Efectos histológicos hepático y renal relacionados con la hiperglicemia producida por el extracto de Angostura trifoliata (Willd) T.S. Elías. Rutaceae / Hepatic and renal histological effects related to hyperglycemia produced by the extract of Angostura trifoliata (Willd) T.S. Elías. Rutaceae

Angostura trifoliata (Willd) T.S. Elías (Rutaceae) es una planta, cuya corteza es empleada en Venezuela para el tratamiento de la diabetes mellitus, la malaria y la disminución de peso. Sin embargo, se ha demostrado que altas dosis de su extracto administrados en forma aguda producen hiperglicemia y alteraciones neurológicas. El objetivo de este estudio fue correlacionar los efectos histológicos a nivel hepático y renal en ratones sanos con la hiperglicemia aguda producida por el extracto de la corteza de esta planta. Métodos: Se realizó un estudio experimental in vivo utilizando el extracto diluido en agua y administrado vía ip a dosis de 452 y 700 mg/kg; se determinó la glicemia utilizando un glucómetro comercial; los efectos histológicos con hematoxilina eosina previa fijación de los órganos con formaldehído al 10%. En todos los casos, se comparó con el grupo control. Resultados: el extracto produjo hiperglicemia significativamente P<0,05. En el tejido hepático causó: pérdida parcial de su arquitectura, binucleación, vasos congestivos con elementos inflamatorios, núcleos hipercromáticos, espacios de Disse dilatados con hematíes y áreas de necrosis. En el riñón originó congestión vascular en los tubos contorneados proximales y distales, concomitante con ruptura y necrosis de la membrana basal. Conclusión: el extracto produce toxicidad hepática y renal que se correlacionan con hiperglicemia, por lo que podría ser considerado como un agente hepatotóxico y nefrotóxico. (AU)

Angostura trifoliata (Willd) T.S. Elías (Rutaceae) is a plant, whose bark is used in Venezuela for the treatment of diabetes mellitus, malaria and weight loss. However, it has been shown that high doses of its extract administered acutely produce hyperglycemia and neurological alterations. The objective of this study was to correlate the histological effects at the liver and kidney level in healthy mice with the acute hyperglycemia produced by the bark extract of this plant. Methods: An in vivo experimental study was carried out using the extract diluted in water and administered ip at doses of 452 and 700 mg/kg; blood glucose was determined using a commercial glucometer; the histological effects with hematoxylin eosin after fixation of the organs with 10% formaldehyde. In all cases, it was compared with the control group. Results: the extract produced hyperglycemia significantly P<0.05. In the liver tissue it caused: partial loss of its architecture, binucleation, congested vessels with inflammatory elements, hyperchromatic nuclei, dilated spaces of Disse with red blood cells and areas of necrosis. In the kidney, it caused vascular congestion in the proximal and distal convoluted tubes, concomitant with rupture and necrosis of the basement membrane. Conclusion: the extract produces liver and kidney toxicity that correlates with hyperglycemia, so it could be considered a hepatotoxic and nephrotoxic agent. (AU)

Evaluation of acute and subacute toxicity of ethanolic extract and fraction of alkaloids from bark of Aspidosperma nitidum in mice.

This study investigated the acute and subacute toxicity of the ethanolic extract (EE) and alkaloid fraction (FA) from A. nitidum. The EE was obtained from trunk bark with ethanol, FA was obtained from the fractionation of EE. To test the acute toxicity, mice were divided into four groups, and the negative controls received water or aqueous solution of dimethyl sulfoxide, whereas the others received EE or FA (2000 mg/kg, orally, single dose). The same controls were used in the subacute trial. However, the animals were treated for 28 days, and the dose used was 1000 mg/kg per day of EE and FA. Daily clinical evaluations of the animals were performed. At the end of the experiment, hematological, biochemical, and histopathological assessments (liver, lung, heart, and kidney) were performed. In the acute and subacute toxicity studies, mice treated with EE and FA did not show any clinical changes, there were no changes in weight gain, hematological and biochemical parameters compared to the control groups (p > 0.05). In the histopathological examination, there was no abnormality in the organs of the treated animals. Therefore, EE and FA did not produce toxic effects in mice after acute and subacute treatment.

Investigation of the Antibacterial Activity and Subacute Toxicity of a Quercus crassifolia Polyphenolic Bark Extract for its Potential Use in Functional Foods.

Oak wood is used in barrels for wine aging. During aging, polyphenols are transferred from the barrels to the liquid. Although the bioactivity of oak polyphenols in wines has been extensively studied, no investigation exists on their toxicological properties, which limits their use as functional safe ingredients for other products. In this work, the chemical composition of a polyphenolic extract of Quercus crassifolia bark (QCBe) was studied by GC-MS. Its antibacterial properties on probiotic and pathogenic bacteria and its subacute-oral toxicity were determined as a way to understand the potential impact from its addition to fermented food as a functional ingredient. QCBe shows a selective inhibition of Escherichia coli compared with Lactobacillus bulgaricus and Streptococcus thermophylus. According to the toxicity evaluation, the subacute no-observed-adverse-effect-level was achieved at 11 mg/kg bw/day, whereas the subacute lowest-observed-adverse-effect-level for kidney damage was at 33 mg/kg bw/day. These results suggest that, given the fact an adverse effect was observed after subacute administration of this extract, further longer term toxicological studies are needed to provide sufficient safety evidence for its use in humans. PRACTICAL APPLICATION: Mexico's yogurt market is growing which creates opportunities for the development of some yogurt products as functional foods. As a first step to evaluate its potential use in yogurt formulation, the antibacterial effect of a Quercus crassifolia polyphenolic extract (QCBe) on probiotic bacteria and its subacute-oral toxicity in rats were studied. A low inhibition on probiotic bacteria growth was observed after QCBe addition to Lactobacillus bulgaricus and Streptococcus thermophylus cultures. Exposure to QCBe for a subacute duration resulted in renal injury in rats at dosages greater than or equal to 33 mg/kg/bw/day. This adverse effect indicates the importance of performing further long-term toxicological assessments prior to the addition of QCBe to a food like yogurt, which is regularly eaten by consumers.

Histopathological alterations in mice under sub-acute treatment with Hintonia latiflora methanolic stem bark extract.

The indiscriminate use of herbal products is increasingly growing worldwide; nonetheless consumers are not warned about the potential health risks that these products may cause. Hintonia latiflora (Hl) is a tree native to the American continent belonging to the Rubiaceae family and its stem bark is empirically used mainly to treat diabetes and malaria; supplements containing Hl are sold in America and Europe without medical prescription, thus scientific information regarding its toxicity as a consequence of a regular consumption is needed. In the present study, the histopathological effect of 200 and 1000 mg/kg of HI methanolic stem bark extract (HlMeOHe) was evaluated in the small bowel, liver, pancreas, kidneys and brain of CD-1 male mice after oral sub-acute treatment for 28 days. No histopathological alterations were observed in the brain and small bowel of the treated animals; however, mice presented diarrhea from day 2 of treatment with both doses. No histological changes were observed in the tissues collected from the animals treated with 200 mg/kg, except for the liver that depicted periportal hepatitis. Animals treated with the higher dose showed in the liver sections hydropic degeneration, hepatitis and necrosis, kidney sections depicted tubular necrosis and in pancreas sections, hydropic degeneration of the pancreatic islets was observed. In conclusion, HlMeOHe damaged the liver with an oral dose of 200 mg/kg, and at 1000 mg/kg injured the kidneys and pancreas of the CD-1 male mice.

Acute and sub-acute oral toxicity studies of the aqueous extract from radix, radix with cortex and cortex of Psammosilene tunicoides in mice and rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Psammosilene tunicoides is one of the important ingredients of a famous Chinese traditional medicine formulation "Yunnan Baiyao". Also, this plant is commonly used as an anodyne and hemostatic agent in southwest China. Currently, little toxicological information is available on its safety following prolonged use. AIM OF THE STUDY: In this study, we sought to evaluate the toxicity of the three different parts of Psammosilene tunicoides: Psammosilenes Radix (PR), Psammosilenes Radix with Cortex (PRC) and Psammosilenes Cortex (PC) by acute and sub-acute toxicity studies. MATERIALS AND METHODS: In the acute toxicity study, mice were orally administrated with different doses of PR, PRC and PC. General behavior and mortality were observed up to 14 days. In sub-acute toxicity study, these aqueous extracts were given orally as a single administration to rats at doses of 0.3, 0.6 and 1.2g/kg/day, respectively, for 28 days. General behavior, body weight, biochemical, hematological, organ coefficients and pathological morphology parameters were detected. RESULTS: In acute study, single oral administration of the aqueous extract of PR, PRC and PC caused dose-dependent general behavior adverse effects and mortality. The LD50 values of PR, PRC and PC were 4.64g/kg, 4.85g/kg and 6.40g/kg, respectively. In sub-acute study, the administration of the extract of PR, PRC and PC during 28 days at all doses reduced spontaneous activities with both genders. Occasional nasal secretion with blood at high doses (1.2g/kg) of PR, PRC and PC were observed. Daily single oral administration provoked varying degrees of growth retardation in female rats. The relative heart and spleen weight in the female rats were reduced after the administration. On the hematological and biochemical analyses, the administration of the extract of PR, PRC and PC during 28 days mainly caused variation of indexes in female rats. Histopathological analysis has shown vascular congestion in heart, thickened alveolar wall and emphysema in lung, and vascular congestion in kidney of rats after sub-acute oral administrations. CONCLUSIONS: As shown in the results, Psammosilene tunicoides has a toxic potential in acute and sub-acute oral administrations. However, there is no direct relationship between toxicity and the cortex. Daily oral administration of three different parts from Psammosilene tunicoides (PR, PRC and PC) may cause damages to heart, lung and kidney in rats. Thus these extracts should be used with caution.

Comparative evaluation of hypoglycemic and hypolipidemic activity of various extract of Anogeissus latifolia bark in streptozotocin-induced diabetic rats.

Background Anogeissus latifolia Wall. (A. latifolia) bark has been traditionally used in the treatment of various diseases which includes diabetes and general debility. The present study was aimed to investigate the comparative hypoglycemic and hypolipidemic activity of various extracts of A. latifolia bark in streptozotocin-induced type 1 diabetic rats. Methods Acute toxicity was carried out at 2 g/kg dose of petroleum ether extract of A. latifolia bark (PEALB), chloroform extract of A. latifolia bark (CEALB) and methanol extract of A. latifolia bark (MEALB) in rats. Diabetes was induced by streptozotocin (STZ, 60 mg/kg, i.p.) and it was confirmed at 72 h. Diabetic rats received above extracts at 100 and 200 mg/kg doses for 28 days. Body weight and blood glucose level were determined at every week after the treatment schedule. Serum biochemical parameters and lipid profile levels were estimated at the end of the study. Results PEALB, CEALB and MEALB were non-toxic and no death was observed at 2 g/kg dose. Administration of MEALB at 100 and 200 mg/kg showed significant (p< 0.01, p< 0.05) improvement in body weight and reduction in blood glucose at third and fourth week of treatment. Altered serum biochemical parameters and lipid profiles level were brought to near normal level significantly (p<0.001) compared to diabetic control rats after the administration of both doses of MEALB. However, PEALB and CEALB did not exhibit significant hypoglycemic and hypolipidemic activity. Conclusions Our findings revealed that long-term (28 days) treatment of MEALB possesses significant hypoglycemic and hypolipidemic activity compared to PEALB and CEALB in type 1 diabetic rats and given evidence to the traditional use of A. latifolia bark in diabetes.

Quantificação de fenóis totais presentes nas cascas de Trichillia catigua A. Juss (Meliaceae) / Quantification of total phenols present in the bark of Trichilia catigua A. Juss (Meliaceae)

Trichillia catigua A. Juss. é uma planta medicinal utilizada principalmente como estimulante, possivelmente devido à presença de fenóis. Entre os métodos utilizados para a determinação de polifenóis em matérias-primas vegetais destaca-se a análise por meio de ensaios espectrofotométricos por apresentarem boa sensibilidade, simplicidade, e ter custos mais acessíveis. O presente trabalho teve o objetivo de validar a metodologia analítica para determinação de polifenóis na casca de catuaba em pó. Utilizou-se o método de Hagerman & Butler para a quantificação dos polifenóis totais encontrando-se 7,96%. O método validado mostrou-se simples, rápido, seletivo, linear, exato, preciso, e robusto para ser executado na rotina de laboratório de controle de qualidade, constituindo uma possibilidade de análise desta planta medicinal.

Trichilia catigua A. Juss. is a medicinal plant used especially as a stimulant, possibly due to the presence of phenols. Among the methods used for the determination of polyphenols in raw plant materials is analysis through spectrophotometric assays since they have good sensitivity, are simple and more affordable. This study aimed to validate the analytical methodology for the determination of polyphenols in the bark of powder "catuaba". The method of Hagerman & Butler was employed in the quantification of total polyphenols, yielding 7.96%. The validated method has proven to be simple, rapid, selective, linear, accurate, precise and robust to be performed in the routine of a laboratory of quality control, constituting a possibility for the analysis of this medicinal plant.

Evaluation of the acute and sub acute toxicity of Annona senegalensis root bark extracts.

OBJECTIVE: To investigate the safety profile of Annona senegalensis (A. senegalensis). METHODS: Dried powdered root-bark of A. senegalensis was prepared by Sohxlet extraction using methanol-methylene chloride (1:1) solution and concentrated to obtain the methanol-methylene chloride extract (MME). MME was fractionated to obtain the n-hexane (HF), ethylacetate (EF) and methanol (MF) fractions. Acute toxicity (LD(50)) test was performed with MME, HF, EF and MF in mice by oral route. The sub acute toxicity studies were performed in rats after 14 days of MME administration while haematological and biochemical parameters were monitored. RESULTS: Medium lethal (LD(50)) values of 1,296, 3,808, 1,265 and 2,154 mg/kg were obtained for the MME, MF, HF and EF, respectively. The sub-acute toxicity studies indicated a significant (P<0.05) increase in the body weight of both the treated rats and the control. The haematological tests indicated no change in the packed cell volume values but a significant (P<0.05) increase in the total WBC count at 100 and 400 mg/kg doses. The differential analysis showed a decrease in the nutrophils and a non-significant increase in the lymphocyte counts. The liver transaminase enzymes, alanin transaminase and aspartate transaminase showed no significant increase compared to the control. Histopathological examination of the liver sections also indicted no obvious signs of hepatotoxicity except with the 400 mg/kg dose that showed degeneration and necrosis of the hepatocytes. CONCLUSIONS: These results indicated that the root bark extracts of A. Senegalensis are safe at the lower doses tested, and calls for caution in use at higher doses in treatment.

Implementation of the three Rs in the human hazard assessment of Brazilian medicinal plants: an evaluation of the cytotoxic and genotoxic potentials of Dipteryx alata Vogel.

In Brazil, medicinal plants are widely used by the indigenous people, which leads to a constant requirement for toxicity tests to be performed on the plant extracts. Although the current Brazilian Directive 90/2004 on the preclinical toxicity testing of phytotherapeutics recommends only in vivo tests, some Brazilian researchers would like to change this situation by implementing the Three Rs in the toxicological testing of medicinal plants. The present study evaluated the cytotoxic and genotoxic potentials of bark extracts from Dipteryx alata Vogel, a medicinal plant of the Brazilian cerrado, by using CHO-K1 (Chinese hamster ovary) cells. An IC50 value was obtained, which corresponded to 0.16mg/ml of plant extract, and from this the equivalent LD50 was determined as 705mg/kg. In order to determine the genotoxic potential of the sample, the frequency of micronucleus formation was assessed. CHO-K1 cells were exposed, during targeted mitosis, to different concentrations of plant extract and cytochalasin B, in the presence and absence of an appropriate metabolic activation system (an S9 mix). The results obtained indicated that it might be possible to implement the Three Rs in assessing the potential human hazard of medicinal plants. The publication of such data can increase awareness of the Three Rs by showing how to optimise the management of animal use, if in vivo toxicological experiments are required.

Acute and sub-chronic oral toxicity studies of an aqueous stem bark extract of Pterocarpus soyauxii Taub (Papilionaceae) in rodents.

UNLABELLED: Pterocarpus soyauxii Taub (Papilionaceae) is used in Cameroonian traditional medicine and pharmacopoeia to treat hypertension, diabetes, gastrointestinal parasitizes and cutaneous diseases. AIM OF THE STUDY: The present investigation was carried out to evaluate the safety of an aqueous stem bark extract of Pterocarpus soyauxii by determining toxicity after acute and sub-chronic oral administration in male and female rodents. MATERIALS AND METHODS: The acute toxicity test was conducted in mice. An aqueous extract of barks was administrated by gavage in single doses of 2.5-12.5 g/kg. General behaviour and mortality were examined for up to 7 days. The sub-chronic toxicity test was performed in rats. The plant extract was administered by daily gavage of 150-600 mg/kg for 42 days. Body weight, food and water intakes were followed weekly. Haematological, biochemical and organ parameters were determined at the end of the 42-day administration. RESULTS: In the acute study in mice, oral administration of the aqueous extract of Pterocarpus soyauxii caused dose-dependent general behaviour adverse effects and mortality. The no-observed adverse effect level (NOAEL) of the extract was 5.0 g/kg. The lowest-observed adverse effect level (LOAEL) was 7.5 mg/kg. Mortality increased with the dose, LD(50) was>10.75 g/kg for the mouse. In the sub-chronic study in rats, daily oral administration of the aqueous extract of Pterocarpus soyauxii did not result in death or significant changes in haematological or biochemical parameters, excepted increased hepatic catalase activity (P<0.05) at the dose of 600 mg/kg. No alteration was observed in body weight, food and water intake. Liver, kidney, lung and pancreas histopathology did not reveal morphological alteration. CONCLUSIONS: The results showed that the aqueous stem bark extract of Pterocarpus soyauxii Taub had very low toxicity in oral acute high dose administration and no toxicity in oral sub-chronic low dose administration and indicate that the plant could be considered safe for oral medication.

Biological activities and safety of Thanaka (Hesperethusa crenulata) stem bark.

ETHNOPHARMACOLOGICAL RELEVANCE: The stem bark powder of Hesperethusa crenulata or Thanaka has been used on the face by Myanmar women for more than a thousand years as a skin care regiment. AIM OF THE STUDY: The aim of the current study was to both verify the safety and evaluate some biological activities of the Thanaka bark. MATERIALS AND METHODS: Maceration of the Thanaka bark powder resulted in hexane, dichloromethane, ethyl acetate, methanol, 85% ethanol and water extracts. For the safety evaluation, cytotoxicity and genotoxicity of each extract were tested. Antibacterial, tyrosinase inhibition, antioxidant and anti-inflammatory activities were evaluated for each extract. RESULTS AND CONCLUSIONS: Extracts from Thanaka bark showed strong anti-inflammatory, significant antioxidation, mild tyrosinase inhibition and slight antibacterial activities. All extracts and the original bark powder showed no detectable genotoxicity while very low cytotoxicity with IC(50) value of more than 12 mg/ml was detected in the water extract. Thus, the use of the Thanaka bark in the form of a watery paste as a skin care regiment is not only safe but also beneficial to skin.

Evaluations of toxicity of Turraeanthus africanus (Méliaceae) in mice.

Turraeanthus africanus (Meliacaeae) is known to possess a broad spectrum of pharmacological, medicinal and therapeutic properties. However, no extensive safety studies have been conducted on these extracts to date. The aim of this study was to evaluate toxicity of the aqueous extract of Turraeanthus africanus (Meliacaeae) after oral and intraperitoneal administration in mice. The acute toxicity was evaluated after single daily administration of the aqueous extract orally at doses of 0, 5, 10, 15, 20, 30 g kg(-1) or by the intraperitoneal route at doses of 0, 3, 6, 9, 12 g kg(-1) of raw material. The subacute toxicity was evaluated only by the intraperitoneal route for 6 weeks at doses of 1.5, 3, 6 g kg(-1) of raw material. Oral doses up to 30 g kg(-1) of the aqueous extract of Turraeanthus africanus (TA) did not produce mortality or significant changes in the general behaviour and gross appearance of internal organs of rats. However, the intraperitoneal administration of the aqueous extract of Turraeanthus africanus caused dose-dependent lethal effects. The acute intraperitoneal toxicity (LD(50)) of TA extract in mice was 7.2 g kg(-1). In subacute toxicity in mice, after the intraperitoneal administration of TA extract for 6 consecutive weeks, the feed consumption was significantly affected at the dose 3 g kg(-1) with P < 0.05 and at the dose 6 g kg(-1) with P < 0.001 and consequently had significant effect with P < 0.05 in body weight of animals. Level of triglyceride of treated animals lowered at dose 1.5 g kg(-1) with P < 0.001 and at dose 3 g kg(-1) and 6 g kg(-1) with P < 0.05. Total cholesterol level of treated animals lowered at dose 1.5 g kg(-1) with P < 0.005 and at dose 3 and 6 g kg(-1) with P < 0.001. HDL cholesterol level of treated animals lowered up to dose 6 g kg(-1) with P < 0.05 while levels of LDL cholesterol, serum and tissue creatinine of treated animals lowered at dose 3 g kg(-1) and dose 6 g kg(-1) with P < 0.05. Serum protein level of treated animal enhanced at dose 1.5 g kg(-1) and at dose 6 g kg(-1) with P < 0.05 while tissue creatinine level of treated animal enhanced with P < 0.001. The histology of liver, kidney and lung of the treated mice indicated morphological change of these organs (data not shown). No significant difference was observed during treatment concerning the haematological parameters. The results suggest that the plant is not toxic through the oral route in mice and that parenteral administration should be avoided.

Occupational allergic contact dermatitis from cinnamon including one case from airborne exposure.

BACKGROUND: The bark of the cinnamon tree is used as a spice; its flavour is from an essential oil containing mainly cinnamal. OBJECTIVE: To report new cases of occupational allergic contact dermatitis (ACD) from cinnamon and a novel case of airborne cinnamon contact allergy. METHODS: We examined the patient material of two dermatological clinics in Helsinki to find cinnamon contact allergic patients and review their clinical records. RESULTS: We found six patients with delayed contact allergy to cinnamon. In four patients, cinnamon was the main cause of occupational ACD. Three of them had dermatitis on their hands and one patient on the face and neck. In the latter case, the exposure was shown to be airborne. In addition, the fifth patient was occupationally sensitized to cinnamon, but it was not the main cause of his hand dermatitis. In the sixth patient, cinnamon allergy was considered to derive from cross-allergy to fragrances. Five of the patients reacted to cinnamal separately and in fragrance mix I. None of the six patients had immediate-type cinnamon allergy. CONCLUSIONS: Occupational contact allergy to cinnamon is rare but needs to be considered in workers handling foods. Cinnamal is possibly the main allergen in cinnamon.

Toxicological and phytochemical studies of Aspidosperma subincanum Mart. stem bark (Guatambu).

Aspidosperma subincanum Mart. is widely used in Brazilian folk medicine to treat digestive disorders. In this study, acute and subchronic toxicity and cytotoxicity of stem bark ethanolic extract of Aspidosperma subincanum (EEAs) have been evaluated. In addition, phytochemical analysis was performed. The EEAs had low acute toxicity in mice with LD50 =1129 +/- 154mg/kg p.o. and 397 +/- 15 mg/kg i.p. The LC50 was 1340 +/- 428 microg/mL in the brine shrimp assay. There was no relevance of serious changes in behavioral, hematological and biochemical parameters and no deleterious effect on vital organs of rats that resulted after 30 days daily exposure to 5 and 100 mg/kg of EEAs. Phytochemical analysis of stem bark of A. subincanum revealed the presence of indole alkaloids, saponins, terpenoids, steroids and tannins and resulted in the isolation of oleic acid and guatambuine as major constituents. Using the method of the dose by factor approach, the human safe dose was 210 mg/70 kg/day. The EEAs appears to be safe and non-toxic in low doses in rodents and domestic preparations used by population have relatively security.

Leaching of contaminants from untreated pine bark in a batch study: chemical analysis and ecotoxicological evaluation.

Low cost sorbents have been widely studied in recent years in the search for filter materials that retain contaminants from water. One promising, low cost material is pine bark, a by-product from the forest industry. Many studies have shown that pine bark has great potential for the treatment of metals and organic substances, as a replacement for other commercial sorbents such as active carbon. However, some potential problems are introduced through the use of natural materials and by-products. One such problem that must be addressed is the possibility of leaching of contaminants from the filter material, especially in the initial filtration step or during flushes of lightly contaminated water, e.g. during rainfall for on-site treatment of storm water or landfill leachate. The aim of this preliminary study was therefore to identify potential risks and limitations of using pine bark as a filter material. Leachate from a standardized batch test was analysed for metals, dissolved organic carbon (DOC) and phenols. In addition to these chemical analyses, an ecotoxicological test was conducted using the test organism Daphnia magna. The results showed significant leaching of DOC and some metals. Only a small fraction of the DOC was present as phenols. The leachate was however found to be toxic to the test organism without pH adjustment, and the EC(50) was established at an approximate leachate concentration of 40%. This was concluded to be related to the low pH in the eluate, since no toxicity was observed after pH adjustment before the toxicity tests.

Toxicity of phenolic compounds extracted from bark residues of different ages.

In Quebec, Canada, industrial bark wastelands cover several hundred hectares of land. Bark residue that has piled up for decades tends to remain free of vegetation for years. To assess the revegetation potential of such sites, we sought to determine those factors responsible for poor plant growth. Phenolic compounds from fresh to 20-year-old bark residues were extracted with four solvents and quantified by high-performance liquid chromatography (HPLC). We simulated solutions (mixtures of standard phenolic compounds) to evaluate the potential toxic effects of phenolic compounds on the rhizobial growth, germination index, plant growth, nodule number, and nitrogen fixation activity of two legume species under laboratory conditions. The concentration of individual phenolic compounds varied from none detected to 350 microg/g bark residue. The extracted phenolic compounds differed among solvents and bark residues. The highest concentration of total phenolic compounds was from fresh bark; most of these were soluble in water or 0.1 M NaOH. For older bark residues, the total phenolic content depended on solvent strength, generally in the order of 2.0 M NaOH > 0.1 M NaOH = hot water > cold water. The biological activity of the simulated bark extracts was not established with the rhizobial growth inhibition test but with the germination index and rhizobium-legume symbiosis tests. With these, the toxicity of the simulated phenolic extracts decreased from fresh to the older bark residues. Plant dry weight, nodule number, and nitrogen fixation activity of vetch (Vicia sativa L.) were less negatively affected by high concentrations of phenolics than birdsfoot trefoil (Lotus corniculatus L.), although birdsfoot trefoil grew at lower concentrations. The rhizobium-legume symbiosis has potential for revegetating bark wastelands with less than 1 year old and older bark residues.

Pharmacological actions of Thespesia populnea relevant to Alzheimer's disease.

Thespesia populnea (Malvaceae) is a large tree found in the tropical regions and coastal forests of India. Various parts of T. populnea are found to possess useful medicinal properties, such as antifertility, antibacterial, anti-inflammatory, antioxidant, purgative and hepatoprotective activity. The present study was undertaken to investigate the effects of T. populnea bark on cognitive functions, total cholesterol levels and cholinesterase activity in mice. A total of 312 mice divided into 52 different groups were employed in the present investigation. The ethanolic extract of T. populnea (TPE) was administered orally in three doses (100, 200 and 400 mg/kg) for 7 successive days to different groups of young and aged mice. The learning and memory parameters were assessed using elevated plus maze and passive avoidance apparatus. TPE (200 and 400 mg/kg, p.o.) showed significant improvement in memory of young and aged mice. TPE also reversed the amnesia induced by scopolamine (0.4 mg/kg, i.p.) and diazepam (1 mg/kg, i.p.). Furthermore, TPE reduced significantly the central (brain) cholinesterase activity in mice. TPE exhibited a remarkable cholesterol lowering property comparable to simvastatin (a standard drug) in the present study. Furthermore, we observed that, T. populnea bark possessed a powerful memory enhancing activity in mice. Since diminished cholinergic transmission and increased cholesterol levels appear to be responsible for development of amyloid plaques and dementia in Alzheimer patients, TPE may prove to be a useful medicine on account of its multifarious beneficial effects, such as memory improving property, cholesterol lowering, anticholinesterase and anti-inflammatory activity. Therefore, T. populnea bark appears to be a promising candidate for improving memory and it would be worthwhile to explore the potential of this plant in the management of Alzheimer patients.

Preliminary toxicity and phytochemical studies of the stem bark aqueous extract of Musanga cecropioides in rats.

These studies were designed to determine the preliminary oral toxicity profile of the crude aqueous stem bark extract of Musanga cecropioides (MCW) in adult Sprague-Dawley rats and its active chemical constituents by way of phytochemistry. The acute oral toxicity study was conducted using limit dose test of Up and Down Procedure according to the OECD/OCDE Test Guidelines on Acute Oral Toxicity (AOT425statPgm, version: 1.0) at a limit dose of 3,000 mg/kg body weight/oral route. Repeat dose oral toxicity studies were conducted by daily oral dosing of 750 mg/kg body weight of MCW dissolved in 1 ml of 0.9% saline and 1 ml of 0.9% saline to rats in the test and control groups, respectively, for 28 days. On day 29, blood samples for bioassays were collected by cardiac puncture under diethyl ether anesthesia. The phytochemical analysis was conducted using standard procedures. The LD(50) estimate of the extract was calculated to be greater than 3,000 mg/kg body weight/oral route. The extract caused a significant (P<0.05) decrease in weight gain, differential eosinophil count and increase in serum creatinine but did not affect the organ weights, other serum electrolytes (Na(+), K(+), HCO(3)(-)), liver enzymes and other hematological indices in test rats. Its phytochemical analysis showed it contains saponins, flavonoids, alkaloids, tannins, phlobatannins, glycosides, reducing sugars and anthraquinones. These results show that the aqueous extract of Musanga cecropioides is relatively safe toxicologically when administered orally. Thus, its use in folkloric medicine as an oral antihypertensive is relatively safe when used over the tested period.

Toxic effect of stem bark and leaf of Euphorbia hirta plant against freshwater vector snail Lymnaea acuminata.

The aqueous stem bark and leaf extracts of plant Euphorbia hirta (family-Euphorbiaceae) have potent molluscicidal activity. Sub-lethal doses (40% and 80% of LC50) of aqueous stem bark and leaf extracts of this plant also significantly (P<0.05) alter the levels of total protein, total free amino acid, nucleic acids (DNA and RNA) and the activity of enzyme protease and acid and alkaline phosphatase in various tissues of the vector snail Lymnaea acuminata in time and dose dependent manner. Euphorbia hirta (family-Euphorbiaceae) commonly known as Dudhi, is a common medicinal plant of India, which is used in variety of diseases i.e. cough, asthma, colic, dysentery, genito urinary diseases.

Evaluation of valuation of toxicity profile of an alkaloidal fraction of the stem bark of Picralima nitida (fam. Apocynacaes).

Dermal and acute toxicity evaluation of the basic alkaloidal fraction of the stem bark of Picralima nitida, which has been shown to have pronounced activity against causative organisms of dermatomycosis in man, was carried out in animals. Acute intraperitoneal toxicity tests showed a dose-dependent toxicity. There was inflammation and necrosis of liver hepatocytes accompanied by reduction in neutrophilic count and a corresponding increase in lymphocytic count. There was no sign of reddening or irritation when applied into the eye conjunctiva. Dermal tests also showed that the fraction caused no sensitization, inflammation or death in the animal models used.