Anti-Inflammatory and Cytotoxic Compounds Isolated from Plants of Euphorbia Genus.

Euphorbia is a large genus of the Euphorbiaceae family. Around 250 species of the Euphorbia genus have been studied chemically and pharmacologically; different compounds have been isolated from these species, especially diterpenes and triterpenes. Several reports show that several species have anti-inflammatory activity, which can be attributed to the presence of diterpenes, such as abietanes, ingenanes, and lathyranes. In addition, it was found that some diterpenes isolated from different Euphorbia species have anti-cancer activity. In this review, we included compounds isolated from species of the Euphorbia genus with anti-inflammatory or cytotoxic effects published from 2018 to September 2023. The databases used for this review were Science Direct, Scopus, PubMed, Springer, and Google Scholar, using the keywords Euphorbia with anti-inflammatory or cytotoxic activity. In this review, 68 studies were collected and analyzed regarding the anti-inflammatory and anti-cancer activities of 264 compounds obtained from 36 species of the Euphorbia genus. The compounds included in this review are terpenes (95%), of which 68% are diterpenes, especially of the types ingenanes, abietanes, and triterpenes (approximately 15%).

Identification and structural modification of ent-rosane diterpenoids from Euphorbia milii inhibiting RANKL-induced osteoclastogenesis.

Phytochemical study on Euphorbia milii, a common ornamental plant, resulted in the identification of thirteen new ent-rosane diterpenoids (1-13), three new ent-atisane diterpenoids (14-16), and a known ent-rosane (17). Their structures were delineated using spectroscopic data, quantum chemical calculations, and X-ray diffraction experiments. Euphomilone F (1) represented a rare ent-rosane-type diterpenoid with a 5/7/6 skeleton. Euphoainoid G (8) was a rare rosane diterpenic acid. Compounds 9 and 10 carried infrequent tetrahydrofuran rings, and compounds 11-13 was 18-nor-ent-rosane diterpenoids. All isolates were evaluated for their inhibitory effects on RANKL-induced osteoclasts. Notably, compounds with aromatic ester groups (2-7) showed promising activities (IC50 < 10 µM), underscoring the significance of acylated A-ring moieties in the ent-rosane skeleton for anti-osteoclastogenesis. Thirteen synthetic derivatives were obtained through esterification of 17. Of these, compound 27 exhibited remarkable improvement, with an IC50 of 0.8 µM, more than a 12-fold increase in potency compared to the parent compound 17 (IC50 > 10 µM). This work presents a series of new ent-rosane diterpenoids with potential antiosteoporosis agents.

Ent-atisane diterpenoids from Euphorbia wallichii and their anti-influenza A virus activity.

The study entailed the investigation of the roots of Euphorbia wallichii, which resulted in the isolation of 29 ent-atisane diterpenoids (1-29), 14 of which were previously unknown. These previously undescribed ones were named euphorwanoids A-N (3-5, 7, 9, and 10-18). Various techniques, including comprehensive spectroscopic methods and calculated electronic circular dichroism, were employed to determine their molecular structures. Additionally, the absolute configurations of ten ent-atisane diterpenoids (1, 2, 5, 6, 8, 9, 11, 12, 14 and 16) were established through X-ray crystallographic analyses. All isolated compounds' potential to inhibit the influenza A virus in vitro were evaluated. Compounds 18, 20, and 24 exhibited notable antiviral activity against the A/Puerto Rico/8/1934 strain. Their effective concentrations for reducing viral activity (EC50 values) were found to be 8.56, 1.22, and 4.97 µM, respectively. An intriguing aspect of this research is that it marks the first instance of ent-atisane diterpenes displaying anti-H1N1 activity. Empirical NMR rules were established with Δδ to distinguish the R/S configurations of C-13 and C-16 in ent-atisanes.

Diterpenoids from Euphorbia peplus possessing cytotoxic and anti-inflammatory activities.

Phytochemical investigation into the medium polar fraction of the ethanol extract of Euphorbia peplus led to the identification of 32 diterpenoids with five structural types. Compounds 1-5 and 7-11 are reported for the first time, while the configuration of 6,7-epoxy group of 6 was revised to be ß-oriented. Compounds 1-5 feature a rare structural variation of the double bond at Δ1 migrating to Δ1(10) in the tigliane-type diterpenoid family. Biologically, compound 21 was found to be the only one to show moderate cytotoxic activity, associated with the presence of a benzoyloxy residue at C-16. Besides, compounds 4, 8, 12, 13, 16, and 19 show significant inhibitory activities against NO production induced by LPS in RAW264.7 macrophage cells, with IC50 values within 2-5 µM. Structure-activity relationship (SAR) analysis revealed that the ingenane-type diterpenoids have the best anti-inflammatory activity, and the esterification at 3-OH or 5-OH is crucial. Further biological researches demonstrated that 13, the predominant metabolite in this plant, exerts anti-inflammatory effects by blocking the activation of NF-κB and MAPK signaling pathways.

Enhancing lathyrane structural diversity and MDR activity by combinatorial modification of lathyrane nucleus and ester side chain: A case study of Euphorbia Factor L1 and Euphorbia Factor L3.

The chemical transformation of lathyrane nucleus through reduction and oxidation reactions using Euphorbia Factor L1 (EFL1) and Euphorbia Factor L1 (EFL3) as examples were investigated, along with a co-modification strategy of lathyrane nucleus and its side ester chain. A total of 38 lathyrane derivatives (5-42) including 34 new compounds were obtained, which greatly enriched the structural diversity of the lathyrane-type diterpenoids. Cytotoxicity against drug-sensitive and drug (adriamycin, ADM) resistant MCF-7 cells showed that 23 out of 38 transformed derivatives possessed obvious cytotoxic activity with IC50 values ranging from 7.0 to 41.1 µM and 3.2 to 45.5 µM, respectively, against both cells, compared to the noncytotoxic EFL1 and EFL3. The multidrug resistance (MDR) reversing activities of these lathyrane derivatives were further evaluated in MCF-7/ADM. Three transformed compounds (reversal fold, RF = 151.33, 62.94 and 47.3 for 27, 37 and 42) showed markedly higher activity than EFL1 (RF = 32.92) and EFL3 (RF = 39.68). Structure-activity relationship study revealed an essential role of C-6/17 and C-12/13 double bonds on lathyrane nucleus for exerting MDR reversal activity. Western blotting analysis showed that 42 could reduce the expression level of P-glycoprotein (P-gp) in MCF-7/ADM cells; however, the most active compound 27 with an unnatural 5/7/7/4 fused-ring diterpenoid skeleton, had no inhibitory effect on P-gp expression.

Structurally intriguing diterpenoids from Euphorbia wallichii Hook. f. with potential antioxidant activity.

Chemical investigation of Euphorbia wallichii Hook. f. led to the isolation of four undescribed rearranged diterpenoids, euphwanoids I-IV (1-4), and six unreported tigliane diterpenoids walliglianes A-F (5-10). Euphwanoids I-III (1-3) possess a rare 6/6/7/3 ring scaffold, euphwanoid IV (4) is the first spiro[tricyclo[5.4.0.02,4]undecane-8,1'-cyclopentane] skeleton to be found in the tigliane family. The structures of compounds 1-10 were established by utilizing spectroscopic data analysis, experimental electronic circular dichroism measurements, 13C NMR calculations, and single-crystal X-ray diffraction. In the preliminary bioassay, compounds 3, 4, and 7 were found to protect BV-2 cells against H2O2-induced cell injury in a dose-dependent manner by the CCK8 assay.

Diverse diterpenoids and a triterpenoid from Euphorbia spinidens Bornm. ex Prokh.

Four previously unreported diterpenoids including three ent-atisanes (1-3) and one ent-abietane (4), along with one known linear triterpenoid (5) and five known diterpenoids including four myrsinanes (6-9), and one abietane (10) have been isolated from the roots of Euphorbia spinidens Bornm. ex Prokh. The structures were determined on the basis of extensive spectroscopic analyses including HR-ESI-MS, 1D and 2D NMR and comparison of the data with those reported in the literature. Antimicrobial potential of isolated compounds were also evaluated. Guionianol B (10) showed good antibacterial activity against Staphylococcus aureus and Bacillus subtilis with MIC value of 6.25 µg/mL.

Three new diterpenoids isolated from Euphorbia nematocypha Hand.-Mazz and their anti-fungal activity.

Three new diterpenoids, named nematocynine A-C (1-3), together with twelve known compounds (4-15) were isolated from the aerial part of Euphorbia nematocypha Hand.-Mazz (Hereinafter referred to E. nematocypha). Their structures were elucidated by detailed spectroscopic analysis and comparison with literature data. In addition, all the compounds were tested for their anti-candida albicans activities used alone or in combination with fluconazole against sensitive strain and resistant strain in vitro. Wherein only compound 11 shows weak activity against candida albicans resistant strain (MIC50 = 128.15 µg/mL) when used alone. Compounds 1, 4, 7, 8, 9, 10, 12, 13 and 15 in combination with fluconazole showed potent anti-fungal activities (MIC50 = 15 ± 5 µg/mL, FICI = 0.05 ± 0.04) against the Candida albicans resistant strain SC5314-FR. The synergistic effects were weaker against the Candida albicans resistant strain SC5314-FR when the compounds 2, 3, 5 and 14 were combined with fluconazole (FICI = 0.16 ± 0.06).

Medicinal Effects, Phytochemistry, Pharmacology of Euphorbia prostrata and Promising Molecular Mechanisms.

Euphorbiaceae is a large family of dicotyledonous angiosperms with diverse genera including Euphorbia prostrata (E. prostrata). Current research has provided scientific evidence for traditional uses of E. prostrata against diverse pathological conditions such as anti-hemorrhoidal, anti-inflammatory, analgesic, wound healing, antioxidant, antibacterial, leishmanicidal, antitumor activity, and so on. The phytochemical screening has revealed the presence of glycosides, phytosterols, flavonoids, polyphenols, tannins, and anthraquinones with chemical structures elucidation of their respective compounds. The uniqueness of such multifactorial compounds present in this species endorses it as the potent therapeutic or prophylactic choice for several fatal diseases. Although ethnomedical applications served as a significant citation for pharmacology, the molecular mechanism has not been reviewed yet. The present paper provides a comprehensive review of research outcomes, pharmacology, toxicology, and molecular signaling of phytochemicals of E. prostrata species as a reference for relevant researchers. The study of bioactive compounds in crude extracts and fractions, the demonstration of primary mechanisms of pharmacology, along with the addition of toxicity, and clinical trials, should be conceded in depth. This review underlines the E. prostrata species that can be a promising phytomedicine since we are committed to excavating more intensely into their pharmacological role.

A partial peroxisome proliferator-activated receptor gamma agonist isolated from the roots of Euphorbia sikkimensis.

Chemical constituents of the Euphorbia sikkimensis roots was investigated and twelve known compounds were isolated, including three ent-atisane diterpenes: ent-(13S)-hydroxyatis-16-ene-3,14-dione (1), ent-(5ß,8α,9ß,10α,11α,12α)-11-hydroxyatis-16-ene-3,14-dione (2), ent-atisane-3-oxo-16α,17-diol (3); two kaurene diterpenes: ent-kaurane-3-oxo-16α,17-diol (4), ent-kaurane-3-oxo-16ß,17-diol (5); one lathyane diterpene of latilagascene B (6); two flavonoids: quercetin (7), luteolin (8); one lignin d-pinoresinol (9); one coumarin scopoletin (10); together with ethyl gallate (11), p-hydroxybenzaldehyde (12). Their structures were identified based on the extensive spectroscopic analysis in comparison with the literature data. Compounds 1, 2, 4, 6 and 9 were isolated from Euphorbia sikkimensis for the first time. The agonistic activity of peroxisome proliferator-activated receptor gamma (PPARγ) for compounds 1, 7, 8, 9 and 11 was evaluated. Compound 1 exhibited moderate agonistic activity for PPARγ receptor with relative fluorescence intensity of 10.19 at 30.0 µM, in comparison with that of the positive control of rosiglitazone (28.50 at 2.0 µM).

Metabolomics-based investigation of the chemical composition changes in Mongolian medicinal plant Euphorbia pekinensis before and after processing with Chebulae Fructus.

Euphorbia pekinensis (EP), known for its diuretic properties, is clinically utilized for treating conditions such as edema and malignant tumors. However, in its raw form, Euphorbia pekinensis is toxic, and oral administration of this crude medicine can lead to gastrointestinal stimulation, resulting in abdominal pain and diarrhea. In Mongolian medicine's ethnomedicinal system, a distinctive processing method called "Chebulae Fructus processing" is employed. Chebulae Fructus is used to mitigate the toxicity of EP and alleviate its purgative effects. Nevertheless, the detoxification mechanism associated with this processing method remains unexplored. It is hypothesized that processing with Chebulae Fructus may alter the chemical composition of EP, and the residual components of Chebulae Fructus within processed Chinese medicine might exhibit pharmacological antagonistic effects, thereby achieving the purpose of processing and reducing toxicity. To investigate this further, a combination of UPLC-QTOF-MS-based metabolomics technology and multivariate statistical analysis was employed to analyze and compare the chemical composition of raw and processed EP. Differential variables contributing to group separation were identified based on specific criteria, including VIP (Variable Importance in Projection) values of ≥ 1 in PLS-DA models, p-values < 0.05, and fold changes (FC) > 1.2 or < 0.8. The resulting differentially expressed features were then identified through database matching, literature review, or manual annotation. In total, 47 components were identified from the PEP samples in both positive and negative ionization modes, primarily belonging to flavonoids, terpenoids, organic acids, glycosides, and fatty acids. Among the raw EP group and PEP S4 group, 10 differential compounds were identified. Notably, one toxic terpene and one phenylpropanoid from EP were downregulated, while two bioactive components from Chebulae Fructus were upregulated in the processed group. The possible conversion reactions of these two processing Q-markers were also elucidated. The characteristic processing with Chebulae Fructus resulted in a change in the composition of this Mongolian medicine EP. Furthermore, this study provides a scientific foundation for optimizing the processing technology of EP and offers insights into the processing of other ethnomedicines with toxic properties.

Identification and Functional Characterization of a Novel Sinapyl Alcohol Acyltransferase from Euphorbia lathyris L.

Methoxyeugenol is a phenylpropene compound derived from plants and has various bioactivities. The chemical synthesis of methoxyeugenol is accompanied by pollution issues, whereas extraction from plants is associated with problems such as low yield and high cost. The production of methoxyeugenol can be effectively addressed through an enzymatic approach. In this study, the acyltransferase genes of Euphorbia lathyris L. were screened by homologous alignment of the transcriptome data of E. lathyris in the late growth stage and the acyltransferase genes of the closely related plant species. The results showed that ElBAHD10 had the closest relationship with earlier reported ScCFAT and PhCFAT, which were found to catalyze the reaction of coniferyl alcohol to generate coniferyl acetate. The ElBAHD10 gene was successfully cloned from E. lathyris and subsequently expressed in Escherichia coli. The purified protein ElBAHD10 catalyzed the reaction of sinapyl alcohol with acetyl CoA and cinnamoyl CoA to form sinapyl acetate and sinapyl cinnamate, respectively. In contrast, the crude ElBAHD10 protein could catalyze sinapyl alcohol to directly generate methoxyeugenol. The recombinant E. coli strain expressing ElBAHD10 produced methoxyeugenol through whole-cell transformation. This study provides insights and lays the foundation for methoxyeugenol production through biosynthetic approaches.

Norsesquiterpenes from the Latex of Euphorbia dentata and Their Chemical Defense Mechanisms against Helicoverpa armigera.

Euphorbia dentata (Euphorbiaceae), an invasive weed, is rarely eaten by herbivorous insects and could secrete a large amount of white latex, causing a serious threat to local natural vegetation, agricultural production and human health. In order to prevent this plant from causing more negative effects on humans, it is necessary to understand and utilize the chemical relationships between the latex of E. dentata and herbivorous insects. In this study, three new norsesquiterpenes (1-3), together with seven known analogues (4-10), were isolated and identified from the latex of E. dentata. All norsesquiterpenes (1-10) showed antifeedant and growth-inhibitory effects on H. armigera with varying levels, especially compounds 1 and 2. In addition, the action mechanisms of active compounds (1-3) were revealed by detoxifying enzyme (AchE, CarE, GST and MFO) activities and corresponding molecular docking analyses. Our findings provide a new idea for the development and utilization of the latex of E. dentata, as well as a potential application of norsesquiterpenes in botanical insecticides.

Discovery of Ingenane Diterpenoids from Euphorbia hylonoma as Antiadipogenic Agents.

Thirteen new Euphorbia diterpenoids, euphylonanes A-M (1-13), and eight known ones were isolated from the whole plants of Euphorbia hylonoma. Compounds 1 and 2 are two rearranged ingenanes bearing a rare 6/6/7/3-fused ring system. Compound 3 represents the first example of a 9,10-epoxy tigliane, while 4-21 are typical ingenanes varying with substituents. Structures were elucidated using a combination of spectroscopic, computational, and chemical methods. Most ingenanes exerted a significant antiadipogenic effect in 3T3-L1 adipocytes, among which 4 was the most active with an EC50 value of 0.60 ± 0.27 µM. Mechanistic study revealed that 4 inhibited the adipogenesis and lipogenesis in adipocytes via activation of the AMPK signaling pathway.

Terpenoids from Euphorbia helioscopia and Their Cytotoxic Activities against H1975 Cells.

Three previously undescribed diterpenoids, helioscopnoids A-C, and eight known compounds were isolated from the whole plants of Euphorbia helioscopia. Their structures were established by extensive analysis of spectra and data comparison with previous literatures. Among them, compound 4 was identified as 24,24-dimethoxy-25,26,27-trinoreuphan-3ß-ol with revised configurations of C-13, C-14, and C-17 (13R*, 14R*, 17R*). Cytotoxicity assays revealed that all compounds exhibited varying levels of cytotoxicity against H1975 cells, with compound 9 displaying the most potent activity, as indicated by cell viability rates of 18.13 % and 20.76 % at concentrations of 20 µM and 5 µM, respectively. This study expands the understanding of E. helioscopia terpenoids' structural diversity and biological activities, contributing to the exploration of potential therapeutic applications.

Rearrangement of the Tetra- and Tricyclic Skeletons of Pepluanol B to Access the Core Structures of Tigliane- and Myrsinane-Type Euphorbia Diterpenes.

Pepluanol B is a new Euphorbia diterpene with an unprecedented tetracyclic backbone. However, its biogenetic relationship with known Euphorbia diterpenes is unclear. We report herein that its ß-hydroxyl ketone motif could undergo a base-promoted retro-aldol/aldol process in two pathways and afford the skeletons of tigliane- and myrsinane-type Euphorbia diterpenes through the formation of the C8-C14 and C7-C13 bonds, respectively. The retro-aldol/aldol cascade indicates that pepluanol B is possibly a biosynthetic precursor of lathyranes and other relevant dipterpenes.

ent-Atisane Diterpenoids from Euphorbia helioscopia and Their Anti-inflammatory Activities.

Phytochemical investigation on the anti-inflammatory fraction extracted from the whole plant of Euphorbia helioscopia L. led to the isolation of three new ent-atisane diterpenoids (1-3) and five known analogues (4-8). The structures and absolute configurations of the new compounds were elucidated by comprehensive analysis of the NMR, MS, IR, ECD, and X-ray crystallography. It is worth mentioning that compound 3 belongs to a rare class of ent-atisane diterpenoid featuring a hydroxyl group at C-9. Bioactivity investigation showed that compounds 4, 7, and 8 exhibited significant inhibitory effects on LPS-induced NO production in a dose-dependent manner, which indicates their anti-inflammatory potential.

Diterpenoids from Euphorbia fischeriana with Kv1.3 Inhibitory Activity.

Euphorbia diterpenoids possess inhibitory effects of Kv1.3 ion channel, but most of this research has focused on diterpenoids with jatrophane-related or ingenane-related skeletons. In the present study, nine undescribed (1-9) and 16 known (10-25) diterpenoids, based on jatrophane, lathyrane, ingenane, abietane, and atisane skeletons, were identified from the methanol extract of the aerial parts of Euphorbia fischeriana. The structures were established by analysis of the spectroscopic data as well as by single-crystal X-ray diffraction analysis. Among the isolated diterpenoids, macrocyclic jatrophanes and lathyranes exerted Kv1.3 blocking activity. Compound 8 exhibited good selectivity on the inhibition of the Kv 1.3 channel rather than hERG channel, with a selectivity index over 7.0. The selective activity of lathyrane diterpenoids indicates that macrocyclic diterpenoids have the potential to be further investigated as therapeutic agents for the treatment of autoimmune diseases.

Photo-induced scandium-catalyzed biomimetic skeleton conversion of lathyrane to naturally rare eupholathone Euphorbia diterpenes.

The naturally scarce eupholathone-type euphornin E (1) was efficiently prepared from abundant lathyrane-type Euphorbia factor L1via a visible-light-induced Sc(OTf)3-catalyzed tandem process. Eupholathones 2 and 3 were also smoothly obtained by changing the reaction solvent. This route provides a convenient method for easily constructing scarce eupholathone- from lathyrane-type Euphorbia diterpenes, and confirms the biogenetic relationship between them from a chemical standpoint. Notably, compound 1 exhibited good anti-HIV activity.

Discovery of two ent-atisane diterpenoid lactones with AChE inhibitory activity from the roots of Euphorbia fischeriana.

Euphorlactone A (1), a rare rearranged ent-atisane norditerpenoid with an undescribed 3-nor-2,4-olide-ent-atisane scaffold, and euphorlactone B (2), a new ent-atisane diterpenoid with an unprecedented seven-membered lactone ring C, were isolated from the roots of Euphorbia fischeriana. Their planar structures with absolute configurations were extensively elucidated by analysis of 1D and 2D NMR data, electronic circular dichroism (ECD) calculations, Rh2(OCOCF3)4-induced ECD curves, and single-crystal X-ray diffraction. Euphorlactone A (ELA) showed a remarkable AChE (acetylcholinesterase) inhibitory activity (IC50 = 2.13 ± 0.06 µM and Ki = 0.058 µM), which was five times stronger than that of the positive control (rivastigmine, IC50 = 12.46 ± 0.82 µM), and further in vitro enzyme inhibition kinetic analysis and molecular docking studies were performed to investigate the AChE inhibitory mechanism.