10味中药提取物对α-葡萄糖苷酶的抑制作用

目的:观察10味中药对α-葡萄糖苷酶的抑制作用,筛选对α-葡萄糖苷酶抑制作用较强的中药。方法:提取大鼠小肠α-葡萄糖苷酶,以麦芽糖为底物,筛选10味中药水提取物体外对α-葡萄糖苷酶活性的抑制作用;选择体外对α-葡萄糖苷酶活性有较强抑制作用的中药提取物,一次性灌胃后对餐后60min血糖的影响;以阿卡波糖(ACAR)作为阳性对照药物。结果:赤芍、山茱萸和桑白皮3味中药对α-葡萄糖苷酶的活性有较强的抑制作用,显示明显的浓度-效应关系,其中桑白皮抑制作用最强,当桑白皮浓度达到10mg/ml时,其对α-葡萄糖苷酶的抑制率已达80%,相当于浓度1mg/ml的ACAR的作用;3种中药体内实验结果表明,3者均可抑制大鼠一次性灌胃麦芽糖60min后血糖水平的升高(P<0.05或P<0.01),与对照组比较,对血糖升高的抑制率以桑白皮组最高(62.09%),并且与ACAR(69.31%)组没有统计学差异(P>0.05)。结论:赤芍、山茱萸和桑白皮3味中药体内、外对α-葡萄糖苷酶活性均有较强的抑制作用。     

金荞麦根茎乙醇提取物抗氧化和对α-葡萄糖苷酶、α-淀粉酶的抑制作用

目的:研究金荞麦根茎乙醇提取物不同极性部位的体外抗氧化活性和α-葡萄糖苷酶、α-淀粉酶的抑制活性。方法:采用系统溶剂法梯度萃取金荞麦乙醇提取液,以获取不同极性部位的金荞麦提取物;采用DPPH、羟自由基和ABTS自由基清除实验对金荞麦根茎乙醇提取物不同极性部位的抗氧化活性进行研究,并以α-葡萄糖苷酶和α-淀粉酶为药物靶点,4-硝基苯-α-D-吡喃葡萄糖苷和淀粉为底物,阿卡波糖为阳性对照,筛选对α-葡萄糖苷酶和α-淀粉酶具有抑制作用的金荞麦根茎乙醇提取物部位。结果:在0~0.2mg/ml浓度范围内,金荞麦根茎乙醇提取物的乙酸乙酯萃取部位对DPPH、羟自由基和ABTS自由基具有很强的清除作用,但略低于维生素C的清除作用。在25mg/ml相同浓度下,金荞麦根茎乙醇提取物中正丁醇萃取部位、乙酸乙酯萃取部位和氯仿萃取部位对α-葡萄糖苷酶的IC50值均低于阳性对照阿卡波糖的IC50值,且抑制率均大于阿卡波糖的抑制率,乙酸乙酯萃取部位对α-淀粉酶的抑制率大于阿卡波糖的抑制率。在25mg/ml相同浓度下,金荞麦根茎乙醇提取物的5个不同萃取部位中,乙酸乙酯萃取部位对α-葡萄糖苷酶和α-淀粉酶的抑制作用最强(抑制率分别为为87.32%、84.57%)。在0~50mg/ml浓度范围内,金荞麦根茎乙醇提取物的不同萃取部位对α-葡萄糖苷酶和α-淀粉酶的抑制作用均呈剂量依赖关系。结论:金荞麦根茎乙醇提取物的乙酸乙酯萃取部位具有很好的抗氧化作用和α-葡萄糖苷酶、α-淀粉酶的抑制作用。     

桑叶提取物抑制α-葡萄糖苷酶活性体系的优化及动力学研究

目的研究桑叶提取物抑制α-葡萄糖苷酶活性反应体系的条件优化及酶动力学。方法采用酶-抑制剂模型法,优化底物浓度、酶用量和反应时间,确定最佳反应体系,研究桑叶提取物对α-葡萄糖苷酶的抑制作用,并采用双倒数作图法研究桑叶提取物的酶抑制动力学特性。结果当蔗糖浓度为40 mg/mL,酶用量为0.2mL(约1.6 U/mL),反应时间为25 min时为最佳反应体系;酶抑制动力学实验表明,桑叶提取物的抑制类型为混合型竞争性抑制,阳性对照为非竞争性抑制。结论桑叶提取物对α-葡萄糖苷酶活性有抑制作用;桑叶提取物对α-葡萄糖苷酶抑制活性为混合性竞争性抑制,可以用于开发降糖药物。     

龙眼叶提取物对α-葡萄糖苷酶抑制活性研究

目的:研究龙眼叶不同提取物对α-葡萄糖苷酶的抑制活性。方法:通过建立体外α-葡萄糖苷酶抑制模型,对龙眼叶提取物进行活性筛选,并对提取物浓度与抑制活性关系进行研究。结果:龙眼叶乙酸乙酯提取物(IC_50=0.105 2mg/mL)和正丁醇提取物(IC_50=0.1261mg/mL)均有较好的α-葡萄糖苷酶抑制作用,抑制活性大于阳性对照药阿卡波糖(IC_50=0.1960mg/mL),且抑制活性呈浓度依赖性。结论:龙眼叶乙酸乙酯和正丁醇提取物对α-葡萄糖苷酶活性有抑制作用,具有开发治疗糖尿病降血糖药物的价值。     

新疆昆仑雪菊5种提取物对α-葡萄糖苷酶活性的影响

目的:研究昆仑雪菊(CTF)提取物对α-葡萄糖苷酶活性的影响。方法:用水提法和有机溶剂萃取法制备昆仑雪菊的提取物,得到雪菊乙酸乙酯提取物、雪菊正丁醇提取物、雪菊总黄酮、雪菊水提物和雪菊中性黄酮;用体外α-葡萄糖苷酶抑制模型,对5种雪菊提取物进行α-葡萄糖苷酶抑制活性筛选,并与阳性对照药阿卡波糖进行比较。结果:昆仑雪菊的5种提取物对α-葡萄糖苷酶的活性均有较强的抑制作用,有4个提取物的抑制率高于阿卡波糖,其中雪菊中性黄酮的活性最强,在0.05 g.L-1时,其酶抑制率高达87.26%。阿卡波糖及5种提取物对α-葡萄糖苷酶抑制作用的IC50分别为:阿卡波糖IC50858.0mg.L-1,雪菊乙酸乙酯提取物IC50 12.5 mg.L-1,雪菊正丁醇提取物IC50 139.5 mg.L-1,雪菊总黄酮IC50 163.5 mg.L-1,雪菊水提物IC50 367.6 mg.L-1,雪菊中性黄酮IC50 5.8 mg.L-1。结论:昆仑雪菊提取物能显著抑制α-葡萄糖苷酶活性。     

木蝴蝶提取物对α-葡萄糖苷酶的抑制作用

目的研究木蝴蝶提取物对α-葡萄糖苷酶的抑制作用。方法将木蝴蝶的80%乙醇提取物依次用石油醚、乙酸乙酯、正丁醇萃取,测定各部分对α-葡萄糖苷酶的抑制作用,并对抑制作用最强的部分进行酶抑制动力学研究。结果正丁醇萃取部分(n-BO)对α-葡萄糖苷酶的抑制作用最强,在试验质量浓度25~212.5 mg/L,其最大抑制率为93.45%,半数抑制浓度(IC50)为47.96 mg/L,抑制活性高于阳性对照阿卡波糖(Acarbose IC50=56.98 mg/L)。抑制动力学表明n-BO为竞争性抑制,抑制常数(Ki)为27.05 mg/L。结论木蝴蝶醇提物中n-BO对α-葡萄糖苷酶具有显著抑制作用,n-BO富集了抑制α-葡萄糖苷酶的有效成分。     

荞麦花总黄酮和槲皮素对α-葡萄糖苷酶活性的影响

目的 观察荞麦花总黄酮和槲皮素对体内外α-葡萄糖苷酶活性的抑制作用,探讨其降血糖机制.方法 提取大鼠小肠α-葡萄糖苷酶,分别测定荞麦花总黄酮及槲皮素对其活性的抑制作用;采用健康雄性SD大鼠为实验对象,随机分麦芽糖(2 g/kg)组、麦芽糖(2 g/kg)+荞麦花总黄酮(0.4 g/kg)组、麦芽糖(2 g/kg)+槲皮素(0.04 g/kg)组、麦芽糖(2 g/kg)+阿卡波糖(0.1 g/kg)组,禁食12 h后灌胃给药,分别于给药前和给药后60 min用血糖仪测血糖.结果 荞麦花总黄酮及槲皮素在浓度20,2,0.2 mg/ml时能够显著抑制α-葡萄糖苷酶的活性(P<0.05),抑制率分别为54.74%,42.91%,35.79%和74.98%,59.38%和45.79% ; 二者对大鼠餐后血糖也有明显的抑制作用,与对照组比较,阿卡波糖、荞麦花总黄酮+麦芽糖和槲皮素+麦芽糖抑制率分别为74.22%,53.06%,64.33%(P<0.01).结论 荞麦花总黄酮和槲皮素在体内外对α-葡萄糖苷酶的活性均有明显的抑制作用,可能是其降血糖机制之一.     

桑不同药用部位总生物碱对α-葡萄糖苷酶活性的抑制作用

目的:比较桑不同药用部位(桑叶、桑枝、桑白皮)总生物碱对α-葡萄糖苷酶活性的抑制作用。方法:采用采用蒸发光散射检测器(ELSD)-高效液相色谱法(HPLC)测定桑不同药用部位总生物碱中1-脱氧野尻霉素(DNJ)含量;以半数抑制浓度(IC 50)为评价指标,以阿卡波糖为阳性对照,以对-硝基苯基-α-D-吡喃葡萄糖苷为底物,采用体外抑制模型评价桑不同部位总生物碱对α-葡萄糖苷酶活性的抑制作用。结果:桑不同药用部位总生物碱中DNJ质量分数为桑白皮生物碱(30.1%)>桑枝生物碱(25.8%)>桑叶生物碱(21.4%)。桑不同药用部位总生物碱对α-葡萄糖苷酶抑制作用强度为桑枝生物碱>桑叶生物碱>桑白皮生物碱>阿卡波糖。结论:在桑枝、桑叶、桑白皮总生物碱中,以桑枝总生物碱对α-葡萄糖苷酶活性抑制作用最强,为桑资源开发辅助降血糖的药品和保健食品提供依据。     

金花茶种子对α-葡萄糖苷酶活性的抑制作用研究

目的 研究金花茶种子乙醇提取物及醇提物的乙酸乙酯部分、正丁醇部分及水溶部分三个极性部位对α-葡萄糖苷酶的抑制作用。方法 采用体外抑制α-葡萄糖苷酶活性模型测定活性并进行酶抑制动力学研究,通过Lineweave-Burk作图法确定抑制类型。结果 金花茶种子乙醇提取物、乙酸乙酯部分、正丁醇部分及水溶部分均有抑制α-葡萄糖苷酶作用,其IC_(50)分别为37.74、335.90、20.53、17.80μg/ml,活性均高于阳性对照药阿卡波糖(484.90μg/ml)。其中阿卡波糖为竞争性抑制剂,其余均为非竞争性抑制剂。结论 金花茶种子为首次报道对α-葡萄糖苷酶有抑制活性,而正丁醇部分与水层部分为其抑制α-葡萄糖苷酶的有效部位。     

三清降糖方对α-葡萄糖苷酶抑制作用的研究

目的:观察三清降糖方对α-葡萄糖苷酶活性的影响.方法:提取大鼠小肠的α-葡萄糖苷酶,测定其含量,通过正交试验确定最佳反应体系,制备三清降糖方水提制剂和醇提制剂,分别配制成25,2.5,0.25,0.025,0.002 5 g·L-1的溶液,以阿卡波糖为阳性药对照组,用葡萄糖氧化酶法测定葡萄糖含量,计算抑制率.结果:三清降糖方水提制剂、醇提制剂对α-葡萄糖苷酶活性的抑制有明显的浓度-效应关系.质量浓度为25 g·L-1三清降糖方水提制剂对α-葡萄糖苷酶活性的抑制率为(64.85±10.5)％,与2.5 g·L-1的阿卡波糖抑制率相当.结论:三清降糖方具有抑制α-葡萄糖苷酶活性的作用.     

桑叶中降糖活性成分筛选及其药效学研究

目的:筛选桑叶中α-葡萄糖苷酶(α-GS苷酶)抑制活性最佳组分,并进行体内降糖活性研究。方法:采用柱层析法对桑叶水提物进行分离,利用体外细胞实验筛选出α-葡萄糖苷酶抑制活性最佳组分,并采用链脲霉素诱导的大鼠高血糖动物模型进行跟踪验证。结果:细胞实验结果表明,桑叶提取物中生物碱的α-葡萄糖苷酶抑制活性最强。体内试验中,与模型组比较,生物碱给药组糖尿病大鼠的血糖有明显降低。结论:桑叶中的生物碱具有显著的降血糖的作用(P0.05)。     

Antibacterial, anti-inflammatory, anti-cholinesterase and mutagenic effects of extracts obtained from some trees used in South African traditional medicine

Extracts obtained from 10 trees used in South African traditional medicine were screened for antibacterial, anti-inflammatory (COX-1 and COX-2) and anti-cholinesterase activities and investigated for potential mutagenic effects using the Ames test. Antibacterial activity was detected using the disc-diffusion and micro-dilution assays. The extracts were tested against Gram-positive bacteria: Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus and Gram-negative bacteria: Escherichia coli and Klebsiella pneumoniae. Of the 78 different plant extracts investigated, 80% showed activity against both Gram-positive and Gram-negative bacteria in the disc-diffusion assay. In the micro-dilution assay, 60% of the plant extracts showed minimum inhibitory concentration (MIC) values < or =1.56 mg ml(-1). The lowest MIC value (0.092 mg ml(-1)) was recorded for an ethyl acetate root extract of Acacia sieberiana against Staphylococcus aureus and Escherichia coli. In the anti-inflammatory assay, 70% of the investigated plant extracts (0.25 mg ml(-1)) inhibited both COX-1 and COX-2 activity (>50% and 70% for water and organic solvent extracts, respectively). An ethyl acetate leaf extract of Trichilia dregeana showed selective inhibition of COX-2 (81%). In the acetylcholinesterase inhibitory test, 21% of the plant extracts were active at a concentration < or =1 mg ml(-1) using the micro-dilution assay. The lowest IC(50) value was 0.04 mg ml(-1) obtained with an ethanol bark extract of Combretum kraussii. None of the investigated plants showed any potential mutagenic effects.     

中药提取物乙酰胆碱酯酶抑制活性的研究

目的研究中药水提物对乙酰胆碱酯酶的抑制活性。方法选取24味中药做研究对象。应用传统的水提的方法制备中药提取物。使用改进了的Elman比色法检测24种中药的水提物对兔大脑乙酰胆碱酯酶抑制活性。结果黄柏的水提物有显著的乙酰胆碱酯酶抑制活性,在50μg/ml浓度下抑制率达75.58%,IC50值为20.03μg/ml。厚朴的水提取物在50μg/ml浓度下抑制率为43.95%,其IC50值为127.17μg/ml。益智仁的水提物有较弱的乙酰胆碱酯酶抑制活性。结论黄柏等中药提取物对乙酰胆碱酯酶具有很好的抑制活性。     

In vitro antimicrobial, anthelmintic and cyclooxygenase-inhibitory activities and phytochemical analysis of Leucosidea sericea

Ethnopharmacological relevance

Leucosidea sericea is used as a vermifuge and in the treatment of ophthalmia by various tribes in southern African countries.

Aim of the study

The study aimed at screening leaves and stems of Leucosidea sericea for pharmacological activity and validating the plant's traditional use. A general phytochemical screening was also carried out.

Materials and methods

Petroleum ether (PE), dichloromethane (DCM), ethanol (EtOH) and water extracts of the plant parts were investigated for antimicrobial, anthelmintic and cyclooxygenase (COX) inhibitory activities. Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus), Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae) and Candida albicans were used for the antimicrobial evaluation. Caenorhabditis elegans was used for the anthelmintic assay using the microdilution technique. Cyclooxygenase-1 and -2 (COX-1 and -2) were used to evaluate the anti-inflammatory potential of the plant extracts. Phytochemical analysis for phenolic compounds, including gallotannins, condensed tannins and flavonoids was done using 50% methanol extracts of the leaves and stems employing spectrophotometric methods.

Results

The leaf extracts exhibited broad spectrum antibacterial activity ranging from 0.025 to 6.25 mg/ml. The most noteworthy minimum inhibitory concentration (MIC) of 0.025 mg/ml was exhibited by PE and DCM leaf extracts against Bacillus subtilis and Staphylococcus aureus, respectively. In the anthelmintic assay, the best minimum lethal concentration (MLC) value of 0.26 mg/ml was observed for the DCM and EtOH leaf extracts. Both leaf and stem organic solvent extracts exhibited high to moderate inhibition against COX-1 and -2 at a screening concentration of 250 μg/ml. At lower concentrations, the extracts displayed a dose-dependent inhibition, with the lowest IC₅₀ values of 0.06 μg/ml (COX-1) and 12.66 μg/ml (COX-2) exhibited by the PE extract of the leaves. Generally, the leaf extracts exhibited better pharmacological activities and contained higher amounts of phenolic compounds than the stem extracts. Alkaloids and saponins were only detected in the leaf and stem extracts, respectively.

Conclusion

The reported results support the local use of Leucosidea sericea against eye infections and as a vermifuge. The pharmacological activities exhibited by the leaf extracts are probably due to their higher phenolic levels.     

The in vitro biological activity of selected South African Commiphora species

Ten South African Commiphora (Burseraceae) species were investigated to validate their use in traditional healing rites. The leaf and stem extracts of each species were analysed for the anti-oxidant (ABTS and DPPH assays), antimicrobial (MIC and death kinetic assays), anti-inflammatory (5-LOX assay), anticancer (SRB assay) properties, as well as the cytotoxic effects (tetrazolium-based assay). The best anti-oxidant activity (ABTS assay) was observed for the stem extracts of Commiphora tenuipetiolata IC(50)=5.10 microg/ml), Commiphora neglecta (IC(50)=7.28 microg/ml) and Commiphora mollis (IC(50)=8.82 microg/ml). Extracts generally exhibited poor anti-oxidant activity in the DPPH assay, with the exception of Commiphora schimperi (stem), Commiphora neglecta (stem), Commiphora tenuipetiolata (stem and leaf), and Commiphora edulis (stem), with IC(50) values ranging between 7.31 and 10.81 microg/ml. The stem extracts exhibited moderate to good 5-LOX inhibitory activity with Commiphora pyracanthoides (stem) displaying the greatest inhibitory effect (IC(50)=27.86+/-4.45 microg/ml). For the antimicrobial (MIC) assay, a greater selectivity was exhibited by the extracts against the Gram-positive bacteria (0.01-8.00 mg/ml) and the yeasts (0.25-8.00 mg/ml) than against the Gram-negative bacteria (1.00-8.00 mg/ml). Using death kinetic studies (time-kill studies), the rate at which Commiphora marlothii (stem) kills Staphylococcus aureus over a 24h period was determined. Mostly, a concentration-dependent antibacterial activity was observed beginning after ca. 30 min. All concentrations exhibited antibacterial activity, with complete bactericidal effect achieved by the 24(th) hour. The most active Commiphora species against the HT-29 cells (SRB anticancer assay) were Commiphora glandulosa (leaf and stem) and Commiphora marlothii (leaf). The MCF-7 cells (SRB anticancer assay) exhibited the highest sensitivity to indigenous Commiphora species, with Commiphora edulis (leaf and stem), Commiphora glandulosa (leaf and stem), Commiphora marlothii (leaf), Commiphora pyracanthoides (leaf and stem), Commiphora schimperi (stem), and Commiphora viminea (stem) all possessing a percentage inhibition greater than 80% at 100 microg/ml. Commiphora glandulosa (leaf and stem) and Commiphora pyracanthoides (leaf and stem) were the two most active species against the SF-268 cells (SRB anticancer assay), with IC(50) values ranging between 68.55+/-2.01 and 71.45+/-1.24 microg/ml. The majority of the Commiphora extracts were largely non-cytotoxic against Graham human kidney epithelial cells when investigated in the MTT assay.     

羊耳菊水提取物体外抑菌活性研究

目的 探讨羊耳菊不同器官水提取物的体外抑菌活性.方法 以金黄色葡萄球菌、铜绿假单胞菌、白色念珠菌等10种微生物为试验菌株,采用药敏纸片扩散法、试管二倍稀释法,对羊耳菊水提取物进行抑菌试验.结果 羊耳菊全株各器官都具有较强的抑菌作用,其中根对10种供试菌种都有抑制作用,抑制范围最广;茎对9种供试菌种有抑制作用,叶对8种供试菌种有抑制作用.羊耳菊各器官对金黄色葡萄球菌与铜绿假单胞菌的抑制作用最强.羊耳菊根、茎、叶对金黄色葡萄球菌的MIC值分别为15.63,62.5,62.5 mg/ml,而其抑菌圈直径分别为14.3,13.8,13.5 mm;羊耳菊根,茎,叶对铜绿假单胞菌的MIC值分别为15.63,31.25,62.5 mg/ml,其抑菌圈直径分别为15.8,15.5,14.0 mm.结论 羊耳菊水提取物体外试验证实了该民间药物具有抗菌活性,也表明了羊耳菊是一种有开发潜力的新抗菌药物资源.     

In vitro Inhibition of Human CYP1A2, CYP2D6, and CYP3A4 by Six Herbs Commonly Used in Pregnancy

Black elderberry, cranberry, fennel, ginger, horsetail, and raspberry leaf, herbs frequently used in pregnancy, were investigated for their in vitro CYP1A2, 2D6, and 3A4 inhibitory potential. Aqueous or ethanolic extracts were made from commercially available herbal products, and incubations were performed with recombinant cDNA‐expressed human CYP enzymes in the presence of positive inhibitory controls. Metabolite formation was determined by validated LCMS/MS or HPLC methodologies. IC₅₀ inhibition constants were estimated from CYP activity inhibition plots using non‐linear regression. The most potent inhibition was shown for fennel towards CYP2D6 and 3A4 with respective IC₅₀ constants of 23 ± 2 and 40 ± 4 µg/ml, horsetail towards CYP1A2 with an IC₅₀ constant of 27 ± 1 µg/ml, and raspberry leaf towards CYP1A2, 2D6, and 3A4 with IC₅₀ constants of 44 ± 2, 47 ± 8, and 81 ± 11 µg/ml, respectively. Based on the recommended dosing of the different commercial herbal products, clinically relevant systemic CYP inhibitions could be possible for fennel, horsetail, and raspberry leaf. In addition, fennel and raspberry leaf might cause a clinically relevant inhibition of intestinal CYP3A4. The in vivo inhibitory potential of these herbs towards specific CYP enzymes should be further investigated. Copyright © 2013 John Wiley & Sons, Ltd.     

Xanthine oxidase inhibitory activity of some Indian medical plants

Xanthine oxidase inhibitory activity was assayed from six species belonging to different families traditionally used for the treatment of gout and related symptoms by indigenous people of India. The aqueous, methanol-water mixture and methanolic extract of these plants were used for the experiment. Of the 18 extracts assayed, 14 extracts demonstrated xanthine oxidase inhibitory activity at 100 microg/ml, among which 10 extracts showed an inhibition greater than 50% and IC(50) values below 100 microg/ml. The methanolic extracts of Coccinia grandis, Datura metel, Strychnos nux-vomica and Vitex negundo showed more than 50% inhibition, hence, they were screened for their in vivo hypouricaemic activity against potassium oxonate-induced hyperuricaemia in mice. Methanolic extracts of Coccinia grandis and Vitex negundo showed a significant decrease in the serum urate level (3.90+/-0.07 mg/dl, P<0.001) and (6.26+/-0.06 mg/dl, P<0.01), respectively, when compared to hyperuricaemic control (11.42+/-0.14 mg/dl). This effect is almost similar to the serum urate level of allopurinol (3.89+/-0.07 mg/dl).