Unusual ingenoids from Euphorbia erythradenia Bioss. with pro-apoptotic effects

Discovery of new 13(17)-epoxymyrsinane diterpenes from aerial flowering parts of euphorbia spinidens Bornm. ex Prokh. with proapoptotic activities against human bladder cancer EJ138 cells

Phytochemical analysis of aerial flowering parts of Euphorbia spinidens Bornm. ex Prokh. from Euphorbiaceae family (local name: Farfion-e-dandaneh-khari) led to the isolation of five diterpenes based on myrsinane backbone. Using HRESI-MS, 1D, and 2D NMR, they were identified as two previously unreported: 33,7,14,15(β)-tetraacetyl-5(α)-butanoyl-13α(17)epoxy-8,10(18)-myrsinadiene (1), 7,14,15(β)-triacetyl-3(β),5(α)-dibutanoyl-13α(17)epoxy-8,10(18)-myrsinadiene (2), and three known diterpenes: 3,7,14,15(β)-tetraacetyl-5(α)-propanoyl-13(17)-epoxy-8,10(18)-myrsinadiene (3), and 3,7,10,14,15(β)-Pentaacetyl-5(α)-butanoyl-13,17-epoxy-8-myrsinene (4), 3,7,10,14,15(β)-pentaacetyl-5(α)-propanoyl-13,17-epoxy-8-myrsinene (5). Compound 5 was previously reported in the roots of the same plant but without NMR data. Therefore, its mass pattern,1H-, and 13C-NMR data are reported. The cytotoxicity and proapoptotic properties of 1-3 were evaluated against EJ-138 bladder carcinoma cells through standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay for cytotoxicity screening and annexin V-FITC/PI apoptosis detection kit. In the cytotoxicity assay, the IC50 values found against EJ-138 were: (1) 41.6 ± 3.54 μM; (2) 38.4 ± 2.54 μM; (3) 57.3 ± 5.4 μM, whilst the IC50 value of doxorubicin was 1.7 ± 0.3 μM, respectively. In apoptosis assay, total apoptosis of compounds 1-3 at higher concentrations (100 μM) were 57.6 ± 3.54, 46.3 ± 2.82, and 57.2 ± 4.35%, respectively.

Myrsinane-Type Diterpenes: A Comprehensive Review on Structural Diversity, Chemistry and Biological Activities

Euphorbia species are important sources of polycyclic and macrocyclic diterpenes, which have been the focus of natural-product-based drug research due to their relevant biological properties, including anticancer, multidrug resistance reversal, antiviral, and anti-inflammatory activities. Premyrsinane, cyclomyrsinane, and myrsinane diterpenes are generally and collectively designated as myrsinane-type diterpenes. These compounds are derived from the macrocyclic lathyrane structure and are characterized by having highly oxygenated rearranged polycyclic systems. This review aims to describe and summarize the distribution and diversity of 220 myrsinane-type diterpenes isolated in the last four decades from about 20 Euphorbia species. Some myrsinane diterpenes obtained from Jatropha curcas are also described. Discussion on their plausible biosynthetic pathways is presented, as well as isolation procedures and structural elucidation using nuclear magnetic resonance spectroscopy. Furthermore, the most important biological activities are highlighted, which include cytotoxic and immunomodulatory activities, the modulation of efflux pumps, the neuroprotective effects, and the inhibition of enzymes such as urease, HIV-1 reverse transcriptase, and prolyl endopeptidase, among other biological effects.

LC-ESI QToF MS Non-Targeted Screening of Latex Extracts of Euphorbia seguieriana ssp. seguieriana Necker and Euphorbia cyparissias and Determination of Their Potential Anticancer Activity

Euphorbia seguieriana ssp. seguieriana Necker (ES) and Euphorbia cyparissias (EC) with a habitat in the Deliblato Sands were the subject of this examination. The latexes of these so far insufficiently investigated species of the Euphorbia genus are used in traditional medicine for the treatment of wounds and warts on the skin. To determine their chemical composition, non-targeted screening of the latexes' chloroform extracts was performed using liquid chromatography coupled with quadrupole time-of-flight mass spectrometry employing an electrospray ionization source (LC-ESI QTOF MS). The analysis of the obtained results showed that the latexes of ES and EC represent rich sources of diterpenes, tentatively identified as jatrophanes, ingenanes, tiglianes, myrsinanes, premyrsinanes, and others. Examination of the anticancer activity of the ES and EC latex extracts showed that both extracts significantly inhibited the growth of the non-small cell lung carcinoma NCI-H460 and glioblastoma U87 cell lines as well as of their corresponding multi-drug resistant (MDR) cell lines, NCI-H460/R and U87-TxR. The obtained results also revealed that the ES and EC extracts inhibited the function of P-glycoprotein (P-gp) in MDR cancer cells, whose overexpression is one of the main mechanisms underlying MDR.

Diterpenoids from Euphorbia gedrosiaca as Potential Anti-Proliferative Agents against Breast Cancer Cells

Isolated diterpenes from various species of Euphorbia are important compounds for drug discovery with a broad spectrum of structures and biological effects. In this study, Euphorbia gedrosiaca, one of the endemic species of Iran, was analyzed in terms of the presence and structural determination of diterpenoid compounds. They were extracted with dichloromethane/acetone (2:1) from aerial parts of this plant and purified by chromatographic methods such as MPLC and HPLC. Four premyrsinane compounds and one myrsinane diterpene were isolated from Euphorbia gedrosiaca. They were characterized by extensive 1D and 2D NMR and HRMS analyses. Additionally, their activities were evaluated against two breast cancer cell lines, MDA-MB-231 and MCF-7, by MTT proliferation assay. They exhibited cytotoxic effects in a dose-dependent manner with promising results, which can help to find possible therapeutic application of diterpenoids in breast cancer treatment.

Euphorbia diterpenoids: isolation, structure, bioactivity, biosynthesis, and synthesis (2013-2021)

Covering: 2013 to 2021As the characteristic metabolites of Euphorbia plants, Euphorbia diterpenoids have always been a hot topic in related science communities due to their intriguing structures and broad bioactivities. In this review, we intent to provide an in-depth and extensive coverage of Euphorbia diterpenoids reported from 2013 to the end of 2021, including 997 new Euphorbia diterpenoids and 78 known ones with latest progress. Multiple aspects will be summarized, including their occurrences, chemical structures, bioactivities, and syntheses, in which the structure-activity relationship and biosynthesis of this class will be discussed for the first time.

The Role of Ingenane Diterpenes in Cancer Therapy: From Bioactive Secondary Compounds to Small Molecules

Diterpenes are a class of critical taxonomic markers of the Euphorbiaceae family, representing small compounds (eg, molecules) with a wide range of biological activities and multi-target therapeutic potential. Diterpenes can exert different activities, including antitumor and multi-drug resistance-reversing activities, and antiviral, immunomodulatory, and anti-inflammatory effects, mainly due to their great structural diversity. In particular, one polycyclic skeleton has been highlighted: ingenane. Besides this natural diterpene, promising polycyclic skeletons may be submitted to chemical modification—by in silico approaches, chemical reactions, or biotransformation—putatively providing more active analogs (eg, ingenol derivatives), which are currently under pre-clinical investigation. This review outlines the current mechanisms of action and potential therapeutic implications of ingenol diterpenes as small cancer molecules.

Plant-Derived Terpenoids: A Promising Tool in the Fight against Melanoma

Simple Summary

Despite the numerous therapies, melanoma remains the deadliest of all skin cancers; however, plant-derived terpenoids are defense molecules that have proven anti-cancer properties. In this review, we present the results of the search for anti-melanoma plant terpenoids. Additionally, we show the effects of combining terpenoids with standard drugs, radiation therapy, or other plant substances on melanoma cell lines and animal models. Finally, we present some examples of drug delivery systems that increase the uptake of terpenoids by melanoma tissue.

Abstract

Melanoma is responsible for the highest number of skin cancer-caused deaths worldwide. Despite the numerous melanoma-treating options, the fight against it remains challenging, mainly due to its great heterogeneity and plasticity, as well as the high toxicity of standard drugs. Plant-derived terpenoids are a group of plant defense molecules that have been proven effective in killing many different types of cancer cells, both in in vitro experiments and in vivo models. In this review, we focus on recent results in the search for plant terpenoids with anti-melanoma activity. We also report on the synergistic action of combining terpenoids with other plant-derived substances, MAP kinase inhibitors, or radiation. Additionally, we present examples of terpenoid-loaded nanoparticle carriers as anti-melanoma agents that have increased permeation through the cancer tissue.

Flavone constituents of Phlomis bruguieri Desf. with cytotoxic activity against MCF-7 breast cancer cells

Phlomis bruguieri (P. bruguieri) is a large genus in the Lamiaceae family, with a wide variety distributed in Euro-Asia, Central Asia, Iran, and China. Phlomis flowers have been used as herbal tea for gastrointestinal disturbances, protection of liver and cardiovascular systems. The aim of this study was to analyse phytochemical of flavonoid constituents in semi polar fraction of P. bruguieri. Methanol extract of plant material (4 kg) yielded 361 g dark green concentrated extract gum. After preliminary fractionation by normal column chromatography on silica gel, Fr. 2 eluted with chloroform: methanol (90:10) selected as semi polar fraction and was more purified using different chromatography columns on silica gel, polyamide SC6 and Sephadex LH-20 adsorbents. Finally one new and three known flavonoids (1-4) were characterized in semi polar fraction. Isolated structures were identified using 1H-NMR, 13C-NMR, 31P-NMR, HSQC, HMBC, negative ESI mass, and UV spectra using different shift reagents. Using standard MTT assay, cytotoxicity of isolated new compound was done against michigan cancer foundation-7 (MCF-7) breast cancer cells. Phytochemical analysis of P. bruguieri resulted in identification of one new 4'-methoxy-luteolin-7-phosphate and three known flavones including luteolin, apigenin, and tricin for the first time in this plant. In MTT cytotoxicity test, 4'-methoxy-luteolin-7-phosphate showed cytotoxicity with IC50 value of 43.65 ± 8.56 μM agasint MCF-7 breast cancer cells.

Isolation and Identification of Two Phenolic Compounds from a Moderately Cytotoxic Fraction of Cousinia verbascifolia Bunge

BACKGROUND

Little information is available about chemical components of the Cousinia genus. A primary cytotoxicity screening on Cousinia verbascifolia showed moderate cytotoxic activity against OVCAR-3 ovarian and HT-29 colon cancer cells. Therefore, the aim of this study is a phytochemical investigation to identify the compounds responsible for this bioactivity.

MATERIALS AND METHODS

Extraction was done through percolation and fractionations by reverse phase column chromatography and normal column chromatography. Using standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay Fr.b8 with moderate cytotoxicity was selected for identification of major components. Fr.b8 was subjected to polyamide column chromatography. More purification was done using a new modified recycle high-performance liquid chromatography (HPLC) with flow splitter.

RESULTS

Two known compounds: Apigenin (flavone) and caffeic acid (phenolic acid) were obtained from phenolic bioactive fraction for the first time from this plant.

CONCLUSIONS

Apigenin and caffeic acid with known antitumor and matrix metalloproteinase inhibitory effects seem to be the bioactive components responsible for moderate cytotoxicity of phenolic fraction. Recycle HPLC following with flow splitting is a new method useful for isolation of closely eluted compounds in HPLC chromatogram.

Ingenane Diterpenoids

Despite a more recent isolation and chemical characterization when compared to phorbol, along with its chemical instability, limited distribution in Nature, and scarce availability, ingenol is the only Euphorbia diterpenoid that has undergone successful pharmaceutical development, with ingenol 3-angelate (ingenol mebutate, Picato(®)) entering the pharmaceutical market in 2012 for the treatment of actinic keratosis. The phytochemical, chemical, and biological literature on members of the ingenane class of diterpenoids is reviewed from their first isolation in 1968 through 2015, highlighting unresolved issues both common to phorboids (biogenesis, relationship between molecular targets, and in vivo activity) and specific to ingenol derivatives (two-dimensional representation, in-out stereoisomerism, versatility of binding mode to PKC, and inconsistencies in the structural elucidation of some classes of derivatives). The biogenesis of ingenol is discussed in the light of the Jakupovic proposal of a dissection between the formation of the macrocyclic Euphorbia diterpenoids and the phorboids, and the clinical development of ingenol mebutate is chronicled in the light of its "reverse-pharmacology" focus.

Bioactivity-guided isolation of new antiproliferative compounds from Juniperus foetidissima Willd

Based on a literature survey on cytotoxic medicinal plants, Juniper species were identified as interesting source of antitumor compounds. Using bioassay-guided fractionation against Caov-4 cancer cells on acetone extract of leaves and branchlets of Juniperus foetidissima led to the isolation of a new 3H-benzofuaran-2-one: 4-methyl-3-methoxy-3H-benzofuaran-2-one (1), a new sesquiterpene: 4,9(α)-dihydroxy-nardosin-6-en (2) and an already known labdane-type diterpene: 15-hydroxy-8(17),13(E)-labdadiene-19-carboxilic acid (3). Compounds 1-3 exhibited cytotoxic effects, with moderate cytotoxicity against the EJ-138 bladder and CAOV-4 ovary cancer cell lines.