New alpha-pyrrolidinonoids and glycosides from Euphorbia humifusa

Antibacterial and antibiofilm efficacy of the preferred fractions and compounds from Euphorbia humifusa (herba euphorbiae humifusae) against Staphylococcus aureus

ETHNOPHARMACOLOGICAL RELEVANCE

Euphorbia humifusa Willd., known as Di-Jin-Cao in Chinese, has long been utilized as a traditional herb for the treatment of furuncles and carbuncles mainly caused by Staphylococcus aureus infection. Despite extensive chemical and pharmacological studies reported previously for E. humifusa, the antibacterial and antibiofilm activities against S. aureus as well as the related mechanism of action (MoA) remain largely obscure.

AIM OF THE STUDY

To investigate the antibacterial and antibiofilm activities of the preferred fractions and compounds from E. humifusa against S. aureus and assess the associated MoA.

MATERIALS AND METHODS

The bioactive fractions and compounds were obtained from the 75% ethanol extract of E. humifusa (75%-EEEH) with the assistance of the related antibacterial and antibiofilm screening. Their antibacterial activities were determined using the broth microdilution method, whilst the inhibition of biofilm formation and the disruption of preformed biofilm were assessed by crystal violet staining and confocal laser scanning microscopy (CLSM). To achieve more effective therapies, the combinatory effects of different components were also studied. The biofilm metabolic activities of isolated compounds were evaluated by 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assay. The scanning electron microscopy (SEM) and quantitative real-time polymerase chain reaction (qRT-PCR) were employed to explore the antibiofilm mechanism.

RESULTS

Fractions DJC06 and DJC07 collected from the ethyl acetate extract of the 75%-EEEH exhibited antibacterial activity (MIC = 256 μg/mL) against S. aureus and further separation of these two fractions led to the isolation and characterization of 22 compounds. Among the isolates, luteolin (LU), quercetin (QU), and kaempferol (KA) are the verified components associated with the antibacterial and antibiofilm activities by displaying individual or combinational MIC values of 8-128 μg/mL and 70.9-99.7% inhibition for biofilm formation. Importantly, QU and KA can work in synergy with LU to significantly enhance the efficacy via destroying cell integrity, increasing membrane permeability, and down-regulating the biofilm-related gene expression.

CONCLUSIONS

The preferred fractions and compounds from E. humifusa exerted desired antibacterial and antibiofilm efficacy against S. aureus via a MoA involving cell morphology disruption and altered genes expression. The findings herein not only support its traditional use in the treatment of furuncles and carbuncles, but reveal E. humifusa is a potential source for producing promising antibiofilm alternatives against S. aureus and highlight the isolated components (LU, QU, KA) that can potentiate the efficacy when used in synergy.

A new anti-vitiligo unsaturated fatty glycoside from Euphorbia humifusa Willd

A new unsaturated fatty glycoside Humionoactosides A, together with four known compounds were isolated from the whole plant of Euphorbia humifusa Willd. Their structures were identified by MS/MS, NMR and ECD spectroscopic analyses, and comparison with the literature data. All compounds were evaluated for the effect on melanogenesis and tyrosinase activity use B16 cells in vitro, and the results showed that compound 1 could significantly improve the formation of melanin (138.7%, 50 μM) and tyrosinase activity (137.2%, 50 μM) compared with the positive control 8-MOP (125.2%, 138.9%, 50 μM) in a dose-dependent manner. This is the first time that those compounds reported from Euphorbia humifusa Willd. with potential anti-vitiligo activity.

Tin powder-promoted allylation and cyclization of 2-(benzylideneamino)isoindoline-1,3-diones

α-Methylene-γ-lactams were synthesized from readily available N-acylhydrazones by a tin-mediated Barbier-type reaction. The method avoids the use of toxic allylstannanes and the reaction proceeds smoothly under mild conditions.

Growth inhibitory effect of paratocarpin E, a prenylated chalcone isolated from Euphorbia humifusa Wild., by induction of autophagy and apoptosis in human breast cancer cells

Five flavones, including four flavonoids and one prenylated chalcone (paratocarpin E), were isolated from E. humifusa. and their chemical structures were established by spectroscopic analyses. We assessed the efficacy of these compounds against the growth of human breast cancer, leukemic, kidney cancer cell lines. Among them, paratocarpin E showed significant cytotoxicity against these cancer cell lines with an IC₅₀ of 19.6μM on the growth of MCF-7 cells. Paratocarpin E treatment of MCF-7 cells resulted in typical apoptotic features via increasing expression of activated caspase-8 and -9 and PARP cleavage. Moreover, paratocarpin E altered the expression of Bax and Bcl-2, leading to the release of cytochrome c from the mitochondria into the cytosol, suggesting that the mitochondria-mediated apoptosis was initiated. In addition, paratocarpin E increased the MDC-positive autophagic vacuoles, the ratio of LC3-II/LC3-I protein levels of Beclin-1, but decreased p62 expression, indicating the potent pro-autophagic effects of paratocarpin E in MCF-7 cells. Mechanistically, cell death induced by paratocarpin E is able to induce apoptosis of MCF-7 cells by activating p38 and JNK signaling pathway while inhibiting Erk pathway. Furthermore, paratocarpin E promotes the activation and nuclear translocation of NF-κB, which plays an important role in balancing paratocarpin E-mediated apoptosis and autophagy. The molecular docking study also revealed that paratocarpin E bound to Fas and NF-κB complex. These findings provide initial evidences that paratocarpin E can be used as a potential anti-cancer drug in future for breast cancer therapy.

Euphorbia humifusa Willd exerts inhibition of breast cancer cell invasion and metastasis through inhibition of TNFα-induced MMP-9 expression

Background

Breast cancer is the most common type of malignancy in women worldwide. Euphorbia humifusa Willd (EuH) is a plant that is widely used as a traditional medicine. However, no systemic studies on the anti-cancer effects of EuH have been reported. The aim of this study is to evaluate the anti-metastatic effect of the EuH.

Methods

Ethyl acetate fraction was prepared from EuH methanol extracts (EA/EuH). Inhibitory effect of EA/EuH on cell migration was determined using an in vitro scratch-wound healing assay. The anti-invasive activity was determined by in vitro three-dimensional spheroid culture system and in vivo syngenic experimental lung metastasis experiment. Gene expression profiles were analyzed by using RT-PCR, real-time PCR, and luciferase reporter assay systems.

Results

Ethyl acetate fraction from the EuH extract (EA/EuH) inhibited the migration and invasive capabilities of highly metastatic MDA-MB-231 breast cancer cells and attenuated syngeneic lung metastasis of mouse 4 T1 breast cancer cells in vivo. Mechanistically, EA/EuH decreased tumor necrosis factor alpha (TNFα)-induced matrix metalloproteinase (MMP)-9 mRNA expression through the inhibition of NF-κB activity in MDA-MB-231 cells.

Conclusion

EuH may be beneficial in the prevention of invasion and metastasis of early stage breast cancer and can be served as an anti-metastatic agent or adjuvant therapy against metastatic breast cancer.

Anti-inflammatory components of Euphorbia humifusa Willd

Two new compounds, euphorbinoside (1) and dehydropicrorhiza acid methyl diester (2), along with 24 known compounds (3-26) were isolated from Euphorbia humifusa Willd. The effects of these compounds on soluble epoxide hydrolase (sEH) inhibitory activity were evaluated. Flavonoid compounds (10-21) exhibited high sEH inhibitory activity. Among them, compounds 12, 13, and 19 greatly inhibited sEH enzymatic activity, with IC50 values as low as 18.05±1.17, 18.64±1.83, and 17.23±0.84 μM, respectively. In addition, the effects of these compounds on lipopolysaccharide (LPS)-induced nitric oxide (NO) and tumor necrosis factor alpha (TNF-α) production by RAW 264.7 cells were investigated. Compounds 3-6, 8, 18, 20-23, and 25-26 inhibited the production of both NO and TNF-α, with IC50 values ranging from 11.1±0.9 to 45.3±1.6 μM and 14.4±0.5 to 44.5±1.2 μM, respectively.

Plant-derived juvenile hormone III analogues and other sesquiterpenes from the stem bark of Cananga latifolia

Juvenile hormone III (JH III) is a larval metamorphosis-regulating hormone present in most insect species. JH III was first isolated from the plant, Cyperus iria L., but the presence of JH III has not been reported in other plant species. In the present study, proof of the existence of JH III and its analogues from Cananga latifolia was established. From an aqueous MeOH extract of C. latifolia stem bark, six compounds were isolated along with nine known compounds. These were identified by using spectroscopic analyses as: (2E,6E,10R)-11-butoxy-10-hydroxy-3,7,11-trimethyldodeca-2,6-dienoic acid methyl ester, (2E,6E)-3,7,11-trimethyl-10-oxododeca-2,6-dienoic acid methyl ester, (2E)-3-methyl-5-[(1S,2R,6R)-1,2,6-trimethyl-3-oxocyclohexyl]-pent-2-enoic acid methyl ester, 1β-hydroxy-3-oxo-4β, 5α,7α-H-eudesmane 11-O-α-l-rhamnopyranoside, 4-epi-aubergenone 11-O-2',3'-di-O-acetyl-α-l-rhamnopyranoside and 4-epi-aubergenone 11-O-2',4'-di-O-acetyl-α-l-rhamnopyranoside. Three of the previously known compounds, (2E,6E,10R)-10-hydroxy-3,7,11-trimethyldodeca-2,6,11-trienoaic acid methyl ester, (2E,6E,10R)-10,11-dihydroxy-3,7,11-trimethyldodeca-2,6-dienoic acid and (2E,6S)-3-methyl-6-hydroxy-6-[(2R,5R)-5-(2-hydroxypropan-2-yl)-2-methyltetrahydrofuran-2-yl]-hex-2-enoaic acid methyl ester have now been found in a plant species. Ultra performance liquid chromatography-quadruple time-of-flight mass spectroscopy (UPLC-QTOF/MS) analysis of the chemical constituents of C. latifolia showed that several were predominant in the sub-fractions of a C. latifolia stem bark extract.

Vasorelaxant action of an ethylacetate fraction of Euphorbia humifusa involves NO-cGMP pathway and potassium channels

ETHNOPHARMACOLOGICAL RELEVANCE

Euphorbia humifusa Willd. (EH) is an important traditional Chinese medicine that has commonly been used for treating bacillary dysentery and enteritis in many Asian countries for thousands of years. EH has a wide variety of pharmacological actions such as antioxidant, hypotensive, and hypolipidemic effects. However, the mechanisms involved are to be defined.

AIM OF THE STUDY

The present study was performed to evaluate the cardiovascular effects of EH in rats.

MATERIALS AND METHODS

Methanol extract of EH (MEH) and ethylacetate fraction of the MEH (EEH) was examined for their vascular relaxant effects in phenylephrine-precontracted aortic rings. Effects of EEH on systolic blood pressure and heart rate were tested in Sprague-Dawley rats.

RESULTS

MEH and EEH induced vasorelaxation in a concentration-dependent manner. Endothelium-denudation abolished the EEH-induced vasorelaxation. Pretreatment of the endothelium-intact aortic rings with N(G)-nitro-L-arginine methylester (L-NAME) and 1H-[1,2,4]-oxadiazolo-[4,3-α]-quinoxalin-1-one (ODQ) significantly inhibited the EEH-induced vasorelaxation. EEH increased cGMP levels of the aortic rings in a concentration-dependent manner and the effect was blocked by L-NAME or ODQ. Extracellular Ca(2+) depletion and treatments with thapsigargin, Gd(3+), and 2-aminoethyl diphenylborinate significantly attenuated the EEH-induced vasorelaxation. Wortmannin markedly attenuated the EEH-induced vasorelaxation. In addition, tetraethylammonium, iberiotoxin, and charybdotoxin, but not apamin, attenuated the EEH-induced vasorelaxation. Glibenclamide, indomethacin, atropine, and propranolol had no effects on the EEH-induced vasorelaxation. Furthermore, EEH decreased systolic blood pressure and heart rate in a concentration-dependent manner in rats.

CONCLUSIONS

The present study demonstrates that EEH induces endothelium-dependent vasorelaxation via eNOS-NO-cGMP signaling through the modification of intracellular Ca(2+), Ca(2+) entry, and large- and intermediate-conductance KCa channel homeostasis. The data also suggest that the Akt-eNOS pathway is involved in the EEH-induced vasorelaxation. EEH induces hypotension and bradycardia in vivo.

New anti-HBV caryophyllane-type sesquiterpenoids from Euphorbia humifusa Willd

Activity-guided fractionation of Euphorbia humifusa for anti-HBV activity led to the isolation of two novel sesquiterpenoids, named humifusane A (1) and humifusane B (2). Their structures were elucidated by spectral data to show that they have a caryophyllane-type precursor structure. The two new sesquiterpenoids showed anti-HBV activities through specifically inhibiting the secretion of HBsAg in HepG2.2.15.

A New Alkaloid and Flavonoids from the Aerial Parts of Euphorbia guyoniana

One novel alkaloid, 1,5-diphenyl-3-styryl-2-pyrazoline 1, in addition with six known flavonoids namely, kaempferol, kaempferol 3-O-glucoside, kaempferol 3-rutinoside, quercetin, quercetin 3-O-glucoside, and rutin, were isolated from the aerial parts of Euphorbia guyoniana. Their structures were established on the basis of physical and spectroscopic analysis, and by comparison with the literature data.

The lecanindoles, nonsteroidal progestins from the terrestrial fungus Verticillium lecanii 6144

Four new indolosesquiterpenes, lecanindoles A-D (1-4), were isolated from fermentations of the terrestrial fungus Verticillium lecanii 6144. The structures of compounds 1-4 were elucidated from analysis of spectroscopic data. Compound 2 was reduced to give 4 and its isomer 5. Compound 4 was found to be a potent and selective progesterone receptor agonist with an EC50 of 1.1 +/- 0.4 nM in a cell-based luciferase reporter assay.