A Facile Total Synthesis of 2-Geranyl-2',3,4',4-tetrahydroxydihydrochalcone with Highly 5-Lipoxygenase Inhibiting Activity

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First Total Synthesis of 7-O-Geranyl-pseudobaptigenin

Total synthesis of 7-O-geranyl-pseudobaptigenin is described, the key steps are Grignard reaction and cyclization reaction.

Facile Syntheses of 3-Isopentenyl Flavone and 3-Geranyl Flavone

Although there was a strong steric effect,isopentenyl and geranyl moieties were successfully introduced into C3 position in flavone skeleton so as to synthesize the 3-isopentenyl flavone and 3-geranyl flavone under two cyclization conditions（AcOH/HCl and concentrated H 2 SO 4 /MeOH） in this report.It was found that the optimum cyclization conditions for 3-isopentenyl flavone and 3-geranyl flavone were,respectively,AcOH/HCl and H 2 SO 4 /MeOH.Furthermore,the donating electron ability is in the sequence 3-geranyl flavone3-isopentenyl flavone according to the density functional theory（DFT） calculations,suggesting the longer alkyl chain at 3-position would be more favorable for enhancing the donating electron ability.The present synthetic routes might reveal potential applicability in our continued studies on the total syntheses of other natural 3-alkyl flavonoids.

Geranylated or prenylated flavonoids from Cajanus volubilis

Five new flavonoid derivatives,cajavolubones A-E(1-5),along with six known analogues(6-11)were isolated from Cajanus volubilis,and their structures were elucidated by spectroscopic analysis and quantum chemical calculations.Cajavolubones A and B(1 and 2)were identified as two geranylated chalcones.Cajavolubone C(3)was a prenylated flavone,while cajavolubones D and E(4 and 5)were two prenylated isoflavanones.Compounds 3,8,9 and 11 displayed cytotoxicity against HCT-116 cancer cell line.

Ultrasensitive room-temperature geranyl acetone detection based on Fe@WO_(3−x) nanoparticles in cooked rice flavor analysis

In the assessment of food quality,geranyl acetone plays a crucial role as a volatile organic compound(VOC)biomarker for diverse agricultural products,while the ultralow concentration detection meeting application requirements has been barely studied.Herein,an iron(Fe)-doped WO_(3−x) gas sensor was employed for greatly sensitive,selective,and scalable geranyl acetone detection.The results proved that precisely-regulated oxygen vacancy(OV)and sophisticatedly-active electron transition of Fe-doped WO_(3−x) nanoparticles were fulfilled by modifying the doping amount of Fe^(3+),leading to the prominently enhanced sensitivity(23.47 at 6 ppm),low limit of detection(LOD)(237 ppb),optimal selectivity,and outstanding long-term stability.Furthermore,the enhancing mechanism of gas sensing performance was substantiated through density functional theory(DFT)calculation,while the practical application for the evaluation of spoiled cooked rice was conducted as well.This study demonstrates a reliable method for detecting a VOC biomarker in cooked rice,which can ensure food security and improve palatability of cooked rice.

Heteromeric and Homomeric Geranyl Diphosphate Synthases from Catharanthus roseus and Their Role in Monoterpene Indole Alkaloid Biosynthesis

Catharanthus roseus is the sole source of two most important monoterpene indole alkaloid （MIA） anti- cancer agents： vinblastine and vincristine. MIAs possess a terpene and an indole moiety derived from terpenoid and shikimate pathways, respectively. Geranyl diphosphate （GPP）, the entry point to the formation of terpene moiety, is a product of the condensation of isopentenyl diphosphate （IPP） and dimethylallyl diphosphate （DMAPP） by GPP synthase （GPPS）. Here, we report three genes encoding proteins with sequence similarity to large subunit （CrGPPS.LSU） and small subunit （CrGPPS.SSU） of heteromeric GPPSs, and a homomeric GPPSs. CrGPPS.LSU is a bifunctional enzyme producing both GPP and geranyl geranyl diphosphate （GGPP）, CrGPPS.SSU is inactive, whereas CrGPPS is a homomeric enzyme forming GPP. Co-expression of both subunits in Escherichia coil resulted in heteromeric enzyme with enhanced activity producing only GPR While CrGPPS.LSU and CrGPPS showed higher expression in older and younger leaves, respectively, CrGPPS.SSU showed an increasing trend and decreased gradually. Methyl jasmonate （MelA） treatment of leaves sig- nificantly induced the expression of only CrGPPS.SSU. GFP localization indicated that CrGPPS.SSU is plastidial whereas CrGPPS is mitochondrial. Transient overexpression of AmGPPS.SSU in C. roseus leaves resulted in increased vindoline, immediate monomeric precursor of vinblastine and vincristine. Although C. roseus has both heteromeric and homomeric GPPS enzymes, our results implicate the involvement of only heteromeric GPPS with CrGPPS.SSU regulating the GPP flux for MIA biosynthesis.

Identification of C-geranylated flavonoids from Paulownia catalpifolia Gong Tong fruits by HPLC-DAD-ESI-MS/MS and their anti-aging effects on 2BS cells induced by H2O2

The fruits of Paulownia catalpifolia Gong Tong are used as a Chinese folk herbal medicine for the treatment of enteritis, tonsillitis, bronchitis, and dysentery, etc. Our previous study has identified new C-geranylated flavanones with obvious anti-proliferative effects in lung cancer A549 cells. In the present study, a new C-geranylated flavone, paucatalinone C(1) and five known C-geranylated flavanones(2-6) were isolated. In addition, a total of 34 C-geranylated flavonoids were detected by HPLC-DAD-ESI-MS/MS coupling techniques from the CH_2Cl_2 extract of P. catalpifolia. Futhermore, anti-aging effects of isolated compounds were evaluated in vitro with premature senescent 2BS cells induced by H_2O_2. Phytochemical results indicated that P. catalpifolia was a natural resource of abundant C-geranylated flavonoids. Diplacone(3) and paucatalinone A(5) were the potent anti-aging agents in the premature senescent 2BS cells induced by H_2O_2 and the C-geranyl substituent may be an important factor because of its lipophilic character.

Geranyl phenyl ethers from Illicium micranthum and their anti-HBV activity

Fourteen new geranyl phenyl ethers(1–14)along with three known compounds(15–17)were isolated from Illicium micranthum,and their structures were elucidated by comprehensive spectroscopic methods.Illimicranins A–H(1–8)were characterized as geranyl vanillin ethers,while 9 and 10 were dimethyl acetal derivatives.Illimicranins I and J(11 and 12)were rare geranyl isoeugenol ethers.Illimicranins K and L(13 and 14)represented the first example of geranyl guaiacylacetone ether and geranyl zingerone ether,respectively.Compounds 1,2 and 15 exhibited anti-HBV(hepatitis B virus)activity against HBsAg(hepatitis B surface antigen)and HBeAg(hepatitis B e antigen)secretion,and HBV DNA replication.

Regioselective synthesis of linalyl compounds via addition reaction of geranyl bromide and tin with carbonyl compounds

Linalyl alkyl or aryl carbinols were regioselectively synthesized by the reaction of geranyl bromide and powdered tin with aldehydes and ketones.

香叶醇及其糖苷在茶树中的积累和对红茶香气的贡献

采用液相质谱联用仪LC-MS、气相质谱联用仪GC-MS分析不同茶树品种、不同组织器官、不同时间香叶醇及其糖苷含量的变化,结果显示:香叶基樱草糖苷在中国变种(Camellia sinensis var. sinensis)中的含量显著高于阿萨姆变种(C.sinensis var. assamica)。香叶基樱草糖苷在茶树幼嫩叶片中含量最高,在根中的含量最低,总体表现出嫩叶>茎>花>根。3月份茶树嫩梢中的香叶醇积累量最高,随着月份的增加而逐渐降低。在祁门红茶加工过程中,香叶基樱草糖苷含量在揉捻阶段显著降低。黄山地区6个品种红茶中,皖茶4号红茶中的香叶醇含量最高;6个品种红茶茶汤中香叶醇的气味活性值(OAV)均>1,分布范围3.93~28.38。Pearson相关性分析显示,有7个萜类合成酶候选基因表达量与香叶基樱草糖苷含量变化呈显著相关。本研究结果为进一步探究香叶醇积累差异成因及形成机制提供理论参考。

洛伐他汀对系膜细胞增生及细胞外基质分泌的影响

目的 :观察洛伐他汀对系膜细胞增生及细胞外基质分泌的影响 ,并探讨其作用的可能机制。 方法 :用MTT法检测细胞增生 ,流式细胞仪检测细胞周期 ,ELISA检测细胞外基质胶原Ⅳ和层粘连蛋白。 结果 :洛代他汀可剂量依赖性地抑制系膜细胞增生 ,影响细胞周期 ,使G0 G1期细胞增多 ,S期细胞减少 ,并能明显抑制胶原Ⅳ和层粘连蛋白分泌 (P <0 0 1)。而香叶基香叶基焦磷酸可阻止洛伐他汀对系膜细胞增生的抑制作用。 结论 :洛伐他汀可显著抑制系膜细胞增生及细胞外基质分泌 ,其机制可能与抑制香叶基香叶基焦磷酸产生而阻止信号传导有关。

中国珍稀植物明党参嫩茎叶挥发油化学成分研究

采用毛细管气相色谱 -质谱 -计算机联用技术对明党参嫩茎叶挥发油的化学成分进行研究。从挥发油中鉴定出 2 7种成分 ,占总油量的 97.50 2 % ,其主要成分是牛儿醇乙酸酯 ( 4 6.636% )、明党参炔 ( 11.4 83% )、β-金合欢烯 ( 10 .986% )。

离子液体中脂肪酶催化合成乙酸香叶酯的研究

对脂肪酶在离子液体中催化香叶醇与乙酸乙烯酯转酯化反应生成乙酸香叶酯的过程进行了研究.考察了水活度、底物酯和醇物质量的比率、温度、离子液体和酶的重复利用对催化得率及催化反应初始速率的影响,其中离子液体的水活度采用水合盐对进行控制,而在考察离子液体和酶的重复利用时采用了未经分离酶的间歇反应的方法.结果表明,随着水活度增加酶在离子液体1-丁基-3-甲基-咪唑六氟磷酸盐中催化反应的初始速率的变化趋势呈钟形曲线.最优的催化反应条件为:水活度为0.28,底物酯和醇物质量比为9.42,30℃.在重复利用12次后,离子液体体积和酶的催化活力都没有明显减少.

糖苷类香料前体的卷烟加香和缓释效果

为开发新型烟用香料,将香叶醇糖苷添加到卷烟中,而后进行烟气分析和评吸。结果表明:含香叶醇糖苷的卷烟烟气中释放出香叶醇,释放量基本与添加量成正比,且释香均匀,香气饱满。结论:香叶醇糖苷可以作为香原料应用到卷烟中。

香料前体香叶醇-β-D-葡萄糖苷的合成、纯化与表征

为了开发热稳定型香原料,采用改进的Koenigs-knorr法立体选择性地合成了香叶醇-β-D-葡萄糖苷(Geranyl-β-D-Glycoside,GGLY);以反相液相色谱法(ReversePhaseHPLC,RP-HPLC)检测并确定最优反应条件;硅胶柱层析梯度洗脱分离制备样品,产物纯度达99.2%;然后综合IR、LC/MS/MS、1HNMR、13CNMR进行结构鉴定,确证制备的产物为香叶醇糖苷。

基于转录组信息的艾纳香牻牛儿基焦磷酸合成酶基因(BbGPPS)的克隆及序列分析

采用RT-PCR和RACE(Rapid amplification of cDNA ends)技术,从艾纳香(Blumea balsamifera L.DC)的叶片中克隆到单萜化合物合成的关键酶牻牛儿基焦磷酸合成酶(BbGPPS)基因。研究结果显示,BbGPPS基因的cDNA全长1 692 bp,包含开放阅读框(ORF)1 083 bp,编码361个氨基酸;亚细胞结构定位于叶绿体,既非膜蛋白也非分泌性蛋白。疏水性分析显示,BbGPPS是亲水性蛋白。同源性比对结果显示,BbGPPS蛋白与其他植物中GPPS蛋白具有高度的相似性,且具有异戊烯基结构域。系统发育分析表明,所有序列被聚为5大类,BbGPPS与其他菊科植物聚类一类,与万寿菊(Tagetes erecta)TeGPPS亲缘关系最近,其次是甜菊(Stevia rebaudiana)SrGPPS。

8-甲氧基-香豆素-3-甲酸香叶酯的合成及在卷烟中的应用

采用酰氯酯化法,以8-甲氧基-香豆素-3-甲酸与香叶醇为原料合成了8-甲氧基-香豆素-3-甲酸香叶酯,经IR,HRMS,1H NMR,13C NMR等鉴定,证实了其结构.采用热解-GC/MS对热解产物进行了分离鉴定,并对8-甲氧基-香豆素-3-甲酸香叶酯进行了卷烟加香试验.结果表明,600℃时,8-甲氧基-香豆素-3-甲酸香叶酯的热解产物中共鉴定出27种成分,主要为烯类、烷类、酸类、醇类、酚类;鉴定出香叶醇,且相对峰面积3.6,说明8-甲氧基-香豆素-3-甲酸香叶酯能在卷烟燃吸温度下释放出一定量的香叶醇;8-甲氧基-香豆素-3-甲酸香叶酯具有改善和修饰卷烟香气,增加甜韵和豆香香韵,减轻刺激性的作用.

固体超强酸催化合成乙酸橙花酯和乙酸香叶酯

研究了固体超强酸催化合成乙酸橙花酯和乙酸香叶酯 ,寻找能替代浓硫酸的新型高效催化剂 ,并对不同催化剂、催化剂用量、反应时间、不同带水剂及带水剂用量等因素对体系的影响作了较详细的探讨。结果发现 ,催化剂的催化效果由强到弱的顺序为 :Fe2 O3 SO4 2 ->ZrO2 SO4 2 ->磷钨酸 >磷钼酸 >对甲苯磺酸 >浓硫酸 ;带水剂能明显提高酯化收率 ,在苯、甲苯、二甲苯 3种带水剂中 ,以甲苯最好 ;优化的反应条件为 :乙酸 7.8g (0 .130 0mol) ,橙花醇香叶醇 15 4g(0 10 0 0mol) ,催化剂Fe2 O3 SO4 2 -0 5g (0 0 0 19mol) ,带水剂甲苯 2 0mL ,反应温度为回流温度 ,反应时间 4h ,酯化收率可达 95 44 %

香叶酯衍生物的合成、表征及其热裂解研究

以香叶醇和不同类型的羧酸为原料，用DCC/DMAP偶合法合成了8种鲜见报道的香叶酯，产率78.5％～93.6％。该方法具有反应条件温和、反应时间短，是一种节能环保、易操作的合成方法。另外，所合成化合物的结构通过高分辨质谱和核磁共振谱进行了确认。并以肉豆蔻酸香叶酯为例，研究了其在300℃、600℃和800℃的热裂解行为，通过气-质联用分析确定其裂解产物有：月桂烯、樟脑萜、β-罗勒烯、香叶醇、5，5-二甲基-1-丙基-1，3-环戊二烯、肉豆蔻酸乙酯和醛等30多种，其中含有多种致香物质，能够有效改善卷烟吸味，增强香气。

(±)-Sepicanin A的首次全合成

以2,4,6-三羟基苯乙酮和2,4-二羟基苯甲醛为原料,经4步以总收率16%得到最终产物——香叶基黄烷酮(±)Sepicanin A.合成的关键步骤是质子酸催化查尔酮形成苯并吡喃酮的同时脱去羟基保护基,一步得到目标产物(±)Sepicanin A.所有新化合物的结构都经过1 H-NMR,IR,MS分析表征.