Croton Gratissimus Research Articles

Croton gratissimus Burch Herbal Tea Exhibits Anti-Hyperglycemic and Anti-Lipidemic Properties via Inhibition of Glycation and Digestive Enzyme Activities.

Over the years, the world has continued to be plagued by type 2 diabetes (T2D). As a lifestyle disease, obese individuals are at higher risk of developing the disease. Medicinal plants have increasingly been utilized as remedial agents for managing metabolic syndrome. The aim of the present study was to investigate the in vitro anti-hyperglycemic and anti-lipidemic potential of Croton gratissimus herbal tea infusion. The inhibitory activities of C. gratissimus on carbohydrate (α-glucosidase and α-amylase) and lipid (pancreatic lipase) hydrolyzing enzymes were determined, and the mode of inhibition of the carbohydrate digestive enzymes was analyzed and calculated via Lineweaver-Burk plots and Michaelis Menten's equation. Its effect on Advanced Glycation End Product (AGE) formation, glucose adsorption, and yeast glucose utilization were also determined. High-performance liquid chromatography (HPLC) was used to quantify the possible phenolic compounds present in the herbal tea infusion, and the compounds were docked with the digestive enzymes. C. gratissimus significantly (p < 0.05) inhibited α-glucosidase (IC50 = 60.56 ± 2.78 μg/mL), α-amylase (IC50 = 35.67 ± 0.07 μg/mL), as well as pancreatic lipase (IC50 = 50.27 ± 1.51 μg/mL) in a dose-dependent (15-240 µg/mL) trend. The infusion also inhibited the non-enzymatic glycation process, adsorbed glucose effectively, and enhanced glucose uptake in yeast cell solutions at increasing concentrations. Molecular docking analysis showed strong binding affinity between HPLC-quantified compounds (quercetin, caffeic acid, gallic acid, and catechin) of C. gratissimus herbal tea and the studied digestive enzymes. Moreover, the herbal tea product did not present cytotoxicity on 3T3-L1 cell lines. Results from this study suggest that C. gratissimus herbal tea could improve glucose homeostasis and support its local usage as a potential anti-hyperglycemic and anti-obesogenic agent. Further in vivo and molecular studies are required to bolster the results from this study.

Phytochemical Properties of Croton gratissimus Burch (Lavender Croton) Herbal Tea and Its Protective Effect against Iron-Induced Oxidative Hepatic Injury.

Oxidative stress plays a vital role in the pathogenesis and progression of various liver diseases. Traditional medicinal herbs have been used worldwide for the treatment of chronic liver diseases due to their high phytochemical constituents. The present study investigated the phytochemical properties of Croton gratissimus (lavender croton) leaf herbal tea and its hepatoprotective effect on oxidative injury in Chang liver cells, using an in vitro and in silico approach. C. gratissimus herbal infusion was screened for total phenolic and total flavonoid contents as well as in vitro antioxidant capacity using ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picryl-hydrazyl (DPPH) methods. Oxidative hepatic injury was induced by incubating 0.007 M FeSO4 with Chang liver cells which has been initially incubated with or without different concentrations (15-240 μg/mL) of C. gratissimus infusion or the standard antioxidants (Gallic acid and ascorbic acid). C. gratissimus displayed significantly high scavenging activity and ferric reducing capacity following DPPH and FRAP assays, respectively. It had no cytotoxic effect on Chang liver cells. C. gratissimus also significantly elevated the level of hepatic reduced glutathione (GSH), superoxide dismutase (SOD), and catalase activities as well as suppressed the malondialdehyde (MDA) level in oxidative hepatic injury. Liquid Chromatography-Mass Spectrometry (LC-MS) analysis of the herbal tea revealed the presence of 8-prenylnaringenin, flavonol 3-O-D-galactoside, caffeine, spirasine I, hypericin, pheophorbide-a, and 4-methylumbelliferone glucuronide. In silico oral toxicity prediction of the identified phytochemicals revealed no potential hepatotoxicity. Molecular docking revealed potent molecular interactions of the phytochemicals with SOD and catalase. The results suggest the hepatoprotective and antioxidative potentials of C. gratissimus herbal tea against oxidative hepatic injury.

English

Essential oil compounds of Croton pseudopulchellus and Croton gratissimus were analysed using Gas Chromatography/Mass Spectrophotometry and screened for antimicrobial activity against Bacillus pimilus (ATCC 29212), Bacillus cereus (ATCC 10702), Staphylococcus aureus (ATCC 3983), Streptococcus faecalis (ATCC 29212), Escherichia coli (ATCC 4983), Klebsiella pneumoniae (ATCC 2983) and Pseudomonas aeruginosa (ATCC 19582) using Agar gel disk diffusion test and minimum inhibitory concentrations. The susceptibilities of all isolates of different essential oil compounds were standardised by National Committee for Clinical Laboratory Standards (NCCLS) 1998). The cytotoxicity test was also carried out to determine the toxicity levels of essential oil compounds. These plants were selected based on their use by traditional healers for treatment of upper respiratory tract, gastrointestinal tract and urinary tract infections. The essential oil compounds of C. pseudopulchellus and C. gratissimus were found to be active against all the test microorganisms, while the preliminary assessment of essential oil compounds from these plants exhibited low cytotoxic activity. &nbsp; Key words: Essential oil, sesquiterpenes, chemical composition, antimicrobial activity.

Histochemical Analysis and Ultrastructure of Trichomes and Laticifers of Croton gratissimus Burch. var. gratissimus (Euphorbiaceae).

Croton gratissimus (Lavender croton) possesses three distinct secretory structures. These include lepidote and glandular trichomes and non-articulated unbranched laticifers. The lepidote trichomes form a dense indumentum on the abaxial surface of the leaves and canopy the glandular trichomes. Although assumed to be non-glandular, transmission electron microscopy (TEM) indicated high metabolic activity within the stalk and radial cells. Glandular trichomes are embedded in the epidermal layer and consist of a single cell which forms a prominent stalk and dilated head. Laticifers occur on the mid-vein of leaves and are predominantly associated with vascular tissue. In the stems, laticifers are associated with the phloem and pith. Both trichome types and laticifers stained positive for alkaloids, phenolic compounds, and lipids. Positive staining for these compounds in lepidote trichomes suggests their involvement in the production and accumulation of secondary metabolites. These metabolites could provide chemical defense for the plant and potentially be useful for traditional medicine.

Phylogeny, Phytomedicines, Phytochemistry, Pharmacological Properties, and Toxicity of Croton gratissimus Burch (Euphorbiaceae).

Croton gratissimus is an important plant in Africa setup and across the globe for its ethnomedicinal uses in managing a wide range of diseases. Its phylogeny, pharmacological properties, ethnomedicinal uses, phytochemistry, and cytotoxicity have been highlighted in various articles and journals. This review article aims to give a comprehensively overviewed literature about Croton gratissimus genus. Authentic literature sources such as books, peer reviewed articles, journals, theses, Google Scholar, Science Direct, and any other validated internet source have been used to develop this review. Croton gratissimus is richly found across different climatic zones because of its ability to adapt to various climatic conditions. It is mainly found in rocky hills as a scrub that is about 12–15 m tall. Its leaves are glossy, green on the top, and silvery underneath. Some of the leaves may look brick red rusty. Croton gratissimus has been explored traditionally to manage a number of diseases among the human race since time immemorial. It has been used to treat different ailments ranging from respiratory tract infections, urinary tract infections, malaria, diabetes, hypertension, dermatological conditions, arthritis, gastrointestinal disorders, fever, sexually transmitted diseases, and infertility. Studies have shown that parts of this plant have antioxidative, antimicrobial, anticholinesterases inhibitory, antidiabetic, antihyperlipidemic, anticonvulsant, antiulcer, antihypertensive, antiproliferative, antiplasmodial, and anti-inflammatory activities. Terpenoids and flavonoids have shown to be the major classes of compounds in this plant. Its toxicity has not been well established; some studies have suggested that Croton gratissimus can cause hepatotoxicity and genotoxicity. More studies are needed to elucidate the compounds and their structures giving this plant a wide range of pharmacological activities, efficacy, safety, and toxicity levels, since the plant has greater ethnomedicinal uses. This would give a great indication of discovering new novelties that can give a breakthrough in drug discovery.

English

Croton gratissimus Burch. and Schrankia leptocarpa DC. are two plants from the Beninese flora which are traditionally used for the treatment of arterial hypertension. The present study investigated the acute toxicity of ethanolic extracts of these plants. The experiment was conducted according to OECD guideline 423 categories 5 using a single dose of 5000mg/kg of the extracts. The average lethal doses (LD50) of the extracts are higher than 5000 mg/kg body weight.&nbsp; The oral administration of C. gratissimus and Schrankia leptocarpa extracts to the rats of all groups provoked a significant decrease in the plasma levels of AST (P &lt; 0.05) compared to the control batch between day 1 and day 14.&nbsp; There was no significant alteration in the creatinine levels in the all treated groups.&nbsp; The authors results showed that acute treatments with C. gratissimus and Schrankia leptocarpa extracts significantly (p&lt;0.05) elevated serum total protein.&nbsp; However, the administration of the Schrankia leptocarpa extract to rats resulted in a statistically significant decrease (p&lt; 0.05) in WBCs, GRA in the different batches between day 1 and day 14. The Schrankia leptocarpa extract caused a significant increase (p&lt; 0.05) in MCV, in haematocrit, in blood platelets between day 1 and day 14. The C. gratissimus extract caused a significant increase (p&lt;0.05) in blood platelets, in neutrophil in the different batches between day 1 and day 14. It appears that the extracts can be used therapeutically and that C. gratissimus may have hepatoprotective and immunostimulatory effects. Finally, Schrankia leptocarpa in addition to an immunostimulant effect could prevent microcytic anaemia. Key words: Croton gratissimus, Schrankia leptocarpa, acute toxicity, lethal doses.

Exploring four South African Croton species for potential anti-inflammatory properties: in vitro activity and toxicity risk assessment

Ethnopharmacological relevanceThe African Continent harbours approximately 26 Croton species. Many Croton species are used in traditional medicine in southern Africa to treat a variety of ailments including malaria, tuberculosis, microbial infection and inflammation. Considering the high diversity of the genus Croton, the ethnopharmacological information available on southern African species is rather limited. Furthermore, the potential for novel anti-inflammatory drug scaffolds has not previously been investigated. Aim of the studyThe aim of the study was to evaluate the potential of four South African Croton species extracts (Croton gratissimus, Croton pseudopulchellus, Croton sylvaticus, and Croton steenkampianus) for anti-inflammatory activity targeting the TLR4 signalling pathway and to assess the potential risk for hepatotoxicity and genotoxicity using an in vitro cellomics approach. Material and methodsLeaf extracts of C. gratissimus, C. pseudopulchellus, C. sylvaticus and C. steenkampianus were prepared using methanol and chloroform (1:1, v/v). The anti-inflammatory activity was determined using LPS induced nitric oxide production in RAW 264.7 macrophages, while the hepatotoxicity and genotoxicity was evaluated using multi-parameter end point analysis in C3A and Vero cells, respectively. Mitochondrial membrane potential, mitochondrial mass, oxidative stress, lysosomal content and lipid accumulation were used as markers to assess the risk for hepatotoxicity. ResultsAll four species attenuated nitric oxide production with negligible cytotoxicity. However, C. gratissimus yielded the most favorable profile. Cell density was significantly reduced in both C3A and Vero cells with the C. gratissimus extract providing a suitable toxicity profile amenable to further high content analysis. While there was no meaningful effect on mitochondrial dynamics, a strong dose dependent increase in lipid content, paralleled by an expansion of the lysosomal compartment, identifies a potential risk for steatosis. Risk for genotoxicity was investigated using the micronucleus assay which revealed a dose dependent increase in micronuclei formation. Changes in nuclear morphology and cell ploidy further strengthens the associated risk for genotoxicity and suggests the extract from C. gratissimus may function as an aneugen. Collectively, the data demonstrates that although the selected species possess anti-inflammatory components, the risk for possible hepatotoxic and genotoxic side effects may negate their prospect towards further drug development.

Production of Biodiesel From Croton gratissimus Oil Using Sulfated Zirconia and KOH as Catalysts

Optimization studies for the esterification and transesterification of oil extracted from Croton gratissimus grains were carried out using the response surface methodology (RMS) that utilizes the central composite design (CCD) and the analysis of variance (ANOVA). A 23 full-factorial rotatable CCD for three independent variables at five levels was developed in each case, giving a total of 20 experiments needed per study. The three design factors chosen for study were the catalyst concentration, methanol-to-oil ratio, and the reaction temperature. The values of the acid value of oil (in esterification) and the percentage FAME yield and FAME purity (in transesterification) were taken as the responses of the designed experiments. In the optimization of the esterification and transesterification processes, the ANOVA showed that both quadratic regression models developed were significant. The optimum operating conditions for the esterification process that could give an optimum acid value of 2.693 mg KOH/g of oil were found to be 10.96 mass% SO42–/ZrO2 catalyst concentration, 27.60 methanol-to-oil ratio, and 64°C reaction temperature. In the optimization of the transesterification process, the model revealed that the catalyst concentration and the methanol-to-oil ratio were the terms that had the most influence on the % FAME yield and the % FAME purity of the final biodiesel product. From the combined regression model, it was established that optimum responses of the 84.51% FAME yield and 90.66% FAME purity could be achieved when operating the transesterification process at 1.439 mass% KOH catalyst concentration, 7.472 methanol-to-oil ratio, and at a temperature of 63.50°C. Furthermore, in the two-step biodiesel synthesis, a predominantly monoclinic-phased sulfated zirconia (SO42–/ZrO2) catalyst exhibited high activity in the esterification of high free fatty acid oil extracted from Croton gratissimus grains. A 91% reduction in the acid value of the Croton gratissimus oil from 21.46 mg KOH/g of oil to 2.006 mg KOH/g of oil, well below the 4 mg KOH/g of oil maximum limit, was achieved. This resulted in the high FAME yield and purity of the biodiesel produced in the subsequent catalytic transesterification of oil using KOH.

Croton gratissimus - essential oil composition and chemometric analysis of an ethnomedicinally important tree from South Africa

Croton gratissimus Burch. is widely used in traditional medicine to treat a range of conditions including malaria, hypertension, diabetes, arthritis, urinary tract infections, gonorrhoea and impotence. The young branches and leaves are pleasantly aromatic, and it is recorded that various ethnic groups in South Africa used the leaves as a perfume. The chemistry of the non-volatile constituents has been widely investigated. However, little scientific data on the volatile constituents are available. Essential oils (EOs) were obtained by hydrodistillation from the leaves and twigs (n = 62) collected at different locations in South Africa. The hydrodistilled oils were analysed with gas chromatography coupled simultaneously to a mass spectrometer (MS) and a flame ionisation detector (FID). GC–MS/FID of the EOs showed the presence of mono- and sesquiterpenes as the major class of compounds. The most abundant compounds were β-pinene (nd–13.7%), sabinene (0.2–16.7%), α-phellandrene (0.4–44.3%), Z-β-ocimene (0.2–12.5%), limonene (0.2–38.3%), p-cymene (0.1–25.2%), phytol (nd–24.9%) and oxidohimachalene (nd–54.6%). Untargeted analysis of the GC–MS data was performed using SIMCA-P + 14.0, and different methods were used to explore possible chemical variation in the data set. After principal component analysis (PCA), the hierarchical cluster analysis (HCA) revealed three major chemotypes. Loadings and contribution plots identified oxidohimachalene as the main chemical marker for chemotype 1. Chemotype 2 was dominated by α-phellandrene, α-pinene and p-cymene, while chemotype 3 was characterised by low yields of α-phellandrene and oxidohimachalene. This study revealed mostly quantitative rather than qualitative variation in the EOs constituents of C. gratissimus.

HPLC-Based Activity Profiling for Antiprotozoal Compounds in Croton gratissimus and Cuscuta hyalina.

In a screening of Sudanese medicinal plants for antiprotozoal activity, the chloroform fractions obtained by liquid-liquid partitioning from ethanolic extracts of fruits of Croton gratissimus var. gratissimus and stems of Cuscuta hyalina Roth ex Schult. exhibited in vitro activity against axenically grown Leishmania donovani amastigotes. This antileishmanial activity was localized by HPLC-based activity profiling. Targeted preparative isolation afforded flavonoids 1–6, 3-methoxy-4-hydroxybenzoic acid (7), and benzyltetrahydroisoquinoline alkaloids laudanine (8) and laudanosine (9) from C. gratissimus, and pinoresinol (10), isorhamnetin (11), (-)-pseudosemiglabrin (12), and kaempferol (13) from C. hyalina. The antiprotozoal activity of 1–13 against L. donovani (axenic and intracellular amastigotes), Trypanosoma brucei rhodesiense (bloodstream forms), and Plasmodium falciparum (erythrocytic stages), and the cytotoxicity in L6 murine myoblast cells were determined in vitro. Quercetin-3,7-dimethylether (6) showed the highest activity against axenic L. donovani (IC50, 4.5 µM; selectivity index [SI], 12.3), P. falciparum (IC50, 7.3 µM; SI, 7.6), and T. b. rhodesiense (IC50, 2.4 µM; SI, 23.2). The congener ayanin (2) exhibited moderate antileishmanial (IC50, 8.2 µM; SI, 12.2), antiplasmodial (IC50, 7.8 µM; SI, 12.9), and antitrypanosomal activity (IC50, 11.2 µM; SI, 8.9). None of the compounds showed notable activity against the intramacrophage form of L. donovani.

Mining Sudanese Medicinal Plants for Antiprotozoal Agents.

Neglected tropical diseases are major health hazards in developing countries. Annually, up to 30 million people are affected by either Chagas disease, African trypansomiasis or leishmaniasis, and more than 200 million by malaria. Most of the currently available drugs have drawbacks in terms of toxicity, limited oral availability, development of resistance, or non-affordability. Tropical plants of the arid zones are a treasure chest for the discovery of bioactive secondary metabolites. This study aims to compile Sudanese medicinal plants, validate their antiprotozoal activities, and identify active molecules. We have performed a survey of medicinal plants of Sudan and selected 62 that are being used in Sudanese traditional medicine. From these, we collected materials such as leaves, stem, bark, or fruit. The plant materials were extracted in 70% ethanol and further fractionated by liquid-liquid partitioning using solvents of increasing polarity. This resulted in a library of 235 fractions. The library was tested in vitro against Plasmodium falciparum (erythrocytic stages), Trypanosoma brucei rhodesiense (bloodstream forms), Trypanosoma cruzi (intracellular amastigotes), and Leishmania donovani (axenic amastigotes). Active fractions were also tested for cytotoxicity. Of the 235 fractions, 125 showed growth inhibitory activity >80% at 10 μg/ml, and >50% at 2 μg/ml against at least one of the protozoan parasites. Plasmodium falciparum was the most sensitive of the parasites, followed by T. b. rhodesiense and L. donovani. Only few hits were identified for T. cruzi, and these were not selective. Contrary to expectation based on phylogeny, but in agreement with previous results, a large number of extracts displayed mutual activity against T. brucei and P. falciparum. HPLC-based activity profiling for selected active extracts was performed to identify the bioactive principles. Active compounds identified by dereplication were guieranone A from Guiera senegalensis J.F.Gmel.; pseudosemiglabrin from Tephrosia apollinea (Delile) DC; ellagic acid and quercetin from Terminalia leiocarpa (DC.) Baill.; and catechin, ethyl gallate, and epicatechin gallate from Vachellia nilotica (L.) P.J.H.Hurter & Mabb. Also the extracts of Croton gratissimus var. gratissimus and Cuscuta hyalina Roth ex Schult. exhibited promising antitrypanosomatid activity. This assessment provides a comprehensive overview of Sudanese medicinal plants and supports the notion that they are a potential source of bioactive molecules against protozoan parasites.

تأثير الحرارة على نشاط مضادات الأكسدة والنمو الميكروبي في بهارات الكومبا وأم غليلة

الخلفية والأهداف: بهار أم غليله وبهار الكومبا عبارة عن شجيرات استوائية تنمو عشوائياً بأفريقيا. تستخدم تقليدياً كخافض للحمى ومانعة للنزيف ومسهل وكدواء لداء الاستسقاء. صممت هذه الدراسة لتقييم النشاط المضاد للأكسدة وللنمو الميكروبي وكذلك السمية لتلك البهارات المحلية أم غليله(أ) والكومبا (ب)، وقياس تأثير أثر المعاملة الحرارية 80مₒ على خصائص النشاط المضاد للأكسدة و للنمو الميكروبي والسمية. الطرق والوسائل: تم شراء العينات من أسواق جبل أولياء والكلالة اللفة - السودان وتجهيزها للتحليل، حيث تم استخلاص جميع العينات بواسطة الايثانول 80% (أ) و(ب) والمستخلص المعامل بالحرارة 80مₒ (ج) و(د) كما تم تحديد نشاط المضاد للأكسدة بواسطة كاشف ((DPPH. النتائج: قد تبين من خلال النتائج أن المستخلصات المعاملة بالحرارة والغير معاملة (ا, ب, ج, ود) تتدرج في نشاطها من الأعلى إلى الأقل على التوالي. تم تقييم النشاط المضاد للنمو الميكروبي لهذه المستخلصات ضد الميكروبات. Bacillssubtilis, Staphylococcus aureus, Escherichia coli, Pseudomonasaeruginosa, and Candida albicans.. أما بالنسبة لسمية مستخلصات أم غليله والكومبا فتم تقييمها باستعمال طريقة (MTT)assay, ولم يستدل على أي سمية في كل منهما. الخلاصة: أظهرت البهارات الإفريقية أم غليلة والكومبا نشاطا مضادا للأكسدة وكمضادات للميكروبات متميزا بالإضافة إلى خلوها من أي سمية حتى في منتجات الغذاء المطبوخة.

Volatiles from African species of Croton (Euphorbiaceae), including new diterpenes in essential oil from Croton gratissimus

The chemistry of essential oils from the leaves of three African species of Croton (C. gratissimus, C. pseudopulchellus and C. sylvaticus) is comprehensively characterised. Two new volatile diterpenes were isolated from C. gratissimus and the structures assigned using 1D and 2D NMR. One is a furanyl-halimane methyl ester (1) assigned as 12-β-furanyl-halima-5,9-dien-4-methylcarboxylate (gratissihalimanoic ester); the other is an abietane ketone (2) assigned as ent-abiet-8(14), 13(15)-dien-3-one, which we have named gratissimone. High relative abundance of diterpenes in a hydrodistilled essential oil is rare and may be considered an interesting discovery. Known non-volatile diterpenes were also isolated, which were assigned as crotohalimaneic acid (3) and hardwickiic acid (4). All diterpenes occur in fresh leaves prior to distillation and extract into apolar or moderately polar solvents, which demonstrates that the two volatiles are not generated during the hydrodistillation. At this stage it is not clear how widespread this diterpene essential oil chemotype is within the species distribution or if any therapeutic effects can be attributed to them. No antimicrobial activity was observed at 1 mg/ml against a range of bacterial strains.

Croton gratissimus leaf extracts inhibit cancer cell growth by inducing caspase 3/7 activation with additional anti-inflammatory and antioxidant activities

BackgroundCroton species (Euphorbiaceae) are distributed in different parts of the world, and are used in traditional medicine to treat various ailments including cancer, inflammation, parasitic infections and oxidative stress related diseases. The present study aimed to evaluate the antioxidant, anti-inflammatory and cytotoxic properties of different extracts from three Croton species.MethodsAcetone, ethanol and water leaf extracts from C. gratissimus, C. pseudopulchellus, and C. sylvaticus were tested for their free radical scavenging activity. Anti-inflammatory activity was determined via the nitric oxide (NO) inhibitory assay on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, and the 15-lipoxygenase inhibitory assay using the ferrous oxidation-xylenol orange assay. The cytotoxicity of the extracts was determined on four cancerous cell lines (A549, Caco-2, HeLa, MCF-7), and a non-cancerous African green monkey (Vero) kidney cells using the tetrazolium-based colorimetric (MTT) assay. The potential mechanism of action of the active extracts was explored by quantifying the caspase-3/− 7 activity with the Caspase-Glo® 3/7 assay kit (Promega).ResultsThe acetone and ethanol leaf extracts of C. pseudopulchellus and C. sylvaticus were highly cytotoxic to the non-cancerous cells with LC50 varying between 7.86 and 48.19 μg/mL. In contrast, the acetone and ethanol extracts of C. gratissimus were less cytotoxic to non-cancerous cells and more selective with LC50 varying between 152.30 and 462.88 μg/mL, and selectivity index (SI) ranging between 1.56 and 11.64. Regarding the anti-inflammatory activity, the acetone leaf extract of C. pseudopulchellus had the highest NO inhibitory potency with an IC50 of 34.64 μg/mL, while the ethanol leaf extract of the same plant was very active against 15-lipoxygenase with an IC50 of 0.57 μg/mL. A linear correlation (r<0.5) was found between phytochemical contents, antioxidant, anti-inflammatory and cytotoxic activities of active extracts. These extracts induced differentially the activation of caspases − 3 and − 7 enzymes in all the four cancerous cells with the highest induction (1.83-fold change) obtained on HeLa cells with the acetone leaf extract of C. gratissimus.ConclusionBased on their selective toxicity, good antioxidant and anti-inflammatory activities, the acetone and ethanol leaf extracts of C. gratissimus represent promising alternative sources of compounds against cancer and other oxidative stress related diseases.

Medicinal applications of plants by Bapedi traditional healers for sore throat and related symptoms in the Limpopo Province of South Africa

This survey reports on medicinally plant used by Bapedi traditional healers (THs) to sore throat and related symptoms. Presently there is no published ethnobotanical literature focusing on these conditions. Face-to-face semi-structured interviews aimed at addressing this gap in knowledge were used to gather data from 156 THs practicing in the Limpopo Province of South Africa. A total of 80 plant species belonging to 73 genera and 43 botanical families, mainly the Fabaceae (10 spp.) and Asteraceae (8 spp.), were recorded as being used by THs. Croton gratissimus, Cryptocarya transvaalensis, Enicostema axillare, Jacaranda mimosifolia, Plumbago zeylanica, Solanum catombelense, Stylochaeton natalensis and Warburgia salutaris emerged as the most preferred species for healing sore throat and related symptoms according to fidelity level index analysis. However, the output of use value calculations positioned Adansonia digitata, Catha edulis, Lasiosiphon caffer and Zanthoxylum capense as Bapedi THs keystone species on the basis of its utility and applications in numerous ailments, scoring the uppermost values. This study showed that Bapedi THs employed a substantial number of plant species to treat the investigated ailments. Healing claim/s of most of these species is presently restricted to the Bapedi THs.

Optimisation of Croton gratissimus Oil Extraction by n-Hexane and Ethyl Acetate Using Response Surface Methodology.

The extraction of oil from Croton gratissimus seeds was studied using the three-factor five-level full-factorial central composite rotatable design (CCRD) of the response surface methodology (RSM). The effect of the three factors selected, viz., extraction time, extraction temperature and solvent-to-feed ratio on the extraction oil yield was investigated when n-hexane and ethyl acetate were used as extraction solvents. The coefficients of determination (R2) of the models developed were 0.98 for n-hexane extraction and 0.97 for ethyl acetate extraction. These results demonstrated that the models developed adequately represented the processes they described. From the optimized model, maximum extraction yield obtained from n-hexane and ethyl acetate extraction were 23.88% and 23.25%, respectively. In both cases the extraction temperature and solvent-to-feed ratio were 35°C and 5 mL/g, respectively. In n-hexane extraction the maximum conditions were reached only after 6 min whereas in ethyl acetate extraction it took 20 min to get the maximum extraction oil yield. Oil extraction of Croton gratissimus seeds, in this work, favoured the use of n-hexane as an extraction solvent as it offered higher oil yields at low temperatures and reduced residence times.

HPTLC fingerprinting of Croton gratissimus leaf extract with Preparative HPLC-MS-isolated marker compounds

The leaves, root and bark of the aromatic African indigenous plant, Croton gratissimus Burch. (Euphorbiaceae), are widely used in traditional medicine to treat coughs, chest complaints, rheumatism, abdominal disorders and fever among others. In Afrikaans it is referred to as “Koorsbessie” which alludes to its traditional use as a pyrogenic. The chemical composition of plants is very complex and analysis and quality control can be very challenging due to natural variability. In addition, very few reference standards from plants, especially from Africa, are commercially available. Due to its visual nature and the holistic fingerprint produced, high performance thin layer chromatography (HPTLC) is often recommended for the quality control of plant material. The aim of this study was to develop an HPTLC fingerprint and isolate marker compounds for inclusion on HPTLC plates to enable quality control. Croton gratissimus leaf samples were collected from various parts of South Africa and extraction was optimised. HPTLC fingerprints were developed and optimised and images were captured before and after derivatisation under UV (254nm, and 366nm) and white light. Preparative high performance liquid chromatography hyphenated to mass spectrometry (HPLC-MS) was used to isolate marker compounds. Method development and optimisation determined the following: most efficient extraction solvent=methanol:water (8:2 v/v); mobile phase=ethyl acetate:acetic acid:formic acid:water (100:11:11:27 v/v/v/v); and derivatising agent=natural product reagent. UPLC-MS analysis and 1D NMR spectroscopy were used to characterise and identify compound 1 as isoorientin and compound 2 as kaempferol-3-β-d-(6″-O-trans-p-coumaroyl) glucopyranoside, which correlated well with published spectral data. The final HPTLC fingerprint with biomarkers included showed good separation for profiling purposes and well-defined bands. The biomarkers at retention factor (Rf) 0.30 and Rf 0.69 for isoorientin and kaempferol-3-β-d-(6″-O-trans-p-coumaroyl) glucopyranoside, respectively, were present in all samples but varied quantitatively. The HPTLC method developed provided a good fingerprint for species authentication. Preparative HPLC-MS played a major role in successfully isolating marker compounds to be used for the quality control of C. gratissimus.

Do South African medicinal plants used traditionally to treat infections respond differently to resistant microbial strains?

Currently antimicrobial resistance is increasing at an alarming rate. Exposure to resistant strains hinders treatment outcomes both in rural and hospital settings. Thus, the aim of this study was to investigate five frequently used South African medicinal plants (Artemisia afra, Lippia javanica, Osmitopsis asteriscoides, Croton gratissimus and Tetradenia riparia) and test these against resistant bacterial strains (Enterococcus faecalis, Staphylococcus aureus, Bacillus cereus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli and Serratia marcescens) and comparatively evaluate efficacy with a reference strain. The conventional antibiotic ciprofloxacin was used as a positive control to also compare susceptibility of the various strains. Most plant samples demonstrated similar or better activity against the resistant strains. A general trend demonstrated that the organic extracts followed by the essential oils were able to withstand resistant strains better than the antibiotics which showed reduced susceptibility. This demonstrates great promise as natural products provide an alternative to fighting the onslaught of antibiotic resistance.

Croton gratissimus Leaf Essential Oil Composition, Antibacterial, Antiplatelet Aggregation, and Cytotoxic Activities

ABSTRACTEssential oil hydrodistilled from the leaves of Croton gratissimus was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) to identify the constituents by comparison of their mass spectra (MS) data and linear retention indices (LRI) with literature. Forty constituents corresponding to 96.7% of the total oil content were identified from the oil sample. The major compounds were sabinene (14.6%), α-phellandrene (12.3%), β-phellandrene (10.7%), α-pinene (6.05%), and germacrene D (5.9%). The essential oil exhibited stronger antibacterial activity with minimum inhibitory concentration (MIC) of 0.6 mg.mL–1 (Staphylococcus aureus), 0.2 mg.mL–1 (S. faecalis), and 1.3 mg.mL–1 (Escherichia coli and Bacillus cereus). In the antiplatelet aggregation inhibitory activity, the oil displayed action against the induced platelet aggregation in the order collagen (IC50 < 1) > thrombin (IC50 1.18) > Adenosine diphosphate (IC50 2.32) > epinephrine (IC50 3.65). The lethal concentration (LC50) of the oil at 8.52 mg.mL–1 was toxic to Artemia salina.

Variation in headspace volatiles and essential oil composition of Croton gratissimus

Variation in headspace volatiles and essential oil composition of Croton gratissimus