-PDA-MS/MS) and quantified using an ultraviolet detector at 210 nm. Further, an ultrasonic-assisted extraction technique for extraction of four bioactive compounds in SSM was developed and optimized using response surface methodology (RSM). The optimal extraction conditions were: extraction time, 30.46 minutes; extraction temperature, 67.95 °C, and methanol concentration 53.85%. The prediction model of RSM was validated with laboratory experiments. The similarity between predicted and actual values was 97.84%. The extraction method is thus a rapid, environment-friendly, energy-saving method can be applied to extract bioactive components from SSM in large quantities.

Soluble epoxide hydrolase inhibitors from Docynia indica (Wall.) Decne.

Nine bioactive compounds, including one new dihydroisocoumarin glycoside, 3S-thunberginol C 6-O-ß-D-glucopyranoside (1a/1b), were isolated by chromatographic separation from the fruits of the Vietnamese medicinal plant Docynia indica (Wall.) Decne. 3S-thunberginol C 6-O-ß-D-glucopyranoside was determined as a mixture of boat-like conformers based on NMR evidence and density functional theory (DFT) calculations. The in vitro inhibition of soluble epoxide hydrolase (sEH) by the isolated compounds was comparable to that of AUDA (positive control), yielding IC50 values ranging from 10.0 ± 0.6 to 88.4 ± 0.2 µM. Among isolated compounds, 3-methoxy-4-hydroxy-benzoic acid (7) and 2',6'-dihydroxy 3',4'-dimethoxychalcone (9) were identified as a potent inhibitor of sEH, with IC50 values of 19.3 ± 2.2 and 10.0 ± 0.6 mM, respectively. These results suggest that the fruits of D. indica may be useful as daily supplements for the prevention of cardiovascular and other sEH-related diseases.[Figure: see text].

Bioactive Compounds from Polygala tenuifolia and Their Inhibitory Effects on Lipopolysaccharide-Stimulated Pro-inflammatory Cytokine Production in Bone Marrow-Derived Dendritic Cells.

The roots of Polygala tenuifolia Wild (Polygalaceae), which is among the most important components of traditional Chinese herbal medicine, have been widely used for over 1000 years to treat a variety of diseases. In the current investigation of secondary metabolites with anti-inflammatory properties from Korean medicinal plants, a phytochemical constituent study led to the isolation of 15 compounds (1-15) from the roots of P. tenuifolia via a combination of chromatographic methods. Their structures were determined by means of spectroscopic data such as nuclear magnetic resonance (NMR), 1D- and 2D-NMR, and liquid chromatography-mass spectrometry (LC-MS). As the obtained results, the isolated compounds were divided into two groups-phenolic glycosides (1-9) and triterpenoid saponins (10-15). The anti-inflammatory effects of crude extracts, fractions, and isolated compounds were investigated on the production of the pro-inflammatory cytokines interleukin (IL)-12 p40, IL-6, and tumour necrosis factor-α in lipopolysaccharide-stimulated bone marrow-derived dendritic cells. The IC50 values, ranging from 0.08 ± 0.01 to 21.05 ± 0.40 µM, indicated potent inhibitory effects of the isolated compounds on the production of all three pro-inflammatory cytokines. In particular, compounds 3-12, 14, and 15 showed promising anti-inflammatory activity. These results suggest that phenolic and triterpenoid saponins from P. tenuifolia may be excellent anti-inflammatory agents.

Enhancement of an In Vivo Anti-Inflammatory Activity of Oleanolic Acid through Glycosylation Occurring Naturally in Stauntonia hexaphylla.

Stauntonia hexaphylla (Lardizabalaceae) has been used as a traditional herbal medicine in Korea and China for its anti-inflammatory and analgesic properties. As part of a bioprospecting program aimed at the discovery of new bioactive compounds from Korean medicinal plants, a phytochemical study of S. hexaphylla leaves was carried out leading to isolation of two oleanane-type triterpene saponins, 3-O-[ß-d-glucopyranosyl (1→2)-α-l-arabinopyranosyl] oleanolic acid-28-O-[ß-d-glucopyranosyl (1→6)-ß-d-glucopyranosyl] ester (1) and 3-O-α-l-arabinopyranosyl oleanolic acid-28-O-[ß-d-glucopyranosyl (1→6)-ß-d-glucopyranosyl] ester (2). Their structures were established unambiguously by spectroscopic methods such as one- and two-dimensional nuclear magnetic resonance and infrared spectroscopies, high-resolution electrospray ionization mass spectrometry and chemical reactions. Their anti-inflammatory activities were examined for the first time with an animal model for the macrophage-mediated inflammatory response as well as a cell-based assay using an established macrophage cell line (RAW 264.7) in vitro. Together, it was concluded that the saponin constituents, when they were orally administered, exerted much more potent activities in vivo than their sapogenin core even though both the saponins and the sapogenin molecule inhibited the RAW 264.7 cell activation comparably well in vitro. These results imply that saponins from S. hexaphylla leaves have a definite advantage in the development of oral medications for the control of inflammatory responses.

Protective Effects of Compounds from Cimicifuga dahurica against Amyloid Beta Production in Vitro and Scopolamine-Induced Memory Impairment in Vivo.

Cimicifuga dahurica has traditionally been used as an antipyretic, analgesic, and anti-inflammatory agent and as a treatment for uterine and anal prolapse. This study has investigated the potential beneficial effects of this medicinal plant and its components on Alzheimer's disease (AD) with a focus on amyloid beta (Aß) production and scopolamine-induced memory impairment in mice. An ethanol extract from C. dahurica roots decreased Aß production in APP-CHO cells [Chinese hamster ovarian (CHO) cells stably expressing amyloid precursor protein (APP)], as determined by an enzyme-linked immunosorbent assay and Western blot analysis. Then, the compounds isolated from C. dahurica were tested for their antiamyloidogenic activities. Four compounds (1-4) efficiently interrupted Aß generation by suppressing the level of ß-secretase in APP-CHO cells. Moreover, the in vivo experimental results demonstrated that compound 4 improved the cognitive performances of mice with scopolamine-induced disruption on behavioral tests and the expression of memory-related proteins. Taken together, these results suggest that C. dahurica and its constituents are potential agents for preventing or alleviating the symptoms of AD.

Identification of potential inflammatory inhibitors from Aster tataricus.

Aster tataricus L.f. is a traditional Eastern Asian herbal medicine used for the relief of cough-related illnesses. In this study, 32 known compounds and two novel monoterpene glycosides were isolated from the roots of A. tataricus. With the aid of reported data, elucidation of the root-extract components was carried out using a multitude of spectroscopic techniques. All isolates were investigated for their ability to inhibit nitric oxide (NO) secretion in lipopolysaccharide-activated RAW264.7 cells. Compound 7 remarkably suppressed NO production with an IC50 value of 8.5 µM. In addition, compound 7 exhibited significant inhibitory activity against the production of inflammatory cytokines (prostaglandin E2, interleukin-6, and interleukin-1 beta) and the expression of inflammatory enzymes (inducible nitric oxide synthase and cyclooxygenase-2) via inhibition of nuclear factor-kappa B activation. Moreover, compound 7 effectively prevented the downstream activation of the mitogen-activated protein kinase signaling pathway by inhibiting phosphorylation of c-Jun N-terminal kinases, extracellular signal-regulated kinases, and p38. These results outline compound 7 as a potential inhibitor for the broad treatment of inflammatory diseases, such as atopic dermatitis, asthma, and various allergies.

Inhibition potential of phenolic constituents from the aerial parts of Tetrastigma hemsleyanum against soluble epoxide hydrolase and nitric oxide synthase.

The aerial parts of Tetrastigma hemsleyanum (APTH) have been used as a functional tea in China. The purpose of the current study was to identify the bioactive constituents with inhibitory activity against soluble epoxide hydrolase (sEH) and inducible nitric oxide synthase (iNOS), which are jointly considered potential therapeutic targets for vascular system diseases. In the present study, 39 compounds (1-39) were isolated from the APTH. Among them, compounds 8, 10, 12, 16, 17, 19, and 32 displayed potential activities, with IC50 values ranging from 4.5 to 9.5 µM, respectively, and all in non-competitive inhibition mode. Compounds 5, 10, 12, 19, and 32 displayed potent iNOS inhibitory effects, with IC50 values ranging from 15.6 to 47.3 µM. The results obtained in this work contribute to a better understanding of the pharmacological activities of T. hemsleyanum and its potential application as a functional food.

Isolation of Two New Compounds and Other Constituents from Leaves of Piper crocatum and Study of Their Soluble Epoxide Hydrolase Activities.

Two new phenolic glucosides, pipercroside A and B (1 and 2), along with 10 known compounds were isolated from the leaves of Piper crocatum Ruiz & Pav. Their chemical structures were elucidated through extensive spectroscopic analyses, including 1D and 2D NMR experiments and HR-ESI-MS analysis and comparison with previously reported data. All the isolated compounds were assessed for soluble epoxide hydrolase (sEH) inhibitory activity. Among them, erigeside II (5) showed inhibitory activity with an IC50 value of 58.5 µM.

Anti-bacterial effects of components from Sanguisorba officinalis L. on Vibrio vulnificus and their soluble epoxide hydrolase inhibitory activity.

Sanguisorba officinalis L. is a traditional herbal medicine, which is prevailingly applied to cure hemorrhoids, wounds and ulcers in Eastern Asian countries. The purpose of this study was to investigate the antibacterial and soluble epoxide hydrolase (sEH) inhibitory effects of the extracts and components from S. officinalis. The methanol extract was divided into ethyl acetate (EtOAc), n-butanol (n-BuOH), and water layers. In our screening procedure, the EtOAc and n-BuOH extracts and compounds (1-2) remarkably suppressed the growth of V. vulnificus in a dose-dependent manner. In addition, the EtOAc extract and compound 1 exhibited significant inhibitory effect on the V. vulnificus induced cytotoxicity on HeLa cells. Furthermore, compound 4 displayed an inhibition against sEH with an IC50 value of 7.0 ± 0.5 µM. A kinetic analysis demonstrated that the inhibitory effect of compound 4 was a mixed type, with an inhibitory constant (Ki) 0.22 ± 0.0 µM.

Identification of Anti-Melanogenesis Constituents from Morus alba L. Leaves.

The individual parts of Morus alba L. including root bark, branches, leaves, and fruits are used as a cosmetic ingredient in many Asian countries. This study identified several anti-melanogenesis constituents in a 70% ethanol extract of M. alba leaves. The ethyl acetate fraction of the initial ethanol extract decreased the activity of tyrosinase, a key enzyme in the synthetic pathway of melanin. Twelve compounds were isolated from this fraction and their structures were identified based on spectroscopic spectra. Then, the authors investigated the anti-melanogenesis effects of the isolated compounds in B16-F10 mouse melanoma cells. Compounds 3 and 8 significantly inhibited not only melanin production but also intracellular tyrosinase activity in alpha-melanocyte-stimulating-hormone (α-MSH)-induced B16-F10 cells in a dose-dependent manner. These same compounds also inhibited melanogenesis-related protein expression such as microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase-related protein-1 (TRP-1). Compound 3 modulated the cAMP-responsive element-binding protein (CREB) and p38 signaling pathways in α-MSH-activated B16-F10 melanoma cells, which resulted in the anti-melanogenesis effects. These results suggest that compound 3, isolated from M. alba leaves, could be used to inhibit melanin production via the regulation of melanogenesis-related protein expression.

Cholinesterases inhibition studies of biological active compounds from the rhizomes of Alpinia officinarum Hance and in silico molecular dynamics.

Six diarylheptanoids (1-6) and two flavonoids (7 and 8) derived from Alpinia officinarum were evaluated for their ability to inhibit acetylcholinesterase. Compound 1 showed the highest degree of inhibition, with an IC50 of approximately 2 µM, followed by moderate degrees of inhibition by 2, 4 and 7, with IC50 values ranging from 20 to 40 µM. The remaining isolated compounds 3, 5, 6 and 8 had IC50 values greater than 50 µM. Enzyme kinetic studies showed that the compounds with high or moderate activity were competitive inhibitors, anchored to the active site of acetylcholinesterase. In particular, compounds 1 and 2 were docked at slightly different positions from those occupied by 4 and 7. Furthermore, molecular dynamics studies showed that compound 1 maintained its interactions with residues Thr74 and Phe295 throughout the simulation trajectory. Our findings suggest that compound 1 is a potential therapeutically relevant inhibitor of acetylcholinesterase.

Isolation and Identification of Benzochroman and Acylglycerols from Massa Medicata Fermentata and Their Inhibitory Effects on LPS-Stimulated Cytokine Production in Bone Marrow-Derived Dendritic Cells.

Massa Medicata Fermentata (MMF), known as Shenqu, is an important traditional Chinese medicine widely used to treat indigestion, vomiting, and diarrhea. In this study, a new benzochroman, 3(S)-3,4-dihydro-5,10-di-ß-d-glucopyranoside-2,2-dimethyl-2H-naphtho(2,3-b)pyran-3-ol (1), and five known galactosyl acylglycerols (2⁻6) were isolated from a methanol extract from MMF. In addition, their chemical structures were determined by chemical and spectroscopic methods, which were compared with the previously reported data. Furthermore, the effects of isolated compounds on lipopolysaccharide (LPS)-stimulated bone marrow-derived dendritic cells were investigated. Compounds 1⁻3 exhibited significant inhibitory effects on the LPS-induced production of IL-6 and IL-12 p40, with IC50 values ranging from 1.6 to 10.2 µM. Compounds 2 and 3 also exhibited strong inhibitory effects on the LPS-stimulated production of TNF-α with IC50 values of 12.0 and 11.2 µM, respectively. The results might provide a scientific basis for the development of the active components in MMF, as well as for novel anti-inflammatory agents.