Antiulcerogenic Potential of the Ethanolic Extract of Ceiba speciosa (A. St.-Hil.) Ravenna Evaluated by In Vitro and In Vivo Studies.

Gastrointestinal diseases, such as peptic ulcers, are caused by a damage in the gastric mucosa provoked by several factors. This stomach injury is regulated by many inflammatory mediators and is commonly treated with proton-pump inhibitors, histamine H2 receptor blockers and antacids. However, various medicinal plants have demonstrated positive effects on gastric ulcer treatment, including plants of the Ceiba genus. The aim of this study was to evaluate the antiulcer and anti-inflammatory activities of the stem bark ethanolic extract of Ceiba speciosa (A. St.-Hil.) Ravenna. We performed a preliminary quantification of phenolic compounds by high-performance liquid chromatography-diode array detection (HPLC-DAD), followed by the prospection of other chemical groups through nuclear magnetic resonance (NMR) spectroscopy. A set of in vitro assays was used to evaluate the extract potential regarding its antioxidant activity (DPPH: 19.83 ± 0.34 µg/mL; TPC: 307.20 ± 6.20 mg GAE/g of extract), effects on cell viability and on the release of TNF-α in whole human blood. Additionally, in vivo assays were performed to evaluate the leukocyte accumulation and total protein quantification in carrageenan-induced air pouch, as well as the antiulcerogenic effect of the extract on an ethanol-induced ulcer in rats. The extract contains flavonoids and phenolic compounds, as well as sugars and quinic acid derivatives exhibiting potent antioxidant activity and low toxicity. The extract reduced the release of TNF-α in human blood and inhibited the activity of p38α (1.66 µg/mL), JAK3 (5.25 µg/mL), and JNK3 (8.34 µg/mL). Moreover, it reduced the leukocyte recruitment on the pouch exudate and the formation of edema, reverting the effects caused by carrageenan. The extract presented a significant prevention of ulcer formation and a higher reduction than the reference drug, Omeprazole. Therefore, C. speciosa extract has demonstrated relevant therapeutic potential for the treatment of gastric diseases, deserving the continuation of further studies to unveil the mechanisms of action of plant bioactive ingredients.

Pigment of Ceiba speciosa (A. St.-Hil.) Flowers: Separation, Extraction, Purification and Antioxidant Activity.

In this work, the extraction procedure of a natural pigment from the flower of Ceiba speciosa (A. St.-Hil.) was optimized by response surface methodology. It is the first time that the extraction of the flower pigment of C. speciosa (FPCS) has been reported, along with an evaluation of its stability and biological activity under various conditions, and an exploration of its potential use as a food additive and in medicine. Specifically, the effects of ethanol concentration, solid-liquid ratio, temperature and time on the extraction rate of FPCS were determined using a Box-Behnken design. The optimum extraction conditions for FPCS were 75% ethanol with a solid-liquid ratio of 1:75 mg/mL) at 66 °C for 39 min. The purification of FPCS using different macroporous resins showed that D101 performed best when the initial mass concentration of the injection solution was 1.50 mg/mL, resulting in a three-fold increase in color value. The yield of dry flowers was 9.75% of fresh petals and the FPCS extraction efficiency was 43.2%. The effects of light, solubility, pH, temperature, sweeteners, edible acids, redox agents, preservatives and metal ions on FPCS were also investigated. Furthermore, the characteristics of FPCS were determined by spectrophotometry at a specific wavelength using the Lambert-Beer law to correlate the mass of FPCS with its absorbance value. An acute toxicological test performed according to Horne's method showed that FPCS is a non-toxic extract and thus may be used as a food additive or in other ingestible forms. Finally, western blotting showed that FPCS prevents lipopolysaccharide-induced hippocampal oxidative stress in mice. The study suggests that FPCS may function as an antioxidant with applications in the food, cosmetics and polymer industries.

A Comparative Analysis of Antimicrobial, Antibiofilm and Antioxidant Activity of Silver Nanoparticles Synthesized from Erythrina Suberosa Roxb. and Ceiba Pentandra.

Biofilm forming bacteria can cause serious health problems that are difficult to combat. Silver nanoparticles (Ag-NPs) synthesized from plant extracts have potential to fight and eradicate biofilmforming bacteria. In the present research, AgNPs were synthesized using leaf and bark extract of Erythrina suberosa Roxb. and Ceiba pentandra L. and their antibiofilm, antioxidant and antibacterial activity was checked. Phytochemical analysis of the plant extracts showed important bioactive compounds such as tannins, saponins, steroids, phenolics, alkaloids, flavonoids and glycosides. The AgNPs were synthesized and confirmed by visual color observation and UV-Vis spectrophotometer. Visual color observation showed that the color of the leaf and bark extracts of E. suberosa and C. pentandra turned into brown. UV-Vis spectra analysis showed absorbance peak range between 430-450 nm. The antioxidant activity of the AgNPs was determined by FRAC (Ferrous reducing antioxidant capacity) assay. Synthesized AgNPs from all sources showed significant antioxidant activity. However, antioxidant activity of E. suberosa AgNPs was significant compared to other sources. Antibacterial activity and biofilm forming assay was analyzed against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The synthesized AgNPs silver nanoparticles showed significant (p ≤ 0.05) antibacterial activity against all the bacteria. The maximum zone of inhibition was found in case of E. suberosa AgNPs bark extract against P. aeruginosa was 20±1.154 mm. The results of biofilm forming assay showed that the AgNPs from all sources significantly (p ≤ 0.05) inhibited the activity of biofilms by all the tested bacteria. From results, it can be concluded that AgNPs synthesized from both plants can be used in developing antimicrobial compounds.

Aqueous Bark Extract of Ceiba speciosa (A. St.-Hill) Ravenna Protects against Glucose Toxicity in Caenorhabditis elegans.

Plants are widely used in folk medicine because of their pharmacological properties. Ceiba speciosa, popularly known as paineira-rosa or tree-of-wool, is a species found in the Northwest of Rio Grande do Sul, being native of the upper Uruguay River, Brazil. The tea obtained from the stem bark is employed in folk medicine to reduce cholesterol, triacylglycerides, and glucose levels. However, there are no studies in the literature proving its efficacy or the safety of its use. For this study, we used Caenorhabditis elegans as an animal model considering its advantages for risk assessment and pharmacological screenings. For the toxicological tests, C. elegans N2 (wild type) was treated with the aqueous extract of the stem bark of C. speciosa (ECE) at the first larval stage (L1) at concentrations of 5, 25, 50, and 250 µg/mL. To evaluate biological activities, we challenged the extract for oxidative stress resistance in the presence of paraquat (0.5 mM), H2O2 (1 mM), and against glucose-induced toxicity. Our results demonstrated that ECE did not alter survival rate, pharyngeal pumping, and reproduction of the nematodes. The extract was not able to protect the nematodes against the toxicity induced by prooxidants. Notably, ECE protected against glucotoxicity by increasing worms' life span and by reducing glucose levels. On the other hand, ECE treatment did not reduce lipid accumulation induced by exogenous glucose feeding, as observed in worms which lipid droplets were tagged with GFP. Based on our results, we believe that the extract is indeed promising for further studies focusing on carbohydrates metabolism; however, it needs to be carefully evaluated since the extract does not seem to modulate lipid accumulation.

Multimodal α-Glucosidase and α-Amylase Inhibition and Antioxidant Effect of the Aqueous and Methanol Extracts from the Trunk Bark of Ceiba pentandra.

Postprandial hyperglycemia and oxidative stress are important factors that worsen the health condition of patients with type 2 diabetes. We recently showed that extracts from Ceiba pentandra mitigate hyperglycemia in dexamethasone- and high diet/streptozotocin-induced diabetes. Herein, we evaluated the postprandial regulatory properties and the antioxidant effects of the aqueous (AE) and methanol (ME) extracts from the stem bark of Ceiba pentandra. The phytochemical analysis of AE and ME was performed using the LC-MS technique and the total phenolic and flavonoid assays. Both extracts were tested for their ability to inhibit superoxide anion (O2 •ـ), hydrogen peroxide (H2O2), protein oxidation, alpha-amylase, and alpha-glucosidase activities. The mode of enzyme inhibition was also determined in a kinetic study. AE and ME were both rich in phenolic and flavonoid compounds. ME was 2.13 and 1.91 times more concentrated than AE in phenolic and flavonoid compounds, respectively. LC-MS allowed the identification of 5 compounds in both extracts. ME and AE inhibited O2 •ـ with IC50 of 51.81 and 34.26 µg/ml, respectively. On H2O2, they exhibited IC50 of 44.84 and 1.78 µg/ml, respectively. Finally, they exhibited IC50 of 120.60 and 140.40 µg/ml, respectively, in the inhibition of protein oxidation induced by H2O2, while showing IC50 of 39.26 and 97.95 µg/ml on the protein oxidation induced by AAPH. ME and AE inhibited alpha-amylase with IC50 of 6.15 and 54.52 µg/ml, respectively. These extracts also inhibited alpha-glucosidase, demonstrating IC50 of 76.61 and 86.49 µg/ml. AE exhibited a mixed noncompetitive inhibition on both enzymes, whereas ME exhibited a competitive inhibition on α-amylase and a pure noncompetitive inhibition on α-glucosidase. These results demonstrate that ME and AE scavenge reactive oxygen species and prevent their effects on biomolecules. Besides, ME and AE inhibit carbohydrate digestive enzymes. These properties may contribute to reduce postprandial hyperglycemia and regulate glycemia in diabetic patients.

Anti-Alzheimer's flavanolignans from Ceiba pentandra aerial parts.

Four flavanolignans, ceibapentains A (1) and B (2) and cinchonains Ia (3) and Ib (4), were isolated for the first time from an ethyl acetate extract of Ceiba pentandra (L) (Bombacaceae) aerial parts. The ceibapentains A (1) and B (2) are new compounds and their structures, including the absolute configurations, were determined by HRESIMS, 1D and 2D NMR, and electronic circular dichroism analyses, then compared with reported data. Compounds 1-4 were tested for their anti-Alzheimer's activity via an assessment of their inhibitory effect on amyloid ß42 aggregation using a thioflavin T assay. The results revealed that cinchonain Ia (3) showed a higher inhibitory effect (91%) than the standard curcumin (70%). Compounds 1, 2, and 4 exhibited moderate activity, with inhibition ratios of 43%, 47%, and 58%, respectively. A molecular docking study on the binding mode of 3 and curcumin with an amyloid ß1-40 peptide fibril structure indicated a high affinity of cinchonain 1a (3) towards amyloid ß1-40 peptide, in agreement with the experimental results.

Ceiba speciosa (A. St.-Hil.) Seeds Oil: Fatty Acids Profiling by GC-MS and NMR and Bioactivity.

This study aimed to evaluate the chemical composition by gas chromatography-mass spectrometry (GC-MS) and Nuclear Magnetic Resonance (NMR) analyses, the antioxidant activities evaluated by different in vitro assays namely 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), Ferric Reducing Ability Power (FRAP), and ß-carotene bleaching tests, and the inhibitory effects of enzymes linked to obesity (lipase, α-amylase, and α-glucosidase) of fixed seed oil of Ceiba speciosa (A. St.-Hil.). Fourteen compounds were identified. Linoleic acid (28.22%) was the most abundant followed by palmitic acid (19.56%). Malvalic acid (16.15%), sterculic acid (11.11%), and dihydrosterculic acid (2.74%) were also detected. C. speciosa fixed oil exerted a promising ABTS radicals scavenging activity with an IC50 value of 10.21 µg/mL, whereas an IC50 of 77.44 µg/mL against DPPH+ radicals was found. C. speciosa fixed oil inhibited lipase with an IC50 value of 127.57 µg/mL. The present investigation confirmed the functional properties of C. speciosa fixed oil, and proposes its use as valuable source of bioactive constituents.

In vitro activities of Ceiba speciosa (A.St.-Hil) Ravenna aqueous stem bark extract.

Several species of the genus Ceiba (Malvaceae) are ethnopharmacologically used. Thus, this study aimed to investigate the in vitro beneficial properties of the aqueous stem bark extract of Ceiba speciosa. The extract presented a great amount of phenolic compounds (117.4 ± 6.2 mg GAE/g). The antioxidant activity was assessed by DPPH (IC50 = 42.87 µg/mL), ORAC (2351.17 µmol TE/g) and FRAP (235.94 µM FeSO4/g) methods. In addition, the extract reduced MCF-7 cell viability as assessed by MTT. However, it prevented mitochondrial membrane depolarization and reduced caspase-9 activity induced by hydrogen peroxide. In conclusion, these findings indicate the extract is an excellent source of natural antioxidants and is able to protect ROS-induced cell death. Therefore, C. speciosa extract may possess beneficial properties for application in pharmaceutical industry as an antioxidant. However, further studies to better elucidate its mechanisms and to isolate its active compounds are required.

Effect of dietary kapok oil supplementation on growth performance, carcass traits, meat quality and sensory traits of pork in finishing-pigs.

Kapok seed and oil from the tropical zone are widely used as pig feed to harden porcine fat in Japan. This study evaluated the effect of dietary kapok oil supplementation on pork quality and sensory traits. Five Duroc pigs each were assigned to an experimental group supplemented with kapok oil and a control group. Dietary kapok oil supplementation had no effect on growth performance and intramuscular fat content in the Longissimus dorsi muscle (LM). Supplemental kapok oil increased saturated fatty acid contents in subcutaneous and intramuscular fat and decreased monounsaturated fatty acid levels (P < 0.05). Off-flavor detection by a trained panel was higher in the experimental than the control group (P < 0.05), but tenderness, juiciness, texture and flavor intensity of LM chops were similar in both groups. The overall palatability of pork as judged by a consumer panel decreased with kapok oil supplementation (P < 0.01). These results indicate that while growth performance, intramuscular fat contents and carcass characteristics were unchanged, while dietary kapok oil supplementation makes firm fat to prevent inferior soft fat in pork, it can lower the palatability of pork due to a decrease in monounsaturated fatty acids.

Kinetic study on microwave-assisted esterification of free fatty acids derived from Ceiba pentandra Seed Oil.

Recently, a great attention has been paid to advanced microwave technology that can be used to markedly enhance the biodiesel production process. Ceiba pentandra Seed Oil containing high free fatty acids (FFA) was utilized as a non-edible feedstock for biodiesel production. Microwave-assisted esterification pretreatment was conducted to reduce the FFA content for promoting a high-quality product in the next step. At optimum condition, the conversion was achieved 94.43% using 2wt% of sulfuric acid as catalyst where as 20.83% conversion was attained without catalyst. The kinetics of this esterification reaction was also studied to determine the influence of factors on the rate of reaction and reaction mechanisms. The results indicated that microwave-assisted esterification was of endothermic second-order reaction with the activation energy of 53.717kJ/mol.

Sorption kinetics and mechanism of various oils into kapok assembly.

Sorption rates of kapok fibers on different oils, such as diesel, cooking oil, used motor oil, and motor oil, were quantitatively evaluated by using a wicking method. Kapok fibers absorbing different oils exhibited large differences in terms sorption coefficients. Microscopic observations of oil wetting on a single kapok showed that the four oils had varying wettability and adhesiveness to kapok, but that all of them penetrated into kapok lumens quickly because of the fiber's low surface energy, which was 40.64 mN/m, and extreme hydrophobicity, with a water contact angle up to 151°. After treatment with chloroform, there were slight changes in oil absorbencies to kapok, but the sorption coefficients for the four oils increased markedly. SEM demonstrated that chloroform treatments caused the smooth surface of the kapok fibers to become highly roughened, with densely vertical grooves that provided more available surface and a larger driving force for oil sorption through the fiber assembly.

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

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 concentration-dependent 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 organs. The antioxidant properties of C. pentandra extracts are additional benefit for their antidiabetic effects.

Decreased thrombin activity by a Congolese herbal medicine used in sickle cell anemia.

ETHNOPHARMACOLOGICAL RELEVANCE: Aqueous extracts from Ceiba pentandra (Malvaceae/Bombacoideae) and Quassia africana (Simaroubaceae) are used as crude medicines for the management of sickle cell anemia (SCA) in the Democratic Republic of Congo (DR Congo). Since it is postulated that the pathogenesis of SCA is associated with an increased blood coagulation activity, the present study is conducted to determine the effect of the two extracts on the coagulation by assessing the thrombin activity and the plasma clotting time. MATERIALS AND METHODS: Thrombin activity was measured by chromogenic assay in the presence of the aqueous extracts (10, 100 or 200 µg/ml); and plasma clotting times were measured by activated partial thromboplastin time (APTT) and prothrombin time (PT) in the presence of C. pentandra (10, 100 or 200 µg/ml) and Q. africana (5, 20 or 50 µg/ml). RESULTS: Reduced thrombin activity and prolonged plasma clotting time measured by APTT were observed in the presence of C. pentandra extract only. However, plasma clotting time measured by PT was not modified by the use of the two extracts. CONCLUSIONS: This study suggests that the aqueous extract of C. pentandra may contain active components that reduce the thrombin activity and prolong the plasma clotting time by affecting the coagulation intrinsic pathway.

Coated kapok fiber for removal of spilled oil.

Based on raw kapok fiber, two kinds of oil absorbers with high sorption capacity were prepared by a facile solution-immersion process. The coated polymer with low surface energy and rough fiber surface play important role in the retention of oil. The as-prepared fiber can quickly absorb gasoline, diesel, soybean oil, and paraffin oil up to above 74.5%, 66.8%, 64.4% and 47.8% of oil sorption capacity of raw fiber, respectively. The absorbed oils can be easily recovered by a simple vacuum filtration and the recovered coated-fiber still can be used for several cycles without obvious loss in oil sorption capacity. The thermodynamic study indicates that the adsorption process is spontaneous and exothermic, with complex physisorption and chemisorption. The results suggest that the coated fiber can be used as a low-cost alternative for the removal of oil spilled on water surface.

Effect of a Congolese herbal medicine used in sickle cell anemia on the expression of plasminogen activators in human coronary aortic endothelial cells culture.

ETHNOPHARMACOLOGICAL RELEVANCE: Aqueous extract of Ceiba pentandra, which is used for the management of sickle cell anemia (SCA) in DR Congo, exhibits antithrombin response by activation of Heparin cofactor II in vitro. This study examines the effect of the plant on the fibrinolytic activity to understand whether it can influence the coagulation-fibrinolysis system, since fibrinolysis disorder is one of the contributing causes of thrombotic crises in SCA. MATERIALS AND METHODS: Fibrinolysis proteins were determined by enzyme-immunoassay in the conditioned medium of cultured endothelial cells after treatment with the extract. Electrophoresis-zymography and RT-PCR tests were conducted to examine the activity and the RNA synthesis of these proteins, respectively. RESULTS: It was found that the extract decreased the activity of both tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA) and plasminogen activator inhibitor type-1 (PAI-1). However, it was revealed that this effect was not the result of an inhibition of their biosynthesis by endothelial cells. CONCLUSION: From the foregoing, it was revealed that the extract inhibited the secretion of the fibrinolytic proteins without affecting their synthesis by endothelial cells. Thus, the extract may not accelerate the digestion of fibrin clot resulting from thrombotic disorders in SCA.

Hypoglycemic and antihyperglycemic effect of Ceiba pentandra L. Gaertn in normal and streptozotocin-induced diabetic rats.

BACKGROUND: Ceiba pentandra (L.) Gaertn, commonly called silk-cotton tree, has been extensively used by traditional medicine practitioners in Northern and Eastern Nigeria in the control and management of diabetes. OBJECTIVE: To evaluate the hypoglycaemic and anti-hyperglycaemic effect of ethanolic extract of Ceiba pentandra bark in normal and streptozotocin induced diabetic rats. METHOD: Screening activity of the extract was carried out by OGTT. Diabetes mellitus was induced with streptozotocin and graded doses of the ethanolic bark extract (200 and 400 mg/kg, b.w.) were then administered to the experimentally diabetic rats. The blood glucose level was measured at different time intervals. RESULTS: The single dose study of C. pentandra extract at two different doses produced no significant hypoglycaemic effect in normal rats but C. pentandra (200 mg/kg) significantly decreased blood glucose level in diabetic rats. In OGTT, C. pentandra (200 mg/kg) significantly reduced elevated glucose level in normal and diabetic rats. In long term (21 days) study, C. pentandra (200 mg/kg) significantly decreased blood glucose level, total cholesterol and triglycerides level, prevented degeneration of liver and pancreas, and increased serum insulin level and liver glycogen content in diabetic rats. Acute toxicity study in rats did not show any signs of toxicity up to the dose of 2000 mg/kg b.w. CONCLUSION: The results reveal that the extract improved glucose tolerance in normal and streptozotocin-induced diabetic rats. Thus the study suggests that the C. pentandra bark extract could be beneficial in the management of type I diabetes.

Evaluation of kapok (Ceiba pentandra (L.) Gaertn.) as a natural hollow hydrophobic-oleophilic fibrous sorbent for oil spill cleanup.

Oil sorption capacity and hydrophobic-oleophilic characteristics of an agricultural product, kapok (Ceiba pentandra), was thoroughly examined. The kapok fiber has a hollow structure with large lumen. Its performance was compared with that of a polypropylene (PP), a widely used commercial oil sorbent for oil spill cleanup. The oils investigated were diesel, hydraulic oil (AWS46), and engine oil (HD40). Reusability of the kapok after application to various oils was also evaluated. Both loose (at its natural state) and densely packed kapok assemblies were examined. Sorption capacities of the packed kapok assemblies were very much dependent on their packing densities. At 0.02gcm(-3), its oil sorption capacities were 36, 43 and 45gg(-1) for diesel, ASW46 and HD40, respectively. The values decreased to 7.9, 8.1 and 8.6gg(-1) at 0.09gcm(-3). Its sorption capacities for the three oils were significantly higher than those of PP. When the oil-saturated kapok assemblies were allowed to drain, they exhibited high oil retention ability, with less than 8% of the absorbed diesel and HD40, and 12% of the absorbed AWS46 lost even after 1h of dripping. When applied on oil-over-water baths, the kapok exhibited high selectivity for the oils over the water; almost all oils spilled could be removed with the kapok, leaving an invisible oil slick on water. After the 4th cycle of reuse, the reused kapok assembly only lost 30% of its virgin sorption capacity if packed at 0.02gcm(-3), and the loss in sorption capacity was much less at higher packing densities. The hydrophobic-oleophilic characteristics of the kapok fiber could be attributed to its waxy surface, while its large lumen contributed to its excellent oil absorbency and retention capacity.

In situ oil/water separation using hydrophobic-oleophilic fibrous wall: a lab-scale feasibility study for groundwater cleanup.

Kapok, a natural plant fiber, possesses excellent hydrophobic-oleophilic characteristics. Its innovative use as hydrophobic-oleophilic wall that allows permeation of oil but not water into an oil recovery well is proposed. Its performance was investigated through laboratory experiments, in which diesel was used as the experimental oil. A two-dimensional hydraulic flume was setup to physically model the oil/water separation by the kapok wall. The influences of packing density, kapok wall thickness and oil thickness on the oil recovery rate were examined. The oil permeability of the packed kapok decreased from 0.0165 cm2 at 34 g/L packing density to 0.0038 cm2 at 70 g/L packing density. The kapok wall exhibited complete rejection of water while allowed oil to permeate through. The excellent oil/water separation by the kapok wall was due to surface interaction between the kapok fibers and the oil, which resulted in spontaneous penetration and permeation of the oil through the kapok wall. The oil recovery rate increased with thickness of the oil layer in the feed stream. When the oil thickness exceeded 60 mm, a constant flux of 3.8-5.0, 3.2-3.3 and 2.5-2.7 L/(m2 min) could be achieved by the kapok wall of 55-, 75- and 95-mm thick, respectively, under the natural pressure gradient. The kapok wall could be reused for several wetting/drying cycles, and only lost 27% of its initial oil permeability.

Evaluation of medicinal plants from Mali for their in vitro and in vivo trypanocidal activity.

Water, methanol and dichloromethane extracts prepared from various parts of 40 medicinal plant species from Mali were investigated for their trypanocidal activity against Trypanosoma brucei brucei. Of a total of 165 extracts tested in vitro in the Low Inoculation Long Incubation Test (LILIT), 24 extracts showed a high trypanocidal activity. Using the Long-Term Viability Assay (LtVA) for corroboration of the results of the 24 extracts, it was found that 15 samples had minimum inhibitory concentration (MIC) values > 10 microg/ml, eight MIC values of 100 microg/ml and one MIC values of 50-100 microg/ml. So far, four extracts with MIC values < or = 100 microg/ml were tested for antitrypanosomal activity in mice, experimentally infected with Trypanosoma brucei brucei. Only, the aqueous extracts of the leaves of Terminalia avicennioides Guill. and Perr. (Combretaceae) and the stem bark of Ceiba pentandra (L.) Gaertn. (Bombacaceae) were able to reduce the parasitaemia in animals treated at the dose of 100 mg/kg b.w. (intraperitoneally, two times daily for 3 days) and of 150 mg/kg b.w. (per os, two times daily for 3 days), respectively. The reduction of parasitaemia was, however, statistically significant (p=0.002) only in case of treatment with Terminalia avicennioides.