Comparison of the skeletal muscle relaxant properties of Portulaca oleracea extracts with dantrolene sodium and methoxyverapamil

The effects of aqueous (AEE), dialysable (DIF) and methanol (MEE) extracts of Portulaca oleracea stems and leaves were compared with those of dantrolene sodium and methoxyverapamil (D-600) with respect to inhibition of twitch tension on the rat phrenic nerve-hemidiaphragm and with respect to contracture induced by nicotinic agonists on the frog rectus abdominis preparations. The extracts, dantrolene and D-600 inhibited twitch tension due to indirect electrical stimulation via the phrenic nerve (NS) on hemidiaphragm muscle, whereas the extracts and dantrolene inhibited, in addition, twitch amplitude due to direct muscle stimulation (MS). The extracts, dantrolene and D-600 also attenuated K+- and caffeine-induced contractures with the extracts and D-600 also reducing the time taken for the K+-induced contracture to fall to basal tension. In addition, the tetanic tension due to NS and MS was attenuated with only the extracts and dantrolene reducing the twitch/tetanus ratio (MS). There was a non-significant but consistent tendency for mutual potentiation between the extracts and dantrolene with respect to their inhibitory effect on twitch amplitude (MS) resulting in a shift to the left of the concentration-response curves to the extracts or dantrolene. This was not evident with the extracts and D-600 or dantrolene and D-600. Simultaneous addition of the extracts and dantrolene resulted in an increase in the rate of twitch tension inhibition and a decrease in the time to maximum relaxation of twitch amplitude (MS). The extracts and D-600 proved more effective in attenuating nicotinic agonist (acetylcholine, carbachol and nicotine)-induced contractures on the rectus abdominis muscle than dantrolene. From these observations, it appears that the Portulaca oleracea extracts mimic, in part, the effect of D-600 and dantrolene on the rat hemidiaphragm and frog rectus abdominis muscles; therefore, the muscle relaxant properties of the extracts may be due, in part, to inhibition of trans-membrane Ca influx, interference with the Ca-induced Ca release process and/or inhibition of the release of intracellular Ca from stores in the sarcoplasmic reticulum.     

Skeletal muscle relaxant properties of the aqueous extract of Portulaca oleracea

The skeletal muscle relaxant properties of an aqueous extract of Portulaca oleracea were examined on the twitch and tetanus tension evoked by electrical stimulation using the rat phrenic nerve-hemidiaphragm and frog sciatic nerve-sartorius muscle preparations and on contractures induced by nicotinic agonists using the rat rectus abdominis muscle preparation. The extract (5-50 X 10(-4) g/ml) produced a dose-dependent initial enhancement, followed by a longer lasting depression of twitch tension as induced by indirect electrical stimulation (NS) as well as direct stimulation (MS) of the diaphragm and sartorius muscle preparations. The augmentation of twitch amplitude (MS) produced by the extract was not significantly antagonised or potentiated by d-tubocurarine (5-50 X 10(-8) M) or physostigmine (5-50 X 10(-8) M) at concentrations which blocked or potentiated NS-induced twitch contractions. Furthermore, tetrodotoxin (5 X 10(-7) g/ml) alone or in combination with d-tubocurarine did not significantly attenuate extract-induced augmentation of twitch contractions to MS. In addition, the depression of twitch tension due to NS was not antagonised by physostigmine but was reversed and/or abolished by Ca2+ (2-5 X 10(-3) M) or potassium thiocyanate (1 X 10(-3) M). Contractures induced by K+ (80 mM) or by tetanic stimulation (20-60 Hz) were significantly reduced by the extract whereas, contracture induced by caffeine (2.5-6.0 mM) was not affected. Ca2+-free Tyrode's solution and EDTA (1.25 X 10(-3) g/ml) potentiated extract-induced depression of twitch tension to MS. On the rectus abdominis, contractures induced by nicotinic agonists (acetylcholine, 3-500 X 10(-7) M; carbachol, 5-500 X 10(-7) M and nicotine, 5-500 X 10(-8) M) were significantly attenuated and/or abolished by the extract (5-10 X 10(-3) g/ml). These observations indicate that the aqueous extract possesses unique skeletal muscle relaxant properties which do not appear to involve interference with cholinoceptor mechanism(s). It appears that the mechanism of action of the extract may involve interference with Ca2+ mobilization in skeletal muscle.     

Evaluation of the gastric antiulcerogenic effects of Portulaca oleracea L. extracts in mice

Portulaca oleracea is commonly used in Iranian folk medicine. The aqueous and ethanolic extracts were studied in mice for their ability to inhibit gastric lesions induced by HCl or absolute ethanol. In addition, their effects on gastric acid secretion were measured. Both extracts showed a dose-dependent reduction in severity of ulcers. The highest dose of extracts exerted similar activity to sucralfate. The oral and intraperitoneal administration of extracts reduced the gastric acidity in pylorus-ligated mice. These results suggest that Portulaca oleracea has gastroprotective action and validates its use in folk medicine for gastrointestinal diseases.     

马齿苋的化学成分研究

目的:研究马齿苋Portulaca oleracea L.全草的化学成分。方法:运用各种柱色谱方法进行化学成分的分离纯化,用波谱解析方法鉴定化合物的结构。结果:从马齿苋的70%乙醇提取物中分离得到五个化合物,分别鉴定为马齿苋酰胺A(1)、马齿苋酰胺B(2)、马齿苋酰胺E(3),以及橙皮苷(4)和咖啡酸(5)。结论:化合物4和5为首次从该植物中分离得到。     

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.     

Skeletal muscle relaxant action of an aqueous extract of Portulaca oleracea in the rat

The aqueous extract of Portulaca oleracea produced skeletal muscle relaxation in rats following i.p. or oral administration, as assessed by the prolongation of pull-up time. The i.p. route of administration was more effective. When compared with chlordiazepoxide (20 mg/kg, i.p.), diazepam (40 mg/kg, i.p.) and dantrolene sodium (30 mg/kg, oral), the extract (200-1000 mg/kg, i.p.) proved a more effective skeletal muscle relaxant. With 1000 mg/kg i.p., 80% lethality was seen. The LD50 in an acute toxicity test in mice was 1040 mg/kg i.p.     

马齿苋提取物对肝癌细胞HepG-2抑制作用的实验研究

目的观察马齿苋提取物对肝癌HepG-2的抑制作用。方法采用MTT比色法观察马齿苋提取物抑制肝癌HepG-2细胞增殖;采用流式细胞仪检测马齿苋对HepG-2细胞周期分布的影响。结果马齿苋提取物可抑制肝癌HepG-2细胞增殖,其作用具有时间和浓度依赖性;可改变细胞周期分布,多数细胞阻滞于S期,与对照组比较,细胞凋亡率差异有显著性(P<0.01)。结论马齿苋提取物可诱导肝癌HepG-2细胞凋亡,改变细胞周期分布,从而抑制细胞增殖。     

马齿苋甜菜红素抗肿瘤实验研究

目的 观察马齿苋甜菜红素联合环磷酰胺(CTX)的抗肿瘤作用.方法 将接种S_(180)瘤细胞的小鼠分为荷瘤对照组、CTX组、马齿苋甜菜红素(高、中、低剂量)+CTX组.给药10 d,进行抑瘤率计算,以及外周血常规、骨髓有核细胞计数、脾脏、胸腺指数、免疫球蛋白、肝肾功能等的检测.结果 与荷瘤对照组相比,CTX组肿瘤生长明显受到抑制.马齿苋甜菜红素低、中、高剂量联合CTX各组抑瘤率明显高于CTX组的抑瘤率.与荷瘤对照组相比,单一CTX处理组脾脏和胸腺指数、IgA、IgG、IgM水平明显降低,WBC、PLT和骨髓有核细胞计数降低,ALT、BUN升高.不同剂量的马齿苋甜菜红素联合CTX处理,可以不同程度地改善脾脏和胸腺指数、IgG、IgM等免疫水平指标,提高WBC、PLT和骨髓有核细胞的数量,降低ALT和BUN.结论 马齿苋甜菜红素对小鼠S_(180)肉瘤有抑制作用,对化疗药物CTX抗S_(180)小鼠具有增效减毒的作用.     

马齿苋抗糖尿病活性成分的研究

目的研究马齿苋抗糖尿病的活性成分。方法马齿苋全草用75%乙醇提取,利用硅胶、凝胶等柱色谱及制备液相色谱进行分离,并根据有机波谱技术鉴定了化合物结构,进一步通过测定各个化合物对胰岛素抵抗的Hep G2细胞葡萄糖消耗量的影响以及黄酮苷类化合物对Akt磷酸化水平的影响来评价其抗糖尿病活性。结果从马齿苋中分离鉴定了9个化合物,分别为芹菜素-4'-O-α-L-鼠李糖苷(1),橙皮苷(2),山柰酚(3),木栓酮(4),6,7-二羟基香豆素(5),反式-对香豆酸(6),金莲花碱(7),咖啡酸(8),二十八烷酸(9),此外化合物1~4能够显著提高胰岛素抵抗Hep G2细胞葡萄糖消耗,其中化合物1的效果最为显著并能降低该细胞Akt的磷酸化水平。结论化合物1为首次从该植物中分离得到并且具有较强的抗糖尿病活性。     

Effect of an aqueous extract of Portulaca oleracea leaves on smooth muscle and rat blood pressure

An aqueous extract of Portulaca oleracea leaves and stems produced a dose-dependent relaxation of guinea pig fundus, taenia coli and rabbit jejunum and a dose-dependent contraction of the rabbit aorta. On spontaneously-beating rabbit right atria and electrically-paced left atria, the extract produced a dose-dependent negative inotropic and chronotropic effects. On rat blood pressure, the extract produced dose-dependent pressor responses. Phentolamine reduced the relaxant effect of the extract on gut smooth muscle and abolished the contractile response on the aorta as well as the pressor response on blood pressure. Guanethidine and tetrodotoxin had no effect on extract-induced relaxant or contractile responses. On rat blood pressure atropine and cyproheptadine had no effect on extract-induced pressor response, whereas propranolol slightly reduced the pressor response. An increase in extracellular calcium reversed the inhibitory effect of the extract on the rabbit atria. The extract may, therefore, act in part on postsynaptic alpha-adrenoceptors and by interference with transmembrane calcium influx.     

马齿苋的化学成分研究进展

对马齿苋的化学成分研究进行综述,将为马齿苋药材、提取物、保健品及药品的进一步开发及其质量控制的研究提供参考依据。     

Effects of Daniellia oliveri stem bark and leaf extracts on rat skeletal muscle.

The stem bark and leaves of Daniellia oliveri were screened phytochemically and the effects of their respective methanol extracts on the skeletal muscle of rats were investigated using the isolated phrenic nerve hemidiaphragm muscle preparation. Both were found to contain tannins, cardiac and saponin glycosides. In addition, the bark, but not leaves, contained cyanogenetic glycosides. The methanol extracts were found to possess neuromuscular blocking properties. The leaf extract appeared to act primarily by inhibiting the influx of extracellular Ca(2+) principally by inhibiting K(+) channels. The inhibitory action of the bark extract appeared to be mediated by interference with transmitter release and an action on multiple sites.     

马齿苋活性成分体内外抗癌作用的初步筛选

目的 观察马齿苋活性成分对人肺腺癌细胞系(A-549 cell)、人喉表皮样癌细胞系(Hep-2 cell)、人宫颈癌细胞系(Hela cell)和人恶性胚胎横纹肌瘤细胞系(RD cell)生长的影响.方法 体外培养条件下用不同浓度的马齿苋活性成分处理4种癌细胞,通过溴化二甲噻唑二苯四氮唑(MTT)试验法测定癌细胞的增殖;同时处理S180荷瘤小鼠,观察荷瘤小鼠的体重、瘤重、死亡率和抑瘤率.结果 马齿苋生物碱对离体培养的A-549肺癌细胞、Hela细胞和Hep-2细胞的增殖均具有明显抑制作用,马齿苋多糖对Hela细胞有较强的抑制作用, 马齿苋脂肪酸对Hep-2细胞有一定的抑制作用,马齿苋黄酮对RD细胞有很强的抑制作用,并存在浓度剂量效应,高浓度抑制作用强.结论 马齿苋活性成分能选择性地杀伤癌细胞,有进一步研究的潜在价值.     

马齿苋在医药领域中的研究与应用

马齿苋作为一种药食同源植物,广泛分布于中国的大部分地区。它在欧洲和地中海国家也很受欢迎。马齿苋含有多种化学成分,具有抗肿瘤、降血糖、抗氧化、抗菌、抗炎等药理活性。它还含有丰富的营养元素,可以作为减肥佳品和保健食品。本文就马齿苋的植物来源、药理作用、化学成分、药理及药代动力学、毒性及安全性评价、临床应用等方面进行综述。     

马齿苋对家兔体内抗氧化能力的影响

每天喂家兔马齿苋干粉8g，11周后观察血清脂质过氧化产物（丙二醛）和超氧化物歧化酶（SOD）活力变化。结果，家兔血清丙二醛（MDA）含量明显低于食用马齿苋前的水平，而血清SOD活力明显高于食用马齿苋前的水平。结果提示，通过提高SOD活力以减少和消除自由基和过氧化脂质对机体的损伤作用可能是野生马齿苋抗衰老功效的机理之一。     

马齿苋黄酮提取及生物活性研究

目的 研究马齿苋黄酮的抑制脂肪堆积和抗氧化能力.方法 用前脂肪细胞模型及羟基自由基抗氧化模型测定马齿苋黄酮体外影响前脂肪细胞3T3-L1增殖及其清除羟自由基能力.结果 高浓度马齿苋黄酮(>200 μg/ml)极显著抑制前脂肪细胞3T3-L1增殖.当马齿苋黄酮浓度大于0.061 mg/ml,随浓度增加,其清除羟自由基能力增强;浓度为0.119 mg/ml时清除率达50%,相当于0.130 mg/ml的维生素C溶液.结论 马齿苋黄酮有较强体外清除羟自由基能力,高浓度(>100 μg/ml)时具有显著抑制前脂肪细胞3T3-L1增殖的能力.     

马齿苋醇提物中羟基二氢博伏内酯的分离及结构鉴定

目的:分离马齿苋(Portulaca oleracea L.)中乙醇提取物中的化学成分。方法:依次采用50%乙醇回流提取、大孔吸附树脂、乙酸乙酯萃取、硅胶柱层析、ODS中压反相柱和Sephadex LH-20对马齿苋中的化学成分进行提取、分离、纯化,最后采用超高效液相色谱进行制备和结构鉴定。结果:1H-NMR、13C-NMR、DEPT、HR-ESI-TOF-MS及二维HSQC、HMBC、NOESY、COSY的核磁共振图谱解析,得到化合物命名为5-羟基-3,4-二甲基-5-戊烷基-2(5H)-呋喃酮,即羟基二氢博伏内酯。结论:羟基二氢博伏内酯为在马齿苋中首次分离得到。     

马齿苋提取物对大鼠心肌缺血再灌注损伤的保护作用

目的:研究马齿苋提取物(Portulaca oleracea extract,PLE)对大鼠心肌缺血再灌注损伤的保护作用并探讨其作用机制。方法:将动物随机分为假手术组、心肌缺血再灌注模型对照组、马齿苋提取物(10、20、40和80mg/kg)预处理组,术前4周开始灌胃给药,每天一次。分别测定各组大鼠心肌梗死面积;检测血清中总抗氧化能力(T-AOC)和谷草转氨酶(AST)、肌酸磷酸激酶(CK)、乳酸脱氢酶(LDH)、丙二醛(MDA)含量;测定心肌组织中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性、过氧化物酶(CAT)活性以及丙二醛(MDA)含量;采用HE染色方法观察心肌组织病理学改变和TUNEL染色观察心肌细胞凋亡状况。结果:与模型对照组相比,马齿苋提取物(40、80mg/kg)预处理组大鼠心肌梗死面积均显著降低;马齿苋提取物(20、40、80mg/kg)预处理组大鼠血清中AST、CK、LDH、MDA含量显著降低、T-AOC显著升高,心肌组织中SOD、GSH-Px、CAT活性显著升高,MDA含量显著降低,心肌组织病理学改变程度和细胞凋亡程度均明显较轻,并且该作用具有剂量依赖性。结论:马齿苋提取物能够有效减小心肌梗死面积、抑制心肌组织病理学改变和细胞凋亡,提示马齿苋提取物对心肌缺血再灌注损伤具有剂量依赖性的保护作用,该作用可能马齿苋提取物能够改善抗氧化酶活性、减轻自由基损伤有关。