A new phenolic compound from Persicaria capitata.

Persicaria capitata was a frequently used Hmong medicinal flora in China. In this study, one new phenolic compound, capitaone A (1) together with 20 known ones, were isolated from the whole herb of P. capitata. Among them, 7 components (4, 9-11, 15-16, 20-21) were discovered from P. capitata for the first time. Their chemical structures were elucidated on the basis of extensive NMR and MS spectrum. Furthermore, three compounds (15, 20, 21) displayed remarkable cytotoxic activities against two human cancer cell lines (A549 and HepG2).

Discovery of a highly potent and orally available importin-ß1 inhibitor that overcomes enzalutamide-resistance in advanced prostate cancer.

Nuclear transporter importin-ß1 is emerging as an attractive target by virtue of its prevalence in many cancers. However, the lack of druggable inhibitors restricts its therapeutic proof of concept. In the present work, we optimized a natural importin-ß1 inhibitor DD1 to afford an improved analog DD1-Br with better tolerability (>25 folds) and oral bioavailability. DD1-Br inhibited the survival of castration-resistant prostate cancer (CRPC) cells with sub-nanomolar potency and completely prevented tumor growth in resistant CRPC models both in monotherapy (0.5 mg/kg) and in enzalutamide-combination therapy. Mechanistic study revealed that by targeting importin-ß1, DD1-Br markedly inhibited the nuclear accumulation of multiple CRPC drivers, particularly AR-V7, a main contributor to enzalutamide resistance, leading to the integral suppression of downstream oncogenic signaling. This study provides a promising lead for CRPC and demonstrates the potential of overcoming drug resistance in advanced CRPC via targeting importin-ß1.

Discovery of the First Raptor (Regulatory-Associated Protein of mTOR) Inhibitor as a New Type of Antiadipogenic Agent.

Raptor, a regulatory-associated protein of mTOR, has been genetically proved to be an important regulator in lipogenesis. However, its druggable potential is rarely investigated, largely due to the lack of an inhibitor. In this study, the antiadipogenic screening of a daphnane diterpenoid library followed by target fishing led to the identification of a Raptor inhibitor, 1c (5/7/6 carbon ring with orthoester and chlorine functionalities). Pharmacodynamic studies verified that 1c is a potent and tolerable antiadipogenic agent in vitro and in vivo. Mechanistic studies revealed that the targeting of Raptor by 1c could block the formation of mTORC1 and then downregulate the downstream S6K1- and 4E-BP1-mediated C/EBPs/PPARγ signaling, eventually retarding adipocyte cell differentiation at the early stage. These findings suggest that Raptor can be explored as a novel therapeutic target for obesity and its related complications, and 1c as the first Raptor inhibitor may provide a new therapeutic option for these conditions.

Diversity of sesquiterpenoids from Stellera chamaejasme with neuroprotective effects.

Chromatographic fractionation of the 95% EtOH extract of the roots of Stellera chamaejasme yielded 20 sesquiterpenoids of four different types, guaiane-, carotane-, sesquicarane-, and alpiniane-types. Among them, sesquistrachanoids A-F were previously undescribed ones, whose structures including absolute configurations were elucidated by spectroscopic methods, the Mo2(OAc)4-induced ECD experiment, and analysis of experimental and calculated 1D NMR and ECD data. Sesquistrachanoid A is a 2,3-seco-guaiane-type sesquiterpenoid with a α-pyrone core and sesquistrachanoid B is the first example of 8,9-seco-guaiane-type sesquiterpenoid featured with an 1,8-δ-lactone core. Sesquistrachanoid C is a guaiane sesquiterpenoid characterized by a peroxide bridge between C-8 and C-10. All sesquiterpenoids were evaluated for their neuroprotective effects on cell damage induced by sodium nitroprusside in PC-12 cells. The bioassay results showed that six compounds at 10 µM could restore the cell viability, being comparable to that of the positive control edaravone. The mechanistic study on the most pronounced activity compound, stelleraguaianone B, demonstrated that it played a neuroprotective role by promoting the mRNA expression of antioxidant enzymes to reduce oxidative stress.

Systematic elucidation of the bioactive alkaloids and potential mechanism from Sophora flavescens for the treatment of eczema via network pharmacology.

ETHNOPHARMACOLOGY RELEVANCE: Sophora flavescens is a frequently used traditional Chinese medicine (TCM) for the treatment of skin disorders, diarrhea, vaginal itching and inflammatory diseases. In particular, the root of S. flavescens combination with other herbs mainly treat eczema ailment in the clinical applications. However, a holistic network pharmacology approach to understanding the mechanism by which alkaloids in S. flavescens treat eczema has not been pursued. AIM OF THE STUDY: To examine the network pharmacological potential effect of S. flavescens on eczema, we studied the alkaloids, performed protein targets prediction and investigated interacting signal pathways. Furthermore, animal experiment was carried out to evaluate its efficacy and real-time quantitative polymerase chain reactions (RT-qPCR) analysis was explored the mechanism of action. MATERIALS AND METHODS: The detail information on alkaloids from S. flavescens were obtained from a handful of public databases on the basis of oral bioavailability (OB ≥ 30%) and drug-likeness (DL ≥ 0.18). Then, correlations between compounds and protein targets were linked using the STRING database, and targets associated with eczema were gathered by the GeneCards database. Human genes were identified and subjected to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and Gene Ontology (GO) functional enrichment analysis. Particularly, matrine, the crucial alkaloid from S. flavescens, was estimated using a 2,4-dinitrochlorobenzene (DNCB)-induced eczema Kunming (KM) mice model, administered (50 mg/kg and 10 mg/kg) to mice for 22 days. On the last day, the activities of serum tumor necrosis factor α (TNF-α), interleukin-4 (IL-4) and histopathologic examinations were determined. For further to elucidate the mechanisms, the mRNA levels of TNF-α, STAT3, TP53, AKT1, IL-6, JUN and EGFR in dorsal skin tissues were also tested. RESULTS: Network analysis collected and identified 35 alkaloids from S. flavescens. Among them, in total 10 dominating alkaloids, including matrine, oxymatrine, sophoridine, sophocarpine, oxysophocarpine, allomatrine, sophoramine, anagyrine, cytisine and N-methylcytisine. And 71 related targets were provided of alkaloids for the treatment of eczema from S. flavescens. Furthermore, matrine dose-dependently (50 or 10 mg/kg, 22 days, apply to dorsal skin) remarkable decreased the serum levels of TNF-α and IL-4, and significantly alleviated the skin lesions. The effects of 50 mg/kg of matrine were almost identical to those of 200 mg/kg of the positive drug dexamethasone (DXM). The further RT-qPCR analyses could reveal that matrine down-regulate TNF-α, STAT3 and TP53 at transcriptional level in dorsal skin tissues. CONCLUSION: Pharmacological network analysis can utilize to illuminate the pharmacodynamic substances and the potential molecular mechanism of S. flavescens for treating eczema. Matrine, as the crucial alkaloid from S. flavescens, could be a promising drug candidate for the treatment of eczema ailment.

Ent-Abietane Diterpenoids from Euphorbia fischeriana and Their Cytotoxic Activities.

The roots of Euphorbia fischeriana have been used as a traditional Chinese medicine for the treatment of tuberculosis and ringworm. In the current study, diterpenoids from the ethyl acetate extract of the roots E. fischeriana and their cytotoxic effects against five cancer lines were investigated. Two new ent-abietane diterpenoids, euphonoids H and I (1-2), as well as their two analogues (3-4) were first isolated from this source. The structures of the two new compounds were elucidated on the basis of spectroscopic data and quantum chemical calculation. Their absolute configurations were assigned via ECD spectrum calculation. The isolated compounds were evaluated for their antiproliferative activities against five cancer cell lines. Compounds 1 and 2 exhibited significant inhibitory effects against human prostate cancers C4-2B and C4-2B/ENZR cell lines with IC50 values ranging from 4.16 ± 0.42 to 5.74 ± 0.45 µM.

Polygonum capitatum, the Hmong Medicinal Flora: A Comprehensive Review of Its Phytochemical, Pharmacological and Pharmacokinetic Characteristics.

Polygonum capitatum, known as "Tou Hua Liao" (Chinese name), is a crucial source of Hmong medicinal plants that has benefited human health for a long time. This folk-medicinal plant is widely distributed in the south-west of China for the treatment of various urologic disorders including urinary tract infections, pyelonephritis, and urinary calculus. The purpose of this paper was to provide a systematic and comprehensive overview of the traditional usages, botany, phytochemistry, pharmacology, pharmacokinetics and clinical applications of this flora. Up until the end of 2022, at least 91 compounds had been reported from P. capitatum, mainly covering the classes of flavonoids, lignanoids, phenols and other components. The compounds and extracts isolated from P. capitatum exhibit a wide range of pharmacological activities, such as anti-inflammatory, antioxidant, antimicrobial, anticancer, analgesic, hypothermic, diuretic and other pharmacological effects. Qualitative and quantitative chemical analyses were also covered. Furthermore, the possible development trends and perspectives for future research on this medicinal plant were also discussed.

Discovery of Highly Potent Daphnane Diterpenoids Uncovers Importin-ß1 as a Druggable Vulnerability in Castration-Resistant Prostate Cancer.

Importins are overexpressed in many cancers and mediate the abnormal nuclear transport of oncogenic factors. The druggable potential of importins still remains unclear, largely because of the lack of potent inhibitors. Herein, the anti-castration-resistant prostate cancer (CRPC) screening of a Euphorbiaceae diterpenoid library followed by target fishing led to the identification of a highly potent importin-ß1 inhibitor, daphnane diterpenoid DD1. DD1 selectively inhibited the growth and survival of CRPC cells at subnanomolar concentrations and completely blocked tumor growth in preclinical models at an extremely low dosage. Mechanistic studies revealed that targeting of importin-ß1 by DD1 significantly reduced the nuclear accumulation of key CRPC drivers, shutting down their downstream oncogenic signaling. Disruption of the predicted binding sites of DD1 on importin-ß1 abolished this anti-CRPC effect. These findings suggest that importin-ß1 is an effective therapeutic target in CRPC and that DD1 as the most potent importin-ß1 inhibitor to date can be developed as therapeutics for treatment of this disease.

Tigliane and rhamnofolane glycosides from Euphorbia wallichii prevent oxidative stress-induced neuronal death in PC-12 cells.

Tigliane and rhamnofolane diterpenoids bearing glycosyl substituents are rarely found in nature. In the current study, seven new tigliane glycosides, euphorwallsides A - G (1-7), and five new rhamnofolane glycosides, euphorwallsides H - L (8-12), were isolated from the whole plants of Euphorbia wallichii. Their structures were elucidated by a combination of spectroscopic, computational, and chemical means. The aglycones of 1-5 represent a rare class of 13-deoxygenated tiglianes, while those of 8-12 represent the first examples of 4-deoxygenated rhamnofolanes. 2, 3, 5, 7, 8, and 12 showed significant neuroprotective effects on sodium nitroprusside (SNP)-induced neuronal death in pheochromocytoma cell line PC-12 at 10 µM, being more active than the clinical drug, edaravone. Mechanistic study revealed that the most active compound, 3, could inhibit reactive oxygen species (ROS) accumulation and restore the mitochondrial membrane potential via modulating the Nrf2 signaling pathway in PC-12 cells.

An unusual indole-diterpenoid with C-17 norcassane skeleton from Euphorbia fischeriana induces HEL cell cycle arrest and apoptosis.

Two new polycyclic diterpenoids, euphkanoids H and I (1 and 2), along with 6 known analogues (2-8) were isolated from the roots of Euphorbia fischeriana, a traditional Chinese medicine. Their structures were identified by spectral methods, and the absolute configurations of 1 and 2 were determined by ECD calculation and single crystal X-ray diffraction, respectively. Compound 1 represents the first example of C-17 norcassane indole-diterpenes. All the isolates were screened for antiproliferative activity against a panel of human cancer cell lines using the MTT assay, and 1 showed significant cytotoxicity against HEL cells (IC50 = 3.2 µM). Simple mechanistic study revealed that 1 could induce cell cycle arrest at G0/G1 phase and apoptosis in HEL cells.

Euphopanes A-C, three new diterpenoids from Euphorbia pekinensis.

Three new diterpenoids, euphopanes A-C (1-3), including one ent-isopimarane (1), one ent-abietane (2) and one cembrane (3), along with five known compounds (4-8) were isolated from the roots of Euphorbia pekinensis. Their structures were elucidated by extensive spectroscopic analysis, and the absolute configurations of compounds 1-3 were determined by ECD calculations. All the isolates were screened for the cytotoxicity against three cancer cell lines (C4-2B, C42B/ENZR, and MDA-MB-231), and compounds 1, 2, and 4 showed significant cytotoxicity against human prostate cancer cells C4-2B with IC50 values of 14.3, 16.9, and 15.3 µM, respectively.

Natural product-based screening led to the discovery of a novel PXR agonist with anti-cholestasis activity.

Cholestasis is a major cause of a series of bile flow malfunction-related liver diseases. Pregnane X receptor (PXR) is a key regulator in endo- and xeno-biotics metabolism, which has been considered as a promising therapeutic target for cholestasis. In this study we conducted human PXR (hPXR) agonistic screening using dual-luciferase reporter gene assays, which led to discovering a series of potent hPXR agonists from a small Euphorbiaceae diterpenoid library, containing 35 structurally diverse diterpenoids with eight different skeleton types. The most active compound 6, a lathyrane diterpenoid (5/11/3 ring system), dose-dependently activated hPXR with a high selectivity, and significantly upregulated the expression of hPXR downstream genes CYP3A4 and UGT1A1. In LCA-induced cholestasis mouse model, administration of compound 6 (50 mg· kg-1. d-1, ip) for 7 days significantly suppressed liver necrosis and decreased serum levels of AST, ALT, Tbili, ALP, and TBA, ameliorating LCA-induced cholestatic liver injury. We further revealed that compound 6 exerted its anti-cholestatic efficacy via activation of PXR pathway, accelerating the detoxification of toxic BAs and promoting liver regeneration. These results suggest that lathyrane diterpenoids may serve as a promising scaffold for future development of anti-cholestasis drugs.

Euphohyrisnoids A and B, Two Highly Rearranged Lathyrane Diterpenoids from Euphorbia lathyris.

Euphohyrisnoids A (1) and B (2), two highly rearranged lathyrane diterpenoids featuring a unique tetracyclo[10.2.2.01,10.03,7]cetane and tricyclo[8.4.1.03,7]pentadecane skeleton, respectively, were isolated from the seeds of Euphorbia lathyris. Their structures were determined by detailed spectroscopic analysis and were further confirmed by single-crystal X-ray diffraction. 1 significantly inhibited adipogenesis in 3T3-L1 adipocytes by retarding cell differentiation at the early stage.

Presegetane diterpenoids from Euphorbia sieboldiana as a new type of anti-liver fibrosis agents that inhibit TGF-ß/Smad signaling pathway.

Seven new diterpenoids, eupholenes A-G (1-7), including two presegetanes (1 and 2), four jatrophanes (3-6), and one paraliane (7), along with 19 known analogues (8-26) were obtained by anti-liver fibrosis bioassay-guided isolation of Euphorbia sieboldiana. Their structures were elucidated by extensive spectroscopic data analyses, chemical methods, ECD calculations, and single-crystal X-ray diffractions. Euphorbesulin A (10), a presegetane diterpenoid (5/9/5 ring system), was identified as a promising anti-liver fibrosis agent that could inhibit the expressions of fibronectin (FN), α-smooth muscle actin (α-SMA), and collagen I in TGF-ß1-stimulated LX-2 cells at a micromolar level. Mechanistic study revealed that 10 suppressed liver fibrosis via inhibition of TGF-ß/Smad signaling pathway, and its potential target was TGF-ß type I receptor. These findings suggested that presegetane diterpenoid could serve as a new type of structural motif in future anti-liver fibrosis drug development.

Lathyrane Diterpenoids as Novel hPXR Agonists: Isolation, Structural Modification, and Structure-Activity Relationships.

Pregnane X receptor (PXR) that orchestrates the intricate network of xeno- and endobiotic metabolism is considered as a promising therapeutic target for cholestasis. In this study, the human PXR (hPXR) agonistic bioassay-guided isolation of Euphorbia lathyris followed by the structural modification led to the construction of a lathyrane diterpenoid library (1-34). Subsequent assay of this library led to the identification of a series of potent hPXR agonists, showing better efficacy than that of typical hPXR agonist, rifampicin. The most active compound, 8, could dose-dependently activate hPXR at micromolar concentrations and significantly up-regulate the expressions of PXR downstream genes CYP3A4, CYP2B6, and MDR1. The structure-activity relationships (SARs) studied in combination with molecular modeling suggested that acyloxy at C-7 and the presence of 14-carbonyl were essential to the activity. These findings suggested that lathyrane diterpenoids could serve as a new type of hPXR agonist for future anticholestasis drug development.

Euphorboside A, a cytotoxic meroterpenoid glycoside with an unusual humulene-phloroglucinol skeleton from Euphorbia kansuensis.

Euphorboside A (1), an unusual meroterpenoid glycoside featuring the incorporation of an acylphloroglucinol moiety into a humulene skeleton to form a 6/6/11 ring system, was isolated from the roots of Euphorbia kansuensis. Its structure was elucidated by extensive spectroscopic analysis, chemical methods, and ECD calculations. Compound 1 was screened for the cytotoxicity against nine cancer cell lines, and 1 showed marked inhibitory activities against human colon cancer RKO and human breast cancer MDA-MB-231 cell lines with IC50 values of 3.70 and 4.15 µM, respectively.

Euphanoids A and B, two new lathyrane diterpenoids with nitric oxide (NO) inhibitory activity from Euphorbia kansuensis.

Two new lathyrane diterpenoids, euphanoids A and B (1 and 2), along with five known compounds (3-7) were isolated from the roots of Euphorbia kansuensis. Their structures were elucidated by spectroscopic analysis, and the absolute configuration of 1 was determined by single crystal X-ray diffraction. All of the isolates were screened for the inhibitory effects on nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW264.7 cells, and compounds 1 and 2 showed pronounced inhibition on NO production with IC50 values of 4.7 and 9.5 µM, respectively, being more active than the positive control, quercetin (IC50 = 10.8 µM).

Diterpenoids from Euphorbia royleana reverse P-glycoprotein-mediated multidrug resistance in cancer cells.

Eight previously undescribed diterpenoids, euphoroyleans A-H, including two cembranes, three ingenanes, two ent-atisanes, and one ent-kaurane, along with 22 known analogues were isolated from the whole plants of Euphorbia royleana. The structures of euphoroyleans A-H, including the absolute configurations, were elucidated by extensive spectroscopic analyses, chemical transformation, and single crystal X-ray diffractions. All the isolates were screened for their chemoreversal abilities on P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) cancer cell line HepG2/DOX, and eight compounds exhibited significant activities. Among them, ingol-3,7,12-triacetate-8-benzoate, the most active MDR modulator with no obvious cytotoxicity, could enhance the efficacy of anticancer drug DOX to ca. 105 folds at 10 µM, being stronger than the positive drug verapamil. Mechanistic study revealed that ingol-3,7,12-triacetate-8-benzoate could inhibit the transport activity of P-gp rather than its expression, and the possible recognition mechanism between compounds and P-gp was predicted by molecular docking.

Secondary metabolites from Isodon ternifolius (D. Don) Kudo and their anticancer activity as DNA topoisomerase IB and Tyrosyl-DNA phosphodiesterase 1 inhibitors.

Based on DNA topoisomerase IB (TOP1) and tyrosyl-DNA phosphodiesterase 1 (TDP1) inhibition of the ethanol extract of the roots of Isodon ternifolius (D. Don) Kudo (Labiatae), its secondary metabolites has been studied. Two new compounds, an ent-abietane diterpenoid isodopene A (1) and a 2,3-seco-triterpene isodopene B (13), along with 25 known compounds were isolated. Their structures were elucidated by spectroscopic analysis and theoretical calculations. The enzyme-based assays indicated that 1 and 13 showed strong (+++) and moderate (++) TOP1 inhibition, respectively. Two chalcone derivatives 11 and 12 were firstly found as dual TDP1 and TOP1 natural inhibitors, and showed synergistic effect with the clinical TOP1 inhibitors topotecan in MCF-7 cells. Compounds 8, 16, and 22 acted as TOP1 catalytic inhibitors with equipotent TOP1 inhibition to camptothecin (++++). Compounds 7 and 8 exhibited significant cytotoxicity against MCF-7, A549, and HCT116 cells with GI50 values in the range of 2.2-4.8 µM. This work would provide valuable information that secondary metabolites from I. ternifolius could be developed as anticancer agents.

Two new abietane diterpenoids from the leaves of Rabdosia serra.

Phytochemical investigation on the leaves of Rabdosia serra led to the isolation of two new abietane diterpenoids, raserranes A (1) and B (2), and four known phenylpropanoids (3-6). Their structures were determined by spectroscopic data. Compound 1 represented the rare examples of abietane diterpenoids featuring a 16-methoxycarbonyl group.