鹿角藤提取物的抑菌活性

采用生长速率法测定鹿角藤甲醇粗提物、石油醚、氯仿、乙酸乙酯、正丁醇4种溶剂萃取物及氯仿萃取物的层析组分对6种靶标菌的抑菌活性。结果表明,在质量浓度5 mg·m L-1条件下,4种萃取物中,氯仿萃取物的抑菌活性最好,尤其是对香蕉炭疽菌及芒果炭疽菌,其抑制率达82.48%、71.57%;氯仿萃取物的进一步层析组分中,E组分的抑菌活性最好,且具有广谱抑菌活性,在质量浓度0.5 mg·m L-1条件下,组分E对香蕉炭疽菌的抑制率达74.12%,具有进一步研究开发的潜质。     

板栗雄花序萃取物抗氧化及抑菌效果

【目的】研究板栗雄花序不同萃取物的抗氧化及抑菌效果,为其进一步开发与利用提供基础。【方法】用不同极性溶剂对板栗雄花序乙醇浸膏进行萃取分离,得到石油醚萃取物、二氯甲烷萃取物、乙酸乙酯萃取物、正丁醇萃取物4个部分;并采用1,1－二苯基－2－三硝基苯肼( DPPH·)自由基清除和硫代巴比妥酸法测定醇提物及不同萃取物的抗氧化能力,以滤纸片琼脂扩散法和共培养测定抗菌活性。利用高效液相色谱法( HPLC)和核磁共振波谱法(NMR)鉴定出板栗雄花序中的鞣花酸(EA),并对其进行初步定量与结构分析。【结果】1)通过系统提取法得到板栗雄花序醇提物提取率为16.6%,其他4种萃取物提取率在2.6%～26.2%,其中乙酸乙酯萃取物提取率最高。2)板栗雄花序醇提物及不同萃取物对 DPPH·自由基、卵黄脂质过氧化物都有一定的清除能力,其中乙酸乙酯萃取浓度为0.01 mg·mL －1时,对 DPPH·清除率达到94.4%,对卵黄脂质过氧化物的清除率为95.69%,与同浓度的抗坏血酸(Vc)和2,6－二叔丁基－4－甲基苯酚(BHT)清除率相当。3)板栗雄花序醇提物对12种细菌都有一定程度的抑制效果,在不同萃取物中乙酸乙酯萃取物抑菌效果最好,对大肠杆菌的最低抑菌浓度为0.98 mg· mL －1,最低杀菌浓度为1.96 mg·mL －1。板栗雄花序样品中有游离鞣花酸,含量为2.267 mg·g －1。【结论】板栗雄花序中含有较多抗氧化和抑菌的活性物质,其醇提物及不同极性萃取物的抗氧化能力存在较大差异,乙酸乙酯萃取物抗氧化活性较高,对清除 DPPH·自由基和脂质过氧化物都有较好的效果。各个萃取物对 G +菌和 G －菌都有一定作用,其中乙酸乙酯萃取相的抑菌活性最好。     

山核桃外果皮中的抑菌活性成分

用不同溶剂对山核桃外果皮甲醇浸膏进行萃取分离,得石油醚相、氯仿相、乙酸乙酯相、正丁醇相,以番茄早疫病菌、苹果腐烂病菌、小麦赤霉病菌、水稻纹枯病菌、黄瓜菌核病菌等5种病菌进行抑菌活性试验.结果表明:正丁醇相抑菌活性最强,氯仿相和石油醚相次之,乙酸乙酯相最弱.对氯仿相进行初步分离,得到7个单体化合物:乔松酮,黄卡瓦胡椒素,5-羟基-4',7-二甲氧基黄酮,5-羟基-2-甲氧基-1,4-萘醌,5-羟基-6,7-二甲氧基黄烷酮,乔松素,β-谷甾醇,均为首次从山核桃中分离得到,它们对玉米大斑病菌和水稻稻瘟病菌孢子萌发均有不同程度的抑制作用.     

核桃内生真菌G8菌株的分离鉴定及抑菌活性

从核桃根部分离得到一株真菌,编号为G8,对其进行生物学观察,初步鉴定为葡萄壳小圆孢菌,并对其进行了复侵染研究,确定其为核桃内生真菌.对此菌株进行液体发酵,研究其发酵液及其萃取物的抑菌活性.结果表明：（1）发酵液的提取物对28种植物病原真菌均有不同程度的抑制作用,各萃取相粗提物在40mg·mL^-1时,乙酸乙酯萃取物的抑制效果最好,其次为正丁醇萃取物,萃余物最弱,但正丁醇萃取物对水稻纹枯、杨树溃疡、小麦雪腐病原菌的抑制率大于其它两相.（2）不同质量浓度的乙酸乙酯萃取物对11个病原真菌的活性实验结果表明：对苹果轮纹、苹果腐烂、小麦根腐、稻瘟4种病原菌的抑制率为100%,对苜蓿炭疽、小麦赤霉、番茄早疫、苹果炭疽和玉米小斑5种病原菌的抑制率表现出极显著差异,对玉米大斑和辣椒疫霉2种病原菌的抑制率无显著差异.（3）乙酸乙酯萃取物对5种细菌的抑菌试验表明,对蜡状芽孢杆菌和马铃薯芽孢杆菌2种细菌表现为抗药性,但不同质量浓度处理间差异不显著.     

白三叶草黄酮含量及其抑菌活性研究

测定了白三叶草提取物的石油醚相、氯仿相、乙酸乙酯相和水相的黄酮含量,并以大肠杆菌、枯草芽孢杆菌、普通变形杆菌、金黄色葡萄球菌和铜绿假单胞菌5种细菌及可可葡萄座腔菌、尖孢镰刀菌、腐皮镰刀菌、多主棒孢霉和尖孢炭疽菌5种真菌为供试菌,采用抑菌圈法和抑制菌丝生长速率法测定了其抑菌活性。结果表明:石油醚相的黄酮含量为12.98 mg/g(12.98%),氯仿相的黄酮含量为13.89 mg/g(13.89%),乙酸乙酯相的黄酮含量为7.4 mg/g(7.4%),水相的黄酮含量为1.5 mg/g(1.5%);石油醚相对5种细菌无明显的抑制作用,氯仿相对普通变形杆菌和铜绿假单胞菌有抑制作用,其最低抑菌浓度(MIC)分别为2 mg/m L和8 mg/m L;乙酸乙酯相对枯草芽孢杆菌、普通变形杆菌和铜绿假单胞菌的有抑制作用,其最低抑菌浓度(MIC)分别为4,4和8mg/m L,仅水相对5种供试菌株有不同程度的抑制作用。氯仿相和乙酸乙酯相对5种真菌均具有抑制作用,氯仿相对5种供试真菌的抑制作用没有明显差异,其EC50分别为3.54、6.42、8.45、3.63和5.90 mg/m L;乙酸乙酯相对多主棒孢霉的抑制抑制作用最强,EC50为2.51 mg/m L,对尖孢镰刀菌的抑制作用最弱,EC50为165.43mg/m L,石油醚相和水相对5种真菌均无抑制作用。     

10种植物醇提物对木腐菌的抑菌活性筛选北大核心

对比了10种植物干叶的50%乙醇提取物对4种常见木材腐朽菌的抑菌活性,筛选出具有广谱杀菌性且效果较好的植物来源,为后续开发植物源木材防腐剂提供依据。以白腐菌采绒革盖菌、黄孢原毛平革菌和褐腐菌密粘褶菌、绵腐卧孔菌为供试真菌,采用生长速率法初步测定香樟、侧柏、闽楠等10种植物醇提物对木腐菌的抑菌效力,比较其不同时间段的(3、5 d和7 d)菌落直径和抑菌率,聚类分析优选出抑菌植物。结果表明:1)在供试浓度为20 mg/mL的条件下,10种植物醇提物对白腐菌和褐腐菌均有一定抑制作用,随着时间延长大多数植物醇提物抑菌活性明显下降,总体抑菌效果褐腐菌比白腐菌更强;2)当菌落培养至7 d时,飞龙掌血、猴樟、圆柏等6种植物对白腐菌和褐腐菌均有抑制作用,其中飞龙掌血和香樟对4种菌均有抑制作用;3)飞龙掌血抑菌率均高于70%,总体抑菌效果较香樟好,而香樟对采绒革盖菌的抑制效果较差,对其他3种菌的抑制效果达到70%以上。聚类分析结果显示,飞龙掌血(1)和香樟(10)的抑菌效果最佳,在不同时间段对4种木材腐朽菌均有较强的抑菌效力,说明这2种植物具有开发植物源木材防腐剂的潜力。     

望江南茎提取物的抑菌活性成分分析

以望江南茎为原料,经超声波乙醇提取后,采用不同极性溶剂萃取得到4种萃取物,通过滤纸片扩散法测试了4种萃取物对金黄色葡萄球菌、白色念珠菌、鲍曼不动杆菌的抑菌活性,发现氯仿萃取物的综合抑菌效果最佳;进一步通过柱层析法分离纯化氯仿萃取物,得到组分1、组分2和组分3;利用质谱法分析确定了具有较强抑菌活性的组分1中起主要抑菌效果的化合物。结果表明：极性较小的组分1抑菌效果显著,组分1中检测出22个化合物,其中黄酮类7个、蒽醌类13个、多酚类1个、香豆素类1个。选择3种单体蒽醌类化合物大黄素、大黄酚和大黄素甲醚进行最低抑菌浓度(MIC)和最低杀菌浓度(MBC)测定,结果表明：3种化合物对鲍曼不动杆菌和金黄色葡萄球菌的MIC值和MBC值均小于氯仿萃取物,其中对金黄色葡萄球菌的抑制活性最强,MIC值均为0.2 g/L,MBC值均为0.39 g/L;大黄素甲醚综合抑制效果最佳,可能为望江南中发挥抑菌活性的主要化合物之一。     

桑叶总黄酮的提取及其抑菌活性研究

以抑菌活性为评价指标,对桑叶总黄酮的提取工艺进行了优化,并对优化条件下得到的粗提物采用不同溶剂进行分级提取和定性分析,测定了各萃取物的总黄酮含量,考察了萃取物对大肠杆菌、金黄色葡萄球菌的抑菌圈直径、最低抑菌浓度,选取抑菌效果最佳的萃取物进行了稳定性实验。结果表明,桑叶总黄酮提取的最佳条件为:温度70℃,乙醇体积分数70%,提取时间4 h,固液比1∶30(g∶mL);抑菌效果最佳的为乙酸乙酯萃取物,且乙酸乙酯部分对温度和紫外线照射的影响均具有良好的稳定性。     

Extraction of Total Flavonoids of Mulberry Leaves and Their Antibacterial Activities

以抑菌活性为评价指标,对桑叶总黄酮的提取工艺进行了优化,并对优化条件下得到的粗提物采用不同溶剂进行分级提取和定性分析,测定了各萃取物的总黄酮含量,考察了萃取物对大肠杆菌、金黄色葡萄球菌的抑菌圈直径、最低抑菌浓度,选取抑菌效果最佳的萃取物进行了稳定性实验.结果表明,桑叶总黄酮提取的最佳条件为:温度70℃,乙醇体积分数70％,提取时间4h,固液比1∶30(g∶mL);抑菌效果最佳的为乙酸乙酯萃取物,且乙酸乙酯部分对温度和紫外线照射的影响均具有良好的稳定性.     

湘西虎杖抑菌成分提取及其抑菌活性研究初报

以乙醇作溶剂,对湘西虎杖抑菌活性物提取条件进行研究,通过抑菌实验得到最佳提取条件为A3B2C3,即90%乙醇、60℃、3h, 该条件下的提取物对细菌生长的抑制活性最强,但对酵母菌无明显的效果,对三种受试细菌的最小抑菌浓度(MIC)为0.25~ 0.5g/ml。提取物经85℃、100℃,15 min 或pH2~8 处理后仍具有较强的抑菌活性,其乙酸乙酯萃取物对三个菌都有较强的抑菌活性。     

Antibacterial and allelopathic activity of extract from Castanea sativa leaves

Following the extraction of Castanea sativa with an aqueous solution of sulfuric acid (pH 3.0), the ethyl acetate soluble fraction was tested for its antibacterial and allelopathic activity. The extract was shown to have pronounced antibacterial effects against seven of the eight strains of Gram-positive and Gram-negative bacteria used (MIC in the range of 64-256 microg/ml and MBC in the range of 256-512 microg/ml). The active fraction was analyzed by TLC and HPLC showing the presence of rutin, hesperidin, quercetin, apigenin, morin, naringin, galangin and kaempferol. Standards of the identified flavonoids were tested against the same bacterial strains. The highest activity was shown by quercetin, rutin and apigenin. The allelopathic effect was tested against Raphanus sativus seed germination. The extract, quercetin, rutin and apigenin caused a decrease in the percentage of seed germination and root and epicotyl growth.     

Cytotoxicity and antibacterial activity of extractives from Wedelia calendulacea

The cytotoxicity and antibacterial activity of petroleum ether, chloroform and methanol extracts of Wedelia calendulacea were assayed by brine shrimp lethality bioassay and standardized disk diffusion method against 19 bacterial strains. Three diterpenes isolated from the plant were also evaluated for in vitro antibacterial activities. The LC50 for the crude extracts against the brine shrimp nauplii were found to be 4.59 microg/ml, 7.99 microg/ml and 14.88 microg/ml, respectively, whereas the positive control, vincristine sulfate showed an LC50 of 0.58 microg/ml. Among the crude extracts and pure compounds tested, (-)-kaur-16-en-19-oic acid isolated from the chloroform extract showed the highest inhibitory activity against most of the bacterial strains with mean zone of inhibition of 10-21 mm at 200 microg/disc.     

Antibacterial effects of commercial essential oils over locally prevalent pathogenic strains in Mexico

Locally prevalent pathogenic bacteria 189 Gram (-) and 135 Gram (+) strains, all isolated from pediatric patients severely infected, were tested in vitro against 11 essential oils from commercial origin. All the strains showed resistance to selected antibiotics. Cinnamomum verum, Origanum vulgare and Thymus vulgaris exhibited the highest and broadest antibacterial activity. Emphasis is made in the potential implications of these resources, uncommon at the clinical setting of the study, employed against non-commercial, locally pathogenic strains, being a step to submit in the ensuing period essential oils from plants used in Mexican traditional medicine.     

广东紫珠抑菌有效部位的筛选

以广东紫珠药材粉末为原料,探讨其不同提取部位的抑菌作用,并筛选其有效部位。对广东紫珠药材用不同极性大小溶剂（石油醚、二氯甲烷、乙酸乙酯、乙醇、70%乙醇、水）回流提取,获得广东紫珠粗提物,用滤纸片法测定其抑菌圈大小（金黄色葡萄球菌、大肠杆菌、奇异变形杆菌、甲型副伤寒沙门氏菌、乙型溶血性链球菌、白色念珠菌）,对抑菌活性明显的提取部位进行梯度萃取,并分别测定其抑菌圈大小,得到广东紫珠抑菌有效部位,并测定其有抑菌作用的有效部位的最小抑菌浓度。结果显示广东紫珠70%乙醇提取物对金黄色葡萄球菌、大肠杆菌、奇异变形杆菌、甲型副伤寒沙门氏菌、乙型溶血性链球菌均表现了不同程度的抑菌活性,初步判定为广东紫珠的抑菌活性部位,70%广东紫珠提取物经过萃取后,石油醚萃取物及二氯甲烷萃取物没有抑菌作用,乙酸乙酯萃取物、正丁醇萃取物及剩余的水部分均有不同程度的抑菌作用。70%乙醇广东紫珠提取物通过二氯甲烷萃取除去部分脂溶性杂质,即得到广东紫珠抑菌部位,可以此为基础寻找广东紫珠抑菌活性成分,为后期开发利用提供理论依据。     

Antimutagenic, antioxidant and antimicrobial properties of Maytenus krukovii bark

The hydroalcoholic extract of Maytenus krukovii bark was investigated for its in vitro mutageno-protective activities by means of the Ames Salmonella/microsome assay. The extract showed an inhibitory effect in both T98 and T100 strains against the mutagenic activity of promutagen 2-aminoanthracene but was not protective against directly acting mutagens sodium azide and 2-nitrofluorene. When tested as a radical scavenger and antioxidant it produced a dose-dependent inhibition. The extract did not show significant antibacterial properties, and was weakly active against dermatophyte and phytopathogenic fungi, but inhibited the growth of phytopathogen Pithyum ultimum.     

Chemical composition and antimicrobial activity of Chamaecyparis obtusa leaf essential oil

The essential oil obtained from the leaves of Chamaecyparis obtusa was analyzed by GC and GC-MS. alpha-Terpinyl acetate, sabinene, isobornyl acetate and limonene were found to be the major components. The oil showed relatively strong antibacterial activities against Gram (+) bacteria and some fungi.     

Antibacterial activity of Salacia beddomei

Leaves and stems of Salacia beddomei were extracted successively with petroleum ether, ethyl acetate and chloroform and tested for their antibacterial activity. Ethyl acetate extracts were found to be most effective against all the tested organisms.     

Phytochemical and antimicrobial study of Chukrasia tabularis leaves

Successive petroleum ether, benzene, chloroform, ethyl acetate and methanol extracts of Chukrasia tabularis leaves were tested for their phytochemical constituents, antibacterial and antifungal activity. The ethyl acetate and methanol extracts were found to be most effective against most of the tested organisms.     

Biologically active steroids from the aerial parts of Vernonia anthelmintica Willd

A new steroid, vernoanthelsterone A (1), and five known steroids were isolated from the aerial parts of Vernonia anthelmintica Willd. Compound 1 possesses a Δ(8(14))-15-one moiety. To our best knowledge, few steroids with this moiety have been reported before. Compounds 1-6 were tested for their antibacterial activities and their effects on estrogen biosynthesis in human ovarian granulosa-like cells (KGN cells). Compound 2 showed the ability to promote estrogen biosynthesis with EC(50) of 56.95 μg/mL and also exhibited the antibacterial activities against Bacillus cereus, Staphyloccocus aureus, Bacillus subtilis and Escherichia coli with MICs ranging from 3.15 to 15.5 μg/mL. The structures of 1-6 were determined on the basis of IR, MS, 1D and 2D NMR.