Croton Species Research Articles

Antiproliferative activity and constituents of leaf extracts of Croton sphaerogynus Baill. (Euphorbiaceae)

Several Croton species have been used in traditional medicine and contain substances active against cancer, such as diterpenoids and alkaloids. Croton sphaerogynus is a shrub from the Atlantic Rain Forest in southeastern Brazil. The main goal of this study was to characterize the main constituents of the leaf extracts of C. sphaerogynus and evaluate their in vitro antiproliferative activity against tumor cell lines. Hexane, dichloromethane and methanol extracts of leaves were analyzed by GC/MS and evaluated for their in vitro antiproliferative activity on the cell lines 786-0 (kidney), HT-29 (colon), K562 (leukemia), NCI-ADR/RES (drug resistant ovary), NCI-H460 (lung), MCF-7 (mammary), PC-3 (prostate), OVCAR-3 (ovary), U251 (glioma) and UACC-62 (melanoma). Relevant constituents in dichloromethane and hexane extracts were abietane, podocarpane and clerodane type furano diterpenes. Dicloromethane and hexane extracts exhibited activity against NCI-H460 (GI50 0.26μg/mL and 0.33μg/mL, respectively) and K562 (GI50 0.60μg/mL and <0.25μg/mL, respectively). Taking into account all cell lines tested, the dichloromethane extract was shown to have higher activity (mean log GI50 0.86) than hexane and methanol extracts (mean log GI50 1.26 and 1.49, respectively). The antiproliferative activity observed in the present work is probably accounted for by the abietane and/or podocarpane diterpenes.

Antiproliferative activity of methanol extracts of four species of Croton on different human cell lines

Several species of Croton have been described with biological activities, mainly due to diterpenes, alkaloids and/or other secondary metabolites. These activities account for the traditional use of Croton species to treat certain diseases in South America, Asia and Western Africa. The crude methanol extracts obtained from leaves and steam bark of Croton dichrous Müll. Arg., C. erythroxyloides Baill., C. myrianthus Müll. Arg. and C. splendidus Mart. ex Colla were tested for antiproliferative activity against ten human cancer cell lines. Chemical analyses of all extracts were carried out by GC/MS and HPLC/MS/MS. The leaf extract obtained from C. erythroxyloides showed potent activity against PC-3 (prostate) and OVCAR-3 (ovary) cell lines. Lupeol is suggested to be involved in such activity. Tiliroside, an acyl-glycosilated flavonoid ubiquitous in all tested extracts, seems to play an important role in the observed moderate activity of most extracts against the leukemia K562 cell lineage.

Foliar trichomes of &lt;i&gt;Croton&lt;/i&gt; L. (Euphorbiaceae: Crotonoideae) from China and its taxonomic implications

Foliar trichomes of 21 species of the genus Croton L. from China have been examined using stereomicroscopy and scanning electron microscopy. Five trichome types characterized by their morphology are identified, viz., stellate, lepidote, simple, dendritic and appressed-rosulate. Only stellate trichome is observed in most species, with only six species that are found to maintain two or three trichome types. Trichome types and density are useful for species identification and sectional classification for Chinese species. Based on the trichome types and other morphological characters, 21 Chinese species are proposed to be placed in five sections. Croton crassifolius belongs to sect. Andrichnia; C. cascarilloides belongs to sect. Monguia; C. mangelong, C. kongensis, C. laevigatus and C. laniflorus belong to sect. Argyrocroton; C. lauioides, C. howii and C. damayeshu belong to sect. Adenophylli. The remaining Chinese Croton species might be placed into sect. Croton. A key for Chinese Croton species based on trichome morphology is provided.DOI: http://dx.doi.org/10.3329/bjpt.v20i1.15468Bangladesh J. Plant Taxon. 20(1): 85-94, 2013 (June)

Further insecticidal activities of essential oils from Lippia sidoides and Croton species against Aedes aegypti L.

This study assessed new insecticidal activities of essential oils from Lippia sidoides and Croton species (Croton zehntneri, Croton nepetaefolius, Croton argyrophylloides, and Croton sonderianus) against Aedes aegypti mosquito. In addition, the acute toxicity upon mice was determined. All essential oils showed inhibition of egg hatching, with IC50 values ranging from 66.4 to 143.2μg mL(-1), larvicidal activity with LC50 ranging from 25.5 to 94.6μg mL(-1), and pupicidal action with PC50 ranging from 276.8 to over 500μg mL(-1). Only L. sidoides, C. zehntneri, and C. argyrophylloides essential oils were able to inhibit the oviposition of female gravid mosquitoes with OD50 values of 35.3, 45.3, and 45.8μg mL(-1), respectively. Oral acute toxicity in mice showed that C. sonderianus and C. argyrophylloides oils are nontoxic (LD50 > 6,000mg.kg(-1)) while C. nepetaefolius, C. zehntneri, and L. sidoides oils are moderately toxic (LD50 3,840; 3,464, and 2,624mg.kg(-1), respectively). The results indicate that these oils are promising sources of bioactive compounds, showing low or no toxicity to mammals.

Anti-Oxidative and Cholinesterase Inhibitory Effects of Leaf Extracts and Their Isolated Compounds from Two Closely Related Croton Species

A comparative evaluation of the antioxidant and acetylcholinesterase inhibitory activity of the leaf extracts of Croton gratissimus and Croton zambesicus (subgratissimus) and compounds isolated from the extracts was carried out to determine their potential and suitability or otherwise as a substitute for each other in the management of oxidative and neurodegenerative conditions. Different antioxidant assays (DPPH, FRAP, β-carotene-linoleic and the lipid peroxidation models) and the microplate assay for acetylcholinesterase (AChE) inhibition were carried out separately to study the activities of the crude leaf extracts and four solvent fractions from each of the two Croton species. Bioassay guided fractionation was used to target antioxidant constituents of the crude extracts and ethyl acetate fractions of 20% aqueous methanol extract of C. gratissimus on silica gel and Sephadex LH-20 columns resulted in the isolation of kaempferol-3-O-β-6’’(p-coumaroyl) glucopyranoside (tiliroside, 2), apigenin-6-C-glucoside (isovitexin, 3) and kampferol (4). The extract of C. zambesicus yielded quercetin-3-O-β-6’’(p-coumaroyl) glucopyranoside-3’-methyl ether (helichrysoside-3’-methyl ether, 1), kaempferol-3-O-β-6’’(p-coumaroyl) glucopyranoside (tiliroside, 2) and apigenin-6-C-glucoside (isovitexin, 3). Three of the isolated compounds and their different combinations were also included in the bioassays. In all the assays performed, the antioxidant capacity and AChE inhibitory effects of C. zambesicus extracts were weaker than those of C. gratissimus. This suggests that C. gratissimus may not be substituted by C. zambesicus, despite the similarity in some of their constituents. Generally, the combinations made from the isolated compounds showed better activities in most of the assays compared to the individual isolated compounds. This suggests mechanisms such as synergism and/or additive effects to be taking place. This study established low, moderate and high antioxidant activities as well as AChE inhibitory effects by the crude extracts, fractions, compounds and compound combinations. This means some of the extracts, isolated compounds and compound combinations could be useful in the management of neurodegenerative conditions and serve as sources of natural neurodegenerative agents.

Croton pascualii(Euphorbiaceae S.S.), a New ArborescentCrotonwith an Accrescent Calyx from the Pacific Slope of Oaxaca, Mexico

Abstract: A new arborescent species of Croton with accrescent pistillate calyx, Croton pascualii, is described and illustrated from the Pacific Slope of Oaxaca, Mexico. It has certain characteristics in common with Croton oerstedianus, a species included in the section Corylocroton. The proposed new species is characterized by its unisexual cymules, large and broadly ovate imbricate sepals of the pistillate flowers, and capsules ca 12 mm long. The foliage and resin of the new species have a pleasant, persistent aromatic fragrance suggestive of Quararibea or of celery (Apium graveolens). Croton pascualii is thus far known only from the Tropical Moist Semi-Evergreen Forest (selva mediana subperennifolia) of the Pacific Slope of Oaxaca, and has been collected in flower from June to September.

Essential Oil of Croton Argyrophylloides: Toxicological Aspects and Vasorelaxant Activity in Rats

Croton argyrophylloides Muell. Arg. is widely used in Brazilian folk medicine to treat diabetes and venereal diseases. This study examined the acute toxicity and cytotoxicity of the essential oil of C. argyrophylloides (EOCA). In addition, vascular effects of the EOCA have been examined. In mice, an oral acute toxicity test revealed that EOCA could be considered as a non toxic essential oil since it showed a very high LD50 (9.84 +/- 0.01 g/kg). In the brine shrimp (Artemia salina) cytotoxic assay, the LC50 value of EOCA was 275 [165-534] microg/mL. EOCA (1-1000 microg/mL) relaxed isolated endothelium-intact aortic rings precontracted with phenylephrine with an IC50 value of 126.7 [89.8-163.7] microg/mL. In rat mesenteric bed preparations precontracted with phenylephrine, EOCA (1-300 microg/mL) also induced a reversible, vasodilator effect with an IC50 value of 46.0 [33.3-58.7] micro/mL. It is concluded that EOCA is a very interesting agent from the point of view of the possibility of therapeutic application. This is because, whilst showing a very small acute toxicity, EOCA also showed maximal efficacy as a vascular antispasmodic agent with a pharmacological potency similar to that of other Croton species essential oils.

The development of Crofelemer: Connecting ethnobotany, conservation, biocultural diversity, global public health and indigenous knowledge

Crofelemer is a novel first in class compound extracted, isolated and purified from the stem bark latex of the widespread pioneer tree species Croton lechleri, (Sangre de Drago). The natural distribution of this species includes the Northwest Amazon regions of Colombia, Ecuador, Peru, Bolivia and adjacent regions of the Brazil. The latex of this species has been utilized by numerous indigenous peoples of the western Amazon basin orally for the treatment of diarrhea, topically for wound healing and many other therapeutic applications. Crofelemer is an acid-labile oligomeric proanthocyanidin. The primary monomers include (+)-gallocatechin; (-)-epigallocatechin; (+)-catechin and (-)-epicatechin. The oligomer predominantly contains 7–11 linked monomers in varying ratios and an average molecular weight ranges from 1800 to 2200 Da. A new drug application (NDA) for crofelemer for the treatment of HIV/AIDS related chronic diarrhea was submitted on December 5, 2011 to the US FDA and was granted a 6 month priority review designation. Crofelemer's antidiarrheal activity is mediated primarily through its action on two chloride channels. Specifically the compound reduces fluid loss and Cl- secretion through inhibition of both the cystic fibrosis transmembrane conductance regulator (CFTR) and calcium activated Cl- channels (CaCC) in the intestinal epithelium. The drug has minimal systemic absorption and has demonstrated an excellent safety profile in global clinical trials with >2,000 patients dosed across multiple trials conducted in numerous countries. Most recently crofelemer demonstrated excellent efficacy and safety in a pivotal Phase 3 trial in HIV patients (ADVENT) in reducing secretory diarrhea with a p-value of 0.0096. Clinical trials have also been conducted at the International Center for Diarrheal Disease Research (ICDDR) in Dhaka, Bangladesh, demonstrating significant reduction in fluid loss in patients with cholera-induced diarrhea, a life-threatening condition that most recently killed 7,000 people Haiti. One goal of Napo is to make certain that crofelemer can be made available to help save lives in cholera outbreaks wherever they may occur in the world.

Validation of the names Croton lenheirensis and Croton pradensis (Euphorbiaceae)

Medeiros D., L. Senna-Valle, and R. J. V. Alves (Universidade Federal do Rio de Janeiro, Museu Nacional, Department of Botany, Quinta da Boa Vista s.n., Bairro Imperial de São Cristóvão, Rio de Janeiro, 20.940-040, Brazil). Validation of the names Croton lenheirensis and Croton pradensis (Euphorbiaceae). J. Torrey Bot. Soc. 139: 345–346. 2012.— The species Croton lenheirensis D. Medeiros, Senna-Valle & Alves and Croton pradensis D. Medeiros, Senna-Valle & Alves from Brazil were published invalidly in 2009, not specifically designating in which herbarium the respective holotypes were deposited. This oversight is corrected with the validation of the specific names; the holotypes are deposited in R.

Effectiveness of Croton cajucara Benth on corrosion inhibition of carbon steel in saline medium

AbstractApplication of corrosion inhibitors is one of the most common practices for the protection of steel structures and their alloys in industry. Since metallic corrosion is a major cause of economic losses in the oil industry, the use of natural inhibitors is an alternative for sustainable technological development. In the present study the effectiveness of the hydroalcoholic extract of the plant species Croton cajucara Benth (CC) dissolved in a microemulsion system (MES‐CC) as well as in dimethyl sulfoxide (DMSO‐CC) was evaluated as corrosion inhibitor on carbon steel AISI 1020 in saline medium. Surface tension measurements of the MES‐CC confirmed micelle formation, and rheological data showed that viscosity varies with temperature. According to potentiodynamic technique and Tafel extrapolation, maximum inhibition efficiencies were effective (93.84% for MES‐CC and 64.73% for DMSO‐CC) with predominant control of cathodic reaction. The adsorption of MES‐CC on carbon steel surface obeys Langmuir adsorption isotherm, while DMSO‐CC was found to follow the Frumkin isotherm.

Foliar cuticular n-alkane of some Croton species from Brazilian semiarid vegetation

Foliar cuticular n-alkane of some Croton species from Brazilian semiarid vegetation

Forest succession and distance from preserved patches in the Brazilian semiarid region

Preserved vegetation fragments can serve as islands or germplasm banks that aid in the recuperation of anthropogenically degraded areas. The present study evaluated the effects of the distance to a preserved forest fragment on the recuperation of an abandoned agricultural field that had been naturally regenerating for 15years in Caruaru, PE, Brazil. Seven 240m transects were laid out perpendicular to the border between the abandoned field and preserved forest fragment, and each transect was divided into twelve 5×20m contiguous plots, thus forming 12 bands at progressive distances from the preserved site. The height and diameter of all live individuals within each plot with a stem diameter ⩾3cm at ground level were recorded. At the community level, the number of individuals, their average heights and their maximum diameters did not demonstrate any statistically significant relationship with increasing distance from the preserved vegetation fragment. Only a few species demonstrated any relationship between the distance to the preserved fragment and density, basal area or ecological importance. The anthropogenically altered area had higher numbers of individuals of autochoric species than the numbers of anemochorous and zoochoric species. The relatively long period of abandonment of the area apparently masked part of the role of the preserved forest fragment in restoring the altered area through dispersal because some species could have sprouted from cut stems, while others could have germinated directly from the soil seed bank. The species Croton blanchetianus and Cordia trichotoma were identified as principal colonizers in the initial phases of succession.

New 3,4-Seco-ent-kaurene Dimers from Croton micans

From the stems of Croton micans Sw., five new 3,4-seco-ent-kaurene dimers: micansinoic acid (1), isomicansinoic acid (2), and the dimethyl (3), monomethyl (4) and monoethyl ester (5) of micansinoic acid were isolated. The structures of the new compounds were elucidated by spectroscopic data interpretation, mainly 1D and 2D NMR experiments and MS. These compounds are the first 3,4-seco-ent-kaurene dimers from a Croton species.

Two New 3,4‐Seco‐ent‐kaurenes and Other Constituents from the Costa Rican Endemic Species Croton megistocarpus

AbstractFollowing our phytochemical studies of Costa Rican plants, we report the isolation of two new 3,4‐seco‐ent‐kaurenes from the aerial parts of Croton megistocarpus (Euphorbiaceae). The structures of the two compounds were elucidated as 14‐[(2‐methylbutanoyl)oxy]‐3,4‐seco‐ent‐kaura‐4(19),16‐dien‐3‐oic acid (1) and 14‐{[(2Z)‐2‐methylbut‐2‐enoyl]oxy}‐3,4‐seco‐ent‐kaura‐4(19),16‐dien‐3‐oic acid (2). In addition, seven known diterpene clerodanes were also isolated and identified. The structures of the compounds were elucidated by spectroscopic methods, including HR‐MS, 1H‐NMR, 13C‐NMR, COSY, HMQC, HMBC, and NOESY experiments.

Variabilidade genética entre acessos do gênero Manihot por meio de marcadores moleculares ISSR

O objetivo deste trabalho foi avaliar a diversidade genética intra e interespecífica de acessos de Manihot por meio de marcadores ISSR. Foram analisadas cinco espécies e duas variedades de Manihot, além de duas espécies do gênero Croton, utilizadas como grupo externo, por meio de 20 oligonucleotídeos iniciadores (Olii) ISSR UBC. Para análise do índice de similaridade entre as espécies e os acessos foram utilizados os coeficientes de Jaccard e de 'simple matching'. Os 20 Olii testados foram altamente polimórficos para todas as espécies analisadas, e 89,7% dos locus foram polimórficos. Há maior similaridade genética entre espécies diferentes de Manihot, como M. dichotoma var. undulata e M. caerulescens, do que entre indivíduos da mesma espécie, como M. dichotoma e M. dichotoma var. undulata.

A revised infrageneric classification and molecular phylogeny of New World Croton (Euphorbiaceae)

AbstractCroton (Euphorbiaceae) is a large and diverse group of plants that is most species‐rich in the tropics. We update the infrageneric classification of the New World species of Croton with new evidence from phylogenetic analyses of DNA sequence data from all three genomes. The relationships of species that were previously placed in conflicting positions by nuclear and chloroplast data, such as C. cupreatus, C. poecilanthus, and C. setiger, are further resolved by adding the nuclear EMB2765 and mitochondrial rps3 genes to the molecular sampling. Analyses of rps3 reveal an accelerated rate of evolution within Croton subg. Geiseleria, the only one of the four subgenera that contains numerous herbaceous, annual species. We provide morphological descriptions, species lists, and a key to the 31 sections and 10 subsections recognized in the New World. New taxa that we describe include C. sects. Alabamenses, Argyranthemi, Cordiifolii, Corinthii, Cupreati, Luetzelburgiorum, Nubigeni, Olivacei, Pachypodi, Prisci, and C. subsects. Cubenses, Jamaicenses, and Sellowiorum. Additional transfers are made to the ranks of subgenus, section, and subsection. A total of 712 species of Croton are currently recognized for the New World, with 702 of them assigned here to section.

Acaricidal Activity against Tetranychus Urticae and Essential Oil Composition of Four Croton Species from Caatinga Biome in Northeastern Brazil

Volatile components of essential oils from the leaves and stems of Croton jacobinensis, C. rhamnifolius, C. muscicapa and C. micans, which are medicinal plants found in the Caatinga biome of northeastern Brazil, were analyzed using GC and GC/MS. The acaricidal activity of these oils against Tetranychus urticae was evaluated using the fumigation method. Oil yields from the Croton species ranged from 1.1 +/- 0.0 to 0.6 +/- 0.0%, w/w, for leaves and 0.7 +/- 0.0 to 0.1 +/- 0.0% for stems. Sesquiterpenoids were dominant in all oils, except the stem oil from C. rhamnifolius, which exhibited a high monoterpene content, and the leaf and stem oils from C. muscicapa, which were rich in phenylpropanoids. The major volatile components of the leaf and stem oils from C. jacobinensis were (Z)-alpha-atlantone (24.3 +/- 0.4%) and trans-isolongifolanone (22.8 +/- 0.5%), respectively. The most abundant constituents detected in C. rhamnifolius were alpha-cedrene epoxide (23.3 +/- 0.1%) and caryophyllene oxide (21.9 +/- 0.0%) in the leaf oil, and camphor (16.6 +/- 0.5%) and tricyclene (12.8 +/- 0.1%) in the stem oil. Foenicolin was the main compound identified in the leaf (50.6 +/- 0.2%) and stem (72.7 +/- 0.6%) oils of C. muscicapa, while alpha-bulnesene (32.9 +/- 0.2%) and guaiol (17.9 +/- 0.7%) were the principal components of C. micans oils. These oils exhibited a high degree of toxicity in the fumigation assay. The stem oils from C. jacobinensis and C. rhamnifolius exhibited high lethality rates, with LC50 values of 0.3 and 0.2 microL/L of air after 24 h, respectively. The results suggest the potential use of stem essential oil, especially from C. rhamnifolius and C. jacobinensis, for the integrated control of Tetranychus urticae.

Effects of the Ethanol Extracts of Leaves and Branches from Four Species of the Genus Croton on Tetranychus urticae Koch (Acari: Tetranychidae)

The two-spotted spider mite Tetranychus urticae is one of the principal agricultural pests, infesting important cultures such as cotton, grapes and tomatoes. In recent years, studies with the objective of using plant extracts as an alternative pest control are being intensified, showing to be a promising alternative and attracting the interest of a growing number of scientists. The present study aimed to evaluate the residual effect of 1% ethanol extracts of leaves and branches of four species of the genus Croton (C. rhamnifolius Kunth, C. sellowii Baill, C. jacobinensis Baillon, C. micans (Baill)) on the spider mite T. urticae. Leaf disks with the mites were immersed for five seconds in the extracts. It could be verified that the leaf extract of C. sellowii caused 69% mortality and the leaf extract of C. Jacobinensis was not toxic to the spider mite. From the experiments it was concluded that the fecundity of the mites was affected and that the extracts were repellent at a concentration of 1%.

Croton monanthogynusandCrotonopsis elliptica(Euphorbiaceae) in Ozark Rock Outcrop Communities: Abundance, Soil Depth, and Substrate Tolerance

Abstract The ecologically similar species Crotonopsis elliptica and Croton monanthogynus were described by Steyermark in his Flora of Missouri as inhabitants of acid rock outcrop communities (sandstone, granite, chert) in the Ozarks but not of limestone outcrops. However, field observations and transect data confirm that C. monanthogynus can be abundant in Ozark limestone outcrop communities, codominating with Isanthus brachiatus and Heliotropium tenellum in the 5 cm to 11 cm soil depth zone, while almost never occurring on sandstone outcrops. Greenhouse experiments revealed that C. elliptica was healthy on sandstone soil, but stunted and sickly on limestone outcrop soil, consistent with its absence from calcareous substrates. In contrast, C. monanthogynus was healthy on both soils, and had greater growth on limestone than on sandstone soil. Contrary to Steyermark's characterization, C. monanthogynus grows abundantly on limestone soils, but is rare or absent on Ozark sandstone outcrops, not because of sub...

Morphology, development and homologies of the perianth and floral nectaries in Croton and Astraea (Euphorbiaceae-Malpighiales)

New observations are presented on the ontogeny, vasculature and morphology of both staminate and pistillate flowers of Croton and Astraea. These data support earlier hypotheses that the filamentous structures in pistillate flowers represent reduced and transformed petals. Staminate flowers of both genera possess five free nectaries, which are vascularised by divergences of the sepal traces in Croton and unvascularised in Astraea. In pistillate flowers, there are five separate non-vascularised nectaries in Astraea, but in Croton there is a single nectariferous disk that is vascularised by divergences of the sepal traces. The nectaries are initiated late in floral development, but their location indicates that they could represent the outer stamen whorl transformed into secretory staminodes. Other glandular structures occur in pistillate flowers of most Croton species, resulting in flowers with two secretory organ whorls. In these cases, the inner whorl is formed by modified staminodes. Our observations support the recent segregation of Astraea species from the larger genus Croton. Despite strong similarities between the two genera, there are clear structural differences, including the presence of colleters in Astraea (absent in Croton), moniliform trichomes on petals (rather than simple trichomes in Croton), non-vascularised nectaries (vascularised in Croton) and reduced, non-secretory filamentous structures (well developed and secretory in Croton).