J Complement Integr Med. 2014; 11(3): 185–193

Christian Kuete Fofie, Sylvie Léa Wansi, Elvine Pami Nguelefack-Mbuyo, Albert Donatien Atsamo, Pierre Watcho, Albert Kamanyi, Tsabang Nole and Télesphore Benoît Nguelefack*

In vitro anti-hyperglycemic and antioxidant properties of extracts from the stem bark of Ceiba pentandra Abstract Background: The goal of the study was to determine the antidiabetic mechanisms and the antioxidant effects of aqueous (decoction and maceration) and methanol extracts from the stem bark of Ceiba pentandra. Methods: These extracts were tested in vitro on glucose uptake by skeletal muscles and liver slices and on glucose release by liver slices. The antioxidant activities of C. pentandra extracts were investigated at concentrations ranging from 1 to 300 µg/mL on 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydrogen peroxide (H2O2)-induced hemolysis, H2O2-induced brain lipid peroxidation, hydroxyl (˙OH) radical as well as their reducing power. Results: The decoction similarly to insulin exhibited a significant glucose lowering activity. In a hyperglycemic milieu, it significantly increased glucose uptake by the liver by 56.57% and in the skeletal muscle by 94.19%. In a hypoglycemic milieu, it significantly reduced glucose release by the liver by 33.94%. The decoction, maceration and methanol extracts exhibited a significant radical scavenging activity on DPPH with respective EC50 of 87.84, 54.77 and 6.15 µg/mL versus 2.24 µg/mL observed with ascorbic acid. All the extracts showed a significant antioxidant effect on hydroxyl radical, against lipid peroxidation and H2O2-induced hemolysis. The decoction showed the greatest antihemolytic effect with a maximum inhibition of 77.57% at the concentration of 100 µg/mL. C. pentandra extracts also showed a concentrationdependent reducing power. Conclusions: These results suggest that the antidiabetic effect of C. pentandra is due to its ability to increase glucose uptake and to reduce glucose release by target *Corresponding author: Télesphore Benoît Nguelefack, Laboratory of Animal Physiology and Phytopharmacology, University of Dschang, Dschang, Cameroon, E-mail: [email protected] Christian Kuete Fofie, Sylvie Léa Wansi, Elvine Pami Nguelefack-Mbuyo, Albert Donatien Atsamo, Pierre Watcho, Albert Kamanyi, Laboratory of Animal Physiology and Phytopharmacology, University of Dschang, Dschang, Cameroon Tsabang Nole, Institute of Medical Research and Medicinal Plants Studies (IMPM), Yaoundé, Cameroon

organs. The antioxidant properties of C. pentandra extracts are additional benefit for their antidiabetic effects. Keywords: antidiabetic, antioxidant, Ceiba pentandra, glucose release, glucose uptake DOI 10.1515/jcim-2014-0031 Received May 17, 2014; accepted July 6, 2014; previously published online July 24, 2014

Introduction Diabetes mellitus is a leading non-communicable disease with multiple etiologies. It affects more than 100 million people worldwide and is considered as one of the five leading causes of death in the world [1]. It results from impairment in glucose uptake by insulin-sensitive tissues (liver, skeletal muscle, adipose tissue and β-pancreatic islets) due to insulin resistance and/or insulin deficiency. Diabetes mellitus is associated with an increased level of free radicals, disturbances of the enzymatic antioxidant defense system and lower concentration of endogenous antioxidants. In consequence, these abnormalities lead to a redox imbalance called oxidative stress [2]. This oxidative stress in turn plays a pivotal role in the maintenance of diabetes as well as in the onset of its various complications. Despite all the medical strategies being put together to control the disease, the number of patients is reaching alarming proportions as it increases days after days. In developing countries, diabetes has seriously worsened the financial and social precariousness of many families, because drugs are not affordable and in some cases not even available. In developed regions, people have become skeptical towards manufactured drugs because of their side effects which include cardiovascular risks, renal and liver failure. Therefore, growing interest is being given to phytomedicine as medicinal plants could be useful tools to overcome the disease. Many plants are being used today to cure or control diabetes. In sub-Saharan regions, Ceiba pentandra is among the list. This plant grows in tropical regions

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and it is used to treat not only diabetes but also hypertension, dizziness, headache, constipation and fever [3]. Given the large number of ethnotherapeutical uses of C. pentandra, it has been subject of many pharmacological studies which revealed that extract from various parts possesses anti-fungal [4], anti-diarrheal [5], anti-ulcer [6], hepatoprotective [7], anthelminthic [8], angiogenesis [9], anti-inflammatory [10] and hypolipidemic [11] activities. C. pentandra is rich in sesquiterpene lactones [12], isoflavones [3] and naphthoquinone [13]. Previous studies have proved that the stem bark [14] and root bark [15, 16] extracts of this plant possess antidiabetic effects on type I diabetes models. But the mechanisms by which this plant exerts its antidiabetic activity are still unknown. The present study therefore aimed at evaluating the hypoglycemic effects of aqueous (decoction and maceration) and methanol extracts from the stem bark of C. pentandra in hypo- and hyperglycemic media using liver and skeletal muscle tissues. Besides, given the high implication of oxidative stress in the onset and maintenance of diabetic status, the antioxidants activities of these extracts were assessed on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, H2O2-induced hemolysis, H2O2induced brain lipid peroxidation and hydroxyl radical. The reducing power of these extracts was also evaluated.

Materials and methods Animals Albino Wistar rats of either sex, weighing 150–200 g, were bred in colony cages under standard environmental conditions (temperature: 22  1°C, light/dark cycle: 12/12 h). The rats were fed with standard commercial diet and water ad libitum. In some experiments, animals were fasted for 24 h before used, but had free access to water. All animals’ procedures were in accordance with the ethical rules of animals care as described by the law 86/609/CEE of the European Committee Guidelines.

Briefly, the decoction was prepared by boiling 100 g of C. pentandra powder in 400 mL of distilled water for 20 min. After filtration, the decoction was aliquoted and evaporated in an oven at 37°C. To obtain the maceration, 200 g of the powder was mixed with 800 mL of distilled water, left in tightly closed container for 72 h, filtered and subsequently evaporated similarly as done with the decoction. The methanol extract was prepared by mixing 400 g of stem bark powder of C. pentandra with 1 L of methanol and kept in a tightly closed container for 48 h. After filtration, the filtrate was concentrated at 70°C under reduced pressure. The extraction yields were 4.41, 1.58 and 1.95% for the decoction, maceration and methanol extract, respectively.

In vitro effects of Ceiba pentandra extracts on glucose uptake and glucose release Animals were anesthetized by intraperitoneal administration of ethyl carbamate (1.5 g/kg). Skeletal muscle and liver were carefully excised and immediately placed in a cooled (4°C) oxygenated perfusion solution of the following composition (mM): NaCl 118, KCl 4.8, CaCl2 2.5, KH2PO4 1.2, MgSO4 1.2, NaHCO3 25, glucose 11.1. After isolation, muscles and liver were sliced according to muscle fibers orientation. In glucose uptake experiments, organs were isolated from 24 h starved rats and incubated in hyperglycemic medium (5 g of glucose/L) while in glucose release studies, liver was obtained from non-starved animals and incubated in glucose-free medium. Muscle and liver slices were then incubated in 10 mL of different media in absence or in presence of extracts (100 µg/mL) or insulin (100 µUI/mL) at 37°C for 90 min, with aeration to enable stirring and provide enough oxygen to tissues. The concentration of plant extracts used was chosen according to a prior pilot study. At the end of the experiment, tissues were removed from the medium, dried for at least 8 h at 55°C and weighed. Glucose concentration in the incubation medium was determined using a commercial kit (BioSystem). Glucose uptake and glucose release were then calculated and expressed as mg/g of tissue/hour.

Preparation of plant extracts The stem bark of C. pentandra was collected in Yaoundé (center region, Cameroon) and a voucher specimen (HNC 43623) was deposited at the national herbarium Yaoundé, after identification by Dr Tsabang Nole. The bark was sliced into pieces, dried in an oven at 34°C and grounded into a powder. From this powder three extracts were prepared: decoction, maceration and the methanol extract.

In vitro antioxidant effects of Ceiba pentandra extracts Free radical scavenging activity The free radical scavenging activity of C. pentandra extracts was determined on DPPH as described by

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Fofie et al.: In vitro anti-hyperglycemic and antioxidant effects of Ceiba pentandra

Nguelefack-Mbuyo et al. [17]. Briefly, 150 µL of varying concentration (1–300 μg/mL) of extracts or ascorbic acid was added to 850 µL of ethanol and the absorbance (D1) read at 517 nm against a blank made up of ethanol. Then 500 µL of DPPH (0.063 mg/mL in ethanol) was added to the medium and incubated in dark for 20 min and absorbance (D2) measured spectrophotometrically at 517 nm. The antioxidant activity (%) was calculated using the following equation: Antioxidant activity ð%Þ ¼ ½ðA0  A1 Þ=A0   100 where A0 is absorbance variation (D2–D1) of the control and A1 the absorbance variation in samples. The EC50 of each tested substance was determined from the inhibition (%).

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compounds or α-tocopherol (used as reference drug) at concentrations ranging from 1 to 100 µg/mL. The reaction started after adding 0.5 mL of H2O2 (25 mM) and the mixture was incubated for 60 min. After the incubation period, 100 µL of reaction mixture was added to 1 mL TBARS reagent (1% w/v orthophosphoric acid and 1% w/ v thiobarbituric acid [TBA] was dissolved in 1% trichloroacetic acid and mildly heated to foster the dissolution of TBA). The solution was heated for 20 min in a boiling water bath and then cooled. The flocculent precipitate obtained after cooling was removed by centrifugation at 1,000 rpm for 10 min [19]. The pink color obtained was measured spectrophotometrically at 535 nm.

Reducing power Protective effect of Ceiba pentandra extracts against H2O2-induced hemolysis The effects of C. pentandra on H2O2-induced hemolysis were assessed as described by Ko et al. [18]. Briefly, heparinized blood samples were collected from healthy anesthetized rats via the abdominal aorta and centrifuged at 1,000 rpm for 10 min. Red blood cells (RBC) were isolated and washed three times in PBS (NaCl: 125 mM and NaH2PO4: 10 mM, pH 7.4). These cells were then suspended at 2% hematocrit in PBS; 800 µL of the RBC suspension was incubated in presence or absence of plant extracts (1–100 µg/mL) or ascorbic acid (1–100 µg/mL; positive control) for 15 min at 37°C. Then, 100 µL of H2O2 solution was added in the medium at the final concentration of 7.5 mM. After a 4 h incubation period, aliquots of the mixture were taken out, diluted with 20 volumes of saline and centrifuged at 3,500 rpm for 10 min. The degree of hemolysis was determined by measuring absorbance (A) spectrophotometrically at 540 nm with a Helios Epsilon spectrophotometer. For complete hemolysis, an aliquot of the RBC suspension was treated with 20 volumes of ice-cold distilled water and after centrifugation, the absorption (B) was measured at the same wavelength. The percentage of hemolysis was then calculated: Hemolysis ð%Þ ¼ ðA=BÞ  100: Lipid peroxidation assay Rats were decapitated, brain was removed carefully and homogenized (10% w/v) with cold 0.1 M phosphate buffer. The filtered homogenate was used as source of poly-unsaturated fatty acids to determine lipid peroxidation. 0.5 mL of brain homogenate was added to 0.5 mL of the test

The reducing power was determined by the method of Athukorala et al. [20] with a little modification. 0.2 mL extract was mixed with 0.5 mL of phosphate buffer (200 mM, pH 6.6) and 0.5 mL of potassium ferricyanide (30 mM) and incubated at 50°C for 20 min. Thereafter, 0.5 mL of trichloroacetic acid (600 mM) was added to the reaction mixture, centrifuged for 10 min at 3,000 rpm. The supernatant (0.5 mL) was mixed with 0.5 mL of distilled water and 0.1 mL of FeCl3 (6 mM) and the absorbance was measured at 700 nm. Butylated hydroxytoluene (BHT) was used as positive control. Tested substances were used at the concentration range of 1–300 µg/mL. High absorbance indicates a high reducing power. As the extracts were colored at high concentrations, correction was made by subtracting the absorbance of each extract at the same dilution from experimental values.

Hydroxyl radical scavenging (˙OH) assay The ascorbic acid–iron–EDTA (ethylenediaminetetraaceticacid) model of ˙OH generating system was used. This is a totally aqueous system in which ascorbic acid, iron and EDTA conspire with each other to generate hydroxyl radicals. The ability of the plant extracts to scavenge hydroxyl radicals was measured by the method of Kunchandy and Rao [21]. Briefly, the reaction mixture (1 mL) consisted of 100 μL of 2-deoxy-D-ribose (28 mM in 20 mM KH2PO4-KOH buffer, pH 7.4), 500 μL of plant extracts or mannitol at different concentrations, 100 μL EDTA (1.04 mM), 100 µL FeCl3 (100 μM), 100 μL of H2O2 (1 mM) and 100 μL ascorbic acid (1 mM) was incubated at 37°C for 1 h. Then 1 mL of thiobarbituric acid (1%) and 1 mL of trichloroacetic acid (2.8%) were added and incubated at 100°C for 20 min.

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After cooling, absorbances were red at 532 nm, against a blank sample.

Drugs Except insulin, all the drugs used were of analytical grade. KOH, NaH2PO4, MgSO4, NaCl, CaCl2, KH2PO4 and K2HPO4 were purchased from BDH (Chemicals Ltd, Poole, England), Mannitol, EDTA and NaHCO3 were obtained from Fluka. Butylated hydroxytoluene (BHT), thiobarbituric acid, trichloroacetic acid, 2-deoxy-D-ribose and ascorbic acid were purchased from Sigma-Aldrich Chemie Gmbh (Taufkirchen, Germany). FeCl3 was purchased from Fisher (France).

Statistical analysis Data are expressed as mean  standard error of the mean. Comparison of parameters among groups was done by oneway and two-way (concentration-related responses) analysis of variance (ANOVA) with Tukey and Bonferroni respectively as post-test using GraphPad Prism version 4.0. When ANOVA was not significant, unpaired t-test was applied. p-Value less than 0.05 was considered as statistically significant.

Results Effects of Ceiba pentandra extracts on glucose uptake As depicted in Figure 1A and B, the decoction from the stem bark of Ceiba pentandra was able to significantly increase glucose uptake by the liver and by the skeletal muscle. One gram of liver from fasted animals consumed about 26.67 mg of glucose per hour. The addition of the decoction or insulin in the incubation medium significantly increased glucose consumption by 56.57% (p < 0.05) and 127.28% (p < 0.001), respectively. In skeletal muscles, glucose uptake increased by 94.19% (p < 0.01) in presence of the decoction and by 135.11% (p < 0.001) in presence of insulin. The maceration and the methanol extracts did not show any significant effect on both tissues.

Effects of Ceiba pentandra extracts on glucose release A significant (p < 0.05) reduction in glucose release was observed in liver slices incubated with the stem bark

Figure 1 Effect of Ceiba pentandra extracts (100 µg/mL) and insulin on in vitro liver and skeletal muscle glucose consumption. Each bar represents mean  SEM of 9 (A) or 6 (B) different experiments carried out in duplicate. *p < 0.05, **p < 0.01, ***p < 0.001 compared to control groups. bp < 0.05, cp < 0.001, compared to insulin groups.

decoction of C. pentandra. Glucose release decreased from 21.04  2.62 mg/g/h in control strips to 16.15  2.56 and 13.90  2.19 mg/g/h in presence of insulin and decoction, respectively. No significant effect was noticed with the other plant extracts (Figure 2).

Effect of Ceiba pentandra extracts on DPPH radical As shown in Figure 3, the methanol and aqueous extracts from C. pentandra stem bark induced a concentrationdependent radical scavenging activity on DPPH. The

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Fofie et al.: In vitro anti-hyperglycemic and antioxidant effects of Ceiba pentandra

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(Emax ¼ 169.60) and the maceration (Emax ¼ 119.13) exhibited a more powerful radical scavenging activity when compared to ascorbic acid (Emax ¼ 96.53). Based on their efficiency index (EI), substances were classified as follow: Ascorbic acid > methanol extract > maceration > decoction.

Effect of Ceiba pentandra extracts on H2O2-induced hemolysis

Figure 2 Effect of Ceiba pentandra extracts (100 µg/mL) and insulin on in vitro liver glucose release. Each bar represents mean  SEM of 8 different experiments carried out in duplicate. *p < 0.05 compared to control group.

All the substances tested (C. pentandra extracts and ascorbic acid) strongly inhibited H2O2-induced hemolysis of RBC. The effect of the decoction was closed to that of ascorbic acid used here as the reference drug, with a maximal inhibitory effect of 77%, obtained at the concentration of 100 µg/mL. The methanol extract exhibited the weakest antioxidant activity but no significant effect was observed between treatments (Figure 4).

Figure 4 Effect of Ceiba pentandra stem bark extracts and ascorbic acid on H2O2-induced hemolysis. Values are expressed as mean  SEM of 9 different experiments. All points are significantly different (p < 0.001) compared to the reference (R) which is hemolysis without any treatment.

Effect of Ceiba pentandra extracts on lipid peroxidation Figure 3 Radical scavenging effect of Ceiba pentandra extracts and ascorbic acid on DPPH. Values are expressed as mean  SEM. Experiments carried out in triplicate. bp < 0.05, cp < 0.001, compared to ascorbic acid.

antioxidant activity of the methanol extract was similar to that of ascorbic acid and both substances nearly reached their maximum effect at the concentration of 10 µg/mL. At the concentration of 300 µg/mL, the decoction

All the plant extracts used inhibited the in vitro brain lipid peroxidation. Each extract exhibited a significant (p < 0.001) dose-dependent antioxidant activity. According to the efficiency index (EI), the reference drug α-tocopherol was significantly more efficient than the extracts. But based on the maximum effect (Emax) all extracts were more potent than α-tocopherol (Figure 5).

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Figure 6 Reducing capacity of Ceiba pentandra extracts. Values are expressed as mean  SEM of 8 different experiments carried out in duplicate; cp < 0.001 compared to butylated hydroxytoluene (BHT).

Figure 5 Effect of Ceiba pentandra extracts on lipid peroxidation induced by H2O2. Values are expressed as mean  SEM of 10 different experiments. a p < 0.05, bp < 0.01, cp < 0.001 compared to α-tocopherol.

Reducing power of Ceiba pentandra extracts The aqueous extracts of C. pentandra exhibited the greatest concentration-dependent reducing power. Their effect was more important than that of BHT used as positive control. The decoction reducing power was significantly higher (p < 0.001) than that of BHT at concentrations ranging from 10 to 300 µg/mL, whereas the maceration reducing capacity was only significantly greater (p < 0.001) than that of BHT at the concentration of 300 µg/mL (Figure 6).

Hydroxyl radical (•OH) scavenging effect of Ceiba pentandra extracts Among all the substances tested, only the methanol extract exhibited a significant high radical scavenging activity compare to the control mannitol. The methanol extract exhibited a concentration depending activity with the higher inhibition percentage (78.35%) registered at concentration of 300 µg/mL. The highest inhibition percentages of the maceration, the decoction and mannitol were respectively 17.74, 14.35 and 32.68 (Figure 7).

Figure 7 Scavenging effect of Ceiba pentandra extracts and mannitol on hydroxyl radical. Values are expressed as mean  SEM of 8 different experiments. c p < 0.001 compared to mannitol.

Discussion The present study was designed to determine the possible mechanisms underlying the antidiabetic and the

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Fofie et al.: In vitro anti-hyperglycemic and antioxidant effects of Ceiba pentandra

antioxidant effects of Ceiba pentandra stem bark extracts. The results obtained in vitro showed that the stem bark decoction from C. pentandra increased glucose uptake by the skeletal muscle and by the liver. In addition, more than insulin, this extract decreased glucose release by the liver. These findings further demonstrate that C. pentandra is endowed with antidiabetic properties as previously shown by Ladeji et al. [14] and Dzeufiet et al. [15] and also indicated that the decoction is the most efficient form of C. pentandra extracts against diabetes. By increasing glucose uptake and decreasing glucose release, this extract favors the storage of glucose by target organs and probably inhibits the hepatic glycogenolysis, limiting the amount of free glucose in the blood. This mechanism is similar to the action of insulin and could be attributed to the presence of catechin, which has been isolated from the stem bark of C. pentandra [22]. In fact, Ueda et al. [23] showed that catechin induces glucose uptake in 3T3-L1 adipocytes by promoting the translocation of GLUT4 to the plasma membrane. This is likely the mechanism by which the stem bark decoction from C. pentandra increases glucose uptake in the skeletal muscle. Likewise, the increase in liver glucose uptake induced by this extract might be due to the activation of the GLUT2-Glucosidase complex in liver cells. However further studies are needed to confirm these hypotheses. Oxidative stress has been implicated in the pathophysiology of various diseases including diabetes mellitus [24], where it is characterized by an increased production of free radicals and/or a sharp reduction of antioxidant defenses [25]. It was therefore thought that the use of antioxidant substances might prevent the development of diabetes and its related complications. Accordingly, antioxidants have shown positive effects in both type 1 and type 2 diabetes [26–28]. The present study showed that the different extracts from C. pentandra stem bark exhibited antioxidant activities on (DPPH), hemolysis of RBC, lipid peroxidation and ˙OH radical. In alcoholic solution, DPPH provides a stable free radical that can be scavenged by antiradical substances. The decoction, maceration, and methanol extracts from the stem bark of C. pentandra significantly scavenged DPPH radicals with a maximum effect exceeding that of ascorbic acid, used as the reference drug. The radical scavenging ability of a substance in this model relies on hydrogen [29] or electron donating capacity. In order to determine by which of these mechanisms C. pentandra extracts exert their activity, their reducing power was evaluated. These extracts exhibited potent concentration-dependent reducing power, suggesting that their

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antioxidant activity is at least partially due to their capacity to release electrons. Oxidative stress can cause damage to biological molecules such as nucleic acids, proteins and lipids. Peroxidation of membrane lipids induces changes in excitability, fluidity and permeability of membranes [30], which can lead to rupture of cell membranes [31]. In the present study, hydrogen peroxide caused hemolysis that was significantly reduced by the plant extracts. It is well known that RBC are powerful hydrogen peroxide scavenger due to their high content in catalase, which converts H2O2 into H2O and O2 [32, 33]. The above result suggests that C. pentandra extracts might prevent RBC hemolysis either by inhibiting the peroxidation of membrane lipids or by boosting endogenous catalase activity. In order to determine the mechanism by which C. pentandra extracts exert their antihemolytic effect, they were tested on H2O2-induced brain lipid peroxidation. It emerged from this that C. pentandra extracts were capable of inhibiting H2O2-induced lipid peroxidation suggesting that the antihemolytic effects of C. pentandra extracts might depend at least partially upon their ability to prevent lipid peroxidation. Lippi et al. [34] demonstrated that anemia in diabetic patients is correlated to mechanical fragility of erythrocytes. This mechanical fragility is linked to oxidative stress [35] that induced membrane lipid peroxidation and weaken the cell membrane. C. pentandra extracts therefore could be beneficial to this group of diabetic patients. In biological systems, one of the most reactive and deleterious species is hydroxyl radical. It is a highly reactive radical formed from the reaction of various hydroperoxides with transition metal ions. It attacks proteins, DNA, polyunsaturated fatty acid in membranes, and most biological molecules [36] and is known to be capable of subtracting hydrogen atoms from membrane lipids [37] and brings about peroxidic reaction of lipids. C. pentandra extracts, especially the methanol extract, exhibited a significant scavenging effect on this radical suggesting that this extract may be helpful against hydroxyl radical generated in a Fenton reaction system. Taken together, these results suggest that the antidiabetic effect of C. pentandra is due to its ability to increase glucose uptake, decrease glucose release and to protect biological molecules from oxidative stress. C. pentandra is hence a promising source of new antidiabetic drugs.

Acknowledgments: The authors are grateful to the International Foundation for Sciences (IFS) for the grant N° F-4576-1 offered to Pr Télesphore Benoît Nguelefack.

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Conflict of interest statement Authors’ conflict of interest disclosure: The authors stated that there are no conflicts of interest regarding the publication of this article. Research funding played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication. Research funding: None declared. Employment or leadership: None declared. Honorarium: None declared.

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Fofie et al.: In vitro anti-hyperglycemic and antioxidant effects of Ceiba pentandra

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Brought to you by | University of Calgary Authenticated Download Date | 5/27/15 1:21 AM

In vitro anti-hyperglycemic and antioxidant properties of extracts from the stem bark of Ceiba pentandra.

The goal of the study was to determine the antidiabetic mechanisms and the antioxidant effects of aqueous (decoction and maceration) and methanol extr...
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