The antihypertensive and vasodilator effects of aqueous extract from Berberis vulgaris fruit on hypertensive rats

The aqueous extract from Berberis vulgaris fruit (B.V.) was tested to evaluate its antihypertensive effects on DOCA-induced hypertension in the rats. Hypertension was induced in male Sprague-Dawley rats (200-250 g) by DOCA-salt injection (20 mg/kg, twice weekly, for 5 weeks, s.c.) plus NaCl (1%) which was added to the animals' drinking water. Then 5 weeks later, the rats were anaesthetized with thiopental (30 mg/kg, i.p.) and the arterial blood pressure was measured. The mean arterial blood pressure and heart rate were 231 +/- 6.4 (mmHg) and 506 +/- 12 (beats/min), respectively. Administration of B.V. extracts significantly reduced the rat arterial blood pressure. In in vitro studies, rings of descending aorta were cut and mounted for isometric tension recording in an organ chamber containing Krebs solution. Mesenteric beds were also removed and perfused with Krebs solution. After 1 h of stabilization, preparations (aortic rings or mesenteric beds) were precontracted with phenylephrine (10(-5) M), then different concentrations of B.V. (0.4, 2 and 4 mg/mL) were added which caused a relaxation in these vessels. To investigate the mechanism of action of the extract, the tissues were incubated with either L-NAME (10(-5) M) or indomethacin (10(-5) M) for 20 min. In the aortic rings L-NAME pretreatment could only reduce the vasodilatory effects of a low concentration of B.V. (0.4 mg/mL), but indomethacin was without effect. In isolated perfused mesenteric beds preincubation with either L-NAME or indomethacin did not modify the vasodilator effects of the aqueous extract from B.V. fruit. The present results suggest that the antihypertensive and vasodilatory effects of B.V. fruit extract are mainly endothelial-independent and it may be used to treat hypertension, a status with endothelial dysfunction.     

Blood pressure depression by the fruit juice of Carica papaya (L.) in renal and DOCA-induced hypertension in the rat

A crude ethanol extract was prepared from the unripened fruit of Carica papaya. Lethality studies showed a dose-mortality relationship with an LD(50) of 325.2 mg/kg in mice administered i.p. Male albino Wistar rats were randomly divided into three batches (15 rats per batch)-renal, DOCA-salt hypertensives and normotensives. Each batch was further divided into three groups-the untreated, hydrallazine and extract treated groups. The mean arterial blood pressure (MAP) and the heart rate were measured in all groups. From the results, the basal (control) MAP were 93.8 +/- 4.5, 175.2 +/- 5. 1 and 181.3 +/- 6.2 mmHg in the normotensive, renal and DOCA-salt hypertensives, respectively. Both hydrallazine (200 microg/100 g i. v) and extract (20 mg/kg.i.v) produced a significant depression of MAP in all groups (p < 0.01 vs controls), but the extract produced about 28% more depression of MAP than hydrallazine in the hypertensive groups. In another group of rats, the extract failed to depress the MAP in rats pretreated with propranolol, but atropine and noradrenaline pretreatment did not prevent the action of the extract on blood pressure. In vitro studies using isolated rabbit arterial (aorta, renal and vertebral) strips showed that the extract (10 microg/mL) produced relaxation of vascular muscle tone which was, however, attenuated by phentolamine (0.5-1.5 microg/mL). It is concluded that the fruit juice of C. papaya probably contains antihypertensive agent(s) which exhibits mainly alpha-adrenoceptor activity.     

Chronic diuretic effect of the water extract of Spergularia purpurea in normal rats

The purpose of this study was to examine the chronic diuretic effect of the water extract of the whole plant of Spergularia purpurea (SP) at different doses (100, 200 and 400 mg/kg) in normal rats. Daily oral administration of the water extract was tested for 4 weeks. Urinary water and electrolytes excretion were determined weekly. Oral administration of the water extract at different doses produced a significant and dose-dependent diuresis and increase in electrolytes excretion. The highest dose (400 mg/kg) of the water extract of SP enhanced urine output from 7.15 +/- 0.42 ml/24 h at the start to 23.01 +/- 0.75 ml/24 h after 4 weeks (p < 0.001). It also produced significant increase in urinary excretion of Na+ (P < 0.01), K+ (P < 0.01) and Cl(-) (P < 0.01). Chronic treatment with SP decreased significantly urine osmolality (P < 0.01 vs. control), while a slight increase in glomerular filtration rate was also observed (P < 0.05) for both doses of water extract (100 and 400 mg/kg). It is concluded that the water extract of whole plant of SP has a significant diuretic effect in rats.     

Evaluation of the antidiarrhoeal activity of Byrsocarpus coccineus

Based on its use in traditional African medicine, the antidiarrhoeal activity of the aqueous leaf extract of Byrsocarpus coccineus, Connaraceae, was evaluated on normal and castor oil-induced intestinal transit, castor oil-induced diarrhoea, enteropooling and gastric emptying. The extract (50, 100, 200 and 400 mg/kg, p.o.) produced a significant (P<0.05) dose dependent decrease in propulsion in the castor oil-induced intestinal transit in mice. The mean peristaltic index (%) for these doses of extract, control (distilled water; 10 ml/kg, p.o.) and morphine (10 mg/kg, s.c.) were 55.27+/-1.86, 53.12+/-3.73, 38.60+/-3.79, 30.25+/-1.27, 89.33+/-5.62 and 20.29+/-3.38, respectively. The effect of the extract at the highest dose was significantly (P<0.05) lower than that of the standard drug. This effect was antagonised by yohimbine (1 mg/kg, s.c.) but not by isosorbide dinitrate (IDN, 150 mg/kg, p.o.). At 200 mg/kg, the extract produced a significant decrease in propulsion in normal intestinal transit. In a dose dependent manner, it delayed the onset of diarrhoea, produced a significant decrease in the frequency of defaecation, severity of diarrhoea and protected the mice treated with castor oil. Mean diarrhoea scores were 30.83+/-1.72, 22.40+/-1.71, 21.43+/-1.32, 13.80+/-0.33, 18.00+/-3.94 and 7.67+/-2.41 for control, extract (50, 100, 200 and 400 mg/kg) and morphine, respectively. This effect was not antagonized by IDN. The extract (400 mg/kg) significantly decreased the volume (ml) of intestinal fluid secretion induced by castor oil (0.60+/-0.23) compared with 1.27+/-0.12 for control. However, there was no significant effect on gastric emptying. The results obtained suggest that Byrsocarpus coccineus possesses antidiarrhoeal activity due to its inhibitory effect on gastrointestinal propulsion, mediated through alpha(2) adrenoceptors, and also inhibition of fluid secretion. Preliminary phytochemical analysis revealed the presence of alkaloids, tannins, saponins, reducing sugars, glycosides and anthraquinones.     

Evaluation of chemopreventive action and antimutagenic effect of the standardized Panax ginseng extract, EFLA400, in Swiss albino mice

In the present investigation the chemopreventive action and antimutagenic effects of a standardized Panax Ginseng extract (EFLA400, processed Panax ginseng extract containing a high titre of ginsenoside Rg3 (>3.0% w/w) known as Phoenix ginseng) in Swiss albino mice have been evaluated. The oral administration of EFLA400 at 1, 3 and 10 mg/kg body weight at pre, peri and post-initiational phases, showed significant reductions in the number, size and weight of the papillomas. A significant reduction in tumour incidence (71.41 +/- 6.73%, 72.19 +/- 4.54% and 70.46 +/- 0.38% at 1, 3 and 10 mg/kg body weight, respectively) was observed in animals in the EFLA400 treated group compared with 100% tumour incidence in the control group. The cumulative number of papillomas during an observation period of 16 weeks was significantly reduced in the EFLA400 treated group (24 +/- 0.94, 16 +/- 1.41 and 11 +/- 1.41 at 1, 3 and 10 mg/kg body weight, respectively). However, the average latent period was significantly increased from 10.81 +/- 0.1 weeks in the control group to 12.39 +/- 0.28 weeks in the treated group (10 mg/kg body weight). The average tumour weight was recorded as 128.55 +/- 8.48, 116.00 +/- 8.48 and 57.5 +/- 3.29 mg in 1, 3 and 10 mg/kg body weight EFLA400 treated groups respectively. Chromosomal aberrations and micronuclei induction was also evaluated in bone marrow cells. These genotoxicity end-points were compared with papilloma occurrence at the same dose levels of carcinogen and ginseng. In the EFLA400 treated groups significantly reduced frequencies of chromosomal aberrations and micronuclei induced by DMBA and croton oil were observed. However, the maximum decrease in the frequencies of chromosomal aberrations and micronuclei were recorded in the 10 mg/kg body weight EFLA400 treated group than that of the 1 and 3 mg/kg body weight EFLA400 treated animals. The results from the present study suggest the dose dependent effectiveness of EFLA400 in chemoprevention and antimutagenicity in Swiss albino mice.     

Curry leaf (Murraya koenigii Spreng.) reduces blood cholesterol and glucose levels in ob/ob mice

We observed that curry leaf (Murraya koenigii) extract possesses the property to decrease blood cholesterol and blood glucose levels in diabetic ob/ob mice. Mice received daily intraperitoneal injections of 80 mg/kg curry leaf extract for 10 consecutive days. The extract significantly decreased blood cholesterol level from 277.6 +/- 16.6 mg/d (day 0) to 182.0 +/- 15.3 mg/d (day 10, p < 0.01 compared with the change in vehicle group). The extract also significantly decreased blood glucose level from 387.0 +/- 15.6 mg/dl (day 0) to 214.0 +/- 26.6 mg/dl (day 10, p < 0.01). In addition, body weight was reduced after extract treatment. Our data suggest that curry leaf may be proved to be of clinical importance in improving the management of high cholesterol level and type 2 diabetes.     

Anti-diarrhoeal activity of the aqueous extract of Mezoneuron benthamianum Baill (Caesalpiniaceae)

The effect of the aqueous extract of Mezoneuron benthamianum (MB) on experimentally induced diarrhoea, intestinal propulsive movement (IPM) and intestinal fluid accumulation (enteropooling) were investigated in rats and mice. The extract (400, 800 and 1600 mg/kg, orally) produced a significant (p<0.05) and dose-dependent reduction in propulsion in the castor oil-induced intestinal transit in mice. The mean peristaltic index (%) for these doses of extract, control, (distilled water, 10 ml/kg, p.o.) and morphine, (10 mg/kg, s.c.) were 73.48, 69.34, 57.27, 89.93 and 31.56, respectively. The effect of the extract at the highest dose was significantly (p<0.05) lower than that of the standard drug. This effect was antagonised by yohimbine (1mg/kg, s.c.). In a dose-dependent manner, the extract delayed the onset of diarrhoea, produced a significant decrease in the frequency of defaecation, severity of diarrhoea and protected the mice treated with castor oil. Total diarrhoea scores were 12.0+/-0.63, 10.3+/-2.06, 8.5+/-2.15, 7.1+/-0.91 and 5.8+/-0.79 for control, extract (400, 800 and 1600 mg/kg) and morphine, respectively. The extract significantly decreased the volume (ml) of intestinal fluid secretion induced by castor oil (1.75+/-0.02 to 0.93+/-0.04) compared with 1.90+/-0.05 for control. The inhibitory effect on fluid accumulation by the extract was also attenuated by yohimbine (1.0 mg/kg). Preliminary phytochemical screening revealed the presence of flavonoids, tannins, cardiac glycosides, anthraquinones and saponins. Administration of the extract up to 2 g/kg (orally) did not produce any toxic effect in the acute toxicity studies in mice. The LD(50) of the extract when given intraperitoneally was 1021.31 mg/kg. The results obtained show that MB possesses anti-diarrhoeal activity due to its inhibitory effects on gastrointestinal propulsion and intestinal fluid accumulation. The antagonistic actions of yohimbine in the experiments suggest a role for the a(2)-adrenergic receptor system.     

Effect of garlic (Allium sativum L.) extract on tissue lead level in rats.

The prophylactic efficacy of garlic (Allium sativum L.) extract to reduce tissue lead (Pb) concentration was evaluated experimentally in rats. Thirty female rats were divided into five groups, keeping group A as a healthy control. Rats of groups B, C, D and E received lead acetate orally at the rate of 5 mg per kg body weight daily for 6 weeks. The garlic extract was tried in three doses, viz. 100 (low), 200 (medium) and 400 mg (high) per kg body weight orally and given simultaneously with lead salt to the rats of group C, D and E, respectively. Mean blood lead concentrations in lead-exposed rats ranged between 0.13+/-0.02 and 0.96+/-0.06 microg/ml, whereas in garlic-treated rats, the range was between 0.16+/-0.01 and 0.80+/-0.05; 0.13+/-0.01 and 0.71+/-0.06 and 0.14+/-0.01 and 0.60+/-0.05 microg per ml in low, medium and high dose groups, respectively. The mean lead concentration in liver, kidneys, brain and bone of lead exposed rats was 2.943+/-0.206, 4.780+/-0.609, 1.019+/-0.100 and 44.075+/-2.60 microg per ml, respectively. Concomitant use of garlic extract at the three different doses was found to reduce lead concentration considerably indicating the potential therapeutic activity of garlic against lead.     

Antidiarrhoeal activity of the ethyl acetate extract of Baphia nitida (Papilionaceae)

In our search for plants useful in the treatment of diarrhoea, we investigated the ethyl acetate extract of Baphia nitida (BN) using intestinal transit, enteropooling and gastric emptying tests in mice and rats. In the castor oil intestinal transit test, BN produced a significant (P<0.05) dose dependent decrease in propulsion with peristaltic index (PI) values of 56.85+/-6.76, 36.84+/-3.04 and 31.98+/-2.60%, respectively at doses of 100, 200 and 400mg/kg vs. 89.33+/-6.28% for control. The effect at 400mg/kg was significantly lower than that of morphine, 10mg/kg, s.c. (20.29+/-3.78%), and was antagonized by isosorbide dinitrate, IDN (150mg/kg, p.o.) but not by yohimbine (1mg/kg, s.c.). This effect was not potentiated by atropine (1mg/kg, s.c.). In the castor oil-induced diarrhoea test, BN produced a significant increase in onset of diarrhoea (103.40+/-8.74, 138.80+/-17.04 and 174.8+/-29.04min, 100 to 400mg/kg, vs. 47.60+/-8.76min for control and 226.10+/-12.57min for morphine). The severity of diarrhoea (diarrhoea score) was dose dependently reduced (19.00+/-2.26, 17.04+/-1.89, 15.00+/-2.05, 100 to 400mg/kg, vs. 31.40+/-2.11 for control and 7.7+/-2.2 for morphine). This effect was not antagonized by IDN or yohimbine. The effect on severity was, however, potentiated by atropine. BN also reduced the number and weight of wet stools but did not have any significant effect on intestinal fluid accumulation and gastric emptying. Results obtained suggest that the ethyl acetate extract of Baphia nitida is endowed with antidiarrhoeal activity possibly mediated by interference with the l-arginine nitric oxide pathway and synergistic with antagonistic action on muscarinic receptors.     

Protective effects of Ginkgo biloba extract against mercury(II)-induced cardiovascular oxidative damage in rats

This study was designed to determine the possible protective effect of Ginkgo biloba extract (EGb) against Hg II-induced oxidative damage and also thromboplastic activity in the aorta and heart tissues. Wistar albino rats of either sex (200-250 g) were divided into four groups. Rats were injected intraperitoneally with (1) control (C) group: 0.9% NaCl; (2) EGb group: Ginkgo biloba extract (Abdi Ibrahim Pharmaceutical Company, Istanbul, Turkey) at a dose of 50 mg/kg/day; (3) Hg group: a single dose of 5 mg/kg mercuric chloride (HgCl(2)); and (4) Hg + EGb group: First day EGb at a dose of 50 mg/kg/day, i.p., 1 hour after HgCl(2) (5 mg/kg) injection; following four days EGb at a dose 50 mg/kg/day, i.p. After decapitation of the rats, trunk blood was obtained and serum tumor necrosis factor-alpha (TNF-alpha), lactate dehydrogenase (LDH) activity, and malondialdehyde (MDA) and glutathione (GSH) levels were analysed. In the aorta and heart tissues total protein, MDA, GSH levels and thromboplastic activity were determined. The results revealed that HgCl(2) induced oxidative tissue damage, as evidenced by increases in MDA levels and decreased GSH levels both in serum and tissue samples. Thromboplastic activity was increased significantly following Hg administration, which verifies the cardiotoxic effects of HgCl(2). Serum LDH and TNF-alpha were elevated in the Hg group compared with the control group. Since EGb treatment reversed these responses, it seems likely that Ginkgo biloba extract can protect the cardiovascular tissues against HgCl(2)-induced oxidative damage.     

Analgesic and antiinflammatory effects of mollic acid glucoside, a 1 alpha-hydroxycycloartenoid saponin extractive from Combretum molle R. Br. ex G. Don (Combretaceae) leaf

The analgesic and antiinflammatory properties of mollic acid glucoside (MAG), a 1 alpha-hydroxycycloartenoid extract from Combretum molle leaf, have been investigated in mice and rats. The effects of graded doses of mollic acid glucoside (MAG, 5-80 mg/kg i.p.) were examined against thermally- and chemically-induced nociceptive pain in mice. Furthermore, the effects of graded doses of the plant extract (MAG, 5-80 mg/kg p.o.) were also investigated on rat paw oedema induced by subplantar injections of fresh egg albumin (0.5 mg/kg). Morphine (MPN, 10 mg/kg i.p.) and diclofenac (DIC, 100 mg/kg i.p.) were used as reference analgesic and antiinflammatory agents for comparison, respectively. Like DIC (100 mg/kg i.p.) and MPN (10 mg/kg i.p.), MAG (5-80 mg/kg i.p.) produced dose-dependent, significant (p < 0.05-0.001) analgesic effects against thermally and chemically induced nociceptive pain in mice. The extractive (MAG, 5-80 mg/kg i.p.) also significantly reduced (p < 0.05-0.001) rat paw oedema induced by subplantar injections of fresh egg albumin in a dose-related fashion. However, the extract (MAG, 5-80 mg/kg i.p.) was found to be less potent than diclofenac (DIC) as an analgesic or antiinflammatory agent. Experimental evidence obtained from this laboratory animal study indicates that the Combretum molle leaf extractive (MAG) possesses analgesic and antiinflammatory properties, and thus lend pharmacological credence to the folkloric, ethnomedical uses of the plant's leaf in the management, control and/or treatment of painful, arthritic and other inflammatory conditions in some rural communities of southern Africa.     

Choto-san prevents occurrence of stroke and prolongs life span in stroke-prone spontaneously hypertensive rats

The effects of long-term oral administration of choto-san (diao-teng-san in Chinese) extract on the occurrence of stroke and life span were investigated in stroke-prone spontaneously hypertensive rats (SHR-SPs). Twenty-four rats were ramdomized into three groups. From 8 weeks of age, 0.1% and 0.3% choto-san groups were given water containing 0.1% (150 mg/kg/day) and 0.3% (450 mg/kg/day) choto-san extract, respectively. A control group was given only water. The mean survival times of the control group, 0.1% and 0.3% choto-san groups were 122.1, 159.8 and 176.8 days, respectively. The percent survivals of both the 0.1% and 0.3% choto-san groups were significantly enhanced compared to the control (Kaplan-Meier analysis followed by log-rank test; 0.1% choto-san: p < 0.05; 0.3% choto-san: p < 0.05). Furthermore, the cumulative percent occurrence of neurological and behavioral signs accompying stroke in the 0.3% choto-san group was significantly inhibited compared to the control (p < 0.05). These results suggested that choto-san prevents the occurrence of stroke and prolongs the life span of SHR-SPs.     

Hypoglycaemic effect of Clausena anisata (Willd) Hook methanolic root extract in rats

This study was designed to examine the hypoglycaemic effect of Clausena anisata (Willd) Hook [family: Rutaceae] root methanolic extract in normal (normoglycaemic) and in streptozotocin-treated diabetic rats. Young adult, male Wistar rats (Rattus norvegicus) weighing 250-300 g were used. Diabetes mellitus was induced in the group of diabetic 'test' rats by intraperitoneal injections of streptozotocin (STZ, 90 mg/kg). In one set of experiments, graded doses of the methanolic root extract of C. anisata (CAME, 100-800 mg/kg p.o.) were administered to both fasted normal and fasted diabetic rats. In another set of experiments, 800 mg/kg of CAME, a dose of the plant extract which produced maximal hypoglycaemic effect in both fasted normal and diabetic rats in the previous set of experiments, was used. The hypoglycaemic effect of this single dose of C. anisata root methanolic extract (i.e. CAME, 800 mg/kg p.o.) was compared with those of insulin (5 micro U/kg s.c.) and glibenclamide (0.2 mg/kg p.o.) in both fasted normal and fasted diabetic rats. Following acute treatment, relatively moderate to high doses of CAME (100-800 mg/kg p.o.) produced dose-dependent, significant reductions (P<0.05-0.001) in the blood glucose concentrations of both fasted normal and fasted diabetic rats. On their own, both insulin (5 micro U/kg s.c.) and glibenclamide (0.2 mg/kg p.o.) produced significant reductions (P<0.01-0.001) in the blood glucose concentrations of the fasted normal and diabetic rats. At a dose of 800 mg/kg p.o., CAME reduced the mean basal blood glucose concentrations of fasted normal and fasted diabetic rats by 57.52 and 51.30%, respectively. C. anisata contains a diverse group of chemical compounds (see Table 1). Since methanol extractives of plants are usually known to contain many chemical compounds, each of which is capable of producing definite biological activities via different mechanisms, it is difficult to draw any logical conclusion on the mechanism of the hypoglycaemic effect of such a diverse mixture of chemical compounds contained in the plant extract used in this study. While it is possible that the hypoglycaemic effect of the plant extract may be due, at least in part, to its terpenoid and coumarin contents, the mechanism of its hypoglycaemic action remains largely speculative, and is unlikely to be due to the stimulation of pancreatic beta-cells and subsequent secretion of insulin. Although C. anisata root methanolic extract is less potent than insulin as an antidiabetic agent, the results of this experimental animal study indicate that the herb possesses hypoglycaemic activity; and thus lend credence to the suggested folkloric use of C. anisata root in the management and/or control of adult-onset, Type-2 diabetes mellitus in some communities of South Africa.     

Evaluation of the analgesic, anti-inflammatory and anti-diabetic properties of Sclerocarya birrea (A. Rich.) Hochst. stem-bark aqueous extract in mice and rats

In order to appraise some of the ethnomedical uses of Sclerocarya birrea (A. Rich.) Hochst., subspecies caffra (Sond.) Kokwaro [family: Anacardiaceae], the present study was undertaken to investigate the analgesic, anti-inflammatory and anti-diabetic properties of the plant's stem-bark aqueous extract in experimental models of pain, inflammation and diabetes mellitus. The analgesic effect of Sclerocarya birrea stem-bark aqueous extract was evaluated in mice, while its anti-inflammatory and anti-diabetic effects were investigated in rats. Diclofenac (DIC, 100 mg/kg p. o.) and chlorpropamide (250 mg/kg p. o.) were used respectively as reference analgesic, anti-inflammatory and anti-diabetic agents for comparison. Like diclofenac (DIC, 100 mg/kg p. o.), Sclerocarya birrea stem-bark aqueous extract (SBE, 100-800 mg/kg p. o.) produced dose-dependent, significant protection (p < 0.05-0.001) against electrical heat-induced pain. The plant extract (SBE, 25-800 mg/kg p. o.) also produced dose- and time-related, sustained and significant reductions (p < 0.05-0.001) in the fresh egg albumin-induced acute inflammation of the rat hind paw oedema. However, the analgesic and anti-inflammatory effects of the plant's extract were found to be approximately 10-15 times less than that of diclofenac. In one set of experiments involving hypoglycaemic/antidiabetic evaluation of the plant's extract, graded doses of Sclerocarya birrea stem-bark aqueous extract (SBE, 25-800 mg/kg p. o.) were separately administered to groups of fasted normal and fasted diabetic rats. In another set of experiments, a single dose of the plant's aqueous extract (SBE, 800 mg/kg p. o.) was used. The hypoglycaemic effect of this single dose of Sclerocarya birrea stem-bark aqueous extract (SBE, 800 mg/kg p. o.) was compared with that of chlorpropamide (250 mg/kg p. o.) in both fasted normal and fasted streptozotocin (STZ)-treated diabetic rats. Following acute treatment, relatively moderate to high doses of Sclerocarya birrea stem-bark aqueous extract (SBE, 25-800 mg/kg p. o.) produced dose-dependent, significant reductions (p < 0.05-0.001) in the blood glucose concentrations of both fasted normal and fasted diabetic rats. Chlorpropamide (250 mg/kg p. o.) also produced significant reductions (p < 0.05-0.001) in the blood glucose concentrations of the fasted normal and fasted diabetic rats. Administration of the single dose of Sclerocarya birrea stem-bark aqueous extract (SBE, 800 mg/kg p. o.) significantly reduced (p < 0.01-0.001) the blood glucose levels of both fasted normal (normoglycaemic) and fasted STZ-treated, diabetic rats. The results of this experimental animal study indicate that Sclerocarya birrea stem-bark aqueous extract possesses analgesic, anti-inflammatory and hypoglycaemic properties. These experimental findings lend pharmacological support to the suggested folkloric uses of the plant's stem-bark in the management and/or control of pain, inflammatory conditions, and adult-onset, type-2 diabetes mellitus in some communities of South Africa.     

银杏提取物和潘生丁对兔心肌缺血再灌注后iNOS基因转录和翻译的影响

目的 研究银杏提取物（Egb761）与潘生丁单用及联用对家免心肌缺血再灌注诱导型一氧化氮合酶（iNOS）的影响。方法 参照文献方法制备兔缺血再灌注模型,35只兔随机分为5组,每组7只,假手术组、模型组、潘生丁（0．8mg／kg）组、银杏（Egb761 40mg／kg）组及联合组,于再灌注30min后分别静脉注射相应的药物,同时检测心肌再灌注晚期iNOS转录水平和翻译水平表达变化。结果 每组动物均存活至实验结束。心肌iNOS转录水平表达分别是假手术组0、模型纽157．11±17．73、潘生丁组202．6±21．84、银杏组356．13±24．18和联合组562．34±35．19,与模型组比较,各用药组心肌iNOS转录水平表达显著增加（P〈0．01）。心肌缺血再灌注中iNOS蛋白翻译水平表达分别是假手术组34．24±15．78、模型组75．70±13．71、潘生丁组116．89±22．57、银杏组143．75±16．05和联合组195．09±22．25,与模型组比较,各用药组iNOS蛋白翻译水平表达均显著增加（P〈0．05或P〈0．01）。结论 潘生丁与银杏提取物单用和联用均增加家兔心肌缺血再灌注晚期iNOS表达,联用增加更明显。     

Central nervous system stimulatory action from the root extract of Plumbago zeylanica in rats

The effects of a 50% ethanol extract of the root of Plumbago zeylanica (P. zeylanica) were investigated on locomotor behaviour and central dopaminergic activity in rats. The effects on the ambulatory behaviour were assessed along with the levels of dopamine (DA) and its metabolite homovanillic acid (HVA) in the striatum after a single oral dose (100, 200 and 300 mg/kg body weight) of the extract. The extract significantly increased the spontaneous motility in animals. The ambulatory and rotatory behaviour in the treated groups were higher than in the control group (p < 0.05). There were marked differences in the ambulatory behaviour between 100 and 300 mg/kg, indicating that the responses were stimulatory and dose-dependent. The stereotypic behaviour which is characteristic of a dopamine agonist showed biphasic effects. However, there was no significant difference between the groups (p > 0.05). The results showed that the extract of the root of P. zeylanica specifically enhanced the spontaneous ambulatory activity without inducing stereotypic behaviour. The neurochemical estimations revealed elevated levels of DA and HVA in striatum compared with the control rats (p < 0.01). The levels were higher for the 100 mg/kg treated group than the other groups. The levels declined by increasing the dosage of the extract to 200 mg/kg and 300 mg/kg, however, these levels remained higher than the control group. The relationship between motor activity and levels of dopamine are not parallel. These behavioural and biochemical results indicated stimulatory properties of the extract of the root of P. zeylanica, which may be mediated by dopaminergic mechanisms in the rat brain.     

Pharmacological evidence favouring the folkloric use of Diospyros mespiliformis Hochst in the relief of pain and fever

The methanol extract of Diospyros mespiliformis was evaluated for its claimed folkloric usage in the relief of pain and fever. Antipyretic, analgesic and anti-inflammatory effects of the extract were evaluated in rats and mice. Studies were carried out on yeast-induced pyrexia in rats, acetic acid-induced writhing in mice, formalin test and egg albumin-induced anti-inflammatory activity in rats. The extract (50 and 100 mg/kg i.p.) gave a potent antipyretic effect for 100 mg/kg and significant activity (P<0.05) against all the analgesic and anti-inflammatory models used. The LD(50) of the extract was estimated to be 513.80+/-33.92 mg/kg i.p. in mice. These results provide support for the use of the plant in relieving pain and fever.     

Cardiovascular effects of the South American medicinal plant Cecropia pachystachya (ambay) on rats

Cecropia pachystachya is used in South America for relieving cough and asthma. In Argentina it is known as "ambay" and grows in the neotropical forests (Ntr C.p.) and in temperate hilly regions (Tp C.p.). To evaluate their cardiovascular profile, the effect of extracts obtained from plants growing in the neotropical region as well as in temperate areas were compared by i.v. administration in normotensive rats. The following parameters were measured: blood pressure (BP) and heart rate (HR). The hypotensive effect was stronger for Ntr C.p., which aqueous extract decreased BP at doses between 90 and 300 mg lyophilised/kg until 46.2 +/- 12% of basal. The extract of Tp C.p. reduced BP to 86.1 +/- 11% of basal (p < 0.05 respect to Ntr C.p.) at 180 mg/kg, but increased HR at 90 and 180 mg/kg (until 133.6 +/- 10.8% of basal, p < 0.05) and produced death by respiratory paralysis at 320 mg/kg (about 3g dry leaves/kg). The hypotensive effects, but not the chronotropic ones, were attenuated by pretreatment with reserpine (5 mg/kg). The plant extracts had not diuretic activity by oral administration in conscious rats, nor produced vasodilation of perfused hindquarters arterial bed precontracted with high-[K] or 100 microM phenylephrine. The results suggest that neotropical ambay is more hypotensive than the one from the temperate hilly region. When it reaches plasma, it could produce hypotension (by central blockade of sympathic innervation of vessels) and tachycardia (by central cholinergic inhibition of heart), although it happens at doses higher than the oral ethnotherapeutic (about 340 mg dried leaves/kg).     

Inhibition of chemically induced inflammation and pain by orally and topically administered leaf extract of Manihot esculenta Crantz in rodents

The aqueous leaf extract of Manihot esculenta Crantz (MELE) is being used orally and topically in traditional African medicine for the treatment of inflammation and pain, and claimed to be safe. The anti-inflammatory effects of MELE (100-400mg/kg, p.o. or 1-4%, w/w in petroleum jelly, topically) were tested against carrageenan-induced paw oedema in rats as well as against xylene-induced ear oedema in mice. The analgesic effect of MELE (100-400mg/kg, p.o. or 1-4%, w/w in petroleum jelly, topically) was tested against acetic acid-induced (20mul, 0.6%, v/v in normal saline, i.p.) and acetylcholine-induced (8.3mg/kg, i.p.) mouse writhing models. At 100-400mg/kg, p.o. and 1-4% (w/w), topically, MELE produced significant inhibitions of carrageenan-induced rat paw oedema and xylene-induced ear swelling in mice. Effects produced by MELE were significantly higher than those produced by indomethacin (10mg/kg, s.c. or 1%, w/w in petroleum jelly) in the anti-inflammatory models. For the analgesic effect, MELE (100-400mg/kg, orally) and (1-4%, w/w, topically), like aspirin (100mg/kg, i.p.) exhibited significant (P<0.05) inhibition of acetic acid- and acetylcholine-induced mouse writhing tests, compared to untreated control. Effects produced by MELE were significantly lower than those produced by aspirin (100mg/kg, i.p.) in the analgesic models, except for the topically administered extract on acetylcholine-induced pain. Acute oral administration up to 10g/kg did not cause death within 14 days, but mortalities were produced in i.p. administered extract with LD(50) of 2.5+/-0.3g/kg. Based on these, the extract may contain orally safe, topically and orally effective anti-inflammatory and analgesic principles, which justify its use in traditional African medicine.     

Effects of a herbal extract on the bone density,strength and markers of bone turnover of mature ovariectomized rats

For many decades, the Chinese have been using herbal medications to treat bone diseases. To examine effects of an extract of ten medicinal herbs on estrogen deficiency bone loss, ten-month-old female rats were randomly divided into three groups: ovariectomized (OVX), OVX treated with herbs (OVX-M) 4 ml/day by gavage, and OVX treated with estrogen (OVX-E) 10 mg subcutaneously (s.c.) twice per week. The bone mineral density (BMD) of the left femur (fBMD), spine (sBMD) and global body (gBMD) were measured at baseline and at 4, 8 and 12 weeks using a Hologic QDR 2000 dual-energy X-ray densitometer. Tibial strength was tested using the Instron Model 5566 electro-mechanical testing machine. The urinary pyridinoline creatinine ratio (Pyd/Cr), deoxypyridinoline creatinine ratio (Dpd/Cr), plasma alkaline phosphatase (ALP), calcium (CA), phosphorus (P) and albumin (ALB) were also determined. Uterine weight was determined at 12 weeks. The results showed that percent changes of fBMD in the OVX (n = 9), OVX-E (n = 8) and OVX-M (n = 8) rats at the 12-week time point were -11.8 +/- 4.6(c), 1.8 +/- 3.1(a), -7.6 +/- 1.9(abc) (p < 0.05-0.001, a: vs. OVX, b: vs. OVX-E, c: vs. baseline); sBMD were -10.7 +/- 4.6(c), -0.3 +/- 5.5(a), -5.9 +/- 3.5(abc); and gBMD were -4.8 +/- 2.3(c), 0.1 +/- 2.4(a), -2.7 +/- 2.6(abc), respectively. Further, the tibia maximum breaking stress and flexural modulus of elasticity in OVX-M rats (295 +/- 33(a), 18,194 +/- 3,264(a)) were significantly higher (p < 0.005-0.001) than that in OVX rats (189 +/- 83, 10,309 +/- 4,930), and similar to OVX-E rats (298 +/- 35(a), 18,766 +/- 2,620(a)). Additionally, the herbal extract reduced the urinary Pyd/Cr, Dpd/Cr and plasma ALP increment followed OVX and was not associated with a rise in uterine weight. In conclusion, the herbal extract demonstrated a therapeutic effect to inhibit bone resorption and to reduce estrogen-dependent bone loss without uterine stimulation. It may have potential as a new approach in treating and preventing postmenopausal osteoporosis (PMOP).