The molecular mechanism of action for the potent antitumor component extracted using supercritical fluid extraction from Croton crassifolius root

ETHNOPHARMACOLOGICAL RELEVANCE

The root of Croton crassifolius has been used as a traditional Chinese medicine (TCM), called Radix Croton Crassifolius, and commonly known as "Ji Gu Xiang" in Chinese. Its medicinal value has been recorded in several medical books or handbooks, such as "Sheng Cao Yao Xing Bei Yao", "Ben Cao Qiu Yuan" and "Zhong Hua Ben Cao". It has been traditional employed for treating sore throat, stomach-ache, rheumatism and cancer.

AIM OF THE STUDY

At present, there are limited studies on the evaluation of low-polarity extracts of roots in C. crassifolius. Consequently, the aim of this study was to evaluate the antitumor effect of the low-polarity extract of C. crassifolius root.

MATERIALS AND METHODS

Extracts were obtained by supercritical fluid extraction. The extracts were tested for antitumor effects in vitro on several cancer cell lines. A CCK-8 kit was used for further analysis of cell viability. A flow cytometer and propidium iodide staining were used to evaluate the cell cycle and apoptosis. Hoechst staining, JC-1 staining and the fluorescence probe DCFH-DA were used to evaluate apoptotic cells. Molecular mechanisms of action were analyzed by quantitative RT‒PCR and Western blotting. Immunohistochemistry was used for the evaluation of xenograft tumors in male BALB/c mice. Finally, molecular docking was employed to predict the bond between the desired bioactive compound and molecular targets.

RESULTS

Eleven diterpenoids were isolated from low-polarity C. crassifolius root extracts. Among the compounds, chettaphanin II showed the strongest activity (IC50 = 8.58 μM) against A549 cells. Evaluation of cell viability and the cell cycle showed that Chettaphanin II reduced A549 cell proliferation and induced G2/M-phase arrest. Chttaphanin II significantly induced apoptosis in A549 cells, which was related to the level of apoptosis-related proteins. The growth of tumor tissue was significantly inhibited by chettaphanin II in experiments performed on naked mice. The antitumor mechanism of chettaphanin II is that it can obstruct the mTOR/PI3K/Akt signaling pathway in A549 cells. Molecular docking established that chettaphanin II could bind to the active sites of Bcl-2 and Bax.

CONCLUSIONS

Taken together, the natural diterpenoid chettaphanin II was identified as the major antitumor active component, and its potential for developing anticancer therapies was demonstrated for the first time by antiproliferation evaluation in vitro and in vivo.

A new diterpenoid from the leaves and twigs of Croton lachnocarpus Benth

A new clerodane diterpenoid, crotolanin A (1), along with three known clerodane diterpenoids, crotoeurin B (2), teucvidin (3) and teucvin (4), was isolated from the ethanol extract of the leaves and twigs of Croton lachnocarpus Benth. Their structures were identified by extensive NMR spectroscopic and HRESIMS analyses. The dopaminergic neuroprotective activity of compounds 1-4 was tested by using transgenic Caenorhabditis elegans pathological model. Compound 2 alleviated dopaminergic neuron degeneration of worms induced by 6-hydroxydopamine (6-OHDA) that represented a potential therapy for Parkinson's disease (PD).

In vitro evaluation of cytotoxic potential of essential oil extracted from leaves of Croton heliotropiifolius Kunth in human tumor cells

Croton heliotropiifolius Kunth, popularly known as "velame," is a shrub that resides in northeastern Brazil. The essential oil of C. heliotropiifolius contains high concentrations of volatile compounds in the leaves and is widely used in folk medicine for many purposes as an antiseptic, analgesic, sedative, and anti-inflammatory agent. Due to the apparent limited amount of information, the aim of this study was to determine the cytotoxic potential of essential oil extracted from leaves of C. heliotropiifolius, utilizing different human cancer cell lines (HL-60, leukemia; HCT-116, colon; MDA-MB435, melanoma; SF295, glioblastoma) and comparison to murine fibroblast L929 cell line. The chemical characterization of the essential oil revealed the presence of large amounts of monoterpenes and sesquiterpenes, the majority of which were aristolene (22.43%), germacrene D (11.38%), ɣ-terpinene (10.85%), and limonene (10.21%). The essential oil exerted significant cytotoxicity on all cancer cells, with low activity on murine L929 fibroblasts, independent of disruption of cell membranes evidenced by absence of hemolytic activity. The cytotoxicity identified was associated with oxidative stress, which culminated in mitochondrial respiration dysfunction and direct or indirect DNA damage (strand breaks and oxidative damage), triggering cell death via apoptosis. Our findings suggest that extracts of essential oil of C. Heliotropiifolius may be considered as agents to be used therapeutically in treatment of certain cancers.

Essential oil from leaves of Croton blanchetianus Baill does not present acute oral toxicity, has antigenotoxic action and reduces neurogenic and inflammatory nociception in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Croton blanchetianus Baill., popularly known as "marmeleiro preto", is an endemic plant from Brazil, being found mainly in the Northeast region. In traditional medicine, the use of medicines based on the leaves of this plant has been reported for the treatment of inflammatory processes, pain, urethral pain, gastrointestinal disorders, rheumatism and headache.

AIM OF THE STUDY

The present work describes the chemical characterization, as well as toxicological evaluation and antinociceptive activity of an essential oil of C. blanchetianus leaves (EOCb).

MATERIALS AND METHODS

The chemical constituents of the oil were identified by gas chromatography coupled to mass spectrometry (GC-MS). In vitro hemolytic activity was tested using mouse blood. Acute toxicity in mice was assessed by the oral or intraperitoneal administration of a single dose of 2000 mg/kg b.w. EOCb (1000 and 2000 mg/kg) was also evaluated for genotoxicity and antigenotoxicity in vivo using the micronucleus test. The antinociceptive activity of EOCb (25, 50 and 100 mg/kg) was evaluated through the abdominal writhing, formalin and tail flick tests.

RESULTS

The chemical characterization indicated as major components α-pinene (21.23%), β-phelandrene (13.92%), terpinolene (13.01%) and germacrene D (10.89%). EOCb did not cause hemolysis and was also neither toxic nor genotoxic, while protected the animals' bone marrow cells from damage caused by cyclophosphamide in oral treatment. However, all animals died after 15 min of intraperitoneal treatment. There was a reduction in the number of abdominal contortions (69.43-89.41%) as well as in licks in the first (38.77-84.47%) and second (59.75-90.74%) phases of the formalin test. In the latter case, the effects were reduced by naloxone and glibenclamide, indicating action via the opioid system and blockage of K+ channels. The latency time in the tail flick test also increased significantly.

CONCLUSION

In conclusion, ingestion of EOCb proved to be safe when administered orally; however, it was lethal intraperitoneally. Additionally, EOCb protected mouse blood cell DNA against the action of cyclophosphamide and showed an antinociceptive effect via the opioid system and dependent on K+ channels.

A New Clerodane from the Leaves of Croton krabas and Its Cholinesterase Inhibitory Activities

Chromatographic separation of the leaves of Croton krabas resulted in the isolation of one new clerodane, crotoeurin D (1), along with two known compounds, 6S-crotoeurin C (2) and blumenol A (3). Their structures were determined based on extensive nuclear magnetic resonance spectroscopic data analysis and mass spectrometry. The absolute configuration of the new clerodane was assigned by nuclear overhauser effect spectroscopy correlations and electronic circular dichroism calculations. Compound 1 exhibited significant acetylcholinesterase and butyrylcholinesterase inhibitory activities. Moreover, the binding modes of 1 revealed that its structure formed strong hydrogen bonds and hydrophobic interactions with the active sites of both enzymes.

Crotofoligandrin, a new endoperoxide crotofolane-type diterpenoid from the twigs of Croton oligandrus Pierre ex. Hutch (Euphorbiaceae)

Crotofoligandrin (1), a new endoperoxide crotofolane-type diterpenoid was isolated from the dichloromethane/methanol (1:1) extract of the twigs of Croton oligandrus Pierre Ex Hutch along with thirteen known secondary metabolites including 1-nonacosanol (2), lupenone (3), friedelin (4), β-sitosterol (5), taraxerol (6), (-)-hardwickiic acid (7), apigenin (8), acetyl aleuritolic acid (9), betulinic acid (10), fokihodgin C 3-acetate (11), D-mannitol (12), scopoletin (13) and quercetin (14). The structures of the isolated compounds were determined based on their spectroscopic data. The crude extract and the isolated compounds were assessed in vitro for their antioxidant, lipoxygenase, butyrylcholinesterase (BChE), urease and glucosidase inhibitory potentials. Compounds 1-3, and 10 displayed activities on all the performed bioassays. All the tested samples showed strong to significant antioxidant activity with compound 1 being the most potent (IC50 39.4 μM).

Deciphering the fluorescence quenching potential of Croton bonplandianum leaves and detection of bioactive molecules using liquid chromatography and mass spectrometry

In this study, liquid chromatography and mass spectrometry were used to screen the active phytochemicals and analyze antioxidant activity of Croton bonplandianum. In addition, cadmium telluride quantum dots were used to analyze the fluorescence quenching capabilities of Croton bonplandianum plants. UPLC-ESI-MS was used to screen polyphenols in the mass range of 100-2000, with both positive and negative ionizations. Based on molecular weight, 7-Spirostanoldihexoside isomer, Rutin, Quercetin hexoside, Kaempferol-3-O-(p-coumaroyl)-glucoside, Kaempferol, Quercetin, and (E) Catechin-(E) Gallocatechin were tentatively identified. In total, 63.34 mg of polyphenols and 20.36 mg of flavonoids were detected. Lipid peroxidation IC₅₀ values were 212, 38, 56, and 365 g/mL for DPPH, ABTS, and superoxide radicals. Reducing power of the plant material showed the maximum absorbance of 0.56 in 500 μg/mL concentration. Furthermore, the plant extract quenched cadmium telluride quantum dots fluorescence in a dose dependent manner. The results from quenching concluded that Croton bonplandianum with QDs might be used as a drug targeting and delivery nanomaterial.

Cytotoxic ent-abietane diterpenoids from the leaves of Croton lachnocarpus Benth

A phytochemical investigation on the 90% ethanol extract of the leaves of Croton lachnocarpus Benth. led to three new ent-abietane diterpenoids, 7β,15-dihydroxy-ent-abieta-8,11,13-trien-3-one (1), 2β,15-dihydroxy-ent-abieta-8,11,13-triene (2), and 7β,13α,15-trihydroxy-ent-abieta-8(14)-en-3-one (3). Structural elucidation of all the compounds were performed by spectral methods such as 1 D and 2 D (¹H-¹H COSY, HMQC, NOESY and HMBC) NMR spectroscopy, in addition to electronic circular dichroism (ECD) spectra. The isolated compounds were tested in vitro for cytotoxic activity against 6 tumor cell lines. As a result, compound 3 exhibited some cytotoxicities against all the tested tumor cell lines with IC₅₀ value less than 30 μM.

Chemistry and Bioactivity of Croton Essential Oils: Literature Survey and Croton hirtus from Vietnam

Using essential oils to control vectors, intermediate hosts, and disease-causing microorganisms is a promising approach. The genus Croton in the family Euphorbiaceae is a large genus, with many species containing large amounts of essential oils, however, essential oil studies are limited in terms of the number of Croton species investigated. In this work, the aerial parts of C. hirtus growing wild in Vietnam were collected and analyzed by gas chromatography/mass spectrometry (GC/MS). A total of 141 compounds were identified in C. hirtus essential oil, in which sesquiterpenoids dominated, comprising 95.4%, including the main components β-caryophyllene (32.8%), germacrene D (11.6%), β-elemene (9.1%), α-humulene (8.5%), and caryophyllene oxide (5.0%). The essential oil of C. hirtus showed very strong biological activities against the larvae of four mosquito species with 24 h LC₅₀ values in the range of 15.38-78.27 μg/mL, against Physella acuta adults with a 48 h LC₅₀ value of 10.09 μg/mL, and against ATCC microorganisms with MIC values in the range of 8-16 μg/mL. In order to provide a comparison with previous works, a literature survey on the chemical composition, mosquito larvicidal, molluscicidal, antiparasitic, and antimicrobial activities of essential oils of Croton species was conducted. Seventy-two references (seventy articles and one book) out of a total of two hundred and forty-four references related to the chemical composition and bioactivity of essential oils of Croton species were used for this paper. The essential oils of some Croton species were characterized by their phenylpropanoid compounds. The experimental results of this research and the survey of the literature showed that Croton essential oils have the potential to be used to control mosquito-borne and mollusk-borne diseases, as well as microbial infections. Research on unstudied Croton species is needed to search for species with high essential oil contents and excellent biological activities.

Crotofolane Diterpenoids and Other Constituents Isolated from Croton kilwae

Six new crotofolane diterpenoids (1-6) and 13 known compounds (7-19) were isolated from the MeOH-CH2Cl2 (1:1, v/v) extracts of the leaves and stem bark of Croton kilwae. The structures of the new compounds were elucidated by extensive analysis of spectroscopic and mass spectrometric data. The structure of crotokilwaepoxide A (1) was confirmed by single-crystal X-ray diffraction, allowing for the determination of its absolute configuration. The crude extracts and the isolated compounds were investigated for antiviral activity against respiratory syncytial virus (RSV) and human rhinovirus type-2 (HRV-2) in HEp-2 and HeLa cells, respectively, for antibacterial activity against the Gram-positive Bacillus subtilis and the Gram-negative Escherichia coli, and for antimalarial activity against the Plasmodium falciparum Dd2 strain. ent-3β,19-Dihydroxykaur-16-ene (7) and ayanin (16) displayed anti-RSV activities with IC50 values of 10.2 and 6.1 μM, respectively, while exhibiting only modest cytotoxic effects on HEp-2 cells that resulted in selectivity indices of 4.9 and 16.4. Compounds 2 and 5 exhibited modest anti-HRV-2 activity (IC50 of 44.6 μM for both compounds), while compound 16 inhibited HRV-2 with an IC50 value of 1.8 μM. Compounds 1-3 showed promising antiplasmodial activities (80-100% inhibition) at a 50 μM concentration.

Biscroyunoid A, an Anti-Hepatic Fibrotic 19-nor-Clerodane Diterpenoid Dimer with a C-16-C-12' Linkage from Croton yunnanensis

Biscroyunoid A (1), a 19-nor-clerodane diterpenoid dimer featuring a unique C-16-C-12' linkage and containing an unusual 4,7-dihydro-5H-spiro[benzofuran-6,1'-cyclohexane] motif, together with its biosynthetic precursor, croyunoid A (2), were isolated from Croton yunnanensis. Their structures were determined by spectroscopic, computational, and single-crystal X-ray diffraction methods. Compound 1 exerted an antihepatic fibrosis effect in LX-2 cells via inhibition of TGFβ-Smad2/3 signaling.

In Vitro Hypoglycemic Diterpenoids from the Roots of Croton yunnanensis

Fifteen compounds including nine new diterpenes were isolated from the roots of Croton yunnanensis. By HRESIMS, NMR, ECD data, and X-ray diffraction analysis, the new compounds were characterized as eight neo-clerodane diterpenes (compounds 1-8) and one 15,16-dinor-ent-pimarane diterpene (9). All diterpenes were assayed for their hypoglycemic activities. Compounds 1-4, 6, 7, and 10 promoted glucose uptake activity in insulin-resistant 3T3-L1 adipocytes. Compounds 1 and 6 showed insulin sensitizing activity, potentiating conspicuously their glucose uptake activity at a concentration of 20 μM when treated synergistically with low-concentration insulin at 1 nM.

Antimicrobial ent-abietane diterpenoids from the leaves of Croton cascarilloide

Three new ent-abietane diterpenoids, 6β-hydroxy-ent-abieta-7,13-dien-3-one (1), 2β,13α,15-trihydroxy-ent-abieta-8(14)-en-3-one (2), and 2β,9α,13β,15-tetrahydroxy-ent-abieta-7-en-3-one (3), were isolated from 90% ethanol extract of the leaves of Croton cascarilloide. Their structures were determined by spectral methods such as 1D and 2D (¹H-¹H COSY, HMQC, NOESY, and HMBC) NMR spectroscopy, in addition to electronic circular dichroism (ECD) spectra. The isolated diterpenoids were tested in vitro for antimicrobial activity against 6 pathogenic microorganisms. As a result, compounds 1-3 exhibited antimicrobial activity against the tested Gram positive bacteria with minimum inhibitory concentration values less than 50 μg/ml.

Mallotucin D, a Clerodane Diterpenoid from Croton crassifolius, Suppresses HepG2 Cell Growth via Inducing Autophagic Cell Death and Pyroptosis

Hepatocellular carcinoma (HCC) is a major subtype of primary liver cancer with a high mortality rate. Pyroptosis and autophagy are crucial processes in the pathophysiology of HCC. Searching for efficient drugs targeting pyroptosis and autophagy with lower toxicity is useful for HCC treatment. Mallotucin D (MLD), a clerodane diterpenoid from Croton crassifolius, has not been previously reported for its anticancer effects in HCC. This study aims to evaluate the inhibitory effects of MLD in HCC and explore the underlying mechanism. We found that the cell proliferation, DNA synthesis, and colony formation of HepG2 cells and the angiogenesis of HUVECs were all greatly inhibited by MLD. MLD caused mitochondrial damage and decreased the TOM20 expression and mitochondrial membrane potential, inducing ROS overproduction. Moreover, MLD promoted the cytochrome C from mitochondria into cytoplasm, leading to cleavage of caspase-9 and caspase-3 inducing GSDMD-related pyroptosis. In addition, we revealed that MLD activated mitophagy by inhibiting the PI3K/AKT/mTOR pathway. Using the ROS-scavenging reagent NAC, the activation effects of MLD on pyroptosis- and autophagy-related pathways were all inhibited. In the HepG2 xenograft model, MLD effectively inhibited tumor growth without detectable toxicities in normal tissue. In conclusion, MLD could be developed as a candidate drug for HCC treatment by inducing mitophagy and pyroptosis via promoting mitochondrial-related ROS production.

Krabasinolide A with anti-HIVs activity from the leaves and twigs of Croton krabas

One new clerodane-type diterpenoid, together with one known, was isolated from the leaves and twigs of C. krabas. The structures of these compounds were elucidated as krabasinolide A (1) and taraxerol (2) by spectroscopic methods (UV, IR, HRESIMS, 1 D, and 2 D NMR), and the relative stereochemistry was confirmed by X-ray diffraction analysis with graphite monochromated Mo-Kα (λ = 0.71073 Å) radiation at 296(2) K. Extracts and compounds 1-2 were evaluated for in vitro antiviral activity.

Tigliane Diterpenoids with Larvicidal, Antifungal, and α-Glucosidase Inhibitory Activities from Croton damayeshu

Thirty-five tigliane diterpenoids and two ent-kaurane diterpenoids were isolated from the leaves of Croton damayeshu, and, among them, compounds 1-10 were characterized as new tigliane diterpenoids. The structures of compounds 1-10 were determined by analysis of their HRESIMS, NMR, and ECD data and by chemical methods. The isolates were assayed for their larvicidal, antifungal, and α-glucosidase inhibitory activities, and compounds 8-10 were found to possess larvicidal activities against Plutella xylostella with LC₅₀ values of 0.19, 0.16, and 0.26 μM, respectively, comparable to the LC₅₀ of 0.14 μM for the positive control, flubendiamide.

Croton lechleri Extracts as Green Corrosion Inhibitors of Admiralty Brass in Hydrochloric Acid

Croton lechleri, commonly known as Dragon’s blood, is a tree cultivated in the northwest Amazon rainforest of Ecuador and Peru. This tree produces a deep red latex which is composed of different natural products such as phenolic compounds, alkaloids, and others. The chemical structures of these natural products found in C. lechleri latex are promising corrosion inhibitors of admiralty brass (AB), due to the number of heteroatoms and π structures. In this work, three different extracts of C. lechleri latex were obtained, characterized phytochemically, and employed as novel green corrosion inhibitors of AB. The corrosion inhibition efficiency (IE%) was determined in an aqueous 0.5 M HCl solution by potentiodynamic polarization (Tafel plots) and electrochemical impedance spectroscopy, measuring current density and charge transfer resistance, respectively. In addition, surface characterization of AB was performed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy techniques. Chloroform alkaloid-rich extracts resulted in IE% of 57% at 50 ppm, attributed to the formation of a layer of organic compounds on the AB surface that hindered the dezincification process. The formulation of corrosion inhibitors from C. lechleri latex allows for the valorization of non-edible natural sources and the diversification of the offer of green corrosion inhibitors for the chemical treatment of heat exchangers.

Sublyratins A-O, Labdane-Type Diterpenoids from Croton sublyratus

Fifteen new labdane-type diterpenoids, sublyratins A-O (1-15), along with four known analogues (16-19) were isolated from the aerial parts of Croton sublyratus. Their structural assignments were challenging due to the stereoisomeric features evident and were achieved by analyzing comprehensively the spectroscopic data and electronic circular dichroism spectra and using X-ray crystallographic analysis. Compounds 9 and 16-18 displayed cytotoxic activity against the HL-60 cell line with IC₅₀ values of 1.5-2.8 μM.

A review of biological activities and phytochemistry of six ethnomedicinally important South African Croton species

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Croton (Euphorbiaceae) encompasses 1300 species, which consist of a variety of trees and shrubs distributed across the world. About 26 species are harboured on the African continent. This genus plays an essential role in African folk medicine. Croton species are traditionally used for the treatment of many diverse conditions such as diabetes, malaria, sexually transmitted diseases, cancer, inflammation, fever, digestive problems and fungal infections.

AIM OF THE REVIEW

To provide a comprehensive overview of the ethnobotany, traditional uses, phytochemistry and biological activities of six selected southern Africa Croton species; C.gratissimus Burch., C. megalobotrys Müll.-Arg., C. menyhartii Gȕrke, C. pseudopulchellus Pax, C. steenkampianus Gerstner and C. sylvaticus Schltdl.).

MATERIALS AND METHODS

Various electronic databases, namely Google, Google Scholar, Scopus, ScienceDirect, Biomed Central and Pubmed, were used to search for information related to the traditional uses, chemistry and pharmacology of Croton species. Books were also consulted to collect all pertinent information.

RESULTS AND DISCUSSION

The ethnopharmacology, phytochemistry and biological activities of southern African Croton species are reviewed. The literature revealed that Croton species are trusted traditional medicines for the treatment of microbial infections and malaria. The non-volatile components of Croton species include flavonoids, terpenoids and alkaloids, while the volatile constituents comprise mainly of monoterpenes (α-phellandrene, α-pinene and 1,8-cineole) and sesquiterpenes (caryophyllene oxide). Most of the reported biological activities (anti-oxidant, antimicrobial, anticancer and antimalarial) were based on in vitro assays and were accredited to various extracts. However, both in vitro and in vivo studies, linking the reported activities to specific compounds, are still lacking.

CONCLUSIONS

Croton species are used in traditional medicine to treat a range of ailments, and various in vitro biological activities have been investigated, with some extracts exhibiting good activity that could be considered for further investigation. The in vitro activities obtained seem to justify the use of Croton species in traditional medicine. Data on in vivo studies are scarce and studies usually focused on a single collection. The need to establish a quality control protocols for the standardisation of these herbal drugs is also important.

Toxic effect of Croton rudolphianus leaf essential oil against Biomphalaria glabrata, Schistosoma mansoni cercariae and Artemia salina

This research investigated the effect of the Croton rudolphianus leaf essential oil (EO) on Biomphalaria glabrata embryos (at different development stages) and adults, Schistosoma mansoni cercariae, and Artemia salina (non-target organism). It was possible to identify 31 compounds in the C. rudolphianus EO through GC-MS analysis. The major compounds from this oil were (E)-caryophyllene (17.33%), an unknown compound (16.87%), bicyclogermacrene (7.1%), δ-cadinene (6.62%) and germacrene D (5.38%). After incubation for 24 h, the EO of C. rudolphianus induced the occurrence of non-viable embryos (dead and malformed), with an LC₅₀ value of 126.54, 133.51, 143.53 and 161.95 µg/mL and an LC₉₀ value of 202.61, 216.48, 232.98 and 271.16 µg/mL to blastula, gastrula, trochophore and veliger embryonic stages, respectively. The EO was more effective against B. glabrata adults (LC₅₀ and LC₉₀ = 47.89 and 78.86 µg/mL, respectively), and S. mansoni cercariae (LC₅₀ and LC₉₀ = 14.81 and 22.15 after 120 mins of exposure, respectively) than against B. glabrata embryos. Concerning the micronucleus assay, the mean frequency of apoptosis, binucleation and micronucleus were 45.33 ± 3.51, 19.33 ± 1.53 and 0.67 ± 0.58 per 1000 cells at 25 µg/mL, which is the highest concentration tested. The oil killed A. salina with LC₅₀ and LC₉₀ values (68.33 and 111.5 µg/mL, respectively) higher than those determined for adult snails and S. mansoni cercariae. In conclusion, C. rudolphianus EO had a toxic effect against B. glabrata adults and embryos, and S. mansoni cercariae. Furthermore, this oil showed to be cytotoxic to hemocytes of B. glabrata. Concerning the non-target organism assay, C. rudolphianus EO was less toxic to A. salina then to adult snails and S. mansoni cercariae. Due to this, the EO from C. rudolphianus leaves is a potential alternative for schistosomiasis control.

Chemical Constituents of the Essential Oil from Ecuadorian Endemic Species Croton ferrugineus and Its Antimicrobial, Antioxidant and α-Glucosidase Inhibitory Activity

Croton ferrugineus Kunth is an endemic species of Ecuador used in traditional medicine both for wound healing and as an antiseptic. In this study, fresh Croton ferrugineus leaves were collected and subjected to hydrodistillation for extraction of the essential oil. The chemical composition of the essential oil was determined by gas chromatography equipped with a flame ionization detector and gas chromatography coupled to a mass spectrometer using a non-polar and a polar chromatographic column. The antibacterial activity was assayed against three Gram-positive bacteria, one Gram-negative bacterium and one dermatophyte fungus. The radical scavenging properties of the essential oil was evaluated by means of DPPH and ABTS assays. The chemical analysis allowed us to identify thirty-five compounds representing more than 99.95% of the total composition. Aliphatic sesquiterpene hydrocarbon trans-caryophyllene was the main constituent with 20.47 ± 1.25%. Other main compounds were myrcene (11.47 ± 1.56%), β-phellandrene (10.55 ± 0.02%), germacrene D (7.60 ± 0.60%), and α-humulene (5.49 ± 0.38%). The essential oil from Croton ferrugineus presented moderate activity against Candida albicans (ATCC 10231) with an MIC of 1000 μg/mL, a scavenging capacity SC₅₀ of 901 ± 20 µg/mL with the ABTS method, and very strong antiglucosidase activity with an IC₅₀ of 146 ± 20 µg/mL.

Serum and colon metabolomics study reveals the anti-ulcerative colitis effect of Croton crassifolius Geisel

BACKGROUND

Croton crassifolius Geisel (CCG, also known as Ji-Gu-Xiang in Traditional Chinese Medicine), is traditionally prescribed for the therapy of rheumatic arthritis and gastrointestinal ulcer. However, the effect of CCG on ulcerative colitis (UC) has not been investigated.

PURPOSE

To explore the therapeutic potential and underlying mechanism of CCG extract against UC by colonic and serum metabolomics.

METHODS

In order to standardize the CCG extract, UPLC-QTOF-MS was used for quantitative and qualitative analysis of the representative terpenoids. C57BL/6J mice were divided into control, Dextran Sulfate Sodium (DSS), mesalazine (100 mg•kg^-1), CCG extract (150 and 600 mg•kg^-1) groups. The mice were provided 3% DSS dissolved in distilled water ad libitum for 7 days except control group. Weight change, disease activity index (DAI), colon lengths and expression of inflammatory mediators iNOS and COX-2 in colonic tissue were determined. Serum and colon metabolomics using UPLC-QTOF-MS technology coupled with multivariate data analysis were performed to reveal the underlying mechanism.

RESULTS

Thirty-five terpenoids in CCG were identified by fingerprint, in which ten representative terpenes were quantified. CCG could relieve the weight loss, the degree of bloody stool and ulcer of colon, as well as significantly lowering the expression level of iNOS and COX-2. Metabolomics analysis showed that 25 biomarkers were obviously interfered by CCG treatment and 16 of them were highly correlated with the efficacy of CCG. The analysis of metabolic pathway showed that the anti-UC effect of CCG was associated with the regulation on linoleic acid metabolism, sphingolipid metabolism, α-linolenic acid metabolism, and glycerophospholipids metabolism.

CONCLUSIONS

The oral administration of CCG significantly alleviated DSS-induced UC symptoms by reducing inflammation and rectifying the metabolic disorder. CCG may provide a new strategy for the management of UC.

Modulation of Cardiopulmonary Toxicity and Oxidative Stress by Phenolic-Rich Fraction of Croton zambiscus Leaves in Rat Exposed to Chronic Mixture of Environmental Toxicants

Chronic mixed toxicant exposure has been implicated in the aetiology of lung and heart failure through prolonged free radical generations. This study was carried out to assess the protective effect of naturally occurring phenolic components from Croton zambesicus (400 mg/kg C-ZAMB) leaves against cardiopulmonary toxicity induced by chronic mixed toxicant (0.5 mL EOMABRSL) in rats. Chronic cardiopulmonary injury via oral administration of 0.5 ml EOMABRSL for 98 days (non-withdrawal) and 70 days (withdrawal) caused unhealthy alteration in the levels of oxidative stress biomarkers [malondialdehyde (MDA), reduced glutathione (GSH), glutathione-S-transferase (GST), superoxide dismutase (SOD) and catalase]. Similarly, both withdrawal and non-withdrawal approaches of EOMABRSL-exposed animals exhibited increase in the activity of eco-51-nucleotidase (51ENT) with corresponding diminution in the activity of lactate dehydrogenase (LDH), i.e. the metabolic fuel for cardiopulmonary wellness. Ultimately, histology examination confirmed hyperplastic, bronchopneumonia and cloudy swelling of cardiovascular cells followed by the accumulation of cellular exudates and haemorrhage in the alveoli and bronchioles. The active antioxidants of 400 mg/kg C-ZAMB leaves were responsible for the biological protection of cardiopulmonary toxicity by modulating the activities of 51ENT and LDH. The oxidative stress was also reversed by 400 mg/kg phenolic C-ZAMB leaves in the heart and lungs. Hence, 400 mg/kg phenolic C-ZAMB leaves may be a natural therapy for the treatment of cardiovascular disorder associated with pulmonary dysfunction in rats.

Evaluation of Antioxidant and Enzyme Inhibition Properties of Croton hirtus L'Hér. Extracts Obtained with Different Solvents

Croton hirtus L'Hér methanol extract was studied by NMR and two different LC-DAD-MSn using electrospray (ESI) and atmospheric pressure chemical ionization (APCI) sources to obtain a quali-quantitative fingerprint. Forty different phytochemicals were identified, and twenty of them were quantified, whereas the main constituents were dihydro α ionol-O-[arabinosil(1-6) glucoside] (133 mg/g), dihydro β ionol-O-[arabinosil(1-6) glucoside] (80 mg/g), β-sitosterol (49 mg/g), and isorhamnetin-3-O-rutinoside (26 mg/g). C. hirtus was extracted with different solvents-namely, water, methanol, dichloromethane, and ethyl acetate-and the extracts were assayed using different in vitro tests. The methanolic extracts presented the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS), and ferric reducing antioxidant power (FRAP) values. All the tested extracts exhibited inhibitory effects on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), with a higher activity observed for dichloromethane (AChE: 5.03 and BChE: 16.41 mgGALAE/g), while the methanolic extract showed highest impact against tyrosinase (49.83 mgKAE/g). Taken together, these findings suggest C. hirtus as a novel source of bioactive phytochemicals with potential for commercial development.

Anti-inflammatory and histopathological studies of leaves extracts of Croton bonplandianus in Albino rats

Non-steroidal anti-inflammatory drugs (NSAIDs) are frequently used for the treatment and prevention of inflammation with the increase in number of side effects. Traditional plants have been used to treat inflammation owing to lesser adverse responses. Croton bonplandianus being an anti-inflammatory plant is extensively utilized all over the world. The methanolic and aqueous leaves extracts of Croton bonplandianus were exposed to anti-inflammatory activity in the carrageenan induced paw edema against standard diclofenac sodium, followed by the histopathlogical examination. The highest dose of methanolic extract were shown significant anti-inflammatory action having a significant P-value (P<0.05-0.001) compared with the diclofenac sodium (P<0.01-0.001) and aqueous extracts (P<0.5-0.01). The histopathological examination illustrated the vasodialation with reduction in the intensity of edema, neutrophils infiltration and other inflammatory cells. C. bonplandianus being a reactive oxygen species scavenger, responsible to exert an excellent anti-inflammatory activity. The present study confirmed the anti-inflammatory potential of drug extracts and authors recommended its utilization in the treatment of pain, inflammation and relevant diseases in future. However, phytochemical screening is to be required for the complete evaluation of active chemical constituent (s).

Croton urucurana Baillon stem bark ointment accelerates the closure of cutaneous wounds in knockout IL-10 mice

ETHNOPHARMACOLOGICAL RELEVANCE

Croton urucurana Baill. (Euphorbiaceae) is a plant used in Brazilian popular medicine for the treatment of wound healing, inflammatory diseases, gastritis, infections, and hemorrhoids.

AIM

The present study aimed to evaluate the in vivo wound healing activity of an ointment based on ethanolic extract of C. urucurana stem bark, at concentrations of 5% and 10%, and to relate it with compounds that could be associated with this activity.

MATERIALS AND METHODS

Analyses by FIA-ESI-IT-MSⁿ were carried out to investigate the chemical composition of C. urucurana. Knockout IL-10 (n = 60) mice and wild type C57 (n = 12) mice were separated into 6 groups to evaluate the wound healing activity. Knockout IL-10 mice: SAL (0.9% saline); BAS (ointment base); SS (1% silver sulfadiazine); CR1 (ointment with extract of C. urucurana 5%); CR2 (ointment with extract of C. urucurana 10%); and wild mice C57: SALC57 (Saline 0.9%). A circular wound with 10 mm in diameter was generated on the dorsal of the animals. Tissue specimen of the wounds were removed on days 7 and 14 of the treatment for histopathological, oxidative status and analyses of pro-and anti-inflammatory cytokines in scar tissue.

RESULTS

In the phytochemical profile, twelve proanthocyanidins were identified (in the form of monomers, dimers, trimers, and tetramers), based on (epi)catechin and (epi)gallocatechin. Furthermore, two quercetin derivatives and two alkaloids were detected. The groups treated with CR1 and CR2 ointments presented higher rate of wound closure, increased total number of cells, mast cells, blood vessels and higher deposition of type III and I collagen. In addition, they showed increased amount of pro-inflammatory cytokines (IL- 2 and IFN-γ), and anti-inflmatory cytokines (IL-4), on the 7th day of treatment.

CONCLUSION

The results presented support the popular use of preparations based on the bark of C. urucurana as a healing compound.

Croton tiglium essential oil compounds have anti-proliferative and pro-apoptotic effects in A549 lung cancer cell lines

As a traditional Chinese medicine, Croton tiglium has the characteristics of laxative, analgesic, antibacterial and swelling. This study aimed to analyze the chemical composition of C. tiglium essential oil (CTEO) extracted from the seeds of C. tiglium and its cytotoxicity and antitumor effect in vitro. Supercritical CO2 fluid extraction technology was used to extract CTEO and the chemical constituents of the essential oil were identified by comparing the retention indices and mass spectra data taken from the NIST library with those calculated based on the C7-C40 n-alkanes standard. In vitro cytotoxicity of the CTEO was assessed against cancer cell lines (A549) and the human normal bronchial epithelial cells (HBE) using the CCK-8 assay. Proliferation was detected by colony formation experiments. Wound scratch and cell invasion assays were used to detect cell migration and invasion. Levels of apoptotic markers, signaling molecules, and cell cycle regulators expression were characterized by Western blot analysis. As the results, twenty-eight compounds representing 92.39% of the total oil were identified in CTEO. The CTEO has significant antitumor activity on A549 cancer cells (IC50 48.38 μg/mL). In vitro antitumor experiments showed that CTEO treatment significantly inhibited the proliferation and migration of A549 cells, disrupted the cell cycle process, and reduced the expression levels of cyclin A, cyclin B and CDK1. CTEO can also reduce mitochondrial membrane potential, activate caspase-dependent apoptosis pathway, and finally induce apoptosis. CTEO may become an effective anti-cancer drug and will be further developed for cancer treatment.

Evaluation of the Biological Efficiency of Silver Nanoparticles Biosynthesized Using Croton tiglium L. Seeds Extract against Azoxymethane Induced Colon Cancer in Rats

BACKGROUND

Colorectal cancer (CRC) is considered as the most common type of gastrointestinal cancers. Chemotherapy became limited due to the adverse side effects. Therefore, the most effective Croton tiglium extract was selected to be incorporated by silver nanoparticles (Ag-NPs) then evaluated against colon cancer induced by azoxymethane (AOM) in rats.

METHODS

Different hematological and biochemical measurements were quantified in addition to markers of oxidative stress. Specific tumor and inflammatory markers were assayed. Colonic tissues were examined histopathologically in addition to immunohistochemistry (IHC). Native proteins and isoenzymes patterns were electrophoretically assayed beside expression of Tumor Protein P53 (TP53) and Adenomatous Polyposis Coli (APC) genes in colonic tissues.

RESULTS

It was found that AOM caused significant (P≤0.05) elevation in the hematological and biochemical measurements. C. tiglium nano-extract restored these measurements to normalcy. Tumor and inflammatory markers elevated significantly (P≤0.05) in sera of AOM induced colon cancer group in addition to increasing peroxidation products with decline in antioxidant enzymes activities in colon tissues. Nano-extract restored these measurements to normalcy in post-treated group. Histopathological study revealed that nano-extract minimized severity of inflammatory reactions in all nano-extract treated groups and prevented  anti-Keratin 20 antibody expression in post-treated group. The lowest similarity index (SI%) values were noticed with electrophoretic protein (SI=71.43%), lipid (SI=0.00%) and calcium (SI=75.00%) moieties of protein patterns, catalase (SI=85.71%), peroxidase (SI=85.71%), α-esterase (SI=50.00%) and β-esterase (SI=50.00%) isoenzymes in colon cancer group. Furthermore, AOM altered the relative quantities of total native bands. The nano-extract prevented the alterations that occurred qualitatively in nano-extract post-treated group and quantitatively in all nano-extract treated groups. Levels of TP53 and APC gene expression increased in AOM injected group and nano-extract restored their levels to normalcy in the post-treated group.

CONCLUSION

C. tiglium nano-extract exhibited ameliorative effect against the biochemical and molecular alterations induced by AOM in nano-extract post-treated group.

Phenolic Profile of Croton urucurana Baill. Leaves, Stems and Bark: Pairwise Influence of Drying Temperature and Extraction Solvent

Cerrado biome represents an area with great biodiversity. Some of its plants have significant ethnopharmacological uses, with specific purposes. Croton urucurana Baill., for instance, was previously acknowledged for its anti-hemorrhagic, anti-inflammatory, antiseptic, healing, and potentially antifungal and entomopathogenic actions. Nevertheless, the compounds supporting these empirical applications are still unknown. Accordingly, this work was designed to achieve a complete characterization of the phenolic profile of different botanical tissues obtained from C. urucurana, and also to verify how different operational conditions (different drying temperatures and extraction conditions) affect that profile. All samples were further characterized by HPLC-DAD-ESI/MSn, and results were compared by advanced chemometric tools. In general, the drying temperatures that maximize the extraction yield of specific individual phenolic compounds were established. Likewise, it was possible to verify that samples extracted with the hydroethanolic solution allowed higher phenolic yields, either in individual compounds (except (epi)catechin-di-O-gallate) or total phenolics. The identification of the best operational conditions and phenolic profiles associated with each C. urucurana botanical part contributes to enabling their use in food or pharmaceutical-related applications.

Diterpenoids with inhibitory activity of nitrite production from Croton floribundus

ETHNOPHARMACOLOGICAL RELEVANCE

Croton floribundus Spreng. (Euphorbiaceae), popularly known as Capixinguí, stands out due to its widespread use in traditional medicine to treat wounds, syphilis, hemorrhoids, eye diseases and as a purgative.

AIM OF THE STUDY

To characterize clerodanes diterpenes from C. floribundus and to evaluate the effects of the fraction and diterpenes (1-5) on inhibition of nitrite production.

MATERIALS AND METHODS

The hydroethanolic root extract of C. floribundus was fractionated on a solid phase extraction column to obtain the fraction named Fr80%. From this, five compounds were obtained and characterized. The absolute configuration of compound 1 was determined by a combination of electronic and vibrational circular dichroism spectroscopies. Additionally, compounds 1-5 were evaluated for their inhibitory effects on nitrite production induced by lipopolysaccharide (LPS) in RAW 264 macrophage cell.

RESULTS

Five clerodane diterpenoids were characterized, and the absolute stereochemistry of 1 was established as 3R,4R,5R,8R,9R,10S,12S. The IC₅₀ values obtained through inhibition of nitrite production were 28.52 ± 2.21 μM (1), 40.26 ± 2.79 μM (2), 25.47 ± 2.16 μM (3), 35.78 ± 2.93 μM (4) and 40.58 ± 4.78 μM (5). In the tested concentrations, the samples presented low toxicity in macrophages.

CONCLUSIONS

Four new diterpenes were characterized from C. floribundus, these being croflorins A-D (1-4) and a known halimane (5). These compounds exhibited inhibitory effect on nitrite production.

19-nor-, 20-nor-, and tetranor-Halimane-Type Furanoditerpenoids from Croton crassifolius

The phytochemical investigation of the roots of Croton crassifolius led to the isolation of 16 new halimane furanoditerpenoids, crohalifuranes A-P (1-16), along with 15 known analogues, 17-31. The new structures including their absolute configurations were elucidated by NMR and MS data analysis, comparison of experimental and calculated electronic circular dichroism data, single-crystal X-ray diffraction data, and chemical methods. Crohalifuranes A (1) and B (2) are tetranor- and 19-nor-halimane diterpenoids featuring a rare decahydroacenaphthene core, respectively, which might be derived from the accompanying crassifoliusin A by loss of the furan ring or the C-19 substituent. Crohalifurane C (3) represents the first example of a 20-nor-halimane diterpenoid, and crohalifurane D (4) is characterized by an unusual 6,20-δ-lactone moiety. All compounds were examined for their inhibitory effects on nitric oxide (NO) production induced by lipopolysaccharide in RAW264.7 cells, and 2 and 23 exhibited moderate inhibition on NO production with IC₅₀ values of 17.2 ± 1.3 and 23.7 ± 1.4 μM, respectively.

Discovery of a novel protein kinase C activator from Croton tiglium for inhibition of non-small cell lung cancer

BACKGROUND

The incidence of non-small cell lung cancer (NSCLC) accounts for approximately 85-90% of lung cancer, which has been shown to be challenging for treatment owing to poorly understanding of pathological mechanisms. Natural products serve as a source of almost all pharmaceutical preparations or offer guidance for those chemicals that have entered clinical trials, especially in NSCLC.

PURPOSE

We investigated the effect of B10G5, a natural products isolated from the Croton tiglium, in human non-small cell lung canceras as a protein kinase C (PKC) activator.

METHODS

The cell viability assay was evaluated by the MTT assay. The apoptosis and cell cycle distribution were assessed by flow cytometry. Reactive oxygen species (ROS) production was determined by using the fluorescent probe DCFDA. Cell migration ability of H1975 cells was analyzed by using the wound healing assay. The inhibiting effect of B10G5 against the phosphorylation level of the substrate by PKCs was assessed by using homogeneous time-resolved fluorescence (HTRF) technology. The correlation between PKCs and overall survival (OS) of Lung Adenocarcinoma (LUAD) patients was analysis by TCGA portal. The binding mode between B10G5 and the PKC isoforms was explored by molecular docking. Protein expression was detected by western blotting analysis.

RESULTS

B10G5 suppressed cell proliferation and colony formation, as well as migration ability of NSCLC cells, without significant toxic effect on normal lung cells. B10G5 induced the cell apoptosis through the development of PARP cleavage, which is evidenced by means of the production of mitochondrial ROS. In addition, the B10G5 inhibitory effect was also related to the cell cycle arrest at G2/M phase. Mechanistically, molecular modelling technology suggested that the potential target of B10G5 was associated with PKC family. In vitro PKC kinase assay indicated that B10G5 effectively activated the PKC activity. Western blotting data revealed that B10G5 upregulated PKC to activate PKC-mediated RAF/MEK/ERK pathway.

CONCLUSION

Our results showed that B10G5, a naturally occurring phorbol ester, considered to be a potential and a valuable therapeutic chemical in the treatment of NSCLC.

Does Croton Argyrophyllus Extract Has an Effect on Muscle Damage and Lipid Peroxidation in Rats Submitted to High Intensity Strength Exercise?

Many species of the genus Croton have been used for anti-inflammatory, antiproliferative, antidiabetic, and antitumor purposes. The objective was to evaluate the effect of a hydroethanolic extract (HEE) from the inner bark of Croton argyrophyllus (Euphorbiaceae) on muscle damage and oxidative stress in rats after high intensity exercise. The animals were divided into four groups: (i) the sedentary group (SV; n = 7), (ii) the exercise vehicle group (EV, n = 7), (iii) the sedentary group HEE (SHG; n = 7) composed of sedentary animals and treated with the hydroethanolic extract of C. argyrophyllus (200 mg/kg, v.o.), and (iv) the HEE exercise group (HEE; n = 7) composed of animals submitted to resistance exercise (RE) and treated with the hydroethanolic extract of C. argyrophyllus (200 mg/kg, v.o.). In the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) test, the HEE showed lower values of inhibition potential (IP%) at 39.79% compared to gallic acid, 87.61%, and lipoperoxidation inhibition at 27.4% (100 µg/mL) or 28.6% (200 µg/mL) (p < 0.001). There was inhibition in free radicals in vivo. The HEE of C. argyrophyllus partially reduced the biomarkers of oxidative stress in muscle tissue and muscular damage (creatine kinase (CK) and Lactate Dehydrogenase (LDH)) (p < 0.05) in rats, and in this sense it can be an aid to the recovery process after exhaustive efforts.

Phytotoxic and nematicide evaluation of Croton ehrenbergii (Euphorbiaceae)

BACKGROUND

Within its natural habitat, Croton ehrenbergii exhibits an innate defense mechanism that is not seen in other plants; it grows unharmed amidst predators and nature, while other species perish. In light of its capacity for defense, C. ehrenbergii was evaluated to better understand the scope of its phytotoxic and nematicide properties. To assess this, fractions obtained by bipartition of a hydro-alcoholic extract, and l-quebrachitol, the main constituent of C. ehrenbergii, were evaluated on Lactuca sativa (dicotyledon) and Lolium perenne (monocotyledon) seeds. Additionally, bipartition fractions and l-quebrachitol were evaluated on a population of Meloidogyne incognita for their nematicide activity.

RESULTS

From this phytochemical research, l-quebrachitol (1), phenylalanine (2), trans-4-hydroxy-N-methylproline (3) and the flavonoids: kaempferol (4), tiliroside (5), nicotiflorine (6) and rutin (7) were identified by spectroscopic analysis. Both methanol and hexane fractions from aerial parts of the plant inhibited the germination and elongation of roots and stems in L. sativa, but not in Lolium perenne, showing that these fractions mostly inhibit the dicotyledon species used in this research. l-Quebrachitol showed slightly higher seed germination inhibition for Lolium perenne in comparison with L. sativa. Three of the fractions evaluated showed nematicide activity against Meloidogyne incognita larvae (J2) at the 48 h benchmark, compared with carbofuran. l-Quebrachitol shows higher mortality after 48 h exposure at a lower concentration than carbofuran.

CONCLUSION

A variety of compounds were isolated from this research, some were common within the Croton genus (4-7), whereas others were not (1-3). This is the first phytochemical, phytotoxic and nematicide report on C. ehrenbergii. Methanol and hexane fractions from the aerial parts of C. ehrenbergii and l-quebrachitol could be used as alternative natural herbicides, predominantly against dicotyledon weed seeds. All fractions had a good mortality percentage against J2 Meloidogyne incognita larvae. © 2019 Society of Chemical Industry.

Supercritical CO2 fluid extraction of croton crassifolius Geisel root: Chemical composition and anti-proliferative, autophagic, apoptosis-inducing, and related molecular effects on A549 tumour cells

BACKGROUND

The use of plant essential oils as pharmaceuticals is a fast-growing market especially in China. Throughout the 20th century, a rapid increase took place in the use of many essential oil-derived products in the medicinal industry as nutraceuticals, medicinal supplements, and pharmaceuticals.

PURPOSE

The objective of this study was to explore the chemical composition of Croton crassifolius essential oil as well as its potential anti-tumour properties and related anti-proliferative, autophagic, and apoptosis-inducing effects.

METHODS

Supercritical CO₂ fluid extraction technology was used to extract CCEO and the chemical constituents of the essential oil were identified by comparing the retention indices and mass spectra data taken from the NIST library with those calculated based on the C7-C40 n-alkanes standard. The cytotoxic activity and anti-proliferative effects of CCEO were evaluated against five cancer cell lines and one normal human cell line via CCK-8 assays. In addition, flow cytometry was used to detect cell cycle arrest. The efficacy of CCEO treatments in controlling cancer cell proliferation was assessed by cell cycle analysis, clonal formation assays, RT-qPCR, and western blot analysis. Autophagic and apoptosis-inducing effects of oils and the associated molecular mechanisms were assessed by flow cytometry, cell staining, reactive oxygen species assays, RT-qPCR, and western blot analysis.

CONCLUSION

Forty compounds representing 92.90% of the total oil were identified in CCEO. The results showed that CCEO exerted a measurable selectivity for cancer cell lines, especially for A549 with the lowest IC₅₀ value of 25.00 ± 1.62 μg/mL. Assessment of the anti-proliferative effects of CCEO on A549 cells showed that the oil inhibited cell proliferation and colony formation in a dose- and time-dependent manner. Investigation of the molecular mechanisms of cell cycle regulation confirmed that the oil arrested A549 cells in G2/M phase by decreasing the expression of cyclin B1-CDK1 and cyclin A-CDK1 and increasing the expression of cyclin-dependent kinase inhibitor (CKI) P21 at both the transcriptional and translational levels. Autophagy staining assays and western blot analysis revealed that CCEO promoted the formation of autophagic vacuoles in A549 cells and increased the expression of autophagy-related proteins beclin-1 and LC3-II in a dose-dependent manner. A series of apoptosis analyses indicated that CCEO induces apoptosis through a mitochondria-mediated intrinsic pathway. This study revealed that CCEO is a promising candidate for development into an anti-tumour drug of the future.

Antioxidant and Hepatoprotective Effects of Croton hypoleucus Extract in an Induced-Necrosis Model in Rats

The aim of this study was to evaluate the antioxidant and hepatoprotective activity of Croton hypoleucus (EC). The present work reports the first pharmacological, toxicological, and antioxidant studies of EC extract on liver injury. Liver necrosis was induced by thioacetamide (TAA). Five groups were established: Croton Extract (EC), thioacetamide (TAA), Croton extract with thioacetamide (EC + TAA), vitamin E with thioacetamide (VE + TAA) and the positive control and vehicle (CT). For EC and EC + TAA, Wistar rats (n = 8) were intragastrically pre-administered for 4 days with EC (300 mg/kg.day) and on the last day, EC + TAA received a single dose of TAA (400 mg/kg). At 24 h after damage induction, animals were sacrificed. In vitro activity and gene expression of superoxide dismutase (SOD), catalase (Cat), and Nrf2 nuclear factor were measured. The results show that EC has medium antioxidant properties, with an IC₅₀ of 0.63 mg/mL and a ferric-reducing power of 279.8 µM/mg. Additionally, EC reduced hepatic damage markers at 24 h after TAA intoxication; also, it increased SOD and Cat gene expression against TAA by controlling antioxidant defense levels. Our findings demonstrated the hepatoprotective effect of EC by reducing hepatic damage markers and controlling antioxidant defense levels. Further studies are necessary to identify the mechanism of this protection.

Sesquiterpenoids from the roots of Croton crassifolius

Phytochemical investigation of Croton crassifolius roots afforded five sesquiterpenes (1-5), including two new sesquiterpenes 6S-hydroxy-cyperenoic acid (1) and crassifterpenoid A (5), together with three known compounds (2-4). The structures of the new compounds were determined by comprehensive spectroscopic methods, and their absolute configurations were determined by quantum chemical ECD calculation. Crassifterpenoid A (5) is the first germacrane-type sesquiterpene isolated from C. crassifolius, which enriched the diversity of chemical constituents in Croton crassifolius. In addition, the cytotoxicities of all compounds against human liver cancer lines HepG2 and Hep3B were determined, but none showed significant activity.

Cytotoxic Tigliane Diterpenoids from Croton damayeshu

Chemical investigation of an EtOH extract of the twigs and leaves of Croton damayeshu afforded 10 new tigliane diterpenoids, crodamoids A-J (1-10), along with five known compounds. Their structures were elucidated by physical data analysis. Compounds 8, 9, and 15 displayed cytotoxic effects against two human tumor cell lines, A549 and HL-60 (IC₅₀: 0.9-2.4 μM).

Antimicrobial activity of leaf extracts and isolated constituents of Croton linearis

ETHNOPHARMACOLOGICAL RELEVANCE

Leaves of Croton linearis, known as "rosemary", are widely used in folk medicine in Caribbean countries to treat fever and colds (associated to infections).

AIM OF THE STUDY

To evaluate the in vitro antimicrobial activity of extracts and fractions derived from C. linearis leaves.

MATERIALS AND METHODS

Bioassay-guided fractionation and isolation of compounds from an ethanolic extract of C. linearis, using flash chromatography and semi-preparative HPLC-DAD-MS (High Performance Liquid Chromatography - Diode Array Detection - Mass Spectrometry). Isolated compounds were characterized by MS, 1D- and 2D-NMR (Nuclear Magnetic Resonance) spectroscopy. The microdilution method with resazurin, as well as direct counting with an optical microscope, were used to determine the in vitro antimicrobial activity against bacteria, fungi and parasites. Moreover, the cytotoxicity on human fetal lung fibroblasts (MRC-5) was evaluated.

RESULTS

The total extract and chloroform fraction (ClF) showed high activity against protozoa with IC₅₀ values ranging from 1 to 26 μg/mL, but also cytotoxicity on MRC-5 and PMM (Peritoneal Murine Macrophages). Seven compounds were isolated and characterized for first time in this species: the alkaloids laudanidine, laudanosine, reticuline, corydine, glaucine and cularine and the flavonoid glycoside isorhamnetin-3-O-(6″O-p-trans-coumaroyl)-β-glucopyranoside. Reticuline showed a weak activity against L. infantum (IC₅₀ 148.0 ± 1.2 μM), while the flavonoid was active against T. cruzi (IC₅₀ 35.6 ± 2.3 μM).

CONCLUSIONS

The results show the antiprotozoal potential of the extract and some isolated constituents, which supports the use of this species in Caribbean folk medicine.

Laevifins A-G, clerodane diterpenoids from the Bark of Croton oblongus Burm.f

A phytochemical investigation of the stem barks of the Malaysian Croton oblongus Burm.f. (Syn. Croton laevifolius Blume) (Euphorbiaceae) yielded seven previously undescribed ent-neo-clerodane diterpenoids, laevifins A - G and the known crovatin (3). Structures were established by a combination of spectroscopic methods including HRESIMS, NMR spectroscopy and X-ray crystallography. The absolute configuration of crovatin and laevifins A-G was established by comparison of experimental ECD and theoretical TDDFT ECD calculated spectra. This is the first report on the occurrence of the sesquiterpenoid cryptomeridiol in a Croton species. In vitro cytotoxicity assays on laevifins A, B and G showed moderate activities against the MCF-7 cancer cell line (IC₅₀ 102, 115 and 106 μM, respectively) while β-amyrin and acetyl aleuritolic acid showed good anti-inflammatory activity on the LPS-induced NF-κB translocation inhibition in RAW 264.7 cells assay with IC₅₀ values of 23.5 and 35.4 μg/mL, respectively.

Antitumor Effect of the Essential Oil from the Leaves of Croton matourensis Aubl. (Euphorbiaceae)

Croton matourensis Aubl. (synonym Croton lanjouwensis Jabl.), popularly known as “orelha de burro”, “maravuvuia”, and/or “sangrad’água”, is a medicinal plant used in Brazilian folk medicine as a depurative and in the treatment of infections, fractures, and colds. In this work, we investigated the chemical composition and in vitro cytotoxic and in vivo antitumor effects of the essential oil (EO) from the leaves of C. matourensis collected from the Amazon rainforest. The EO was obtained by hydrodistillation using a Clevenger-type apparatus and characterized qualitatively and quantitatively by gas chromatography coupled to mass spectrometry (GC–MS) and gas chromatography with flame ionization detection (GC–FID), respectively. In vitro cytotoxicity of the EO was assessed in cancer cell lines (MCF-7, HCT116, HepG2, and HL-60) and the non-cancer cell line (MRC-5) using the Alamar blue assay. Furthermore, annexin V-FITC/PI staining and the cell cycle distribution were evaluated with EO-treated HepG2 cells by flow cytometry. In vivo efficacy of the EO (40 and 80 mg/kg/day) was demonstrated in C.B-17 severe combined immunodeficient (SCID) mice with HepG2 cell xenografts. The EO included β-caryophyllene, thunbergol, cembrene, p-cymene, and β-elemene as major constituents. The EO exhibited promising cytotoxicity and was able to cause phosphatidylserine externalization and DNA fragmentation without loss of the cell membrane integrity in HepG2 cells. In vivo tumor mass inhibition rates of the EO were 34.6% to 55.9%. Altogether, these data indicate the anticancer potential effect of C. matourensis.

Cytotoxic 8,9-seco-ent-kaurane diterpenoids from Croton kongensis

Chemical study on the ethanolic extract generated from the aerial parts of Croton kongensis led to the isolation of three new 8,9-seco-ent-kaurane diterpenoids, kongeniods A‒C (1‒3), together with seven known analogs (4-10). The structures of these compounds were assigned by spectroscopic data analysis. The vitro cytotoxic tests showed that compounds 1-3 exhibited strong activities against HL-60 cell lines with IC₅₀ values of 0.47, 0.58, and 1.27 μM, respectively.

Six new diterpenoids from Croton laevigatus

Six new ent-labdane-type diterpeniods (1‒6), along with one known compound, were identified from the twigs and leaves of Croton laevigatus. Their structures were elucidated on the basis of extensive spectroscopic interpretation. Compounds 2 and 7 showed inhibitory activity against protein tyrosine phosphatase 1B (PTP1B) with IC₅₀ values of 4.11 and 8.33 μg/ml, respectively.

Phorbol Rearrangements

An alternative procedure for isolation of 4β-phorbol from seeds of Croton tiglium has been developed, and an artifact containing a furan ring formed by rearrangement of 12,13,20- O-triacylated phorbol derivatives into (6b S,7 R,8 R,8a S)-2-(hydroxymethyl)-5,7,9,9-tetramethyl-3,7,8,9,9a,9b-hexahydrocyclopropa[3',4']benzo[1',2':3,4]cyclohepta[1,2- b]furan-6b,8,8a-triol (8a) has been characterized. A mechanism involving an oxidative rearrangement and a decarboxylation for formation of the artifact is proposed.

Assessment of acute, 14-day, and 13-week repeated oral dose toxicity of Tiglium seed extract in rats

BACKGROUND

Seed of mature Croton tiglium Linne, also known as Tiglium seed (TS), has been widely used as a natural product due to its several health beneficial properties including anti-tumor and antifungal activities. Despite its ethnomedicinal beneficial properties, toxicological information regarding TS extract, especially its long-term toxicity, is currently limited. Therefore, the objective of the present study was to evaluate acute and subchronic toxicity of TS extract in rats after oral administration following test guidelines of the Organization for Economic Cooperation and Development (OECD).

METHODS

Toxicological properties of TS extract were evaluated by toxicity assays to determine its single-dose acute toxicity (125, 250, 500, 1000, or 2000 mg/kg), 14-day repeated-dose toxicity (125, 250, 500, 1000, or 2000 mg/kg) and 13-week repeated-dose toxicity (31.25, 62.5, 125, 250, and 500 mg/kg) in Sprague-Dawley rats and F344 rats. Hematological, serum biochemical, and histopathological parameters were analyzed to determine its median lethal dose (LD50) and no-observed-adverse-effect-level (NOAEL).

RESULTS

Oral single dose up to 2000 mg/kg of TS extract resulted in no mortalities or abnormal clinical signs. In 13-week toxicity study, TS extract exhibited no dose-related changes (mortality, body weight, food/water consumption, hematology, clinical biochemistry, organ weight, or histopathology) at dose up to 500 mg/kg, the highest dosage level suggested based on 14-day repeat-dose oral toxicity study.

CONCLUSION

Acute oral LD50 of TS extract in rats was estimated to be greater than 2000 mg/kg. NOAEL of TS extract administered orally was determined to be 500 mg/kg/day in both male and female rats. Results from these acute and subchronic toxicity assessments of TS extract under Good Laboratory Practice regulations indicate that TS extract appears to be safe for human consumption.

Biologically Active Orbitides from the Euphorbiaceae Family

A comprehensive overview of natural orbitides isolated from Euphorbiaceae species and their most relevant biological activities are presented. Euphorbiaceae is a large and diverse family, which comprises about 300 genera, and is known as an important source of medicines and toxins. Several classes of secondary metabolites have been described for this taxon, however, orbitides have been broadly reported in Jatropha and Croton genera. Additionally, the latex is documented as the main source of orbitides in this family. Based on their structural and functional diversity, orbitides present a large variety of biological activities described as cytotoxicity, antimalarial, antibacterial, antifungal, enzymatic inhibition, and immunosuppressive, although the mechanism of action still needs to be further investigated. In recent years, the discovery of bioactive cyclic peptides from different sources has grown exponentially, making them promising molecules in the search for new drug leads. This review also highlights the attempts made by many researchers to organize the orbitides nomenclature and amino acid numbering, as well the important progress recently achieved in the biosynthetic study area.

Amelioration of CCl4 induced liver injury in swiss albino mice by antioxidant rich leaf extract of Croton bonplandianus Baill

The progress in industrialization has blessed mankind with a technologically superior lifestyle but poor management of industrial waste has in turn poisoned nature. One such chemical is carbon tetra chloride (CCl4), which is a potent environmental toxin emitted from chemical industries and its presence in the atmosphere is increasing at an alarming rate. Presence of CCl4 in human body is reported to cause liver damage through free radical mediated inflammatory processes. Kupffer cells present in the liver are potentially more sensitive to oxidative stress than hepatocytes. Kuffer cells produced tumor necrosis factor-α (TNF-α) in response to reactive oxygen species (ROS), that might further cause inflammation or apoptosis. In this study hepatoprotective capacity of antioxidant rich extract of Croton bonplandianus Baill. (CBL) was evaluated on CCl4 induced acute hepatotoxicity in murine model. Hydro-methanolic extract of C. bonplandianus leaf was used for evaluation of free radical scavenging activity. Liver cells of experimental mice were damaged using CCl4 and subsequently hepatoprotective potential of the plant extract was evaluated using series of in-vivo and in-vitro studies. In the hepatoprotective study, silymarin was used as a positive control. Antioxidant enzymes, pro-inflammatory markers, liver enzymatic and biochemical parameters were studied to evaluate hepatoprotective activity of Croton bonplandianus leaf extract. Free radical scavenging activity of CBL extract was also observed in WRL-68 cell line. The phytochemicals identified by GCMS analysis were scrutinized using in-silico molecular docking procedure. The results showed that CBL extract have potent free radical scavenging capacity. The biochemical parameters were over expressed due to CCl4 administration, which were significantly normalized by CBL extract treatment. This finding was also supported by histopathological evidences showing less hepatocellularnecrosis, inflammation and fibrosis in CBL and silymarin treated group, compared to CCl4 group. ROS generated due to H2O2 in WRL-68 cell line were normalize in the highest group (200 μg/ml) when compared with control and negative control (CCl4) group. After molecular docking analysis, it was observed that the compound α-amyrin present in the leaf extract of C. bonplandianus has better potentiality to protect hepatocellular damages than the standard drug Silymarin. The present study provided supportive evidence that CBL extract possesses potent hepatoprotective capacity by ameliorating haloalkane induced liver injury in the murine model. The antioxidant and anti-inflammatory activities also affirm the same. The synergistic effects of the phytochemicals present in CBL are to be credited for all the hepatoprotective activity claimed above.

Ent-Clerodane Diterpenes from the Bark of Croton oligandrus Pierre ex Hutch. and Assessment of Their Cytotoxicity against Human Cancer Cell Lines

New clerodane diterpenes, 12-epi-megalocarpodolide D (2) and an epimeric mixture of crotonolins A (3) and B (4), were isolated from the bark of Croton oligandrus following a bioassay-guided isolation protocol. Known compounds, megalocarpodolide D (1), 12-epi-crotocorylifuran (5), cluytyl-ferulate (6), hexacosanoyl- ferulate (7), vanillin (8), acetyl-aleuritolic acid (9) and lupeol (10), were also isolated. The structures of the isolated compounds (1–10) were elucidated by spectroscopic means. The cytotoxicity of compounds 1–10 was assessed against A549, MCF7, PC3 and PNT2 cell lines using the MTT assay. Compounds 1 and 2 showed moderate levels of activity against both A549 and MCF7 cells with 1 being the most active with IC₅₀ values of 63.8 ± 13.8 and 136.2 ± 22.7 µM against A549 and MCF7 cells, respectively. The epimeric mixture of 3 and 4 was moderately active against A549 and PC3 cells (IC₅₀ = 128.6 ± 31.0 and 111.2 ± 2.9 µM, respectively).

Volatile organic compounds and nitric oxide as responses of a Brazilian tropical species to ozone: the emission profile of young and mature leaves

The emission profile of volatile organic compounds (VOCs) and nitric oxide (NO) in young and mature leaves of Croton floribundus was assessed in plants exposed to filtered air (FA) and ozone-enriched filtered air (FA+O₃). After the period of exposure, leaves were enclosed in polyethylene terephthalate bags and VOCs were collected in young and mature leaves. Both young and mature leaves constitutively emitted the same VOC, but the concentrations were higher in young leaves. O₃ exposure induced the emission of sesquiterpenes (mainly β-caryophyllene) known as antioxidant compounds that may scavenge O₃. Young leaves were the highest emitters of sesquiterpenes. O₃ induced a rapid accumulation of NO in different tissues and leaf developmental stages; this accumulation was marked in palisade and spongy parenchyma cells in young and mature leaves, respectively. O₃ altered the levels of the signaling compound methyl salicylate (MeSA). Moreover, our data showed that NO together with VOC emissions, such as geranyl acetate, α-cadiene, trans-farnesol, cis-β-farnesene, and MeSA, participate of plant defense mechanisms against the oxidative damage caused by O₃.

Diterpenoids from Croton crassifolius include a novel skeleton possibly generated via an intramolecular [2+2]-photocycloaddition reaction

Five previously undescribed terpenoids (cracrosons D-H), including three clerodane diterpenoids, together with 16 known diterpenoids were isolated from Croton crassifolius (Euphorbiaceae). Cracroson D features a previously undescribed carbon skeleton with an unprecedented cyclobutane ring. Their structures, including their absolute configurations, were elucidated using spectroscopic and single-crystal X-ray diffraction analyses along with CD calculations. A plausible biogenetic pathway for cracroson D is also proposed, which was supported by the experimental results. Additionally, all of the compounds were evaluated in vitro for cytotoxicity against T24 and A549 cells using the CCK-8 method.