Ethnopharmacology, phytochemistry and pharmacology: a successful combination in the study of Croton cajucara

Diabetes-Related Mechanisms of Action Involved in the Therapeutic Effect of Croton Species: A Systematic Review

Over the years, ethnopharmacological and phytochemical investigations have been conducted to understand the potential effects of the Croton genus on several diseases. It has been revealed that these terpenoid-rich species traditionally used to treat gastrointestinal diseases, heal wounds, and relieve pain have a wide range of therapeutic effects; however, those used to treat diabetes, as well as their action mechanisms, have not been reviewed so far. Therefore, the main objective of this review was to compile all Croton species that have shown pharmacological effects against diabetes and describe their action mechanisms. Through a search of the literature, 17 species with hypoglycemic, antihyperglycemic, antilipidemic, antihypertensive, antioxidant, and anti-inflammatory effects were found. Among the mechanisms by which they exerted these effects were the inhibition of α-glucosidases, the promotion of insulin secretion, and the increase in glucose uptake. Interestingly, it was found that some of them may have antihyperglycemic properties, although there were no ethnopharmacological reports that support their traditional use. Moreover, others only presented studies on their hypoglycemic effect in fasting, so further works are encouraged to describe the mechanisms involved in lowering fasting blood glucose levels, such as hepatic glucose production, especially for C. cajucara, C. cuneatus, C. gratissimus var. gratissimus, C. guatemalensis, and C. membranaceus. It is expected that this review contributes to the plant science knowledge of the genus, and it can be used in future references on the identification and development of new molecules/phytomedicines that help in the treatment of diabetes.

Relevance of Indian traditional tisanes in the management of type 2 diabetes mellitus: a review

Background

Tisanes are a potential source of phytochemicals to reduce disease risk conditions and are used to protect from non-communicable diseases, globally. A few tisanes have gained more popularity than others depending on their chemical composition based on the geographical origin of the used herb. Several Indian tisanes have been claimed to have traits beneficial to people with or at a high risk of type 2 diabetes mellitus. Under the concept, the literature was reviewed and compiled into a document to highlight the chemical uniqueness of popular Indian traditional tisanes to be more informative and potent as per modern medicine to overcome type 2 diabetes mellitus.

Methods

An extensive literature survey was conducted using computerized database search engines, such as Google Scholar, PubMed, ScienceDirect, and EMBASE (Excerpta Medica database) for herbs that have been described for hyperglycemia, and involved reaction mechanism, in-vivo studies as well as clinical efficacies published since 2001 onwards using certain keywords. Compiled survey data used to make this review and all findings on Indian traditional antidiabetic tisanes are tabulated here.

Results

Tisanes render oxidative stress, counter the damage by overexposure of free radicals to the body, affect enzymatic activities, enhance insulin secretion, etc. The active molecules of tisanes also act as anti-allergic, antibacterial, anti-inflammatory, antioxidant, antithrombotic, antiviral, antimutagenicity, anti-carcinogenicity, antiaging effects, etc. WHO also has a strategy to capitalize on the use of herbals to keep populations healthy through effective and affordable alternative means with robust quality assurance and strict adherence to the product specification.

Automatic Identification of Players in the Flavonoid Biosynthesis with Application on the Biomedicinal Plant Croton tiglium

The flavonoid biosynthesis is a well-characterised model system for specialised metabolism and transcriptional regulation in plants. Flavonoids have numerous biological functions such as UV protection and pollinator attraction, but also biotechnological potential. Here, we present Knowledge-based Identification of Pathway Enzymes (KIPEs) as an automatic approach for the identification of players in the flavonoid biosynthesis. KIPEs combines comprehensive sequence similarity analyses with the inspection of functionally relevant amino acid residues and domains in subjected peptide sequences. Comprehensive sequence sets of flavonoid biosynthesis enzymes and knowledge about functionally relevant amino acids were collected. As a proof of concept, KIPEs was applied to investigate the flavonoid biosynthesis of the medicinal plant Croton tiglium on the basis of a transcriptome assembly. Enzyme candidates for all steps in the biosynthesis network were identified and matched to previous reports of corresponding metabolites in Croton species.

Anil Kumar N, Sharopov F, Ramírez-Alarcón K, Ruiz-Ortega A, Abdulmajid Ayatollahi S, Valere Tsouh Fokou P, Kobarfard F, Amiruddin Zakaria Z, Iriti M, Taheri Y, Martorell M, Sureda A, N. Setzer W, Durazzo A, Lucarini M, Santini A, Capasso R, Adrian Ostrander E, -ur-Rahman A, Iqbal Choudhary M, C. Cho W, Sharifi-Rad J. Antidiabetic Potential of Medicinal Plants and Their Active Components

Diabetes mellitus is one of the major health problems in the world, the incidence and associated mortality are increasing. Inadequate regulation of the blood sugar imposes serious consequences for health. Conventional antidiabetic drugs are effective, however, also with unavoidable side effects. On the other hand, medicinal plants may act as an alternative source of antidiabetic agents. Examples of medicinal plants with antidiabetic potential are described, with focuses on preclinical and clinical studies. The beneficial potential of each plant matrix is given by the combined and concerted action of their profile of biologically active compounds.

Acute oral toxicity and antioxidant studies of an amine-based diselenide

Background

Organochalcogen compounds have attracted the interest of a multitude of studies for their promising Pharmacological and biological activities. The antioxidant activity and acute toxicity of an organoselenium compound, 1-(2-(2-(2-(1-aminoethyl)phenyl)diselanyl)phenyl)ethanamine (APDP) was determined in mice.

Methods

Mice were randomly divided into four groups, with each group comprising of seven animals. Canola oil (1ml/kg of body weight) was administered to 1st group, while 2nd, 3rd & 4th groups were administered with 10 mg/kg, 30 mg/kg & 350 mg/kg of APDP respectively. APDP was administered by Intragastric gavage as a single oral dose.

Results

The APDP oral administration was found to be safe up to 350 mg/kg of body weight and no deaths of animals were recorded. The lethal dose 50 (LD₅₀) for APDP was determined at 72 h and was estimated to be > 350 mg/kg. After acute treatment, all mice were sacrificed by decapitation to determine the antioxidant enzymes and lipid peroxidation values for the treated mice liver. No fluctuation in lipid peroxidation, vitamin C and non protein thiol (NPSH) levels was observed due to the administration of APDP. hepatic α-ALA-D activity, catalase (CAT), superoxide dismutase (SOD) and the biochemical parameters were evaluated. Experimental observation demonstrated that APDP protected Fe(II) induced thiobarbituric acid reactive substances (TBARS) production in liver homogenate significantly (p < 0.05). The administration of APDP (an amine-based diselenide) both in vitro and in vivo clearly demonstrated that this potential compound has no acute toxicity towards mice among all the tested parameter.

Conclusion

On the basis of experimental results, it is concluded that APDP is a potential candidate as an antioxidant compound for studying pharmacological properties.

Clerodane Diterpenes from Croton Species: Distribution and a Compilation of their 13C NMR Spectral Data

The present work is a review of the literature of clerodane diterpenes from Croton species. It contains a compilation of 13C NMR data of 83 of these diterpenoids and their biological activities. This review covers a period from 1969 to October 2005 and 224 references are cited.

New Prenylated Dihydrostilbenes from Croton Laevifolius

Two prenylated dihydrostilbenes have been isolated from the methanol extract of the flower of Croton laevifolius. The structures of these compounds were assigned as 3,5,3′,4′-tetrahydroxy-2,6,2′-tris(3-methylbut-2-enyl)dihydrostilbene (laevifolin A) and 3,5,3′,4′-tetrahydroxy-2,6,5′-tris(3-methylbut-2-enyl)dihydrostilbene (laevifolin B) based on spectroscopic evidence, including UV, IR, 1D and 2D NMR, and mass spectra. The chemotaxonomic significance of the presence of these dihydrostilbene derivatives is briefly discussed.

Estrogenic terpenes and terpenoids: Pathways, functions and applications

Terpenes are made of the isoprene unit (C₅), and along with their derivatives, terpenoids, they are widely distributed in plants as active ingredients involved in anti-inflammation, anti-carcinogenesis and neuroprotection. Estrogenic terpenes and terpenoids are an important category of phytoestrogens and have been used as traditional medicines. The comprehensive list of estrogenic terpenes and terpenoids includes hemi-, mono-, sesqui-, di-, tri-, tetra- and polyterpenes, their derivatives, and meroterpenes, along with the signaling pathways and cellular functions on which their estrogenicity is exerted. Signaling pathways are further classified as bidirectional or unidirectional, the latter being further divided into two types depending upon the presence of both ligands, or the absence of one or both ligands. Although estrogenic activity of terpenes and terpenoids was evaluated by ligand-binding assays, yeast two-hybrid assays, reporter-gene assays, transcription assays, protein assays, cell assays and animal testing, the mechanism of estrogenic activity is still not fully understood. Applications of estrogenic terpenes and terpenoids are categorized into cancer treatment and prevention, cardioprotection, endocrine toxicity/reproductive dysfunction, food/supplement/traditional medicine, immunology/inflammation, menopausal syndromes and neuroprotection, where their benefits are discussed based on their availability, stability and variations.

Phytochemical analysis and anti-inflammatory evaluation of compounds from an aqueous extract of Croton cajucara Benth

Croton cajucara Benth. is a medicinal plant popularly used in the Brazilian Amazonia, where it is known as sacaca, being consumed as tea, decoction or infusion of the leaves and stem bark. From a decoction of the leaves, a comprehensive phytochemical analysis was developed by liquid chromatography-mass spectrometry. Many compounds were identified for the first time in C. cajucara, such as O-glycosides of kaempferol and quercetin, flavonoid-C-glycosides, tannins and cinnamic acid derivatives. These compounds were fractionated by polarity and assayed for their anti-inflammatory activity, using a model of mice edema, induced by an intraplantar injection of carrageenan. All fractions exhibited anti-inflammatory properties.

Adverse effects of Croton urucurana B. exposure during rat pregnancy

ETHNOPHARMACOLOGICAL RELEVANCE

Croton urucurana presents several beneficial pharmacological properties. In Brazil, women who intend to interrupt the pregnancy indiscriminately use extracts of this plant as an abortifacient agent.

AIM OF STUDY

To evaluated the effect of aqueous extract of Croton urucurana latex on the maternal-fetal repercussions in rats.

METHODS

Pregnant rats were randomly distributed into four experimental groups: Control=treated with water (vehicle); Treated 200=treated with a dose 200mg/kg; Treated 400=dose 400mg/kg and; and Treated 800=dose 800mg/kg. The rats were orally treated by gavage with Croton urucurana or vehicle (water) during whole pregnancy. At term of pregnancy, all rats were killed to obtain maternal blood and tissues samples and fetal weight and anomaly analyses.

RESULTS

C. urucurana treatment (Treated 400 and Treated 800) showed elevated liver enzymatic activities, reduced fetal body weight and placental efficiency. The Treated 800 group presented increased maternal total protein and cholesterol levels, and heart relative weight. All treated groups presented reduced maternal body weight and food intake, and increased pre-implantation loss rate compared to those of Control group. In addition, the treatment contributed to increased skeletal and visceral anomalies with higher doses.

CONCLUSION

Croton urucurana treatment caused maternal toxicity, which contributed for impairment embryo fetal development. These results showed that the indiscriminate use of plants during pregnancy should be avoided to prevent potential risk on maternal health as well as their offspring.

Clerodane diterpenes: sources, structures, and biological activities

Covering: 1990 to 2015The clerodane diterpenoids are a widespread class of secondary metabolites and have been found in several hundreds of plant species from various families and in organisms from other taxonomic groups. These substances have attracted interest in recent years due to their notable biological activities, particularly insect antifeedant properties. In addition, the major active clerodanes of Salvia divinorum can be used as novel opioid receptor probes, allowing greater insight into opioid receptor-mediated phenomena, as well as opening additional areas for chemical investigation. This article provides extensive coverage of naturally occurring clerodane diterpenes discovered from 1990 until 2015, and follows up on the 1992 review by Merritt and Ley in this same journal. The distribution, chemotaxonomic significance, chemical structures, and biological activities of clerodane diterpenes are summarized. In the cases where sufficient information is available, structure activity relationship (SAR) correlations and mode of action of active clerodanes have been presented.

Evaluation of the anti-diarrheal activity of the leaf extract of Croton macrostachyus Hocsht. ex Del. (Euphorbiaceae) in mice model

Background

Traditional healers in Ethiopia use a wide range of medicinal plants with antidiarrheal properties. Among these, Croton macrostachyus is one such plant claimed to have an antidiarrheal activity in Ethiopian folklore medicine. Previous studies showed that the crude extract is endowed with the claimed property. The present study was undertaken to further the claim by screening different fractions for the said activity so that it could serve as a basis for subsequent studies.

Methods

The fractions were obtained by successive extraction in soxhlet apparatus with solvents of different polarity (chloroform & methanol) followed by cold maceration of the deposit of the methanol fraction with distilled water. The antidiarrheal activity was evaluated using castor oil induced diarrheal model, charcoal meal test and anti-enteropooling test in mice. The test groups received various doses (300, 400, 500 mg/kg and an additional dose of 1000 mg/kg for the aqueous fraction) of the fractions, whereas positive controls received either Loperamide (3 mg/kg) or Atropine (5 mg/kg) and negative controls received vehicle (10 ml/kg).

Results

In the castor oil induced model, the chloroform (at all test doses) and methanol (at 400 & 500 mg/kg) fractions significantly delayed diarrheal onset, decreased stool frequency and weight of feces. The aqueous fraction was however devoid of significant effect at all the tested doses. Chloroform and methanol fractions produced a significant dose dependent decline in the weight and volume of intestinal contents while the aqueous fraction did not have a significant effect. All the fractions produced a significant anti-motility effect either at all doses (chloroform fraction) or at middle and higher doses (methanol and aqueous fractions).

Conclusion

The present study demonstrated that the chloroform and methanol fractions possessed significant anti-diarrheal activity. Nevertheless, the aqueous fraction showed only significant anti-motility effect at the higher dose (1000 mg/kg) employed in the study.

Croton grewioides Baill. (Euphorbiaceae) Shows Antidiarrheal Activity in Mice

Based on chemotaxonomy, we decided to investigate the possible antidiarrheal activity in mice of a crude ethanolic extract obtained from aerial parts of Croton grewioides (CG-EtOH). We tested for any possible toxicity in rat erythrocytes and acute toxicity in mice. Antidiarrheal activity was assessed by determining the effect of CG-EtOH on defecation frequency, liquid stool, intestinal motility and intestinal fluid accumulation. CG-EtOH showed no in vitro cytotoxicity and was not orally lethal. In contrast, the extract given intraperitoneally (at 2000 mg/kg) was lethal, but only in females. CG-EtOH produced a significant and equipotent antidiarrheal activity, both in defecation frequency (ED₅₀ = 106.0 ± 8.1 mg/kg) and liquid stools (ED₅₀ = 105.0 ± 9.2 mg/kg). However, CG-EtOH (125 mg/kg) decreased intestinal motility by only 22.7% ± 4.4%. Moreover, extract markedly inhibited the castor oil-induced intestinal contents (ED₅₀ = 34.6 ± 5.4 mg/kg). We thus conclude that CG-EtOH is not orally lethal and contains active principles with antidiarrheal activity, and this effect seems to involve mostly changes in intestinal secretion.

Antileishmanial activity and trypanothione reductase effects of terpenes from the Amazonian species Croton cajucara Benth (Euphorbiaceae)

BACKGROUND

Leishmaniasis comprises several infectious diseases caused by protozoa parasites of Leishmania genus. In recent years, there has been a growing interest in the therapeutic use of natural products to treat parasitic diseases. Among them Croton cajucara Benth. (Euphorbiaceae) is a plant found in the Amazonian region with a history of safe use in folk medicine.

PURPOSE

The purpose of this study was to investigate the effects of clerodane diterpenes, trans-dehydrocrotonin (DCTN), trans-crotonin (CTN) and acetylaleuritolic acid (AAA) obtained from powdered bark of C. cajucara against promastigotes, axenic and intracellular amastigotes of Leishmania amazonensis. Furthermore, the effects of DCTN and CTN on the trypanotiona reductase enzyme were also investigated. The extraction of the terpenes was carried out as previously reported (Maciel et al., 1998; 2003).

METHODS

The effect of the isolated compounds (DCTN, CTN and AAA) from the bark of C. cajucara was assessed in vitro against promastigotes, axenic amastigotes and intracellular amastigotes of L. amazonensis by counting of remaining parasites in a Neubauer chamber in comparison to pentamidine used as standard drug. The action of natural products on trypanothione reductase was assessed using soluble protein fraction of promastigotes. The assays were performed by incubation with HEPES, EDTA, NADPH and trypanothione disulfide to quantify the NAPH consumption by TryR.

RESULTS

The results showed very high efficacy, especially of the diterpene DCTN, against promastigotes (IC50 = 6.30 ± 0.06 µg/ml) and axenic amastigotes (IC50 = 19.98 ± 0.05 µg/ml) of L. amazonenesis. The cytotoxic effect of the best active natural product was evaluated on mouse peritoneal infected macrophages (IC50 = 0.47 ± 0.03 µg/ml in 24 h of culture), and the treatment revealed that DCTN never reaches toxic concentrations while reducing the infection and, most importantly, with no toxicity (>100 µg/ml with 0% of macrophage kill) when compared to pentamidine (37.5 µg/ml with 100% of macrophage kill). Furthermore, all of the natural products assayed on the trypanothione reductase enzyme inhibited the enzyme activity compared to the control.

CONCLUSION

Clerodane diterpenes from C. cajucara showed promising in vitro antileishmanial effects against L. amazonensis, specially the DCTN with no macrophage toxicity up to the assayed concentration. In addition, the action on trypanothione reductase enzyme revealed a possible mechanism of action.

Croton antisyphiliticus Mart. attenuates the inflammatory response to carrageenan-induced pleurisy in mice

The aim of this study was to investigate the anti-inflammatory effect of the crude hydroalcoholic extract (CHE) from the aerial parts of Croton antisyphiliticus, its fractions and isolated compounds derived from it on the mouse model of pleurisy induced by carrageenan. The aerial parts of C. antisyphiliticus were dried, macerated and extracted with ethanol to obtain the CHE, which was fractionated by liquid-liquid extraction using solvents with increasing polarity to obtain hexane (Hex), ethyl acetate (EA) and aqueous (Aq) fractions. Vitexin and quinic acid were isolated from Aq fraction. Capillary electrophoresis analysis, physical characteristics and spectral data produced by infrared (IR), nuclear magnetic resonance ((1)H and (13)C NMR) and mass spectrometry analyses were used to identify and elucidate the structure of the isolated compounds. The experimental model of pleurisy was induced in mice by a single intrapleural injection of carrageenan (1 %). Leukocytes, exudate concentrations, myeloperoxidase (MPO) and adenosine-deaminase (ADA) activities and nitrate/nitrite (NOx), tumor necrosis factor-α (TNF-α) and interleukin-17 (IL-17) levels were determined in the pleural fluid leakage at 4 h after pleurisy induction. Animals pre-treated with CHE, Hex, EA, Aq, vitexin and quinic acid exhibited decreases in leukocytes, exudate concentrations, MPO and ADA activities and NOx levels (p < 0.05). Also CHE, Hex, EA and vitexin but not quinic acid inhibited TNF-α and IL-17 levels (p < 0.05). C. antisyphiliticus caused anti-inflammatory effect by inhibiting the activated leukocytes, exudate concentrations, NOx, TNF-α, and IL-17 levels. The compounds vitexin and quinic acid may be responsible for this anti-inflammatory action.

Synadenium umbellatum Pax. promotes cell cycle arrest and induces apoptosis in K-562 leukemia cells

Chronic myeloid leukemia (CML) is a clonal myeloproliferative disease that shows apoptosis resistance. The introduction of imatinib mesylate has revolutionized the treatment of CML, but imatinib resistance may develop at any time and inevitably leads to disease progression. Synadenium umbellatum Pax. belongs to the Euphorbiaceae family and is popularly used in Brazil for the treatment of cancer. The cytotoxicity of Euphorbiaceae is associated with the ability of these plants and their bioactive compounds to induce apoptotic tumor cell death. Therefore, we aimed to investigate the cytotoxicity and the mechanisms of death induced by S. umbellatum extract in leukemic cells. S. umbellatum cytotoxicity was evaluated by trypan blue exclusion assay and flow cytometric analysis of the cell cycle; the mechanisms involved in K-562 cell death were investigated by light microscopy and flow cytometry. The results demonstrate that S. umbellatum is cytotoxic to leukemic cells in a concentration-dependent manner. Morphological analysis revealed that S. umbellatum treatment induced K-562 cell death by an apoptotic pathway. Furthermore, data indicate ROS overproduction, alterations in mitochondrial membrane potential, phosphatidylserine externalization and activation of caspase 9. Taken together, the results demonstrate that S. umbellatum extract arrested the cell cycle and triggered apoptosis at several levels in K-562 cells.

Treatment with aqueous extract from Croton cajucara Benth reduces hepatic oxidative stress in streptozotocin-diabetic rats

Croton cajucara Benth is a plant found in Amazonia, Brazil and the bark and leaf infusion of this plant have been popularly used to treat diabetes and hepatic disorders. The present study was designed to evaluate the oxidative stress as well as the therapeutic effect of Croton cajucara Benth (1.5 mL of the C. cajucara extract i.g.) in rats with streptozotocin-induced diabetes. Croton cajucara Benth was tested as an aqueous extract for its phytochemical composition, and its antioxidant activity in vitro was also evaluated. Lipid peroxidation and superoxide dismutase, catalase, and glutathione reductase activities were measured in the hepatic tissue, as well as the presence activation of p65 (NF-κB), through western blot. Phytochemical screening of Croton cajucara Benth detected the presence of flavonoids, coumarins and alkaloids. The extract exhibited a significant antioxidant activity in the DPPH-scavenging and the hypoxanthine/xanthine oxidase assays. Liver lipid peroxidation increased in diabetic animals followed by a reduction in the Croton-cajucara-Benth-treated group. There was activation of p65 nuclear expression in the diabetic animals, which was attenuated in the animals receiving the Croton cajucara Benth aqueous extract. The liver tissue in diabetic rats showed oxidative alterations related to the streptozotocin treatment. In conclusion the Croton cajucara Benth aqueus extract treatment effectively reduced the oxidative stress and contributed to tissue recovery.

Investigation of Ehrlich ascites tumor cell death mechanisms induced by Synadenium umbellatum Pax

ETHNOPHARMACOLOGICAL RELEVANCE

Synadenium umbellatum Pax. is widely found in South America and empirically used in Brazil for the treatment of several diseases, mainly cancer. The aim of the study was to investigate cell death mechanisms induced by Synadenium umbellatum Pax. using Ehrlich ascites tumor (EAT) cells, as well as the myelotoxicity potential of this plant.

MATERIALS AND METHODS

S. umbellatum cytotoxicity was evaluated in EAT cells by trypan blue exclusion and MTT reduction test and the mechanisms involved in EAT cell death were investigated by light and fluorescence microscopy, flow cytometry and immunocytochemistry. Investigation of S. umbellatum myelotoxicity was performed by clonogenic assay of colony forming unit- granulocyte macrophage (CFU-GM).

RESULTS AND CONCLUSION

Our results demonstrated that S. umbellatum decreased the viability of EAT cells using both methods. Morphological analyses revealed that S. umbellatum-treatment induced EAT cell death by apoptotic pathway. We demonstrated the occurrence of reactive oxygen species (ROS) overgeneration, increased intracellular Ca(2+) concentration, alteration in mitochondrial membrane potential, phosphatydylserine externalization, and activation of caspases 3, 8, and 9. However, S. umbellatum produced myelotoxicity in bone marrow cells in a concentration-dependent manner. In comparison to EAT cells, the effects of S. umbellatum in bone marrow cells were 8-fold lower. Taken together, our results showed that S. umbellatum induced apoptosis in EAT cells at several levels and seems more toxic to tumor cells than to normal bone marrow cells.

Hepatics alterations and genotoxic effects of Croton cajucara Benth (SACACA) in diabetic rats

CONTEXT

Croton cajucara Benth is a plant found in Amazonia, Brazil and the bark and leaf infusions of this plant have been popularly used to treat diabetes and hepatic disorders.

OBJECTIVES

This study investigated effects hepatics alterations and genotoxic and antidiabetic effect of Croton cajucara Benth bark extracts treatment in streptozotocin-induced diabetic rats.

METHODS

Male Wistar rats were divided into six groups: control rats; control rats treated with Croton cajucara Benth extract during 5 and 20 days; diabetic rats, and diabetic rats treated with Croton cajucara Benth during 5 and 20 days. Diabetes was induced by a single intraperitoneal injection of streptozotocin (70 mg/kg). Eight weeks later we measured glucose, triglyceride, cholesterol and hepatic transaminases on blood. The bone marrow micronucleus assay was used to assess the genotoxic activity of Croton cajucara Benth.

RESULTS

Treatment with aqueous extrat of Croton cajucara was able to significantly reduce levels of triglycerides in diabetic animals, however, did not modify significantly the levels of glucose and cholesterol in these animals. There was no significant elevation in liver transaminases in the control group treated with Croton cajucara Benth, as there was no genotoxic effect of treatment in this model. Our results did not show a significant effect on glucose and cholesterol reduction, the treatment was able to significantly reduce triclycerides plasmatic level. There was no significant alterations on hepatic transferase in the animals from the control group treated with Croton cajucara Benth. It was observed no genotoxic effect of the treatment in the model studied.

CONCLUSION

In this study Croton cajucara bark extract showed absence of hepatotoxicity in this animal model and presented a hypolipidemic activity, and could be used to reverse dyslipidemia associated with diabetes and to prevent the cardiovascular complications that are very prevalent in diabetic patients.

Casbane diterpene as a promising natural antimicrobial agent against biofilm-associated infections

Croton nepetaefolius is a native plant from northeastern Brazil that belongs to the Euphorbiaceae family. The biological action of this plant has been extensively explored, being the secondary metabolites responsible for its properties alkaloids, diterpenes, and triterpenes. This study aimed to evaluate the ability of casbane diterpene (CD), isolated from the ethanolic extract of C. nepetaefolius, to inhibit microbial growth and biofilm formation of several clinical relevant species (bacteria and yeasts). It was found that CD possessed biocidal and biostatic activity against the majority of the species screened, with minimal active concentrations ranging between 125 and 500 µg/mL. In addition, it was observed that biofilm formation was inhibited even when the planktonic growth was not significantly affected. In conclusion, CD showed potential to be a natural tool for the treatment of diseases caused by different infectious microorganisms.

Vitamin E Ameliorates High Dosetrans-Dehydrocrotonin-Associated Hepatic Damage in Mice

trans-Dehydrocrotonin ( t-DCTN), the diterpenoid from Croton cajucara Bentham, exhibits hypoglycemic and hypolipidemic activities, but in high doses is associated with a discrete hepatotoxicity. In the search for measures to mitigate this, pretreatment with the antioxidants N-acetylcysteine and vitamin E has been examined. Mice that received a high dose t-DCTN (100 mg/kg) manifested hepatic damage, as evidenced by significant elevations in serum ALT and AST, and hepatic GSH, and histological alterations, which could be obliterated by pretreatment with vitamin E, but not with N-acetylcysteine, possibly by creating an effective antioxidant balance.

Flavonoids from the stems of Croton caudatus Geisel. var. tomentosus Hook

A new flavone, named crotoncaudatin (1), was isolated from the stems of Croton caudatus Geisel. var. tomentosus Hook., together with nine known analogues: 3,5,6,7,8,3',4'-heptamethoxyflavone (2), tangeretin (3), nobiletin (4), 5,6,7,4'-tetramethoxy-flavone (5), sinensetin (6), kaempferol (7), tiliroside (8), kaempferol-3-O-rutinoside (9) and rutin (10). The structures of the above compounds were established by a combination of spectroscopic methods, including HR-ESI-MS, 1H-NMR, 13C-NMR, HMQC and HMBC spectra. All compounds were isolated from and identified in this species for the first time and compounds 1-6 are new for the genus Croton.

Cytotoxic diterpenoids from Croton argyrophylloides

Two new diterpenes, 1 and 2, together with the known ent-15-oxo-kaur-16-en-18-oic acid (3), were isolated from the bark of Croton argyrophylloides. The structural characterization of 1 and 2 was determined on the basis of spectroscopic data interpretation. The cytotoxicity of each compound was evaluated against HL-60 (leukemia), MDAMB-435 (melanoma), SF-295 (glioblastoma), and HCT-8 (colon carcinoma) human tumor cell lines and against human peripheral blood mononuclear cells. The hemolytic potential in mouse erythrocytes was also tested for 1-3.

Encapsulation and release characteristics of DCTN/PLGA microspheres

In the present study, poly (D,L-lactic-co-glycolic)-acid microspheres containing trans-Dehydrocrotonin (DCTN) were prepared by the double emulsion method. The hypoglycemic activity of DCTN-loaded microspheres was monitored in normal glycemic mice after administration of a daily dose of DCTN (50 mg kg(-1) body weight) for 7 days. Spherical microspheres with two populations of particles with 3.20 +/- 0.10 and 7.60 +/- 0.70 microm mean diameter size microm were observed. The encapsulation efficiency of DCTN was 85.5 +/- 3.9%. The in vitro kinetic profile of DCTN from PLGA-microspheres was initially fast (burst effect of 19.4% at 2 h). Such a burst step was maintained until achieving 35.7+/-2.0% at 7h, followed by a gradual release of DCTN attaining a maximum drug release at 55.7 +/- 2.6% within 30 h. DCTN was able to reduce glucose levels (14.3%) of normal glycemic animals and this effect was improved by its encapsulation into microspheres (26.8%). The optimum glucose levels in the blood of animals treated with DCTN suspension and DCTN-loaded microspheres were 119.21 +/- 19.75 mg dL(-1) at day 5 and 103.08 +/- 18.88 mg dL(-1) at day 7, respectively. DCTN-loaded microspheres are thus offered as a potential delivery system for the treatment of metabolic diseases characterized by hyperglycemia.

Anti-inflammatory compounds from leaves and root bark of Alchornea cordifolia (Schumach. & Thonn.) Müll. Arg

Alchornea cordifolia is one of the most widely-used plants in traditional medicine throughout Africa, principally for inflammatory, antimicrobial and parasitic diseases. In continuation of our investigations on its anti-inflammatory activity, we fractionated the leaf and root bark extracts and isolated six compounds which exhibited significant topical anti-inflammatory activity in the mouse ear oedema model using croton oil at a dose of 90 microg/cm2. Daucosterol (2), acetyl aleuritolic acid (4), N1,N2-diisopentenyl guanidine (5) and N1,N2,N3-triisopentenyl guanidine (6) were shown to be more active than indomethacin, while beta-sitosterol (1) and di(2-ethylhexyl) phthalate (3) were less effective. This is the first report on the presence of compounds 1, 2, 3 and 4 in this plant and of the anti-inflammatory activity of 3, 5 and 6. These compounds may account, at least in part, for the use of A. cordifolia in folk medicine to treat inflammation.

Isolation and identification of mosquito larvicidal compound from Abutilon indicum (Linn.) Sweet

Larvicidal activity of crude hexane, ethyl acetate, petroleum ether, acetone and methanol extracts of five medicinal plants, Abutilon indicum, Aegle marmelos, Euphorbia thymifolia, Jatropha gossypifolia and Solanum torvum were assayed for their toxicity against the early fourth-instar larvae of Culex quinquefasciatus. The larval mortality was observed after 24 h exposure. All extracts showed moderate larvicidal effects; however, the highest larval mortality was found in petroleum ether extract of A. indicum. In the present study, bioassay-guided fractionation of A. indicum led to the separation and identification of a beta-sitosterol as a potential new mosquito larvicidal compound with LC50 value of 11.49, 3.58 and 26.67 ppm against Aedes aegypti L, Anopheles stephensi Liston and C. quinquefasciatus Say (Diptera: Culicidae), respectively. 1H NMR, 13C NMR and mass spectral data confirmed the identification of the active compound. beta-sitosterol has been recognized as the active ingredient of many medicinal plant extracts. All the crude extracts when screened for their larvicidal activities indicated toxicity against the larvae of C. quinquefasciatus. This article reports the isolation and identification of the beta-sitosterol as well as bioassay data for the crude extracts. There are no reports of beta-sitosterol in the genus A. indicum, and their larvicidal activities are being evaluated for the first time. Results of this study show that the petroleum ether extract of A. indicum may be considered as a potent source and beta-sitosterol as a new natural mosquito larvicidal agent.

Gastroprotective effect and cytotoxicity of terpenes from the Paraguayan crude drug "yagua rova" (Jatropha isabelli)

A new jatrophone derivative (6), jatrophone (3), jatropholone A (4) and jatropholone B (5), acetyl aleuritolic acid (1), cyperenoic acid (2) and a monoterpene were isolated from the rhizomes of the Paraguayan crude drug Jatropha isabelli. The compounds were characterized by spectroscopic means. The gastroprotective effect of jatrophone, jatropholone A and B as well as 9beta,13alpha-dihydroxyisabellione 6 and the triterpene 1 was assessed in the HCl/EtOH-induced gastric lesions model in mice. Jatrophone elicited a strong gastroprotective effect with no significant differences between 25, 50 or 100 mg/kg and reducing lesions from 88 to 93%. The jatropholones A and B showed remarkable differences in the gastroprotective assay. Jatropholone A presented a dose-related response, with maximum effect (54% lesion reduction) at the highest dose (100 mg/kg), jatropholone B showed a strong action at all the doses, reducing lesions by 83-91%. The cytotoxicity of the compounds was assessed towards fibroblasts and AGS cells. Jatrophone was toxic against both cell lines (IC50 values: 2.8 and 2.5 microM, respectively). Jatropholone B (5) was not cytotoxic while jatropholone A (4) displayed a selective effect against AGS cells (IC50: 49 microM). The relevance of stereochemistry in the biological effects is clear comparing the effect of jatropholone A and B against AGS cells, with IC50 values of 49 and > 1000 microM for the beta and alpha C-16 isomers, respectively. The results provide scientific support for the use of "yagua rova" as a gastroprotective crude drug in Paraguayan traditional medicine.

Disappearing, displaced, and undervalued: a call to action for Indigenous health worldwide

"What sets worlds in motion is the interplay of differences, their attractions and repulsions. Life is plurality, death is uniformity. By suppressing differences and peculiarities, by eliminating different civilisations and cultures, progress weakens life and favours death. The ideal of a single civilisation for everyone implicit in the cult of progress and technique, impoverishes and mutilates us. Every view of the world that becomes extinct, every culture that disappears, diminishes a possibility of life!"

Anti-inflammatory activity of cacalol and cacalone sesquiterpenes isolated from Psacalium decompositum

The hexane extract and two sesquiterpenic compounds, cacalol and cacalone, were isolated from the roots and rhizomes of Psacalium decompositum. Then, their anti-inflammatory activity was evaluated in carrageenan-induced rat paw edema and 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ear edema. Indomethacin was used as the anti-inflammatory agent of reference. In the rat paw model of inflammation, both the hexane extract and the sesquiterpenes isolated from Psacalium decompositum showed a clear dose-dependent inhibition of the carrageenan-induced edema (P < 0.05), with important differences among them during the temporal course of the inhibition. In the TPA-induced mouse ear edema all tested compounds showed anti-inflammatory activity in dose-dependent manner (P < 0.05). In both models, cacalone showed the most prominent anti-inflammatory activity. We conclude that some of the beneficial effects attributed to Psacalium decompositum in traditional medicine can be related with the anti-inflammatory activity of cacalol and cacalone.

Croton cajucara BENTH. Leaf Extract Scavenges the Stable Free Radical DPPH and Protects Against Oxidative Stress Induced by Paraquat

Antioxidant effects of extracts from Croton cajucara BENTH. leaves was investigated in different in vitro and in vivo models. Extracts showed inhibitory radical scavenging activity against the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) (75%, 43% and 25% of the standard trolox at 1, 10 and 100 mg/ml, respectively; IC50 218 mg/ml). Percentage survival of Saccharomyces cerevisiae cells treated with 10 mM paraquat increased by 21% and 55%, when 1 mg/ml and 10 mg/ml concentrations of the extract, respectively, were added. The cytosolic concentration of TBARS increased in animals treated with paraquat (+283%), while values did not significantly differ from the controls in rats additionally receiving the leaf extract. Paraquat administration also induced a significant increase in hydroperoxide-initiated chemiluminiscence (+76%), that was partially prevented by the leaf extract (+31%). Liver SOD activity was a 158% higher in animals receiving paraquat as compared to the controls. This effect was abolished by administration of the leaf extract. Paraquat administration did not significantly modify the activity of GPx or catalase. Croton cajucara extract increased GPx and catalase activities in paraquat treated-animals by 342% and 70%, respectively. Our results confirm that Croton cajucara leaf extract present radical scavenging activity and reduce oxidative stress induced by paraquat, suggesting the beneficial use as a potential source of antioxidant agents of natural origin.

Plant active components - a resource for antiparasitic agents?

Plant essential oils (and/or active components) can be used as alternatives or adjuncts to current antiparasitic therapies. Garlic oil has broad-spectrum activity against Trypanosoma, Plasmodium, Giardia and Leishmania, and Cochlospermum planchonii and Croton cajucara oils specifically inhibit Plasmodium falciparum and Leishmania amazonensis, respectively. Some plant oils have immunomodulatory effects that could modify host-parasite immunobiology, and the lipid solubility of plant oils might offer alternative, transcutaneous delivery routes. The emergence of parasites resistant to current chemotherapies highlights the importance of plant essential oils as novel antiparasitic agents.

Chronic treatment with bark infusion fromCroton cajucaralowers plasma triglyceride levels in genetic hyperlipidemic mice

Aqueous infusion and preparations containing dehydrocrotonin (DHC) and essential oil from Croton cajucara bark were tested for plasma lipid-lowering effects in genetically modified hyperlipidemic mice. Two mouse models were tested: 1) primary hypercholesterolemia resulting from the LDL-receptor gene knockout, and 2) combined hyperlipidemia resulting from crosses of LDL-receptor knockout mice with transgenic mice overexpressing apolipo protein (apo) CIII and cholesteryl ester-transfer protein. Mice treated with bark infusion, DHC, essential oil, or placebos for 25 days showed no signals of toxicity as judged by biochemical tests for liver and kidney functions. The bark infusion reduced triglyceride plasma levels by 40%, while essential oil and DHC had no significant effects on plasma lipid levels. The bark infusion treatment promoted a redistribution of cholesterol among the lipoprotein fractions in combined hyperlipidemic mice. There was a marked reduction in the VLDL fraction and an increase in the HDL fraction, in such a way that the (VLDL + LDL)/HDL ratio was reduced by half. The bark infusion treatment did not modify cholesterol distribution in hypercholesterolemic mice. In conclusion, C. cajucara bark infusion reduced plasma triglycerides levels and promoted a redistribution of cholesterol among lipoproteins in genetically combined hyperlipidemic mice. These changes modify risk factors for the development of atherosclerotic diseases.Key words: hyperlipidemia, transgenic mice, Croton cajucara, dehydrocrotonin, cholesterol.

Natural killer cell activity and anti-tumour effects of dehydrocrotonin and its synthetic derivatives

In this work, the anti-tumour properties of dehydrocrotonin and its derivatives were investigated in vitro and in vivo using the Ehrlich ascites tumour model. Treatment of Ehrlich ascites tumour-bearing mice with 20 mg/kg dehydrocrotonin for 4 days significantly increased survival, whereas administration of dehydrocrotonin derivatives was ineffective in affording protection. Compound IV exhibited little activity against Ehrlich tumour cells in vitro. Investigation of the effects of dehydrocrotonin treatment on total natural killer (NK) cell activity of tumour-bearing mice as a possible mechanism of dehydrocrotonin action in vivo revealed that this sesquiterpene lactone significantly improved NK cytotoxicity against YAC-1, a Moloney virus-induced mouse T-cell lymphoma of A/SN origin. As expected, tumour growth in non-treated mice markedly suppressed NK cell cytolysis. No effects on NK functional activity were observed in normal mice receiving dehydrocrotonin. In summary, only the natural compound exhibits anti-tumour efficacy and immunomodulatory actions in vivo, which may be related to its chemical structure.