Soluble epoxide hydrolase inhibitors of indolinone alkaloids and phenolic derivatives from Cimicifuga dahurica (Turcz.) Maxim

Traditional uses, phytochemistry, pharmacology, quality control and clinical studies of Cimicifugae Rhizoma: a comprehensive review

Cimicifugae Rhizoma, generally known as "Sheng Ma" in China, has great medicinal and dietary values. Cimicifugae Rhizoma is the dried rhizome of Cimicifuga foetida L., Cimicifuga dahurica (Turcz.) Maxim. and Cimicifuga heracleifolia Kom., which has been used to treat wind-heat headache, tooth pain, aphtha, sore throat, prolapse of anus and uterine prolapse in traditional Chinese medicine. This review systematically presents the traditional uses, phytochemistry, pharmacology, clinical studies, quality control and toxicity of Cimicifugae Rhizoma in order to propose scientific evidence for its rational utilization and product development. Herein, 348 compounds isolated or identified from the herb are summarized in this review, mainly including triterpenoid saponins, phenylpropanoids, chromones, alkaloids, terpenoids and flavonoids. The crude extracts and its constituents had various pharmacological properties such as anti-inflammatory, antitumor, antiviral, antioxidant, neuroprotective, anti-osteoporosis and relieving menopausal symptoms. The recent research progress of Cimicifugae Rhizoma in ethnopharmacology, phytochemistry and pharmacological effects demonstrates the effectiveness of its utilization and supplies valuable guidance for further research. This review will provide a basis for the future development and utilization of Cimicifugae Rhizoma.

Systematically identifying the anti-inflammatory constituents of Cimicifuga dahurica by UPLC-Q/TOF-MS combined with network pharmacology analysis

Cimicifuga dahurica (Turcz.) Maxim, which is also regarded as the main origin of "Shengma" in the Chinese Pharmacopoeia, has been used as a cooling and detoxification agent for thousands of years. Our previous phytochemical investigations of C. dahurica extracts (CDEs) led to the isolation of a series of 9,19-cycloalkane triterpenoids and phenolic acids showing a potential anti-inflammatory activity. However, the chemical profiling of CDEs and the material basis of its anti-inflammatory effect in vivo has not been clarified. In the present study, the CDE chemical profile and prototype components in rat plasma were identified via ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. As a result, a total of 106 components were identified or tentatively characterized in CDEs, including 54 triterpenoids, 35 phenolic acids, eight amides and nine other type constituents (39 compounds were confirmed with the reference standards). In addition, 20 prototype components (15 triterpenoids and five phenolic acids) were identified in rat plasma, which potentially related to the anti-inflammatory effects of CDEs. Moreover, the anti-inflammatory activities of the main prototype components were further evaluated by their inhibitory effects on the production of NO, as well as the expressions of iNOS and COX-2 in lipopolysaccharide-stimulated RAW264.7 cells, which indicated that 9,19-cycloalkane triterpenoids may play an anti-inflammatory role by down-regulating the expression of iNOS.

3'-O-Acetyl-24-Epi-7,8-Didehydrocimigenol-3-O-β-DXylopryranoside Decreases Amyloid Beta Production in Amyloid Precursor Protein-Transfected HeLa Cells

Extracellular beta amyloid (Aβ) plaques are the neuropathological hallmarks of Alzheimer’s disease (AD). Accordingly, reducing Aβ levels is considered a promising strategy for AD prevention. 3’-O-acetyl-24-epi-7,8-didehydrocimigenol-3-O-β-D-xylopryranoside significantly decreased the Aβ production and this effect was accompanied with reduced sAPPβ production known as a soluble ectodomain APP fragment through β-secretases in HeLa cells overexpressing amyloid precursor proteins (APPs). This compound also increased the level of sAPPα, which is a proteolytic fragment of APP by α-secretases. In addition, 3’-O-acetyl-24-epi-7,8-didehydrocimigenol-3-O-β-D-xylopryranoside decreased the protein level of β-secretases, but the protein levels of A disintegrin and metalloproteinase (ADAM) family, especially ADAM10 and ADAM17, are increased. Thus, 3’-O-acetyl-24-epi-7,8-didehydrocimigenol-3-O-β-D-xylopryranoside could be useful in the development of AD treatment in the aspect of amyloid pathology.

Discovery of Soluble Epoxide Hydrolase Inhibitors from Chemical Synthesis and Natural Products

Soluble epoxide hydrolase (sEH) is an α/β hydrolase fold protein and widely distributed in numerous organs including the liver, kidney, and brain. The inhibition of sEH can effectively maintain endogenous epoxyeicosatrienoic acids (EETs) levels and reduce dihydroxyeicosatrienoic acids (DHETs) levels, resulting in therapeutic potentials for cardiovascular, central nervous system, and metabolic diseases. Therefore, since the beginning of this century, the development of sEH inhibitors is a hot research topic. A variety of potent sEH inhibitors have been developed by chemical synthesis or isolated from natural sources. In this review, we mainly summarized the interconnected aspects of sEH with cardiovascular, central nervous system, and metabolic diseases and then focus on representative inhibitors, which would provide some useful guidance for the future development of potential sEH inhibitors.

N-Benzyl-linoleamide, a Constituent of Lepidium meyenii (Maca), Is an Orally Bioavailable Soluble Epoxide Hydrolase Inhibitor That Alleviates Inflammatory Pain

Lepidium meyenii (maca), a plant indigenous to the Peruvian Andes, recently has been utilized globally for claimed health or recreational benefits. The search for natural products that inhibit soluble epoxide hydrolase (sEH), with therapeutically relevant potencies and concentrations, led to the present study on bioactive amide secondary metabolites found in L. meyenii, the macamides. Based on known and suspected macamides, 19 possible macamides were synthesized and characterized. The majority of these amides displayed excellent inhibitory potency (IC50 ≈ 20-300 nM) toward the recombinant mouse, rat, and human sEH. Quantitative analysis of commercial maca products revealed that certain products contain known macamides (1-5, 8-12) at therapeutically relevant total concentrations (≥3.29 mg/g of root), while the inhibitory potency of L. meyenii extracts directly correlates with the sum of concentration/IC50 ratios of macamides present. Considering both its in vitro efficacy and high abundance in commercial products, N-benzyl-linoleamide (4) was identified as a particularly relevant macamide that can be utilized for in vivo studies. Following oral administration in the rat, compound 4 not only displayed acceptable pharmacokinetic characteristics but effectively reduced lipopolysaccharide-induced inflammatory pain. Inhibition of sEH by macamides provides a plausible biological mechanism of action to account for several beneficial effects previously observed with L. meyenii treatments.

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.

Two new chemical constituents from the rhizomes of Actaea dahurica

A new phenylpropanoid allopyranoside (1) and a new indolinone alkaloid (2) were isolated from the rhizomes of Actaea dahurica (syn. Cimicifuga dahurica). The structures of those two compounds were deduced as cimicifugaside F (1) and 3E,11E-(3-methyl-2-butenylidene acid)-2-indolinone-1-O-β-d-glucopyranoside (2) by detailed analysis of their MS, 1D and 2D NMR data and comparison with literatures. Additionally, the isolates were evaluated for their inhibitory effects on the production of NO by LPS-stimulated RAW 264.7 macrophages.

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

Nine bioactive compounds, including one new dihydroisocoumarin glycoside, 3S-thunberginol C 6-O-β-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-β-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.[Formula: see text].

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 (Aβ) production and scopolamine-induced memory impairment in mice. An ethanol extract from C. dahurica roots decreased Aβ 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 Aβ generation by suppressing the level of β-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.

Stereoselective three-component cascade synthesis of α-substituted 2,4-dienamides from gem-difluorochloro ethanes

Herein, we describe a new transition metal-free Claisen rearrangement for the synthesis of α-substituted 2,4-dienamides. The one-pot, stereoselective three-component cascade reaction between a series of propargyl alcohols, amines, and gem-difluorochloro ethane derivatives afforded various polysubstituted 2,4-dienamides in good yields. This synthetic method for 1,1-captodative dienes, α-substituted 2,4-dienamides, can be utilized for preparing pharmaceutical analogues containing an indolin-2-one or lactone moiety.

Prospective for cytochrome P450 epoxygenase cardiovascular and renal therapeutics

Therapeutics for arachidonic acid pathways began with the development of non-steroidal anti-inflammatory drugs that inhibit cyclooxygenase (COX). The enzymatic pathways and arachidonic acid metabolites and respective receptors have been successfully targeted and therapeutics developed for pain, inflammation, pulmonary and cardiovascular diseases. These drugs target the COX and lipoxygenase pathways but not the third branch for arachidonic acid metabolism, the cytochrome P450 (CYP) pathway. Small molecule compounds targeting enzymes and CYP epoxy-fatty acid metabolites have evolved rapidly over the last two decades. These therapeutics have primarily focused on inhibiting soluble epoxide hydrolase (sEH) or agonist mimetics for epoxyeicosatrienoic acids (EET). Based on preclinical animal model studies and human studies, major therapeutic indications for these sEH inhibitors and EET mimics/analogs are renal and cardiovascular diseases. Novel small molecules that inhibit sEH have advanced to human clinical trials and demonstrate promise for cardiovascular diseases. Challenges remain for sEH inhibitor and EET analog drug development; however, there is a high likelihood that a drug that acts on this third branch of arachidonic acid metabolism will be utilized to treat a cardiovascular or kidney disease in the next decade.

The insight of in vitro and in silico studies on cholinesterase inhibitors from the roots of Cimicifuga dahurica (Turcz.) Maxim

Cholinesterases (ChEs) are enzymes that break down neurotransmitters associated with cognitive function and memory. We isolated cinnamic acids (1 and 2), indolinones (3 and 4), and cycloartane triterpenoid derivatives (5-19) from the roots of Cimicifuga dahurica (Turcz.) Maxim. by chromatography. These compounds were evaluated for their inhibitory activity toward ChEs. Compound 1 was determined to have an IC50 value of 16.7 ± 1.9 μM, and to act as a competitive inhibitor of acetylcholinesterase (AChE). Compounds 3, 4 and 14 were found to be noncompetitive with IC50 values of 13.8 ± 1.5 and 6.5 ± 2.5 μM, and competitive with an IC50 value of 22.6 ± 0.4 μM, respectively, against butyrylcholinesterase (BuChE). Our molecular simulation suggested each key amino acid, Tyr337 of AChE and Asn228 of BuChE, which were corresponded with potential inhibitors 1, and 3 and 4, respectively. Compounds 1 and 4 were revealed to be promising compounds for inhibition of AChEs and BuChEs, respectively.

Inhibition Potential of Cycloartane-Type Glycosides from the Roots of Cimicifuga dahurica against Soluble Epoxide Hydrolase

A phytochemical assay-guided fractionation of the 95% ethanol extract of Cimicifuga dahurica roots afforded 29 9,19-cycloartane triterpenoid glycosides, including the new cimiricasides A-F (1-6). The structures of 1-6 were established using contemporary NMR methods and from the HRESIMS data, and the sugar moiety in each case was confirmed by acid hydrolysis and subsequent GC/MS analysis. Compounds 2, 4, 5, 7-9, 18, 25, and 29 showed soluble epoxide hydrolase inhibitory effects with IC₅₀ values of 0.4 ± 0.1 to 24.0 ± 0.2 μM. The compounds were analyzed by enzyme kinetic studies to explore the binding mode between the ligand and receptor. Compounds 4 (mixed type), 8, 18, and 29 (noncompetitive type) bound to a preferred allosteric site, while compounds 2, 5, 7, 9, and 25 had competitive interactions at the active site. The binding mechanism of selected inhibitors was investigated using molecular docking and dynamics simulations.