银杏外种皮中银杏酸的体外抗肿瘤活性研究

目的:探讨银杏酸对肿瘤细胞和正常细胞生长的影响.方法:从银杏外种皮中制备纯度90%的银杏酸同系混合物.采用MTT法,检测银杏酸对各细胞株生长的抑制作用.结果:银杏酸浓度为5.0μg/ml时,对肿瘤细胞生长都有明显的抑制作用,其中对肺癌LTEP-a-2细胞抑制率达到59.1%,而对正常细胞无影响;高浓度银杏酸对正常细胞和肿瘤细胞生长的抑制作用趋于一致.结论:银杏酸对体外培养的肿瘤细胞有较强抑制作用,浓度低于5.0μg/ml时对正常细胞生长无影响.     

银杏酸及银杏酚的提取分离工艺探讨

银杏外种皮含有醇、酚、酸等多种化学物质 ,不但有恶臭味 ,而且对较多人的皮肤会发生强烈的刺激作用 ,引起瘙痒 ,出现皮炎水疱 ,严重者出现痉挛和皮肤灼伤 ,这说明银杏外种皮中含有较多的活性成分[1] 。有研究者曾用银杏外种皮作过杀虫剂及有关农药的研究探讨 [2 ] 。多年来 ,银杏外种皮一直作为废物被丢弃 ,这既浪费了资源又污染了环境 ,为更好地综合开发利用银杏资源 ,我们采用甲醇提取、乙醚萃取法 ,从银杏外种皮中提取出了银杏酸、银杏酚 ,为银杏外种皮的进一步开发利用奠定了基础。1　提取工艺银杏外种皮用 70 %甲醇浸提 ,浓缩液用乙醚…     

银杏酸单体的抗菌活性研究

目的:从银杏外种皮中得到银杏酸混合物及三种单体,研究银杏酸的抗菌活性及其侧链与活性的关系.方法:采用二倍稀释法测定了银杏酸混合物、各单体及水杨酸的最低抑菌浓度.结果:银杏酸混合物对痤疮丙酸杆菌等G 菌具有良好的抑制作用.水杨酸无侧链,无抗菌活性.银杏酸侧链为C13:0时抑菌效果最强.结论:银杏酸的侧链是其产生抗菌活性的主要效应部位,侧链长短是银杏酸抗菌作用强弱的关键.     

银杏酸单体的抗肿瘤活性研究

目前银杏叶和白果的开发利用已很多,但银杏外种皮的利用率低。研究发现外种皮中含有较多的银杏酸(ginkgolic acids,GAs),为6-烷基或6-烯基水杨酸,6位上的侧链碳原子数可从13至19、侧链双健数可从0至3个,是一系列同系物的混合物。银杏酸是银杏中除了黄酮和内酯外的另一具有重要生理活性的组分,具有致敏性、细胞毒性和免疫毒性等作用,在传统意义上是银杏产品中的有毒成分[1]。而现在对于银杏酸有了新的认识,银杏酸具有多种生理药     

银杏酸的分离制备及HPLC分析

目的：利用银杏外种皮分离制备银杏酸，并测定银杏酸含量。方法：采用石油醚超声萃取和硅胶柱层析法从银杏外种皮中分离制备银杏酸；用高效液相色谱法测定银杏酸含量。色谱柱为HiQsilC18柱，流动相为甲醇3％HAc溶液(90：10，V／V)，流速1ml／min，检测波长为310nm，柱温40℃。结果：银杏酸在l.144—5．720μg范围内线性关系良好(r=0．9978)，平均回收率97．50％，RSD为1．70％。结论：可从银杏外种皮中分离制备银杏酸；银杏酸含量测定方法准确、可靠，可用于样品中银杏酸含量的分析。     

银杏酸凝胶制剂的研制及制剂中银杏酸的含量测定

银杏酸(Ginkgolic acid,GA)主要存在于银杏(Ginkgo biloba L.)外种皮和叶中,为6-烷基或6-烯基水杨酸的衍生物,6位上的侧链碳原子数可从13至19,侧链双键数可为0至3.常见银杏酸的结构见图1[1].研究表明[2～6],银杏酸具有抗菌、抗炎、抗肿胀等作用,对痤疮丙酸杆菌和金黄色葡萄球菌等有较好的抑制作用,可用于治疗多种皮肤病如痤疮、疥疮、皮炎等.本文以银杏酸为主药、卡波普940为基质,制备凝胶外用制剂,用于治疗寻常性痤疮,并采用HPLC法测定制剂中GA含量.     

RP-HPLC法制备银杏酸的研究

目的 研究5种银杏酸单体的RP—HPLC制备分离条件。方法 将银杏外种皮的环己烷提取物经过预处理，采用HPLC-MS鉴定，RPHPLC分离、制备银杏酸单体。结果 该制备方法所得的5种银杏酸单体纯度超过98％。结论 通过HPLC—MS检测确定银杏总酚酸不同物质的出峰位置，在制备柱上可以获得多种银杏酸单体，分离产物达到该类产品检测用对照物质的质量要求。     

银杏外种皮的化学成分和药理活性研究进展

阐述了银杏外种皮的化学成分和药理活性研究的最新进展。银杏外种皮含有黄酮类、内酯类、银杏酚酸、多糖和氨基酸等化学成分 ,具有抑菌杀菌作用 ,杀虫作用 ,抗肿瘤作用 ,致突变、致癌作用 ,抗过敏作用 ,过敏作用 ,对免疫功能的影响 ,清除自由基、抗衰老等药理活性。指出了银杏外种皮研究存在的主要问题和今后研究的主要方向。     

银杏酸单体化合物的制备

 目的研究银杏酸单体化合物的制备方法，为银杏酸的应用研究提供参考，为银杏提取物中银杏酸的定量分析提供单体对照品。方法银杏外种皮用石油醚回流提取，提取物通过硅胶柱色谱分离，得银杏酸混合物，再经制备柱反复分离，得银杏酸单体。结果石油醚回流提取法所得银杏酸得率为4.06%，纯度84.59%,提取率达62.9%。银杏酸混合物经制备色谱多次分离后，得到6种银杏酸单体，其中一种为新发现的化合物，纯度均达95%以上。结论单体制备方法较为简便，可用于高纯度银杏酸单体的制备。     

银杏外种皮化学成分的分离和鉴定

从银杏外种皮中分出５个化合物，其中２个系首次从外种皮中分离得到，分别鉴定为银杏黄素（ｇｉｎｋｇｅｔｉｎ）和异银杏黄素（ｉｓｏｇｉｎｋｇｅｔｉｎ）。另３个化合物为氢化白果酸，白果酚和白果醇。     

In Vitro Antibacterial Activity and Synergistic Antibiotic Effects of Phlorotannins Isolated from Eisenia bicyclis Against Methicillin‐Resistant Staphylococcus aureus

Six phlorotannins, isolated from Eisenia bicyclis, were evaluated for antibacterial activity against methicillin‐resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentrations (MIC) of the compounds were in the range 32 to 64 µg/mL. Phlorofucofuroeckol‐A (PFF) exhibited the highest anti‐MRSA activity, with an MIC of 32 µg/mL. An investigation of the interaction between these compounds and the β‐lactam antibiotics ampicillin, penicillin, and oxacillin revealed synergistic action against MRSA in combination with compound PFF. To our knowledge, this is the first report on the anti‐MRSA activity of phlorotannins from E. bicyclis. The results obtained in this study suggest that the compounds derived from E. bicyclis can be a good source of natural antibacterial agents against MRSA. Copyright © 2012 John Wiley & Sons, Ltd.     

Antibacterial activity and synergistic antibiotic mechanism of trialdehyde phloroglucinol against methicillin-resistant Staphylococcus aureus

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has become a critical global concern. Identifying new anti-S. aureus agents or therapeutic strategies are urgently needed to treat S. aureus infection. The present study investigated the antibacterial activity of 16 phenolic compounds against MRSA, four of which exhibited antibacterial activity. Their antibacterial activities increased in a dose-dependent manner but showed different responses with the extension of treatment time. Trialdehyde phloroglucinol (TPG) and 2-nitrophloroglucinol (NPG) maintained stable antibacterial activity; however, that of dichlorophenol and myricetin decreased rapidly over 24 hr of treatment. Checkerboard and time-kill assays indicated that TPG and NPG exhibited strong synergistic antibacterial activities with penicillin or bacitracin. Microscopic observation and membrane integrity analysis showed that the combination of TPG and penicillin destroyed the MRSA cell membrane, resulting in the leakage of intracellular biomacromolecules, marked changes in surface zeta potential, and the collapse of membrane potential. Moreover, the combination significantly decreased penicillinase activity and penicillin-binding protein 2a mRNA expression, inhibiting MRSA growth. Taken together, these results demonstrated that the combination of the phloroglucinol derivative TPG and penicillin has significant synergistic anti-MRSA activity and can serve as a potential therapeutic strategy to treat MRSA infections.     

Antibacterial activity of Curcuma longa L. against methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) has been emerging worldwide as one of the most important hospital and community pathogens. Therefore, new agents are needed to treat MRSA associated infections. The present study investigated the antimicrobial activity of ethyl acetate, methanol and water extracts of Curcuma longa L. (C. longa) against MRSA. The ethyl acetate extract of C. longa demonstrated a higher antibacterial activity than the methanol extract or water extract. Since the ethyl acetate extract was more active than the other extracts, the study examined whether the ethyl acetate extract could restore the antibacterial activity of beta-lactams and alter the MRSA invasion of human mucosal fibroblasts (HMFs). In the checkerboard test, the ethyl acetate extract of C. longa markedly lowered the MICs of ampicillin and oxacillin against MRSA. In the bacterial invasion assay, MRSA intracellular invasion was significantly decreased in the presence of 0.125-2 mg/mL of C. longa extract compared with the control group. These results suggest that the ethyl acetate extract of C. longa may have antibacterial activity and the potential to restore the effectiveness of beta-lactams against MRSA, and inhibit the MRSA invasion of HMFs.     

Inhibitory effects of Caesalpinia sappan on growth and invasion of methicillin-resistant Staphylococcus aureus

In the present study, we investigated antimicrobial activity of Caesalpinia sappan against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and effect of Caesalpinia sappan extract on the invasion of MRSA to human mucosal fibroblasts (HMFs). Chloroform, n-butanol, methanol, and aqueous extracts of the Caesalpinia sappan showed antimicrobial activity against standard methicillin-sensitive Staphylococcus aureus (MSSA) as well as MRSA. Methanol extract of Caesalpinia sappan demonstrated a higher inhibitory activity than n-butanol, chloroform, and aqueous extracts. In the checkerboard dilution method, methanol extract of Caesalpinia sappan markedly lowered the minimal inhibitory concentrations (MICs) of ampicillin and oxacillin against MRSA. To determine whether methanol extract of Caesalpinia sappan inhibits the MRSA invasion to HMFs, the cells were treated with various sub-MIC concentrations of methanol extract and bacterial invasion was assayed. MRSA invasion was notably decreased in the presence of 20-80 microg/ml of Caesalpinia sappan extract compared to the control group. The effect of Caesalpinia sappan extract on MRSA invasion appeared dose-dependent. These results suggest that methanol extract of Caesalpinia sappan may have antimicrobial activity and the potential to restore the effectiveness of beta-lactam antibiotics against MRSA, and inhibit the MRSA invasion to HMFs.     

Comparative study on the antibacterial activity of phytochemical flavanones against methicillin-resistant Staphylococcus aureus

Differently substituted flavanones were isolated from Leguminosae and their antibacterial activity was comparatively studied against methicillin-resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentrations (MICs) of phytochemical flavanones to clinical isolates of MRSA were determined by a serial agar dilution method. The structure-activity relationship has indicated that 2′,4′- or 2′,6′-dihydroxylation of the B ring and 5,7-dihydroxylation of the A ring in the flavanone structure are important for significant anti-MRSA activity and that substitution with a certain aliphatic group at the 6- or 8-position also enhances the activity. Among the thirteen flavanones tested, tetrahydroxyflavanones with these structural characteristics isolated from Sophora exigua and Echinosophora koreensis showed intensive activity to inhibit the growth of all MRSA strains at 3.13-6.25 μg/ml. The present hydroxyflavanones would be useful in the phytotherapeutic strategy against MRSA infections.     

Isopimaric acid from Pinus nigra shows activity against multidrug-resistant and EMRSA strains of Staphylococcus aureus

The diterpene isopimaric acid was extracted from the immature cones of Pinus nigra (Arnold) using bioassay-guided fractionation of a crude hexane extract. Isopimaric acid was assayed against multidrug-resistant (MDR) and methicillin-resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentrations (MIC) were 32-64 microg/mL and compared with a commercially obtained resin acid, abietic acid, with MICs of 64 microg/mL. Resin acids are known to have antibacterial activity and are valued in traditional medicine for their antiseptic properties. These results show that isopimaric acid is active against MDR and MRSA strains of S. aureus which are becoming increasingly resistant to antibiotics. Both compounds were evaluated for modulation activity in combination with antibiotics, but did not potentiate the activity of the antibiotics tested. However, the compounds were also assayed in combination with the efflux pump inhibitor reserpine, to see if inhibition of the TetK or NorA efflux pump increased their activity. Interestingly, rather than a potentiation of activity by a reduction in MIC, a two to four-fold increase in MIC was seen. It may be that isopimaric acid and abietic acid are not substrates for these efflux pumps, but it is also possible that an antagonistic interaction with reserpine may render the antibiotics inactive. 1H-NMR of abietic acid and reserpine taken individually and in combination, revealed a shift in resonance of some peaks for both compounds when mixed together compared with the spectra of the compounds on their own. It is proposed that this may be due to complex formation between abietic acid and reserpine and that this complex formation is responsible for a reduction in activity and elevation of MIC.     

甘肃道地中药大黄、黄芩对多重耐药菌的抑菌活性

目的：观察甘肃道地中药材大黄、黄芩的体外抑菌活性,为临床中药治疗耐药菌感染提供参考。方法：采用煎煮法制备大黄、黄芩中药原液,用肉汤稀释法测定两种药液对产超广谱β-内酰胺酶（ESBLs）大肠埃希菌和耐甲氧西林金黄色葡萄球菌（MRSA）的最小抑菌浓度。结果：大黄对产超广谱β-内酰胺酶（ESBLs）大肠杆菌和耐甲氧西林金黄色葡萄球菌（MRSA）的最小抑菌浓度分别为250mg／mL和125mg／mL。黄芩对耐甲氧西林金黄色葡萄球菌（MRSA）的最小抑菌浓度为250mg／mL;对产超广谱β-内酰胺酶（ESBLs）大肠杆菌未见明显抑菌作用。结论：大黄、黄芩对临床常见的多重耐药菌有不同程度的抑菌活性,且大黄的抑菌活性优于黄芩;大黄对金黄色葡萄球菌抑菌活性优于大肠埃希菌。     

隐丹参酮抑菌作用机制研究

目的研究隐丹参酮对金黄色葡萄球菌(SA)、耐甲氧西林金黄色葡萄球菌(MRSA)、β-内酰胺酶阳性的金黄色葡萄球菌(ESBLs-SA)3种金黄色葡萄球菌的抑菌活性及抑菌机制。方法采用纸片扩散法测定隐丹参酮的抑菌圈和最低抑菌浓度(MIC),液体培养法测定其半数抑菌浓度(IC50值),并通过测定隐丹参酮与3种金黄色葡萄球菌作用前后电导率变化、碱性磷酸酶(AKP)的含量变化、胞外蛋白含量变化和SDS-PAGE电泳蛋白谱带变化,初步阐明隐丹参酮对金黄色葡萄球菌、耐甲氧西林金黄色葡萄球菌、β-内酰胺酶阳性的金黄色葡萄球菌的抑菌机制。结果由抑菌圈、最低抑菌浓度和半数抑菌浓度可以看出,隐丹参酮对金黄色葡萄球菌的抑制作用略强于耐甲氧西林金黄色葡萄球菌和β-内酰胺酶阳性的金黄色葡萄球菌;经隐丹参酮作用后,3种金葡菌的电导率、碱性磷酸酶及胞外蛋白含量均增大,SDS-PAGE电泳显示蛋白谱带也明显发生变化。结论隐丹参酮对金黄色葡萄球菌、耐甲氧西林金黄色葡萄球菌和β-内酰胺酶阳性的金黄色葡萄球菌具有明显的抑制作用,隐丹参酮破坏细菌细胞壁和细胞膜的结构,导致细胞膜通透性增加,进而使细胞内容物外泄;同时隐丹参酮对细菌蛋白质的合成有一定影响,使菌体内蛋白质减少,影响和阻碍细胞内蛋白质的表达,最终导致细菌正常生理功能的丧失。     

Antimicrobial activity of xanthones from Calophyllum species, against methicillin-resistant Staphylococcus aureus (MRSA).

During the past 5 years, a considerable number of known and new xanthones from the Calophyllum species of Sri Lanka have been isolated and characterized. We have investigated the antimicrobial activity of Calophyllum xanthones, with a special reference to methicillin-resistant Staphylococcus aureus (MRSA). These activity studies were carried out using the agar plate method. Calozeloxanthone, a xanthone which has been isolated from C. moonii and C. lankensis, showed the highest activity against methicillin-resistant S. aureus (MRSA) strains at a concentration of 8.3 microg/ml. Hence, calozeyloxanthone appears to hold promise as an antimicrobial agent in the treatment of infections with S. aureus, including methicillin-sensitive S. aureus (MRSA), and should be investigated further.     

丹参生品及不同炮制品的体外抗菌活性研究

目的研究丹参不同炮制品(清炒、炒炭、米炒、酒炙和醋制丹参)的体外抗菌活性。方法采用纸片扩散法研究丹参不同炮制品对金黄色葡萄球菌(SA)、耐甲氧西林的金黄色葡萄球菌(MRSA)和β-内酰胺酶阳性金黄色葡萄球菌(ESBLs)的抑制活性。结果丹参生品及不同炮制品对SA和MRSA的抑制作用略强于ESBLs,对SA的抗菌效果最强;其中炒丹参的甲醇总提取物质量浓度在50 mg/mL对SA、MRSA、ESBLs的抑菌圈直径最大且相同;对相应样品的MIC值进行比较,显示各样品体外抗菌活性大小依次为:丹参生品及炮制品的甲醇提取物>石油醚和乙酸乙酯提取物>正丁醇提取物。结论本实验证明炒丹参和酒丹参的抗菌活性明显增强,而丹参炭的抗菌活性明显减弱,但仍具有一定的抗菌活性。