Cytotoxic biomonitored study of Euphorbia umbellata (Pax) Bruyns

In vitro toxicity of latex, its terpenoidal fractions and isolated phorbol esters from Euphorbia umbellata (Pax) Bruyns on monocytic and melanoma cells

In Brazil, latex from Euphorbia umbellata (African milk tree) has been increasingly used in folk medicine to treat several types of cancer, including melanoma. The effect of lyophilized latex (LL), its hydroethanolic extract (E80), triterpene (F-TRI)- and diterpene (F-DIT)-enriched fractions, along with six isolated phorbol esters from LL and phorbol 12-myristate 13-acetate (PMA) on J774A.1, THP-1, SK-MEL-28, and B16-F10 cell line viability were evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. The compounds were identified by 2D-NMR and HRESIMS. The effect of the LL, extract and fractions on cell viability was also assessed through a resazurin reduction assay. At 100 μg/ml, LL, and its fractions moderately inhibited J774A.1 (37.5-59.5%) and THP-1 (12.6-43.6%) metabolism. LL (IC50 70 μg/ml) and F-TRI (IC50 68 μg/ml) were barely more effective against B16-F10 cells, and only F-TRI exerted an inhibitory effect on SK-MEL-28 cells (IC50 66-75 μg/ml). The samples did not effectively inhibit THP-1 growth (IC50 69-87 μg/ml, assessed by MTT). B16-F10 was susceptible to PMA (IC50 53 μM) and two 12-phenylacetate esters (IC50 56-60 μM), while SK-MEL-28 growth was inhibited (IC50 58 μM) by one of these kinds of esters with an additional 4β-deoxy structure. Synagrantol A (IC50 39 μM) was as effective as PMA (IC50 47 μM) in inhibiting J774A.1 growth in a dose-dependent manner. Furthermore, an in silico study with target receptors indicated a high interaction of the compounds with the PKC proteins. These results provide useful knowledge on the effect of tigliane-type diterpenes on tumor cell from the perspective of medicinal chemistry.

Chemical Profiles and Cytotoxic Activities of Essential Oils from Six Species of Baccharis Subgenus Coridifoliae (Asteraceae)

Several Baccharis species are popularly known in traditional medicine as "carquejas", "vassouras", "ervas-santas" and "mio-mios", and are used as anti-inflammatories, digestives, and diuretics. This study aimed to investigate the chemical compositions and cytotoxic activities of essential oils (EOs) of six Baccharis species belonging to subgenus Coridifoliae, namely B. albilanosa, B. coridifolia, B. erigeroides, B. napaea, B. ochracea, and B. pluricapitulata. GC/MS analyses of the EOs showed that the oxygenated sesquiterpenes spathulenol (7.32-38.22 %) and caryophyllene oxide (10.83-16.75 %) were the major components for all the species. The EOs of almost all species were cytotoxic against cancer (BT-549, KB, SK-MEL and SK-OV-3) and normal kidney (VERO and LLC-PK1) cell lines, whereas B. erigeroides EO showed cytotoxicity only against LLC-PK1. This article augments the current knowledge about the chemical-biological properties of Baccharis subgenus Coridifoliae and discusses the therapeutic potentials of these economically unexploited plants.

Bioactive Secondary Plant Metabolites from Euphorbia umbellata (PAX) BRUYNS (Euphorbiaceae)

The species Euphorbia umbellata has been used to treat inflammatory diseases, cancer, and ulcers. Biological activities reported in the literature, including antiproliferative, cytotoxic and anti-inflammatory, are attributed to the chemical constituents present in its composition as terpenes and polyphenolic compounds. The most recurrently verified metabolites in the Euphorbiaceae family plant species are terpenes, of which euphol is a major constituent with broadly reported cytotoxic, antinociceptive and anti-inflammatory effects; it frequently appears in various extracts obtained from the plant. Euphol has a documented inhibitory effect on neutrophil chemotaxis and can modulate the complement system. Since complement system activation is intimately intertwined with autoimmune and inflammatory diseases, tumor growth promotion and metastasis, plant metabolites from Euphorbia umbellata might influence the outcomes of inflammatory processes. We believe that this is the first review presenting the current knowledge on Euphorbia umbellata secondary metabolites and their biological activities.

Tap the sap - investigation of latex-bearing plants in the search of potential anticancer biopharmaceuticals

Latex-bearing plants have been in the research spotlight for the past couple of decades. Since ancient times their extracts have been used in folk medicine to treat various illnesses. Currently they serve as promising candidates for cancer treatment. Up to date there have been several in vitro and in vivo studies related to the topic of cytotoxicity and anticancer activity of extracts from latex-bearing plants towards various cell types. The number of clinical studies still remains scarce, however, over the years the number is systematically increasing. To the best of our knowledge, the scientific community is still lacking in a recent review summarizing the research on the topic of cytotoxicity and anticancer activity of latex-bearing plant extracts. Therefore, the aim of this paper is to review the current knowledge on in vitro and in vivo studies, which focus on the cytotoxicity and anticancer activities of latex-bearing plants. The vast majority of the studies are in vitro, however, the interest in this topic has resulted in the substantial growth of the number of in vivo studies, leading to a promising number of plant species whose latex can potentially be tested in clinical trials. The paper is divided into sections, each of them focuses on specific latex-bearing plant family representatives and their potential anticancer activity, which in some instances is comparable to that induced by commonly used therapeutics currently available on the market. The cytotoxic effect of the plant's crude latex, its fractions or isolated compounds, is analyzed, along with a study of cell apoptosis, chromatin condensation, DNA damage, changes in gene regulation and morphology changes, which can be observed in cell post plant extract addition. The in vivo studies go beyond the molecular level by showing significant reduction of the tumor growth and volume in animal models. Additionally, we present data regarding plant-mediated biosynthesis of nanoparticles, which is regarded as a new branch in plant latex research. It is solely based on the green-synthesis approach, which presents an interesting alternative to chemical-based nanoparticle synthesis. We have analyzed the cytotoxic effect of these particles on cells. Data regarding the cytotoxicity of such particles raises their potential to be involved in the design of novel cancer therapies, which further underlines the significance of latex-bearing plants in biotechnology. Throughout the course of this review, we concluded that plant latex is a rich source of many compounds, which can be further investigated and applied in the design of anticancer pharmaceuticals. The molecules, to which this cytotoxic effect can be attributed, include alkaloids, flavonoids, tannins, terpenoids, proteases, nucleases and many novel compounds, which still remain to be characterized. They have been studied extensively in both in vitro and in vivo studies, which provide an excellent starting point for their rapid transfer to clinical studies in the near future. The comprehensive study of molecules from latex-bearing plants can result in finding a promising alternative to several pharmaceuticals on the market and help unravel the molecular mode of action of latex-based preparations.

Ethanolic extracts of Pakistani euphorbiaceous plants induce apoptosis in breast cancer cells through induction of DNA damage and caspase-dependent pathway

BACKGROUND

Numerous plants of Euphorbiaceae, thespurgefamily are traditionally used for the treatment of different diseases and recent studies also reported anti-oxidant, anti-inflammatory, and anti-tumor activities of these plants. However, the medicinal potential of several indigenous euphorbiaceous plants of Pakistan is not described yet. Therefore, we intended to evaluate the in vitro anti-breast cancer potential of 10 euphorbiaceous plants of Pakistan.

METHODS

Cytotoxic screening of ethanolic extracts of selected plants was performed by MTT assay. The qualitative phytochemical analysis was performed to find the major groups of chemicals responsible for cytotoxic activity. To determine the genotoxic effect of plant extracts, microscopic analysis was carried out. Flow cytometry and fluorescent microscopic analysis were done to detect apoptosis. To find out the expression analysis of cell cycle and cell death regulatory genes, quantitative real-time polymerase reaction (qRT-PCR) was performed.

RESULTS

Among the 10 tested plants, ethanolic extracts of Croton tiglium (CTL) and Euphorbia royleana (ERA) were found to possess the highest anti-proliferative activity against breast cancer cells (MDA-MB-231, MCF-7), with IC₅₀ values 100 and 80 µg/mL respectively. The phytochemical analysis confirmed the presence of phenols, flavonoids, and steroids in both plant extracts, whereas, glycosides and saponins were found only in CTL and ERA, respectively. The cellular aberrations and nuclear morphologies with a distinct DNA laddering pattern substantiated the genotoxic effects. Furthermore, our data showed that CTL and ERA induce cell cycle arrest at the G1/S phase by down-regulating the CDK4 and Cyclin D1 expression followed by caspase-dependent induction of apoptosis in both MCF-7 and MDA-MB-231 cells. However, based on the activation of initiator and executioner caspases, two distinct types of apoptotic pathways are proposed for these plants. The CTL prompted extrinsic while ERA triggered the intrinsic pathways of apoptosis.

CONCLUSION

Our data demonstrate the strong anti-proliferative and caspase-dependent apoptotic potential of CTL and ERA against breast cancer cells. Further studies are suggested to find clinical implications of these plants in breast cancer therapeutic.

Evaluation of the antioxidant and cytotoxic potency of Euphorbia rigida and Arbutus andrachne methanol extracts in human hepatocellular carcinoma cell lines in vitro

Background

Ethnobotanical studies on plants and their active compounds take a great interest in traditional medicine. After pharmacological and toxicological studies, there will be a possibility to be used in therapy. This study aimed to examine the in vitro antioxidant and cytotoxic activity of the methanol extracts of Arbutus andrachne L. and Euphorbia rigida M.Bieb. 10, 25, 50, 75, 100 and 150 µg mL−1 concentrations of A. andrachne and E. rigida were tested for antioxidant activity by using DPPH radical scavenging assays, total antioxidant capacity (phosphomolybdate assay) and and metal ion chelating activity. In addition, in vitro cytotoxic effects of this plants methanol extracts on Hep3B and HepG2 human hepatocellular carcinoma cell lines were evaluated at 24, 48 and 72 h. The cytotoxicity test was carried using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay.

Results

Methanol extract obtained from both plants showed increased antioxidant activity depending on the increase in concentration. When A. andrachne and E. rigida methanol extracts were compared in free DPPH scavenging activity, total antioxidant capacity and metal ion chelating activity, A. andrachne methanol extract was found more effective than E. rigida. Results from MTT assay revealed that except for 72 h treatment of HepG2 cells with 400 and 500 µgmL−1 extract concentrations, A. andrachne methanol extract did not show significant cytotoxic effects on either Hep3B or HepG2 cells at any concentration and treatment time. On the contrary, it significantly increased proliferation in Hep3B cells from 48 h and at a concentration of 100 µg mL−1. E. rigida methanol extract exhibited statistically significant cytotoxic activity on HepG2 cells after 48 and 72 h treatment. However, the treatment concentrations of E. rigida methanol extract were not as effective on Hep3B cells as on HepG2 cells.

Conclusions

According to our findings, it was determined that A. andrachne methanol extract did not have cytotoxic activity on neither Hep3B nor HepG2 cells, while E. rigida methanol extract had cytotoxic activity especially on HepG2 hepatocellular carcinoma cells. Further research is needed to identify and purify the active ingredients in E. rigida extracts.

Immunomodulatory and cytotoxic activities of euphol

AIMS

This study evaluated the effect of euphol isolated from Euphorbia umbellata (Pax) Bruyns latex on the activation of complement pathways (classical (CP), alternative (AP) and lectin (LP)), neutrophil chemotaxis, cytotoxic activity, cell morphology and death in HRT-18 and 3T3 cells lines.

MAIN METHODS

CP and AP were assessed using hemolytic assays and ELISA for LP; neutrophil chemotaxis was performed using Boyden's chamber; cytotoxicity was evaluated by neutral red methodology and characteristics of cell death were assessed by cell morphology with hematological staining.

KEY FINDINGS

Although euphol increased CP activation (38% at a concentration of 976.1 μM), an inhibitory effect on AP, LP (31% and 32% reduction in the concentration of 976.1 μM) and neutrophil chemotaxis (inhibit 84% of neutrophil migration at a concentration 292.9 μM) was observed. In addiction euphol was able to induce significant cell death in a time-dependent manner, presenting an IC₅₀ of 70.8 μM and 39.2 μM for HRT-18 and 3T3 cell lines respectively and it was also observed apoptotic characteristics as cellular rounding, chromatin condensation and blebs formation for both cell lines.

SIGNIFICANCE

Euphol has a potential use for the treatment of complement-related inflammatory diseases due to its ability to downregulate inflammation. On the other hand, the controlled activation of CP can contribute to complement-dependent cytotoxicity in the context of monoclonal antibody-based cancer treatment.

Phorbol Esters from the Latex of Euphorbia umbellata: Bioguided Isolation of Highly Potent HIV-1 Latency Interrupters in Virus Reservoir Cells

Three known compounds, 20-deoxyphorbol-5β-hydroxy-12-tiglate-13-isobutyrate (1), 20-deoxyphorbol-5β-hydroxy-12-tiglate-13-phenylacetate (2), and 4-deoxy-4β-phorbol-12-tiglate-13-phenylacetate (3), were reisolated from the latex of Euphorbia umbellata through a bioguided fractionation process to target HIV-1 latency reactivation. The in vitro bioassay using infected T-cell lymphoblasts (J-Lat 10.6), complemented with surface CD4 receptor downregulation assessment, led to isolation of the compounds as a highly active ternary mixture. Effective purification of the individual compounds was achieved by first subjecting a phorbol-enriched fraction (previously prepared from crude latex) to MPLC, followed by semipreparative HPLC and characterization by 1D and 2D NMR spectroscopy and (+)-HRESIMS. Compared with a positive control, the isolated compounds were effective in reactivating 68-75% of the virus latency in the range of 9.7-0.097 μM for compound 1, 8.85-0.088 μM for compound 2, and 9.1-0.091 μM for compound 3, with the latter maintaining steady effectiveness down to a 10^-5 dilution. Accordingly, compound 3 may serve as a promising lead compound for the development of anti-HIV drugs based on latency reactivation therapy.

Effects of the Latex of Synadenium grantii Hook F. (Euphorbiaceae) on a Preclinical Model of Canine Prostate Cancer

Prostatic cancer (PC) stands out in terms of its occurrence, pathophysiology, and unfavorable prognostics in humans and dogs. Natural drugs bear an integrative potential for conventional antineoplastic treatments. In this context, the bioproducts of Synadenium grantii have been empirically used in different parts of Brazil for the integrative treatment of prostate cancer in humans. However, there is no availability of scientific evidence of the antitumor effects of S. grantii. Therefore, this study aimed to investigate the bioactive compounds in the latex of S. grantii using the high-resolution mass spectrophotometry (HRMS) and to evaluate its cytotoxic effects on primary canine PC cell cultures. Four fragments of phorbol ester were identified as potential bioactive compounds using the HRMS. With the help of an MTT ([3-(4,5-dimethyldiazol-2-yl)-2,5 diphenyltetrazolium bromide]) assay, two canine prostatic carcinoma cell lines (PC 1 and PC2) showed a decrease in the tumor cell count, with an Inhibitory concentration 50 (IC₅₀)of 0.8469 and 0.6068 mg/ml, respectively, for PC1 and PC2. In conclusion, the latex of S. grantii contains phorbol esters in its composition, and its aqueous solution has a cytotoxic effect on canine metastatic PC cells in vitro.

Ficus Carica L. Latex: Possible Chemo-Preventive, Apoptotic Activity and Safety Assessment

Hepatocellular carcinoma is the third cause of cancer-related mortality with the low 5-year survival in which more than 50 percent of patients have recurrent cancer within 2 years of treatment. The present study investigated the cytotoxicity and lethal dose of Ficus carica L. (Figure) latex and phytochemical composition of effective fraction. Figure latex was collected in summer and 4 fractions of Figure latex were prepared. The cytotoxic effect of each fraction was studied and the most effective fraction was selected for apoptosis assay, acute toxicity study, and phytochemical analysis using column chromatography. The isolated compounds were identified by ¹H-NMR, ¹³C-NMR, and mass spectroscopy. Chloroform fraction was the most effective fraction with the IC₅₀ value of 0.219 and 0.748 mg/mL for HepG2 and NIH cell lines, respectively. Presence of cells in early apoptotic phase was documented by flow cytometry assay. Single dose administration of 2g/kg of fraction did not cause any death. Phytochemical analyses confirmed presence of lupeol acetate and lupeol palmitate in chloroform fraction. The present study revealed that the chloroform fraction is not only 3.4 times more toxic in HepG2 cell line but also has low in-vivo toxicity which could be considered as a good candidate for a chemo-preventive agent.

Effects of Euphorbia umbellata extracts on complement activation and chemotaxis of neutrophils

ETHNOPHARMACOLOGICAL RELEVANCE

The species Euphorbia umbellata (leitosinha) has been traditionally used for the treatment of inflammatory diseases and cancer.

AIM OF THE STUDY

Evaluation the effect of E. umbellata latex extracts obtained with hexane, chloroform, ethyl acetate and methanol on the activation of the complement pathways and neutrophil chemotaxis.

MATERIALS AND METHODS

The latex was partitioned using Soxhlet apparatus and hexane, chloroform, ethyl acetate and methanol as solvents. The classical and alternative pathway activity were performed by hemolytic assays with sensitized sheep or rabbit erythrocytes, respectively; the lectin pathway activity was quantified by ELISA, through the measurement of C4 molecules and the chemotaxis of human neutrophils was performed using 1% casein as the chemotactic inducer and Boyden's chamber. GC-Q-ToF and NMR analyses were applied to evaluate the chemical composition of E. umbellata latex extracts.

RESULTS

All E. umbellata latex extracts exhibited an inhibitory effect on the activation of the alternative pathway. Methanol and ethyl acetate extracts inhibited the classical pathway while chloroform extract activated this pathway. Ethyl acetate and hexane extracts inhibited lectin activation. All E. umbellata extracts inhibited casein-induced neutrophil chemotaxis. Terpenes and phenolic compounds have been suggested to be present in the E. umbellta latex extracts.

CONCLUSION

The E. umbellata latex was able to modulate the functions of the immune system. Thus, it is possible to infer that the terpenes and phenolic compounds of the phytocomplex of E. umbellata latex can contribute for the activity on the complement pathways.

New Diterpene Compound from Euphorbia connate Boiss., 3,7,14,15-Tetraacetyl-5-Propanoyl-13(17)-Epoxy-8,10(18)-Myrsinadiene, Inhibits the Growth of Ovarian Cancer Cells by Promoting Mitochondrial-Mediated Apoptosis

Ovarian cancer due to the difficulties in early clinical diagnosis and absence of successfull treatment has poor prognosis and high mortality among all gynecological malignancies. Many evidence has revealed that plants of the Euphorbiaceae family are precious sources of novel bioactive compounds with anti-tumor activities. 3,7,14,15-tetraacetyl-5-propanoyl-13(17)-epoxy-8,10(18)-myrsinadiene (TPEM) is a new myrsinane-type diterpene isolated recently by our group from aerial parts of Euphorbia Connata and the present study was aimed to explore its inhibitory effects on growth of two human ovarian cancer cells, OVCAR-3, and Caov-4. The obtained results indicated that growth of OVCAR-3 and Caov-4 cells was significantly inhibited by TPEM in a dose-dependent manner, with the IC50 values of 41.27 ± 1.52 and 36.44 ± 2.41 µM, respectively. Furthermore, using Annexin V-FITC and PI staining it was confirmed that the induced cell death was mainly mediated through apoptotic pathway. Further observations such as decrease in the mitochondrial membrane potential (ΔΨm), increase in the activity of caspase-3 and elevation of the Bax/Bcl-2 ratio suggested the role of mitochondria in the induction of apoptosis by TPEM. ROS level was also remarkably increased in OVCAR-3 and Caov-4 cells in response to TPEM treatment. In conclusion, these findings provide first evidences about potential anticancer properties of TPEM.

Enriched Terpenes Fractions of the Latex of Euphorbia umbellata Promote Apoptosis in Leukemic Cells

The current study was carried out by a bioguided fractionation of a hexane extract of the latex of Euphorbia umbellata against leukemic cells. Samples were analyzed by NMR, GC/MS, triterpenes quantification, and MTT reduction assay. Morphological, cell cycle, mitochondrial membrane potential and caspases 3/7 analyses were performed for the dichloromethane and ethanol fractions, and selectivity index for the dichloromethane fraction. NMR analysis presented characteristic signals of terpenes and steroids, data were confirmed by the quantification of triterpenes and GC/MS analysis. MTT reduction assay demonstrated that HL-60 was the most sensitive cell lineage against dichloromethane and ethanol fractions. Compounds of these matrices caused morphological changes compatible with apoptosis induction, altered cell cycle, increment of depolarized population cells and activation of caspases 3/7. Selectivity indices were higher than 22.44. Bioguided-fractionation study showed that samples of the latex of E. umbellata raised the activity of the phytocomplex against leukemic cells, and the cytotoxicity can be associated with an apoptosis pathway.

Pharmacokinetics and cytotoxic study of euphol from Euphorbia umbellata (Bruyns) Pax latex

BACKGROUND

Medicinal plants are an important source to identify new active pharmaceutical compounds. Traditionally, the sap of Euphorbia umbellata is widely used to treat cancer and inflammatory conditions. These effects have been attributed to the presence of terpenes and phenolic compounds in the extracts of this plant. Euphol, a tetracyclic triterpene alcohol, is one of the major compounds present in Euphorbia species, and some biological activities have been attributed to this compound.

PURPOSE

This study aimed to evaluate the in vitro cytotoxicity of euphol against Jurkat, HL-60, K-562, B16F10, and HRT-18 cells lines, as well as the biological stability, distribution, metabolism properties in vitro, and the determination of the concentration of euphol in the plasma and liver of rats.

METHODS

The MTT reduction assay was used to evaluate the cytotoxicity of euphol against cancer cell lines, and the selectivity index, the morphology and cell cycle assays to evaluate the death mechanisms in K-562 and B16F10 lineages. UHPLC-MS was applied for the in vivo evaluation of the concentration of euphol in plasma and liver, and in vitro metabolic stability in human liver microsomes and S9 fraction, plasma protein binding, and stability in simulated gastric and intestinal fluids assays.

CONCLUSIONS

This study demonstrated that euphol exhibited cytotoxic effects against a variety of cancer cells lines, selectivity against leukemia and possibly, the mechanism involved is apoptosis. The evaluation of stability, distribution, and metabolism properties showed that euphol was unstable in gastric and intestinal fluids, presenting moderate plasma protein binding with two hours elimination half-life and possible phase II liver metabolism. All the results suggested that further studies could be developed to prove the viability of euphol as an anticancer agent.