Effects of Daniellia oliveri bark on isolated rat bladder.

The stem bark of Daniellia oliveri was screened phytochemically and a methanol extract prepared.-Condensed tannins, saponins, cyanogenetic and cardiac glycosides were identified in the crude drug. The cardiac glycoside components in the methanol extract were precipitated with acetone to yield a reddish-brown residue. The n-butanol soluble fraction of an aqueous solution of this residue tested positive for cardiac glycosides and was shown by TLC to contain steroidal compounds. This fraction was subjected to pharmacological studies on isolated rat bladder smooth muscle. It had no effect on purinergic neurotransmission but was a noncompetitive antagonist for muscarinic receptors.     

Pharmacological activities of extracts of Daniellia oliveri (Rolfe) Hutch. and Dalz. (Leguminosae)

Extracts of the stem bark of Daniellia oliveri using hexane, ethyl acetate and methanol were tested for analgesic, antipyretic and antiinflammatory activities. The hexane extract exhibited a dose related analgesic activity whilst the methanolic extract was active in the induced inflammatory condition. The ethyl acetate extract was relatively inactive and none of the extracts showed any antipyretic activity. Metabolic cage studies showed that a 70% ethanolic extract of the bark caused significant decreases in body weight, food intake, urine and stool output of rats. This extract also exhibited a competitive antagonism on histamine-induced contractions of the guinea-pig ileum and a non-competitive inhibition of acetyl choline-induced contraction of the frog rectus abdominis muscle.     

Effects of stembark and leaf extracts of Bridelia ferruginea on skeletal muscle

The ethanolic extracts of the leaves and stembark of Bridelia ferruginea were separately investigated for their effects on skeletal muscle using the phrenic nerve-hemidiaphragm muscle preparation from rats. The bark extract inhibited twitch tension induced by direct electrical stimulation (muscle) (MS) but not indirect electrical stimulation (nerve) (NS) of the diaphragm. It inhibited tetanus tension to both nerve (TNS) and muscle stimulation (TMS), had no effect on K⁺-induced contracture and reduced the minimal fusion frequency (MFF). The leaf extract had no effect on twitch tension to NS and MS or K⁺-induced contracture but increased tetanus tension to TNS or TMS as well as MFF. These findings suggest that the bark extract does not affect influx of extracellular Ca²⁺ but inhibits the intracellular mobilization of Ca²⁺. The leaf extract also had no effect on influx of extracellular Ca²⁺ but most likely facilitated the intracellular mobilization of Ca²⁺. Thus, the intracellular action of the bark extract is opposite to that of the leaf extract.     

Effects of extracts of seed and leaf of Piper guineense on skeletal muscle activity in rat and frog

The pharmacological effects of leaf and seed extracts of Piper guineense were investigated on phrenic nerve hemidiaphragm activity following electrical stimulation in vitro. The Leaf and seed extracts (10 micrograms-1 mg/mL) and (50-800 micrograms/mL) respectively produced biphasic effects consisting of an initial enhancement followed by secondary transient or prolonged depression of twitch tension in response to electrical stimulation of both muscle and nerve. These effects were similar to that of decamethonium (2-800 mg/mL). An increased concentration of extracellular Ca2+ in vitro reversed the twitch contraction inhibited by the leaf and seed extracts in a dose related pattern following electrical stimulation. It is concluded that the leaf and seed extracts of Piper guineense possess among other pharmacological properties, a depolarizing neuromuscular blocking action.     

Effects of Sclerocarya birrea (A. rich) hochst (anacardiaceae) leaf extracts on calcium signalling in cultured rat skeletal muscle cells.

Sclerocarya birrea is a plant used widely to treat many diseases in Burkina Faso, although no scientific data has been reported about its mechanism of action. In the present study the effects of its leaf extracts were investigated on calcium signalling in rat cultured skeletal muscle cells. The results show that the different extracts (crude decoction, aqueous, ethanolic and chloroformic extracts) have significant antagonistic effect on caffeine-induced calcium release from sarcoplasmic reticulum. Crude decoction is the most active followed by ethanolic, aqueous and chloroformic extracts in dose-dependent manner and can partly justify the use of the plant in traditional medicine.     

Effects of extracts of Portulaca oleracea on skeletal muscle in vitro

Extracts of Portulaca oleracea inhibited twitch tension due to direct (MS) and indirect electrical stimulation via the phrenic nerve (NS) of the rat hemidiaphragm muscle. The rank order of potency was dialysable extract greater than or equal to methanol extract greater than diethylether extract, although all exhibited equal efficacy. The non-dialysable extract did not inhibit twitch tension due to MS or NS. The dialysable, methanol and diethylether extracts inhibited tetanus tension, and attenuated the area under the K+- and caffeine-induced contracture. The contracture induced by nicotinic agonists and K+ on the rectus abdominis muscle was significantly inhibited by these extracts.     

Antimalarial activity and cytotoxicity of Evodia fatraina stem bark extracts

Stem bark extracts of Evodia fatraina (Rutaceae) were tested for antimalarial activity in vitro on Plasmodium falciparum using an isotopic semi-microtest and in vivo on Plasmodium berghei in mice. Ethyl acetate extract showed moderate antimalarial activity in vitro (IC50 = 8.5 micrograms ml-1). However, ethanolic extract exhibited significant potency in vivo (65% suppression of parasitaemia). Moreover, low toxicity against HeLa cells and L 929 fibroblasts was observed with ethanolic extract (IC50 = 95 micrograms ml-1 and 60 micrograms ml-1, respectively).     

Daphne gnidium L. bark and leaf extracts: skin damage by topical application

This study was performed in the rabbit to evaluate the tolerability of the methanol extracts of D. gnidium bark and leaves in single topical application, after repeated application and after UV exposure, as these preparations prove to have good antibacterial and antimycotic activities. The results of the acute primary irritation, phototoxicity and sensitization tests show that D. gnidium leaf extract has a good cutaneous tolerability, while the bark extract could not be used by topical application due to its capability to induce photochemical skin damage. © 1998 John Wiley & Sons, Ltd.     

Analgesic and anti-inflammatory effects of Cassia siamea Lam. stem bark extracts

Aim of the study

The present study was carried out to investigate analgesic and anti-inflammatory activities of Cassia siamea Lam stem bark extracts. We have also determined the cytotoxicity of each extract.

Materials and methods

C. siamea, a widespread medicinal plant traditionally used in sub-Saharan Africa, was collected in Congo Brazzaville. Stem bark was extracted with petroleum ether (CSE1), chloroform (CSE2), ethanol (CSE3) and water (CSE4). Analgesic, anti-inflammatory and antipyretic activities of these extracts were assessed in rats with hot plate test, paw pressure and carrageenan induced paw oedema. Cytotoxicity was assessed against KB and Vero cells.

Results

At the doses used (100, 200, and 400 mg/kg) ethanol and water extracts showed significant and dose-dependent analgesic and anti-inflammatory effects. None of the extracts had cytotoxic activity on KB and Vero cell lines and the most active extracts (CSE3 and CSE4) had no acute toxicity.

Conclusions

The study highlighted the analgesic and anti-inflammatory of C. siamea stem bark. Four major families of compounds present in the plant may explain these activities: triterpenes (lupeol, oleanolic acid, ursolic acid, friedelin, betulin), flavonoids (apigenin, kaempferol, luteolin), anthraquinones (emodin), phytosterols (stigmasterol, beta-sitosterol).     

Effects of Thymus species extracts on rat duodenum isolated smooth muscle contraction

The diethylether, ethylacetate and butanolic extracts from Thymus webbianus and Thymus leptophyllus were tested for spasmolytic activity. Pre-incubation of the isolated rat duodenum with these extracts for 10 min produced a concentration-dependent inhibition of acetylcholine-induced contractions. This effect was at least ten times greater with the apolar extracts than with the polar extracts.     

Effects of leaf and root extracts of Nauclea latifolia on purinergic neurotransmission in the rat bladder

The leaf and root parts or their combination of Nauclea latifolia were separately extracted and their pharmacological effects on purinergic transmission in the bladder investigated. The leaf extract was very potent in potentiating purinergic neurotransmission by potentiating ATP induced contractions. These actions were more pronounced than the depression of potassium chloride evoked contraction of the bladder. The root extract depressed purinergic contraction of the bladder by a direct depressant action on the bladder smooth muscle since it did not modify ATP induced contractions. The leaf and root extracts antagonized each other when combined together. It is concluded that the leaf and root extracts of N. latifolia possess interesting pharmacological actions on the bladder.     

Antimicrobial properties of stem bark extracts from Phyllanthus muellerianus (Kuntze) Excell

Ethnopharmacological relevance

The plants of the genus Phyllanthus (Euphorbiaceae) are widely distributed in most tropical and subtropical countries, and have long been used in folk medicine to treat several diseases. Particularly, Phyllanthus muellerianus (Kuntze) Excell, commonly called “mbolongo” in Cameroon, is used by pygmies baka as a remedy for tetanus and wound infections.

Aim of the study

To investigate the antimicrobial properties of Phyllanthus muellerianus (Kuntze) Excell (family Euphorbiaceae) stem bark used in Cameroon by baka pygmies as a remedy for wound healing and tetanus.

Materials and methods

Aqueous and methanol extracts with and without defatting treatment, were prepared and their activity against Clostridium sporogenes ATCC 3584, Staphylococcus aureus ATCC 6538, Streptococcus mutans ATCC 25175, Streptococcus pyogenes ATCC 19615, Escherichia coli ATCC 10536, Candida albicans ATCC 10231, was evaluated on the basis of the minimum inhibitory concentration (MIC) and the minimum bactericidal-fungicidal concentration (MBC-MFC) by the macrodilution method.

Results

Water extract showed a weak activity against Clostridium sporogenes (MIC 900 μg/mL) and resulted inactive at the tested concentrations against all the other microorganisms. The defatted methanol extract, inactive against Staphylococcus aureus, Escherichia coli, Candida albicans, exhibited a very interesting activity against Clostridium sporogenes and Streptococcus pyogenes (MIC 100 μg/mL and 300 μg/mL, respectively), which seems to validate the use of this plant in pygmies traditional medicine for the treatment of tetanus and wound infections. The activity found against Streptococcus mutans (300 μg/mL), aetiological agent of caries, may suggest a possible use of this plant as natural remedy to prevent dental diseases.

Conclusions

The activity against streptococci and Clostridium sporogenes ATCC 3584, showed by stem bark extracts of Phyllanthus muellerianus, traditionally used by baka pygmies to treat wound infections and tetanus, is reported for the first time.     

Antiprotozoal screening and cytotoxicity of extracts and fractions from the leaves,stem bark and root bark of Alstonia congensis

Ethnopharmacological relevance

To evaluate the antiprotozoal activity and cytotoxicity of extracts and fractions from the leaves, root bark and stem bark of Alstonia congensis (Apocynaceae), used in traditional medicine against parasitic diseases.

Materials and methods

The aqueous and 80% MeOH extracts, and a series of fractions and subfractions from the leaves, stem and root bark of Alstonia congensis were tested in vitro for their antiprotozoal activity against Trypanosoma brucei brucei, Trypanosoma cruzi, Lesihamania infantum and the chloroquine and pyrimethamine-resistant K1 strain of Plasmodium falciparum. Their cytotoxicity on MRC-5 cells (human lung fibroblasts) was evaluated as well.

Results

The aqueous and 80% MeOH extracts and a series of subfractions of each plant part exhibited pronounced antiprotozoal activity against the K1 strain of Plasmodium falciparum with IC₅₀ values ranging from 2 to 5 µg/ml, and good activity against Trypanosoma brucei brucei and Trypanosoma cruzi with IC₅₀ values ranging between 5 and 10 µg/ml. The residual 80% MeOH extract from the leaves, and the total alkaloid extract from stem and root bark were the only subfractions active against Leishmania infantum with IC₅₀ values <10 µg/ml. None of the samples from the root bark was cytotoxic against MRC-cell lines (CC₅₀>64 µg/ml). In general, the aqueous extract (traditional decoction) showed the highest selectivity, especially against Plasmodium falciparum.

Conclusion

These results can partly support and justify the traditional use of these plant parts of Alstonina congensis as raw materials for the preparation of traditional remedies to treat parasitic diseases such as malaria and trypanosomiasis.     

Anti-inflammatory and anti-nociceptive activities of the stem bark extracts from Allanblackia monticola STANER L.C. (Guttiferae)

THE AIM OF THIS STUDY: was to assess the anti-inflammatory and mechanism of action of Allanblackia monticola (Guttiferae). The anti-inflammatory activity "in vivo" of the methylene chloride/methanol extract, methanol and methylene chloride fractions of stem barks of Allanblackia monticola, administered orally at doses of 37.5; 75; 150 and 300 mg/kg, was evaluated on carrageenan-induced oedema in rats to determine the most active fraction. Indomethacin, inhibitor of cyclo-oxygenase was used as reference drug. The effects of the most active fraction were then examined on the rat paw oedema caused by histamine, serotonin, arachidonic acid and dextran followed by its ulcerogenic effect. The results showed that the methylene chloride fraction of Allanblackia monticola was more effective on the oedema caused by the carrageenan. The anti-nociceptive activity of the methylene chloride fraction was assessed using the acetic acid-induced abdominal constriction model, formalin test and hot plate test. At 150 mg/kg, Allanblackia monticola caused maximum inhibitions of inflammation induced by carrageenan (83.33%), by histamine (42.10%), by dextran (40.29%) and by arachidonic acid (64.28%). Allanblackia monticola (75-300 mg/kg) did not cause significant modification of the oedema induced by serotonin. Concerning the anti-nociceptive properties of the plant, the methylene chloride fraction (75-300 mg/kg) caused a dose-dependent inhibition on abdominal contractions induced by acetic acid (32.34-77.37%) and significantly inhibited the inflammatory pain caused by formalin (40.71-64.78%). Allanblackia monticola did not increase the latency time in the hot plate test. Like indomethacin (10mg/kg), the fraction at the dose of 150 mg/kg caused ulceration of the gastric mucous membrane in treated rats. These results show that Allanblackia monticola has an anti-inflammatory and analgesic activities with gastric ulcerative side effects.     

Depolarizing neuromuscular junctional blocking action of Parthenium hysterophorus leaf extracts in rat.

Electromyographic (EMG) and electrodiagnostic studies were made on sciatic nerve-anterior tibialis muscle in vivo in rats administered with a sublethal dose of Parthenium hysterophorus dry leaf powder 100 mg/100 g body weight of rat. Nerve-evoked and muscle-evoked compound muscle action potentials were recorded at different frequencies of stimulations and at different time intervals. The EMG studies revealed depolarizing neuromuscular junctional (NMJ) blocking effects of the leaf extract. The decrement-increment (D-I) phenomena and the EMG pattern in general showed a resemblance to an established anticholinesterase agent like neostigmine. The studies confirm that the leaf extract contains a proven and promising new depolarizing NMJ blocker.     

Toxicological studies on stem bark, leaf and seed kernel of yellow oleander (Thevetia peruviana)

A comparative study of the toxic effects of extracts from stem bark, leaf and seed kernel of yellow oleander (Thevetia peruviana) in albino rats was carried out. Male and female albino rats weighing 150-200 g were administered crude aqueous extracts of stem bark, leaf and seed kernel of the plant by intraperitoneal injection or exposed to baits prepared with the dry extracts of the plant parts. The control groups either received distilled water by injection, or were fed non-poisoned baits. Extracts from all the plant parts were toxic, and produced marked poisoning symptoms that culminated in death. Poisoning symptoms manifested earlier (10 min after treatment) in rats administered aqueous kernel extracts intraperitoneally as against 45 min to several hours in rats poisoned by ingestion of toxicant. Poisoning symptoms indicated serious cardiac, neuromotor and mental malfunctioning, and manifested as tachycardia, arrhythmia, paralysis, ataxia and disorientation. The lethal dose was lowest (507 mg/kg) with the concentrated aqueous kernel extract (CAKE), and highest (5700 mg/kg) with the bait formulated using 40% of the kernel meal - FKM(B). Rats treated by injection with aqueous kernel extract (AKE) died faster within 10 h, than those with the aqueous leaf or stem bark extracts that died after 260 h. No mortality or abnormal behavioural changes were observed among animals in the control groups.     

Effects of Inula viscosa leaf extracts on abortion and implantation in rats

The anti-implantation and mid-term abortifacient effects exhibited by administration of Inula viscosa leaf extracts, were studied in rats. The aqueous extract administered i.p. on day 1-6 of gestation, totally diminished fetal implantation and caused a significant (P<0.05) reduction in the number of corpora lutea and blood progesterone levels. Meanwhile, administration on day 13-15 of gestation exhibited mid-term abortion. Furthermore, petroleum ether and dichloromethane, but not methanol, extracts exhibited pronounced abortifacient effects. The results of this study are in agreement with the traditional reputation of this plant as abortifacient. Further, the plant possesses anti-implantational and luteolytic effects.     

Effects of the aqueous and methylene chloride extracts of Bidens pilosa leaf on fructose-hypertensive rats.

We investigated the effects of the aqueous (150-350 mg/kg) and methylene chloride (150-300 mg/kg) extracts of Bidens pilosa on fructose-induced hypertension in rats. Food and liquid intake were measured as well as systolic blood pressure and plasma levels of glucose, insulin, cholesterol, triglycerides and creatinine. Fructose feeding for 6 weeks induced hypertension, hyperinsulinemia and increased plasma triglyceride levels in male Wistar rats. The aqueous and methylene chloride extracts of B. pilosa reversed the high blood pressure and hypertriglyceridemia developed due to fructose feeding but did not have any effects on plasma levels of insulin and glucose. High doses of the extracts reduced plasma creatinine levels and tended to increase plasma cholesterol. These results suggest that the extracts of B. pilosa possess hypotensive effects whose mechanism of action is not related to insulin sensitivity.     

桑叶提取物对MSG肥胖大鼠胰岛素抵抗的影响

[目的]研究桑叶提取物改善L-谷氨酸钠诱导的MSG大鼠胰岛素抵抗的影响。[方法]选取桑叶中总多糖、总黄酮和总生物碱提取物作为受试药物。复制MSG大鼠模型,随机分为模型对照组、罗格列酮组、非诺贝特组、桑叶总多糖高、低剂量组,桑叶总黄酮高、低剂量组,桑叶总生物碱高、低剂量组;另选健康SD大鼠作为正常对照组。连续给药8周,实验期间进行蔗糖耐量和胰岛素耐量实验。给药8周后腹主动脉取血,检测空腹葡萄糖和血清胰岛素含量,并计算胰岛素敏感指数。[结果]桑叶提取物各给药组对MSG大鼠空腹血糖和血清胰岛素有明显的抑制作用,并具有一定的改善糖耐量和胰岛素耐量,升高胰岛素敏感指数的作用。[结论]桑叶总多糖、总黄酮和总生物碱能够明显改善MSG大鼠胰岛素抵抗,为桑叶改善糖尿病前期糖脂代谢异常的药效基础提供实验依据。     

Radical scavenging and angiotensin converting enzyme inhibitory activities of standardized extracts of Ficus racemosa stem bark

The present study evaluated the radical scavenging and angiotensin converting enzyme (ACE) inhibitory activity of cold and hot aqueous extracts of Ficus racemosa (Moraceae) stem bark. The extracts were standardized using HPLC. Radical scavenging activity was determined using 1,1‐diphenyl‐2‐picrylhydrazyl radical and angiotensin converting enzyme inhibitory activity using rabbit lung and partially purified porcine kidney ACE. HPLC profiles of cold aqueous extract (FRC) showed the presence of bergenin, an isocoumarin, while hot aqueous extract (FRH) was found to contain ferulic acid, kaempferol and coumarin in addition to bergenin. FRH showed significantly higher (p ≤ 0.01) radical scavenging activity than FRC and butylated hydroxytoluene (BHT), consequently resulting in a significantly lower (p ≤ 0.01) IC₅₀ value than FRC and BHT. Both the extracts exhibited a dose dependent inhibition of porcine kidney and rabbit lung ACE. FRH showed significantly higher (p ≤ 0.01) activity than FRC with lower IC₅₀ values of 1.36 and 1.91 μg/mL respectively, for porcine kidney and rabbit lung ACE, compared with those of FRC (128 and 291 μg/mL). Further, a significant correlation (r = 0.893; p ≤ 0.05) was observed between radical scavenging activity and ACE‐inhibitory activity. This is the first report on the ACE‐inhibitory activity of F. racemosa stem bark suggesting its potential to be utilized as a therapeutic alternative for hypertension. Copyright © 2010 John Wiley & Sons, Ltd.