Synthesis and antibacterial activities of pleuromutilin derivatives

Six new pleuromutilin derivatives were designed and synthesized, confirmed by MS, IR and ^1H NMR techniques. And the antibacterial activities were primarily evaluated in vitro. The results indicated that most of the derivatives showed more potent activities against corresponding bacterial strains than that of pleuromutilin. Especially, compounds 4d and 5b had obvious activities against salmonella compared with pleuromutilin.

Synthesis and antibacterial activity of C-2(S)-substituted pleuromutilin derivatives

In order to probe the effect of C-2(S)-substituted groups in the antibacterial activity,a series of novel C-2(S)-substituted pleuromutilin analogues of SB-225586 were synthesized and evaluated for their in vitro antibacterial activity.The results of antibacterial activities indicated that C-2(S)-substituted pleuromutilin derivatives retained appreciable antibacterial activity,and the 2-fluorination compounds 6a and 6b are more potent than the corresponding 2-hydroxylation analogues 7a and 7b.

A New Pleuromutilin Derivative: Synthesis,Crystal Structure and Antibacterial Evaluation

A new pleuromutilin derivative, 14-O-[（4,6-diaminopyrimidine-2-yl） thioacetate] mutilin, was synthesized and structurally characterized by IR, NMR spectra and single-crystal X-ray diffraction. This compound contains a 5-6-8 tricyclic carbon skeleton and a pyrimidine ring. Its crystal is of orthorhombic system, space group P21 with a = 10.0237（6）, b = 12.6087（7）, c = 10.3749（8） A, fl = 101.48（1）°, V = 1284.99（14） A3, Z = 2, F（000） = 540, Oc（Mg/m3） = 1.299, # = 0.165 mm1, R = 0.0649 and wR = 0.0797. The in vitro antibacterial activity study using Oxford cup assay showed this compound displayed more potent activity than pleuromutilin and similar antibacterial activity to that oftiamulin.

Syntheses,Crystal Structures and Antibacterial Evaluation of Two New Pleuromutilin Derivatives

Two new pleuromutilin derivatives, 14-O-[（4-amino-6-methoxyl-pyrimidine-2-yl）-thioacetyl] mutilin（4） and 14-O-[4-amino-1-methyl-6-oxo-1,6-dihydropyrimidin-2-yl）thioacetyl] mutilin（5）, were synthesized and structurally characterized by IR, NMR spectra, HRMS and single-crystal X-ray diffraction. These compounds contain a 5-6-8 tricyclic carbon skeleton and a pyrimidine ring. Compound 4 is in the monoclinic system, space group P1211 with a = 10.2517（4）, b = 12.5655（4）, c = 10.3435（4）A, V = 1315.69（8） A^3, Z = 2, Dc = 1.309 g/cm3, F（000） = 558, μ = 0.166 mm^-1, S = 1.047, R = 0.0457 and w R = 0.0934 for 4721 unique reflections（R（int） = 0.0322） with I 〉 2σ（I）. Compound 5 belongs to the orthorhombic system, space group P212121 with a = 7.3667（4）, b = 13.9990（7）, c = 29.0434（13） A, V = 2995.1（2） A^3, Z = 4, Dc = 1.250 g/cm^3, F（000） = 1216, μ = 0.153 mm^-1, S = 1.031, R = 0.0545 and wR = 0.0982 for 5242 unique reflections（R（int） = 0.0476） with I 〉 2σ（I））. The in vitro antibacterial activity study showed the title compounds 4 and 5 displayed slightly less activity against methicillin-resistant Staphylococcus aureus（MRSA） and methicillin-resistant Staphylococcus epidermidis（MRSE）, and lower potent against Escherichia coli（E.coli） and Bacillus subtilis（B.subtilis） when compared to those of tiamulin fumarate.

Antimicrobial resistance characteristics and phylogenetic relationships of pleuromutilin-resistant Enterococcus isolates from different environmental samples along a laying hen production chain

Antimicrobial resistance in the laying hen production industry has become a serious public health problem.The antimicrobial resistance and phylogenetic relationships of the common conditional pathogen Enterococcus along the laying hen production chain have not been systematically clarified.105 Enterococcus isolates were obtained from 115 environmental samples (air,dust,feces,fies,sewage,and soil) collected along the laying hen production chain (breeding chicken,chick,young chicken,and commercial laying hen).These Enterococcus isolates exhibited resistance to some clinically relevant antibiotics,such as tetracycline (92.4%),streptomycin (92.4%),and erythromycin (91.4%),and all strains had multidrug resistance phenotypes.Whole genome sequencing characterized 29 acquired antibiotic resistance genes (ARGs) that conferred resistance to 11 classes of antibiotics in 51pleuromutilin-resistant Enterococcus isolates,and lsa(E),which mediates resistance to pleuromutilins,always co-occurred with lnu(B).Alignments with the Mobile Genetic Elements database identified four transposons (Tn554,Tn558,Tn6261,and Tn6674) with several ARGs(erm(A),ant(9)-la,fex(A),and optrA) that mediated resistance to many clinically important antibiotics.Moreover,we identified two new transposons that carried ARGs in the Tn554 family designated as Tn7508 and Tn7492.A complementary approach based on conventional multi-locus sequence typing and whole genome single nucleotide polymorphism analysis showed that phylogenetically related pleuromutilin-resistant Enterococcus isolates were widely distributed in various environments on different production farms.Our results indicate that environmental contamination by antimicrobial-resistant Enterococcus requires greater attention,and they highlight the risk of pleuromutilin-resistant Enterococcus and ARGs disseminating along the laying hen production chain,thereby warranting effective disinfection.

氨基酸取代的苯基醚类截短侧耳素衍生物的合成与抗菌活性研究

目的设计合成截短侧耳素衍生物,寻找广谱、高效、安全的新化合物。方法以天然产物截短侧耳素为起始原料,合成3个氨基苯醚类截短侧耳素衍生物和8个氨基酸取代的苯基醚类截短侧耳素衍生物,并进行活性测试、初步成药性评价以及分子对接研究。结果设计合成了11个未见文献报道的新型截短侧耳素衍生物,其结构经核磁、ESI-MS和HRMS确证。大多数化合物对标准金黄色葡萄球菌和标准大肠埃希菌的抗菌活性均优于lefamulin,并且其细胞毒活性低(IC50>10μmol/L),理化性质预测良好。分子对接结果表明,化合物侧链连接的氨基苯醚与氨基酸能够与结合空腔的核苷酸形成更多的氢键相互作用。结论氨基苯酚以及氨基酸的修饰有助于提高截短侧耳素类抗生素的抗菌活性和理化性质。

截短侧耳素衍生物PCI对48株牛源耐甲氧西林金黄色葡萄球菌临床菌株的抗菌活性

为了探讨截短侧耳素衍生物PCI对48株牛乳腺炎耐甲氧西林金黄色葡萄球菌临床菌株的体内外抗菌活性,采用微量肉汤稀释法测定了PCI对金黄色葡萄球菌和耐甲氧西林金黄色葡萄球菌(MRSA)标准菌株,以及48株牛乳腺炎耐甲氧西林金黄色葡萄球菌临床菌株的最小抑菌浓度(MIC),并进行了小鼠大腿感染试验。结果表明,PCI对金黄色葡萄球菌和MRSA的MIC均为0.0078μg/mL,对牛源MRSA临床菌株的MIC为0.0078~0.125μg/mL;小鼠大腿感染试验结果表明,PCI减轻了肌肉组织的变性和坏死,且大腿组织载菌量显著低于延胡索酸泰妙菌素组(P<0.05),极显著低于模型组(P<0.0001)。综上所述,PCI对48株牛乳腺炎耐甲氧西林金黄色葡萄球菌临床分离菌株具有优异的抗菌活性,能够减轻MRSA造成的大腿肌肉感染。

Design, synthesis and antibacterial activity of novel pleuromutilin derivatives with 4H-pyran-4-one and pyridin-4-one substitution in the C-14 side chain

A series of novel pleuromutilin derivatives with 4H-pyran-4-one and pyridin-4-one substitution in the C-14 side chain have been designed and synthesized. In vitro antibacterial activity evaluation showed that most of the derivatives exhibited potent antibacterial activity against drug resistant Gram-positive strains. Compounds 12 a, 12 d, and 28 are the most active derivatives in this series, displaying activity comparable to that of retapamulin and BC-3781. As the metabolic stability of this series is not satisfactory, further modifications are going on to improve their pharmacokinetic profile.

Synthesis and antibacterial activity of pleuromutilin derivatives with novel C(14) side chain

In order to find novel antibacterial agents with superior antibacterial activity and overcoming multidrug resistance,a series of pleuromutilin derivatives with novel C（14） side chain were synthesized and evaluated for their in vitro antibacterial activities.The results of antibacterial acticities indicated that most of the derivatives showed potent activities against Gram-positive organisms.In particular,compound lOd exhibited the most potent inhibitory activity compared with pleuromutilin and linezoid,emerged as potential molecule for further investigation.

提高截短侧耳素产量的研究进展

截短侧耳素(Pleuromutilin)是萜类化合物中半合成抗生素的合成前体之一,是由大型担子菌产生的次级代谢产物。截短侧耳素产生菌属于真核生物,改造相对复杂,但市场需求量在不断扩大,可见在对截短侧耳素产生菌的改良中挑战和应用潜力并存。本文总结了截短侧耳素的生物合成途径,并对截短侧耳素产生菌的诱变育种、基因工程育种及其异源表达等有关增产的相关研究进行了综述,以期对截短侧耳素产生菌进行更深入的了解,为后续的菌种改良提供参考。

截短侧耳素类抗生素及其耐药研究进展

截短侧耳素(Pleuromutilins)是从担子菌纲侧耳属Pleurotus mutilus和Pleurotus passeckerianus中分离得到的二萜类抗生素,对革兰阳性菌和支原体具有良好的抗菌活性。截短侧耳素类药物用途广泛,泰妙菌素(Tiamulin)和沃尼妙林(Valnemulin)作为兽用药用于防治由病原微生物引起的猪痢疾、支原体肺炎等疾病;人用批准的瑞他莫林(Retapamulin)和来法莫林(Lefamulin)主要用于治疗球菌感染和获得性细菌性肺炎。近年来,截短侧耳素类药物耐药监测表明,在病原微生物的rplC、rplD、23sRNA、Cfr和vga基因中报道了多种新的突变位点,导致侧耳素类药物敏感性降低。本文对已上市的截短侧耳素类药物进行回顾,并对近十年该类药物的耐药机制研究进行综述,以期为新型截短侧耳素类药物的创制提供参考。

截短侧耳素杂合体的抗耐甲氧西林金黄色葡萄球菌活性

耐甲氧西林金黄色葡萄球菌(MRSA)是一种高度耐药的细菌,是院内和社区感染的主要致病菌之一。万古霉素被誉为是治疗MRSA的最后一道防线,拯救了数以万计感染MRSA的重症患者。然而,耐万古霉素MRSA已然出现,在不久的将来临床医师面对MRSA可能会面临无药可用的窘境。因此,亟须开发新型抗MRSA药物。截短侧耳素是由侧耳菌(Pleurotus mutilus)产生的一类三环二萜类抗生素,可通过抑制肽酰基转移酶使细菌蛋白质的合成受阻,对包括MRSA在内的多种致病菌具有广谱活性。将截短侧耳素母核与其他具有抗MRSA活性的药效团相结合所得的杂合体可同时作用于MRSA的不同靶点,故合理地设计截短侧耳素杂合体可能会获得新型抗MRSA药物。本文探讨了截短侧耳素杂合体的抗MRSA活性及构—效关系,为进一步研究提供参考。

盐酸沃尼妙林的全合成研究

以异丁醛为起始原料,经氨加成、硫粉氧化关环、双键还原、开环四步反应自制得到重要中间体1-氨基-2-甲基丙-2-硫醇盐酸盐(二甲基半胱胺盐酸盐),收率72.2%。再将L-缬氨酸在D-氨基酰化酶的作用下转为D-缬氨酸,收率46%。D-缬氨酸经成盐、胺化得到中间体D-缬氨酸邓盐,最后苯磺酰化截短侧耳素与1-氨基-2-甲基丙-2-硫醇盐酸盐发生亲核反应,然后与氨基保护的缬氨酸进行酰胺化反应,最后脱掉保护基,用盐酸处理,采用溶媒结晶的方法提纯,即得到盐酸沃尼妙林,总收率88.2%,产物结构经核磁氢谱、碳谱进行表征。本研究概括了盐酸沃尼妙林的全合成工艺路线,该法大大降低了生产成本,已适用于工业化生产。

截短侧耳素及其衍生物的研究进展

截短侧耳素是重要的二萜类兽用抗生素。发现至今,针对其衍生物进行了深入研究,发现了抗菌活性更强、应用范围更广的泰妙菌素、沃尼妙林、retapamulin和一系列水溶性衍生物等。其中retapamulin是2007年4月FDA批准的近二十年来第一个新的局部应用的抗菌药物,同时作为第一个人用截短侧耳素衍生物,标志着此类抗生素实现了从兽用到人用的飞跃。本文就截短侧耳素的作用机制、生物合成及其衍生物应用等方面的最新进展做简要概述。

菌渣中截短侧耳素含量的高效液相色谱法测定

目的:建立截短侧耳素的提纯及含量测定方法。方法:采用甲醇从发酵菌渣中提纯截短侧耳素后,用高效液相色谱法(HPLC)测定其含量。色谱分析条件:采用Agilent-ODSC18色谱柱(5μm,4.6mm×250mm),流动相为甲醇-体积分数为0.5%甲酸溶液(体积比为60:40),流速1mL/min,检测波长为205nm,进样量20μL,柱温30℃。结果:截短侧耳素在341～2730mg/L范围内,线性关系良好(r=0.9999);平均加样回收率为99.2%,相对标准偏差为0.54%(n=6)。结论:此方法简便、灵敏、稳定、可靠,可用于截短侧耳素的含量测定。

截短侧耳素溶剂提取工艺的优化

采用溶剂法提取截短侧耳素产生菌Pleurotus mutilis烘焙菌体中的截短侧耳素。筛选适宜的提取溶剂,在单因素实验的基础上通过正交实验对提取过程中的多个影响因素进行了筛选和优化,确定提取工艺为:液料比4∶1(mL:g)的醋酸丁酯为提取溶剂,提取时间为10 min,振摇转速为140 r/min,提取次数为3次,截短侧耳素的提取率为94.56%。工艺条件简单、稳定可行,具有实际应用价值。

内生真菌SEF15927对截短侧耳素的微生物羟化研究

目的研究植物内生真菌SEF15927对截短侧耳素的转化作用。方法利用液体培养生长细胞对截短侧耳素进行生物转化。发酵液经乙酸乙酯萃取和硅胶柱层析分离获得一个羟化产物。运用质谱和核磁共振光谱鉴定结构。结果转化产物为2-羟基截短侧耳素。结论植物内生真菌SEF15927为一具有高转化率的截短侧耳素羟化菌株,

人用截短侧耳素类抗生素的研究现状与发展趋势

为了应对日益严重的细菌耐药性问题,人们不断研发具有新型作用机制的抗菌药物,其中截短侧耳素及其衍生物作为重要的一类兽用抗生素,具有独特的作用机制,其特点不易产生交叉耐药性。已经上市的泰妙菌素、沃尼妙林均具有抗菌谱广及较强的抗菌活性,而2007年4月批准的瑞他莫林是近二十年来首个新的局部应用的抗菌药物,被认为是第一个人用截短侧耳素衍生物,标志着截短侧耳素类从兽用跨越到人用领域。本文就截短侧耳素的作用机制、耐药机制、人用截短侧耳素的临床研究现状以及新型截短侧耳素衍生物研发等方面的最新进展做简要概述。

高效液相色谱法测定截短侧耳素的含量

建立了截短侧耳素含量的 HPLC检测方法。采用 Agilent Zorbax C18色谱柱（250 mm×4.6 mm，5μm），流动相为CH3 CN-0.02 mol·L-1 KH2 PO4缓冲溶液（50∶50，体积比），流速1.0 mL·min-1，检测波长205 nm，进样量20μL，柱温25℃。结果表明，截短侧耳素浓度在0.12-2400μg·mL-1范围内与峰面积线性关系良好（R＝0.9998），平均回收率为98.7％，检出限为2.24 ng，定量限为6.84 ng。该法简便、准确、专属性好。

局部外用药Retapamulin的药理与临床研究进展

Retapamulin(SB-275833)是截短侧耳素类化合物的半合成衍生物,为一种选择性细菌蛋白质合成抑制剂,在体外对G+菌包括金葡球菌、化脓链球菌和一些G-菌(如流感嗜血杆菌、卡他莫拉菌)均有极好的抗菌活性。2007年4月通过美国FDA审批,目前该产品尚未在中国上市,文中对其作用机制、抗菌活性、药动学、临床研究及不良反应等做一综述。