罗汉果果实中抑菌活性组分的研究

目的 确定并纯化罗汉果果实中的抑茵组分.方法 制备罗汉果干果的粗提物,并通过一种快速的颜色指示法检测其抗菌活性.罗汉果果实提取物对变形链球菌(S.mutans)有很强的抑制活性.为了进一步分离活性组分及成分,通过HPLC对其进行分离,并通过上述筛选方法对不同组分的抑茵活性进行快速筛选,对有活性的组分通过血琼脂法进行验证.结果 罗汉果果实提取物对变形链球菌(S.mutans)有很强的抑制活性;将其粗提物通过HPLC进行分离得到50个组分,罗汉果果实提取物的两个HPLC组分,#18-19和#34-35对于变形链球茵(S.mutans)有很强的抑制活性,而其它的组分没有或只有很弱的活性.罗汉果苷V无抑茵活性.结论 罗汉果果实提取物具有较强的抑茵活性;罗汉果果实的抑茵活性不是由罗汉果苷,而是由罗汉果中另外的活性组分或成分产生的.罗汉果果实具有进一步开发为抗茵药物和保健品的潜力.     

桑叶中糖苷酶抑制活性组分的筛选

目的:筛选桑叶中具有糖苷酶抑制活性的组分。方法:采用柱色谱法将桑叶水提物进行分离,并利用体外糖苷酶抑制模型对活性部位进行跟踪研究,进一步通过小鼠体内糖耐量实验验证其效果。结果:体外和体内实验结果表明桑叶提取物中生物碱、黄酮、多糖等部位均有糖苷酶抑制活性,其中生物碱组分活性最强。结论:桑叶的降糖作用与各组分的糖苷酶抑制活性有关。     

罗汉果叶茎根的抑菌活性组分的研究

目的通过以活性为导向的提取分离的方法，首次研究罗汉果全植株中的抑菌活性组分。方法通过提取得到罗汉果全植株各个部分—果实、叶、茎和根的提取物，然后运用一种快速颜色指示法和血琼脂法研究检测它们的抑菌活性。结果罗汉果的非果实部分及果实对于口腔细菌转糖链球菌S．mutans具有很强的抑菌活性。为了进一步研究并分离活性组分，将其粗提物通过Amberlite XAD树脂进行分离纯化，再通过同样的检测方法进行抗菌活性测定，对有活性的组分通过血琼脂法进行验证。结论罗汉果叶、茎和根（非果实部分）以及果实都具有较强的抑菌活性；罗汉果的非果实部分具有进一步开发为抗菌药物和保健品的潜力。     

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)。     

花椒属植物对口腔致病菌的抗菌活性

目的：比较6种花椒属(Zanthoxylm)植物乙醇提取物对口腔致病菌的抗菌活性，从中寻找抗菌的活性物质。方法：用于抗菌活性实验的口腔致病菌是变形链球菌(Streptococcus mutans ATCC 25175)，放线菌(Aainomyces naeslundii ATCC 12104)和嗜血放线伴生杆菌(Actinobacillus actinomycetemicomtans ATCC 43717)。抗菌实验为琼脂扩散法(agar diffusion assays)和最低抑菌浓度法(MIC)。结果：拟蚬壳花椒(Z．lactura)的根对这些口腔致病菌表现出最强的抗菌活性，其次是两面针(Z．nitidum)和异叶花椒(Z．dimorphyllum)的根。进而对异叶花椒(Z．dimorphyllum)的根进行化学成分研究，分离到4个已知化合物，其中化合物Canthin-6-one对这三种口腔致病菌均有很强的抗菌能力，最低抑菌浓度(MIC)在15．6和62．5μg／mL之间。结论：Canthin-6-one可能是异叶花椒抗菌活性的物质基础。     

大叶桉黄酮类化合物的分析及抑菌活性的研究

目的:分析大叶桉Eucalyptus robusta.Sm干燥叶中黄酮类化合物的含量,并研究其抗菌的生物活性.方法:采用紫外分光光度法测定含量,粗提物通过聚酰胺柱分离总黄酮Flavoinds,在平板培养基上比较黄酮类化合物与土霉素Oxytetracycline抑制大肠杆菌Escherichia-coil、金黄色葡萄球菌Staphylocccusaureus、蜡样芽孢杆菌Bacterium cactus的活性.结果:总黄酮含量为0.903%,提取率为4.306%,抑菌活性明显优于土霉素.结论:该植物叶作为类抗生素饲料添加剂的开发具有较高的实用及经济价值.     

大叶桉黄酮类化合物的分析及抑菌活性的研究

目的：分析大叶桉Eucalyptus robusta．Sm干燥叶中黄酮类化合物的含量，并研究其抗菌的生物活性。方法：采用紫外分光光度法测定含量，粗提物通过聚酰胺柱分离总黄酮Flavoinds，在平板培养基上比较黄酮类化合物与土霉素Oxytetracycline抑制大肠杆菌Escherichia—coil、金黄色葡萄球菌Staphylocccus aureus、蜡样芽孢杆菌Bacterium cactus的活性。结果：总黄酮含量为0．903％，提取率为4．306％，抑菌活性明显优于土霉素。结论：该植物叶作为类抗生素饲料添加剂的开发具有较高的实用及经济价值。     

杜仲内生真菌的分离鉴定及抗菌活性筛选

目的从药用植物杜仲的根茎叶中分离内生真菌,并进行初步鉴定和抗菌活性筛选。方法经显微形态观察进行内生真菌的分离鉴定,采用菌饼法和纸片法进行抗菌活性筛选。结果从杜仲植物中分离获得62株内生真菌,有47个菌株至少对1种指示菌具有抗菌活性,40株的代谢产物至少对1种指示菌具有抗菌活性,青霉属(Penicinium)的抗菌活性高且抗菌谱广。结论杜仲植物内生真菌中广泛分布着有抗菌活性的菌株。     

紫金砂体外抗菌活性的研究

目的紫金砂提取物及其提取部位抗菌活性的研究。方法95%乙醇提取,系统溶剂萃取分离得到5个部位,采用纸片扩散法对提取物及提取部位进行体外抗菌活性研究。结果紫金砂提取物对金黄色葡萄球菌、大肠杆菌具有抑制作用,氯仿提取部位对大肠杆菌、枯草芽胞杆菌具有抑制作用,正丁醇提取部位对大肠杆菌、绿脓杆菌具有抑制作用。结论紫金砂提取物及提取部位具有抗菌活性。     

应用体外模型从植物提取物中筛选治疗雄激素源性脱发的5a-还原酶抑制剂

目的应用5a-还原酶抑制剂体外筛选模型,寻找植物提取物中天然5a-还原酶抑制剂,用于雄激素源性脱发的治疗。方法通过HPLC测定底物睾酮(T)在酶促反应中的下降速率计算酶活力,建立5a-还原酶抑制剂体外筛选模型。采用此体外模型对多种植物提取物进行酶抑制作用筛选,继而对筛出的植物提取物采用制备液相进行组分分离制备,测定各段组分酶抑制活性,最终找出具有酶抑制作用的活性成分。结果通过体外模型筛选发现有酶抑制活性的咖啡提取物,并找到其活性成分咖啡鞣酸。结论通过体外模型筛选5a-还原酶抑制剂,结合制备液相分离植物提取物组分,是发现新活性物质的有效手段     

Further evaluation of Rwandan medicinal plant extracts for their antimicrobial and antiviral activities.

A total of 45 Rwandan plant extracts, belonging to 37 different plant species out of 21 families, were investigated for their antibacterial, antifungal, and antiviral properties. The plants were selected on the base of their ethnomedicinal use against infections and autoimmune diseases. From all the plant extracts tested, only Clematis hirsuta (leaves) showed a pronounced antifungal activity against Candida albicans and the dermatophytes Trichophyton rubrum, Epidermophyton floccosum, and Microsporum canis. Seven plant extracts showed a high antiviral activity against the DNA-virus Herpes simplex type 1, while five and three plant extracts were highly active against the RNA-viruses Coxsackie and Polio, respectively. Only Macaranga kilimandscharica (leaves) showed an interesting anti-measles activity, whereas Eriosema montanum (leaves) and Entada abyssinica (leaves) were highly active against Semliki forest virus. Some plant extracts showed an antibacterial activity against Gram-positive bacteria and Mycobacterium fortuitum, but none of them were active against the Gram-negative bacteria tested.     

Antibacterial activity of plant extracts from the families Fabaceae, Oleaceae, Philadelphaceae, Rosaceae and Staphyleaceae

The selected plant extracts exhibited antibacterial activity. The strongest effect was manifested by extracts prepared from Gymnocladus dioicus, Amelanchier ovalis, Exochorda racemosa, Holodiscus discolor, Philadelphus microphyllus, Philadelphus coronarius and Pelargonium tabulare. The percentage inhibition of bacterial growth was 0-41.8%. In addition it was found that extracts isolated from Amelanchier ovalis, Exochorda racemosa and Pelargonium tabulare were specifically effective only against the bacterial strains tested.     

Antimicrobial screening of Cassia occidentalis L. in vivo and in vitro

Ethanol extracts of different parts and the calli of Cassia occidentalis, and sequential extracts (petroleum ether, benzene, chloroform, ethanol and water) of whole plant and metabolite-rich fractions (anthraquinones, sennosides and flavonoids) of leaves, pods, flowers and callus have been tested against indicator human pathogenic bacteria and fungi. Likewise, an ethanol extract (whole plant) was tested against selected viruses and for antitumour and cytotoxicity following established protocols. The anthraquinones were found to be more active against E. coli and S. aureus (IZ 22 mm) while sennosides were more active against A. flavus (IZ 28 mm). However, no antiviral, antitumour or cytotoxicity effect was exhibited against the test systems. © 1998 John Wiley & Sons, Ltd.     

Screening of Taiwanese crude drugs for antibacterial activity against Streptococcus mutans

Preliminary antibacterial screening of local crude drugs was carried out using the cariogenic bacterium, Streptococcus mutans. Of 79 aqueous extracts tested, 6 crude drugs were shown to have significant antibacterial activity with minimal inhibitory concentration equal to or lower than 7.8 mg/ml (expressed in terms of dry starting material). Of these effective crude drugs, Morus australis, Ludwigia octovalvis and Thuja orientalis were very effective in inhibiting the growth of serotypes c and d of S. mutans (MIC less than or equal to 2.0-7.8 mg/ml). Elephantopus scaber, Artemisia vulgaris, Mosla chinensis and Orthosiphon aristatus also exhibited considerable antibacterial activity (MIC = 7.8-23.4 mg/ml) against both serotypes. In the presence of 5% sucrose, the antibacterial potency of the majority of the extracts did not change for type c, while the potency decreased about one-half for type d.     

In vitro antimicrobial activity of ethanol and water extracts of Cassia alata

Crude ethanol and water extract of leaves and barks from Cassia alata were tested in vitro against fungi, (Aspergillus fumigatus and Microsporum canis), yeast (Candida albicans) and bacteria (Staphylococcus aereus and Escherichia coli). C. albicans showed concentration-dependent susceptibility towards both the ethanol and water extracts from the barks, but resistant towards the extracts of leaves. The degree of susceptibility varied, the water extract from barks showed bigger inhibition zone than the ethanol extracts (12-16 and 10-14 mm, diameter respectively). The growth of Aspergillus fumigatus and Microsporum canis were not affected by all types of the plant extracts. Results were comparable to standard antifungal drug Tioconazole (18 mm diameter) at equivalent concentration. The anti-bacterial activity of C. alata extracts on S. aureus was detected with only the leaves extracts using water and ethanol. The water extract exhibited higher antibacterial activity than the ethanol extract from leaves (inhibition zones of 11-14 and 9-11 mm, respectively). E. coli showed resistance to all types of extracts. Based on the current findings, it can be concluded that this plant has antimicrobial activity, which is as potent as standard antimicrobial drugs against certain microorganisms.     

The pharmacological screening of Pentanisia prunelloides and the isolation of the antibacterial compound palmitic acid.

The uses of Pentanisia prunelloides in Zulu traditional medicine indicate that the plant is believed to be effective in relieving inflammation, bacterial and viral infections and also stimulating uterine contraction. Aqueous, ethanolic and ethyl acetate extracts of leaves and roots were screened for prostaglandin-synthesis inhibitors and antibacterial and antiviral activity. In the results of the anti-inflammatory assay all the extracts showed cyclooxygenase-1 inhibition. The ethanolic and ethyl acetate extracts showed greater antibacterial activity than the aqueous extracts against Gram-positive (Bacillus subtilis, Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae). Both root and leaf extracts were found to inhibit viral replication of the Influenza A virus. The ethyl acetate extract was fractionated by silica vacuum liquid chromatography and anti-inflammatory activity was found to be most pronounced in the more polar fractions. The presence of antibacterial activity was confirmed by running the fractions on a thin layer chromatography (TLC) plate and performing a bioautographic assay. The active fraction was further purified by TLC and the major antibacterial compound in the ethyl acetate root extract was identified by GC/MS as palmitic acid.     

Antimicrobial activity of certain Indian medicinal plants used in folkloric medicine

Fifty medicinal plants belonging to 26 families were studied for their antimicrobial activity. Among 50 plants tested, 72% showed antimicrobial activity. About 22 plant extracts from 15 families exhibited activity against both Gram-positive and Gram-negative bacteria. Fourteen plants belonging to 11 families did not show activity against any of the bacteria tested. Only nine plant extracts showed antifungal activity. The bulb extracts of A. cepa and A. sativum exhibited activity against both filamentous and non-filamentous fungus. Eight plant extracts belonging to seven families exhibited both antibacterial and antifungal activity.