Antiplatelet and antithrombotic activities of methanol extract of Usnea longissima

The antiplatelet and antithrombotic activities of a methanol extract of a medicinal lichen, Usnea longissima, were investigated on platelet aggregation in vitro and on pulmonary thrombosis in vivo. The extract showed concentration dependent inhibitory effects on ADP-induced platelet aggregation, with an IC50 value of 3.6 mg/mL. Using an in vivo mouse thrombotic model in which mice were challenged with an intravenous injection of collagen and epinephrine mixture, oral administration of the extract prior to the injection produced a significant inhibition of thrombotic death or paralysis at 100-200 mg/kg body weight. Aspirin, a representative antiplatelet drug, produced a significant inhibition of thrombotic death at 10-20 mg/kg body weight. The mouse tail bleeding time was significantly prolonged by the addition of the extract. On the other hand, the extract did not show any fibrinolytic activity or alter the coagulation parameters such as activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) in rat platelets in vitro. These results suggested that the antithrombotic activity of U. longissima extract might be due to antiplatelet activity rather than anticoagulant activity.     

Methanol extract of the oyster mushroom, Pleurotus florida, inhibits inflammation and platelet aggregation

The antiinflammatory and platelet aggregation inhibiting activities of the methanol extract of Pleurotus florida Eger, an edible and commercially grown mushroom, were investigated. The extract showed significant activity in ameliorating acute inflammation induced by carrageenan and chronic inflammation by formalin at 500 and 1000 mg/kg body weight. The effect was comparable to the standard reference drug, diclofenac. The extract also showed significant platelet aggregation inhibiting activity of washed human platelets. Adenosine 5'-diphosphate (ADP) induced platelet aggregation was inhibited by 88% to 95% at a concentration of 500 microg/mL of the extract after a preincubation time of 5, 10 and 20 min. The marked antiinflammatory and platelet aggregation inhibiting properties of this mushroom suggest its potential therapeutic use against vascular disorders.     

毛冬青皂苷B3的抗血栓作用研究

目的从毛冬青根中分离、鉴定毛冬青皂苷B3,研究其抗血栓作用。方法色谱法、重结晶法分离、精制毛冬青皂苷B3,薄层色谱对照及波谱分析法对毛冬青皂苷B3进行结构鉴定。采用体内血栓形成试验、体外血凝块溶解试验及二磷酸腺苷(ADP)诱导血小板聚集试验,观察毛冬青皂苷B3的抗血栓作用。结果体内抗血栓试验显示,毛冬青皂苷B3对胶原蛋白-肾上腺素诱发的血栓形成所致小鼠的偏瘫和死亡及FeCl3诱导的大鼠腹主动脉血栓形成均有明显的抑制作用;在体外实验中,对家兔血凝块无明显的溶解作用,对ADP诱导的离体家兔血小板聚集也无明显的抑制作用。结论毛冬青皂苷B3可能为毛冬青抗血栓作用的物质基础之一,其体内抗血栓形成的作用可能与其促进血凝块溶解和抗ADP诱导的血小板聚集无关。     

葡萄籽原花青素对血小板聚集与实验性血栓形成的影响

目的 观察葡萄籽原花青素对血小板聚集和实验性血栓形成的影响.方法 ①大鼠血栓形成实验按随机数字表法分为5组:生理盐水(对照)组、阿司匹林(ASP)组(60 mg/kg)及原花青素100 mg/kg、200 mg/kg、400 mg/kg组,每组各10只.②小鼠血栓形成实验按随机数字表法分为5组,生理盐水(对照)组、阿司匹林组(84mg/kg)及原花青素140mg/kg、280mg/kg、560mg/kg组,各10只.实验动物采用二磷酸腺苷(ADP)、胶原(COL)、花生四烯酸(AA)灌胃,诱导大鼠血小板聚集;采用大鼠动-静脉旁路丝线上血检形成和胶原蛋白-肾上腺素诱发小鼠体内血栓形成,两种方法均以阿司匹林为阳性对照.结果 ①原花肯素高、中、低剂量组均可抑制大鼠颈总动脉-颈外静脉血流旁路血栓的湿重:高、中剂量对血栓干重有明显作用,但不及阿司匹林.②原花青素高剂量组可对抗胶原蛋白-肾上腺素混合诱导剂引起的血栓形成,减少动物死亡数.⑨原花青素中、高剂量组均可抑制ADP、COL、AA诱导的大鼠血小板聚集及两种方法引起的实验性血栓形成.结论 原花青素具有抑制实验性血栓形成和抗血小板聚集作用.     

泽兰有效部分对血小板聚集和血栓形成的影响

目的 研究泽兰有效部分L．F04：对血小板聚集和血栓形成的影响，探讨其活血化瘀作用机制。方法用高分子右旋糖酐静脉推注造成大鼠血瘀证模型，观察泽兰L.F04对二磷酸腺苷(ADP)诱导的大鼠体内血小板聚集以及体内动静脉旁路血栓、体外旋转环内血栓形成的影响。结果 L．F04 0．408，0．204g／kg对模型组大鼠ADP诱导的体内血小板最大聚集率明显增加皆有显著的抑制。且呈剂量依赖关系；与对照组相比，血瘀模型大鼠体外血栓质量明显增加，长度仅有增加趋势，L．F04高、低剂量(0．408，0．204g／kg)皆有抗血栓形成作用，L．F04高剂量对血栓干质量、湿质量的减轻尤为明显；L．F04高、低剂量对实验性动静脉旁路血栓形成均有明显的抑制作用，抑制率分别为27．41％，27．14％。结论泽兰L．F04可显著抑制血小板聚集及体内、外血栓形成。     

Inhibition of rat platelet aggregation by Urtica dioica leaves extracts

Platelet hyperactivity plays an important role in arterial thrombosis and atherosclerosis. The present study was undertaken to investigate the effects of different extracts of Urtica dioica leaves on platelet aggregation. Rat platelets were prepared and incubated in vitro with different concentrations of the tested extracts and aggregation was induced by different agonists including thrombin (0.5 U/mL), ADP (10 microm), epinephrine (100 microm) and collagen (5 mg/mL). The crude aqueous extract inhibited thrombin-induced platelet aggregation in a dose-dependent manner. At 1 mg/mL, the percent inhibition was 17.1 +/- 4.2%. Soxhlet extraction of the plant leaves with different successive solvents showed that the ethyl acetate extract exhibited the most antiaggregant effect with an inhibition of 76.8 +/- 6.1% at 1 mg/mL. Flavonoids isolated from the plant leaves, produced a strong inhibitory effect on thrombin-induced platelet aggregation with an IC(50) of 0.25 +/- 0.05 and 0.40 +/- 0.04 mg/mL for genins and heterosidic flavonoids, respectively. Flavonoids also markedly inhibited platelet aggregation induced by ADP, collagen and epinephrine. It is concluded that Urtica dioica has an antiplatelet action in which flavonoids are mainly implicated. These results support the traditional use of Urtica dioica in the treatment and/or prevention of cardiovascular disease.     

血竭总黄酮对实验性静脉血栓及体外血小板聚集的抑制作用

目的：观察血竭总黄酮对大鼠实验性静脉血栓形成及ADP、PAF诱导的大鼠和兔的血小板聚集的影响。方法：采用结扎大鼠腹主静脉造成的静脉血栓模型。结果：血竭总黄酮（160mg/kg,80mg/kg,40mg/kg）灌胃对大鼠实验性静脉血栓有明显的抑制作用（抑制百分率分别为73．53％,65．77％,39．75％）,对ADP、PAF诱导的血小板聚集也有 明显抑制作用,并且呈剂量依赖关系。结论：血竭总黄酮具有明显的抑制静脉血栓形成及抗血小板聚集作用。     

Antithrombotic Effect of a Polysaccharide Fraction from Laminaria japonica from the South China Sea

Some in vitro studies have identified an antithrombotic effect of polysaccharides from Laminaria japonica, but this activity remains to be confirmed in vivo. In this study a polysaccharide fraction termed PLG was extracted from L. japonica in the Beibu Gulf in Guangxi, China, and its antithrombotic effects explored in rat models of carotid and venous thrombosis. Its anticoagulation and antiplatelet properties were assessed by measuring the prothrombin time (PT), activated partial thromboplastin time (APTT) and ADP‐induced platelet aggregation rate (Agg_max). Its effects on bleeding time were measured using the tail transection method. It was found that pretreatment with an intraperitoneal injection of PLG at 2.5 or 5.0 mg/kg significantly prolonged the occlusion time in the carotid thrombosis model, and a dose of 5.0 mg/kg reduced the thrombus weight in the venous thrombosis model. Pretreatment with PLG (5.0 mg/kg) increased the APTT and decreased the ADP‐induced platelet Agg_max. Neither dose of PLG significantly prolonged the bleeding time compared with the control group. In an in vitro anticoagulation assay using human plasma, PLG at 57.14, 28.57 and 28.57 μg/mL inhibited APTT and PT in a concentration‐dependent manner. The results show that PLG possesses antithrombotic activity in a rat model, and that it may prove to be clinically useful in humans. Copyright © 2011 John Wiley & Sons, Ltd.     

In vitro antioxidant and antithrombotic activity of Hemidesmus indicus (L) R.Br

The methanolic extract of Hemidesmus indicus (L) R.Br. (Asclepiadaceae) roots was found to inhibit lipid peroxidation and scavenge hydroxyl and superoxide radicals in vitro. The amount required for 50% inhibition of lipid peroxide formation was 217.5 micro g/ml. The concentrations needed to scavenge hydroxyl and superoxide radicals were 73.5 and 287.5 micro g/ml, respectively. The intravenous administration of this extract (5mg/kg body weight) in rabbits delayed the plasma recalcification time and enhanced the release of lipoprotein lipase enzyme significantly. The extract also inhibited ADP-induced platelet aggregation in vitro (50-250 micro g), which was comparable to commercial heparin.     

Cardamom extract as inhibitor of human platelet aggregation

The inhibitory activity of cardamom extract was studied on human platelets. Platelet aggregation and lipid peroxidation were evaluated with platelet rich plasma (PRP) and platelet membranes, respectively, obtained from blood of healthy volunteers. Human platelets were subjected to stimulation with a variety of agonists including ADP (2.5 mM), epinephrine (2.5 mM), collagen (10 mM), calcium ionophore A 23187 (6 microM) and ristocetin (1.25 microg/mL). The IC50 were 0.49, 0.21, 0.55 and 0.59 mg with ADP, epinephrine, collagen and calcium ionophore A 23187, respectively, and no inhibition with ristocetin. The inhibitory effect was dose dependent with concentrations varying between 0.14 and 0.70 mg and time dependent at IC50. Lipid peroxidation induced by iron--ascorbic acid system in platelet membranes was analysed with malondialdehyde (MDA) as an index. An increase in concentration of cardamom has decreased the MDA formation significantly. Hence, it may be said that aqueous extract of cardamom may have component(s), which protect platelets from aggregation and lipid peroxidation.     

Inhibition of experimental gastric lesion and inflammation by Phyllanthus amarus extract

Methanolic extract of Phyllanthus amarus Shum & Thonn (Euphorbiaceae) 50, 200, and 1000 mg/kg body weight significantly inhibited gastric lesions, induced by intragastric administration of absolute ethanol (8 ml/kg). Mortality, increased stomach weight, ulcer index, and intraluminal bleeding were reduced significantly by Phyllanthus amarus. Biochemical analysis indicated that reduced glutathione (GSH) of gastric mucosa produced by ethanol administration was significantly elevated by treatment with Phyllanthus amarus extract. Aqueous and methanol extracts of Phyllanthus amarus produced an inhibition of rat paw edema up to 42% compared to control in 3h and continued up to 8h. Anti-oxidant activity of the extract as well as presence of tannins in the extract may be responsible for these observed activities.     

Evaluation of antinociceptive,antinflammatory activities and phytochemical analysis of aerial parts of Urtica urens L.

The antinociceptive and antiinflammatory activities of the ethanol extract of the aerial part of Urtica urens were determined by experimental animal models. U. urens extract was found to possess significant antinociceptive activity in chemically induced mouse pain models (ED₅₀ 39.3 mg/kg: 17.2–74.5 mg/kg) in the writhing test and 62.8% inhibition of the licking time in the late phase of the formalin test at a dose of 500 mg/kg p.o. and antiinflammatory activity on carrageenan‐induced rat hind paw edema (41.5% inhibition at a dose of 300 mg/kg i.p.). The extract displayed activity neither in the thermal model of pain nor in the topical inflammation model. The major component of the extract was determined as chlorogenic acid (670 mg/1000 g dry weight) and could be partly responsible for this activity. Copyright © 2010 John Wiley & Sons, Ltd.     

Evaluation of khat (Catha edulis Forssk) for antifertility activity in rats

The effect of the methanolic extract of khat (Catha edulis Forssk) was studied on female fertility in rats. The parameters included the effect on oestrus cycle, implantation, foetal loss, abortion, inhibition of uterotrophic activity and teratogenicity. The extract, in the doses of 250 and 500 mg/kg, produced dose dependent and significant anti-implantation activity. However, it failed to produce complete infertility in this dose range. Treatment of animals during day 8 to day 12 of pregnancy produced significant abortifacient activity. There was significant decrease in the weight and length of foetuses delivered by rats treated with the extract but there were no gross abnormalities in the organs of the offsprings. It also produced significant anti-oestrogenic activity as assessed by the mean weight of the uteri of rats treated with oestradiol and its combination with the khat extract.     

Lysosomal membrane stabilization and anti-inflammatory activity of Clerodendrum phlomidis L.f., a traditional medicinal plant

Ethnopharmacological relevance Clerodendrum phlomidis L.f., is used to treat several inflammatory diseases and arthritis in Indian traditional system and folk medicine.Aim of the study The aim of the present study was to evaluate the scientific basis of antiinflammatory activity of different organic solvent extracts of Clerodendrum phlomidis and to evaluate the active crude extract for its antiarthritic activity in FCA induced animal model.Materials and methods The antiinflammatory activity of Clerodendrum phlomidis was studied using the carrageenan and cotton pellet induced inflammatory models. The crude ethanol extract was standardized with the known standard using HPLC. The antiarthritic activity was studied using Freund's complete adjuvant induced rat model. For antiarthritic activity, the active crude extract was administered at the concentrations of 100, 200 and 400 mg/kg body weight. The effect of the ethanol extract on serum SGOT, SGPT, ALP, levels of pro-inflammatory cytokines, plasma lysosomal enzymes and protein bound carbohydrates of FCA arthritic animals were studied.Results The ethanol extract at 100, 200, and 400 mg/kg, showed maximum inhibition of inflammation induced by carrageenan (100 mg/kg - 47.73%; 200 mg/kg - 54.00% and 400 mg/kg - 65.15%). In cotton pellet induced granuloma, the ethanol extract at different concentrations showed significant reduction in granuloma weight. In FCA induced arthritis, the ethanol extract showed a significant reduction in paw thickness (100 mg/kg - 51.71%; 200 mg/kg - 57.58% and 400 mg/kg - 62.48%). The levels of lysosomal enzymes and protein bound carbohydrates were significantly decreased in the ethanol extract treated groups compared with the arthritic control. The pro-inflammatory cytokine levels were significantly decreased in a dose dependent manner in all the Clerodendrum phlomidis treated groups.Conclusion Clerodendrum phlomidis displays considerable potency in antiinflammatory action and has prominent antiarthritic effect on adjuvant induced arthritis. Future studies will provide new insights into the antiinflammatory activity of Clerodendrum phlomidis and isolation of compound from it may eventually lead to development of a new class of antiinflammatory agent.     

Iridoid glycosides extracted from Zhizi (Fructus Gardeniae) decrease collagen-induced platelet aggregation and reduce carotid artery thrombosis in an in vivo rat model

Objective

To investigate the anti-platelet aggregation and antithrombotic effects in rats of iridoid glycosides extracted from Zhizi (Fructus Gardeniae).

Methods

The present study evaluated the antithrombotic activity of iridoid glycosides (IGs) in a rat model of carotid artery thrombosis. The effects on coagulation, such as thromboplastin time (APTT), thrombin time (TT) and prothrombin time (PT), and the effect on collagen-induced platelet aggregation in vivo were investigated. Rats were intragastrically administered IGs (50, 100 or 200 mg/kg) twice daily for 3 days.

Results

IGs were shown for the first time to have an antithrombotic action through the inhibition of platelet aggregation, with little effect on the coagulation time of peripheral blood. Our results also showed that IGs may significantly and dose-dependently reduce arterial thrombus load in a model of carotid artery thrombosis and inhibit collagen-induced platelet aggregation in rats. IGs (100 or 200 mg/kg) had no significant effect on APTT and PT, but did lengthen TT at a higher dose.

Conclusion

These data, together with the previously reported neuroprotective effects of IGs in rats with cerebral ischemia, suggest that the antithrombotic action of IGs may potentially contribute to the treatment of cerebral ischemic diseases, including cerebral apoplexy.     

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.     

Hypoglycaemic properties of the aqueous root extract of Morinda lucida (Benth) (Rubiaceae). Studies in the mouse

The aqueous root extract of Morinda lucida (Rubiaceae) Benth, exhibited potent hypoglycaemic effects in both normoglycemic and alloxan-induced diabetic mice by oral administration. This effect was dose-dependent and more potent than that observed with chlorpropamide (1-(p-chlorobenzene-sulphanyl)-3-propylurea). In the normoglycaemic mice, the extract (140 mg/kg body weight) produced a fall in blood sugar of 32% + 1% while at 280 mg/kg body weight there was a 52% + 2% fall over the same time interval. In alloxan-induced diabetic mice, the reaction time of the extract was longer with a single dose of the extract producing a significant hypoglycaemic effect 4 h after administration. In diabetic mice, a dose of 140 mg/kg body weight of the plant extract caused a fall in blood sugar of 51% + 1% while a dose of 280 mg/kg produced a fall of 60% + 2%.     

Anticonvulsant,anxiolytic and sedative activities of the aqueous root extract of Securidaca longepedunculata Fresen.

Aim of the study

The objective of this study is to investigate the anticonvulsant, anxiolytic and sedative activities of the aqueous root extract of Securidaca longepedunculata.

Materials and methods

The anticonvulsant effect of the aqueous root extract (100, 200 and 400 mg/kg) was evaluated in mice using the strychnine- and picrotoxin-induced seizure models. Its anxiolytic activity was evaluated using the elevated plus maze (EPM) and the Y maze (YM) methods (14 and 32) while the hexobarbitone induced sleep and the hole board models were used to evaluate the sedative and exploratory activities in mice respectively. The acute toxicity studies and phytochemical analysis of the extract were also carried out.

Results

The extract (100–400 mg/kg) produced a significant (P < 0.01) dose dependent increase in onset of convulsion compared to the control for strychnine- and picrotoxin-induced seizures. It also produced a significant (P < 0.01) dose dependent prolongation of the cumulative time spent in the open arms of the elevated plus maze and Y maze compared with the control. The extract (100–400 mg/kg) produced significant (P < 0.01) reduction in the time of onset of sleep induced by hexobarbitone. The prolongation of hexobarbitone sleeping time by the extract (200 mg/kg) was comparable to that produced by diazepam (3 mg/kg). At doses of 100–400 mg/kg, the extract produced a dose dependent decrease in exploratory activity of the mice. The reduction in exploratory activity produced by the extract (400 mg/kg) was greater than that of chlorpromazine (1 mg/kg). The results obtained from the experiments indicate that the extract has central nervous system depressant and anxiolytic activities. The LD₅₀ obtained for the acute toxicity studies using both oral and intraperitoneal routes of administration were 1.74 g/kg and 19.95 mg/kg respectively.

Conclusion

These findings justify the use of Securidaca longepedunculata in traditional medicine for the management of convulsion and psychosis.     

Anti-inflammatory, analgesic and anti-lymphocytic activities of the aqueous extract of Crinum giganteum

The anti-inflammatory, anti-lymphocytic and analgesic properties of Crinum giganteum, a popular herb used for the management of asthma and other respiratory disorders was investigated in rats and mice. The extract dose-dependently produced significant (P<0.05) inhibition of formalin induced pain in rats. It also demonstrated significant (P<0.01) inhibition of abdominal constriction induced with 0.75% v/v acetic acid in mice. On the cotton pellet induced granulomatous tissue formation in rats, the extract significantly (P<0.05) decreased the weight. However, no significant inhibition was observed in the egg albumin-induced inflammation in rats. Oral administration of this extract in rats for 14 days significantly affected (P<0.05) the total leukocyte count and the overall percentage lymphocytes. The intraperitoneal and per oral LD(50) were 627+/-5.8mg/kg and 1486+/-18.9 mg/kg in mice and 520+/-10.2mg/kg and 1023+/-4.3 mg/kg in rats, respectively. Preliminary phytochemical analysis of the extract indicates the presence of tannins. These results therefore indicate that C. giganteum bulb contains biologically active principles, which have potentials for the treatment of inflammatory processes.     

Antidiarrhoeal activity of Hypoxis hemerocallidea Fisch. & C. A. Mey. (Hypoxidaceae) Corm (‘African potato’) aqueous extract in rodents

This study investigated the antidiarrhoeal activity of Hypoxis hemerocallidea corm aqueous extract (APE) on experimentally‐induced diarrhoea, gastrointestinal motility, intestinal transit and enteropooling in rodents. H. hemerocallidea corm aqueous extract (APE, 50–400 mg/kg, p.o.) produced dose‐dependent and significant (p < 0.05–0.01) protection of rats and mice against castor oil‐induced diarrhoea, inhibited intestinal transit and delayed gastric emptying. Like atropine (1 mg/kg, p.o.), APE (50–400 mg/kg, p.o.) produced dose‐dependent and significant (p < 0.05–0.01) antimotility effect, and caused dose‐related inhibition of castor oil‐induced enteropooling in the animals. Like loperamide (10 mg/kg, p.o.), APE (50–400 mg/kg, p.o.) dose‐dependently and significantly (p < 0.05–0.01) delayed the onset of castor oil‐induced diarrhoea, decreased the frequency of defaecation and reduced the severity of diarrhoea in the rodents. Compared with control animals, APE (50–400 mg/kg, p.o.) dose‐dependently and significantly (p < 0.05–0.01) decreased the volume of castor oil‐induced intestinal fluid secretion, and reduced the number, weight and wetness of faecal droppings. APE (50–400 mg/mL) also produced concentration‐related and significant (p < 0.05–0.01) inhibitions of the spontaneous, pendular contractions of the rabbit isolated duodenum, and attenuated acetylcholine (ACh, 0.1–5.0 µg/mL)‐induced contractions of the guinea‐pig isolated ileum. Although the precise mechanism of the antidiarrhoeal activity of APE could not be established, the results of this study indicate that APE possesses antidiarrhoeal activity. This finding supports the use of ‘African potato’ as a natural supplementary remedy for the treatment, management and/or control of diarrhoea in some rural communities of southern Africa. Copyright © 2009 John Wiley & Sons, Ltd.