基于抗肿瘤活性的达玛烷型人参皂苷（元）结构修饰

现代社会中恶性肿瘤己经是常见病、多发病,对人类生命健康造成了极大的威胁.常规化疗药物往往不仅对肿瘤细胞具有毒性,对正常细胞也有较大毒性,限制了其在临床上的应用.人参是一种被广泛应用的传统中药,临床前和临床研究已证实其具有抗肿瘤活性,而人参皂苷是其发挥抗肿瘤疗效的主要物质基础.作为人参皂苷的主要组成部分,达玛烷型人参皂苷在其抗肿瘤活性方面发挥了重要作用,其结构修饰成为了研究热点.综述了达玛烷型人参皂苷结构修饰的主要反应类型和抗肿瘤构效关系,为人参皂苷在抗肿瘤方面的开发利用提供参考.     

人参皂苷Rb1的药理活性研究进展

人参皂苷Rb₁是人参二醇系皂苷的代表成分之一，属于达玛烷型三萜皂苷类化合物, 主要分布于五加科植物中，具有多种生物活性。作者从心血管系统、抗衰老、逆转肿瘤细胞耐药、肿瘤化疗的辅助用药、促进周围神经再生等几个方面，对人参皂苷Rb₁近10年来的研究进展进行了综述。     

达玛烷型皂苷（元）抗肿瘤活性构效关系的研究进展

通过查阅整理近10年国内外有关达玛烷型皂苷和新型皂苷元的发现和活性评价的研究文献，综述了其抗肿瘤活性与构效关系，为其的进一步的开发利用提供参考。     

中药皂苷类化合物生物转化研究进展

皂苷广泛存在于药用植物中,按母核结构可分为三萜和甾体皂苷,具有多种药理活性。众多研究发现皂苷中糖基部分的组成与其药理活性密切相关,改变皂苷分子中的糖基数量和结构能改变皂苷的药理活性及其生物利用度,为开发药物提供更多的化合物资源。相较于传统的化学方法,皂苷生物转化修饰糖基部分具有选择性高、成本低、污染小等优点,被广泛用于次级皂苷与皂苷元的制备。通过对皂苷脱糖基转化生成较高生物活性的次级皂苷与苷元的研究进展进行综述,为皂苷类化合物生物转化研究提供思路和方法。     

人参中三萜类化学成分的研究

人参皂苷系人参根和根茎的活性成分,参与调节多种生理活性。在我们前文总结的基础上,本文概述人参根和根茎、茎叶、果实、种子和红参中三萜类化学成分的研究,为源于人参的现代中药的研究与开发提供科学依据。迄今,已从人参分离鉴定了201个三萜类化合物,其中189个归属为达玛烷型三萜及其衍生物,10个归属为齐墩果酸型三萜,2个归属为羽扇豆烷型三萜;不但在含量上,而且在化学结构多样性上,达玛烷型三萜及其衍生物占绝对优势地位。     

植物中联苄类化合物研究进展

联苄类化合物广泛存在于多种植物中,尤其是苔藓植物。此类化合物结构新颖且具有抗肿瘤、抗氧化、抗真菌及昆虫拒食等多样的生物活性。从联苄、双联苄类化合物的植物来源、化学成分、生物活性、筛选方法、构效关系及其全合成等方面对近年来的研究报道进行综述,为联苄类化合物的开发利用提供参考。     

三七皂苷合成及调控机制的研究进展

三七是我国传统的名贵药材,在活血祛瘀、通脉活络、改善心肌缺血等方面具有重要的临床效果。三七主要活性成分为三七皂苷,包括人参皂苷Rb1,人参皂苷Rg1和三七皂苷R1,均属于达玛烷型四环三萜化合物。本文对三七皂苷的生物合成途径及分子调控机制的最新研究进行了分析、整理和归纳,基于其他植物的研究结果,认为达玛烷型四环三萜皂苷主要通过乙酸/甲羟戊酸途径合成,包括异戊烯基焦磷酸、二甲基烯丙基焦磷酸的合成,2,3-氧化鲨烯的合成及环化、羟基化、糖基修饰等过程,涉及鲨烯合成酶、法呢基焦磷酸合成酶、鲨烯环氧酶、达玛烯二醇合成酶、糖基转移酶等关键合成酶,分析了关键合成酶的作用、表达特性、不同物种来源关键酶氨基酸序列的同源性及其对皂苷积累的影响;同时分析了三七皂苷对重金属、植物激素、内生真菌、温度、营养因子等环境因素刺激的响应方面,二者之间关系复杂,但皂苷类成分含量与各因子在一定范围或特定因子刺激下呈正相关。目前,相关研究主要集中在各个独立的关键酶基因的表达特性和对外界因子的响应,对于具体的催化过程、结构修饰和转录水平的调控仍处于初级阶段,缺乏系统性和完整性的认知。     

天然达玛烷型皂苷降血糖作用的研究进展

达玛烷型皂苷属于四环三萜皂苷,是人参属植物人参Panax ginseng、三七P.notoginseng、西洋参P.quinquefolium和非人参属植物绞股蓝Gynostemma pentaphyllum中的主要成分。目前研究发现,达玛烷型皂苷具有显著的调节血糖作用,这就为其开发利用和糖尿病及其并发症的防治提供了科学依据。综述人参、西洋参、三七和绞股蓝中达玛烷型皂苷在降血糖方面的研究进展。     

大叶山楝萜类化学成分及其生物活性研究进展

大叶山楝Aphanamixis grandifolia为楝科山楝属植物,具有舒筋活络、通痹及祛风除湿等功效。大叶山楝中含有柠檬苦素类衍生物、甘遂烷型三萜、达玛烷型三萜、环阿尔廷烷型三萜、二萜及倍半萜等萜类化合物,具有杀虫、抗肿瘤、抗炎、抗疟疾和抑菌等生物活性。对大叶山楝萜类化学成分及其生物活性研究进展进行综述,以期为该植物的研究和开发利用提供参考。     

黄酮类化合物的化学结构修饰

黄酮类化合物在中药材植物中广泛存在,具有多种生理功能,这与其结构的多样性相对应。目前在掌握其分子全面构效信息的基础上,增强其生理活性或者扩展其应用范围的分子结构修饰成为研究热点。其中化学法分子修饰占重要地位。本文对化学法分子修饰的三个方面:衍生化、与金属离子螯合和化学反应制备进行了介绍,最后指出应重视对各种黄酮类化合物构效关系的研究与总结及新的有效修饰方法的研究与应用等。     

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??This paper summarized the chemical constituents and pharmacological activities of Gynostemma pentaphyllum based on systematic literature research.G. pentaphyllum mainly contains dammarane-type saponins and a total of 165 gynostemma saponins were obtained from 1976 to 2011.In recent years, some new gypenosides were isolated and identified. Two hundred and one gypenosides were classified and summarized in this paper. In addition, G. pentaphyllum also contains a variety of other chemical components including flavonoids, polysaccharides, amino acids, and trace elements, which are worth further research.The pharmacological effects of G. pentaphyllum including antitumor, regulating blood lipid, hypoglycemic, liver protection, anti-senility and improving immunity effects were summarized.This review will provide some information for further research of G. pentaphyllum.     

Triterpene saponins from Vietnamese ginseng (Panax vietnamensis) and their hepatocytoprotective activity

The methanol extract of Vietnamese ginseng (Panax vietnamensis) was found to possess hepatocytoprotective effects on D-galactosamine (D-GalN)/tumor necrosis factor-alpha (TNF-alpha)-induced cell death in primary cultured mouse hepatocytes. Further chemical investigation of the extract afforded two new dammarane-type triterpene saponins, ginsenoside Rh(5) (1) and vina-ginsenoside R(25) (2), as well as eight known dammarane-type triterpene saponins, majonoside R(2) (3), pseudo-ginsenoside RT(4) (4), vina-ginsenosides R(1) (5), R(2) (6), and R(10) (7), ginsenosides Rg(1) (8), Rh(1) (9), and Rh(4) (10), and a known sapogenin protopanaxatriol oxide II (11). Their structures were elucidated on the basis of spectral analysis. In addition, by the using LC-electrospray ionization (ESI)-MS method, five known saponins, ginsenosides Rb(1), Rb(2), Rc, Rd, and Re (12--16), were also identified in the extract. Among the compounds isolated, majonoside R(2) (3), the main saponin in Vietnamese ginseng, showed strong protective activity against D-GalN/TNF-alpha-induced cell death in primary cultured mouse hepatocytes. This demonstrates that the hepatocytoprotective effect of Vietnamese ginseng is due to dammarane-type triterpene saponins that have an ocotillol-type side chain, a characteristic constituent of Vietnamese ginseng.     

Dammarane-type triterpene saponins from Panax japonicus

Six new dammarane-type saponins (1-6), together with 11 known saponins (7-17), were isolated from Ye-Sanchi, the underground part of Panax japonicus collected in the South of Yunnan Province, China. Their structures were elucidated by chemical and spectroscopic means.     

Sphaeropsidones, phytotoxic dimedone methyl ethers produced by Diplodia cupressi: a structure-activity relationship study

Sphaeropsidone and episphaeropsidone are two phytotoxic dimedone methyl ethers produced by Diplodia cupressi, the causal agent of a canker disease of cypress in the Mediterranean area. In this study, eight derivatives obtained by chemical modifications and two natural analogues were assayed for phytotoxic and antifungal activities, and a structure-activity relationship was examined. Each compound was tested on nonhost plants and on five fungal pathogenic species belonging to the genus Phytophthora. The results provide insights into structure-activity relationships within these compounds. It was found that the hydroxy group at C-5, the absolute C-5 configuration, the epoxy group, and the C-2 carbonyl group appear to be structural features important in conferring biological activity. The conversion of sphaeropsidone into the corresponding 1,4-dione derivative led to a compound showing greater antifungal activity than its precursor. This finding could be useful in devising new natural fungicides for practical application in agriculture.     

Structures of new dammarane-type Triterpene Saponins from the flower buds of Panax notoginseng and hepatoprotective effects of principal Ginseng Saponins

The saponin fraction from the flower buds of Panax notoginseng exhibited protective effect on liver injury induced by d-galactosamine and lipopolysaccharide. From the saponin fraction with hepatoprotective effect, five new dammarane-type triterpene saponins, notoginsenosides-O (1), -P (2), -Q (3), -S (4), and -T (5), were isolated together with nine known protopanaxadiol oligoglycosides. The structures of the new saponins were elucidated on the basis of chemical and physicochemical evidence. The principal dammarane-type triterpene saponins from the roots and flower buds of Panax notoginseng were found to show potent hepatoprotective effects.     

中药多糖的分子修饰及其药理活性研究进展

中药多糖的分子修饰是运用物理、化学、生物等方法对其主链或侧链的某些特殊结构或功能基团进行修饰,使多糖的某些物理化学性质和空间结构发生改变,以增强其生物活性。其中物理方法包括超声波方法和辐照技术;化学方法主要有硫酸化、磷酸化、乙酰化、羧甲基化、烷基化、磺酰化和硒化等方法;生物方法也称酶法,分为酶降解法和酶合成法。经过分子修饰后中药多糖的物化性质和空间结构发生一定改变,使得多糖的免疫调节、抗病毒、抗肿瘤、抗氧化等药理活性明显增强。就近年来中药多糖的主要分子修饰方法及分子修饰后多糖的药理活性研究进展进行综述。     

褐藻中岩藻聚糖硫酸酯构效关系研究进展

褐藻是海洋生物活性物质的重要来源,岩藻聚糖硫酸酯(fucoidan)作为一种主要分布于褐藻细胞壁基质中的水溶性硫酸化杂多糖,已被证明具有抗氧化、抗凝血、抗炎症、抗病毒、抗肿瘤、免疫调节、降血糖等生物活性,但褐藻中岩藻聚糖硫酸酯结构复杂多样,呈现出生理活性的多样性。天然岩藻聚糖硫酸酯相对分子质量大、结构复杂,对多样化的结构解析和构效关系研究缺乏系统性,以至于岩藻聚糖硫酸酯研究进展缓慢、国际认可程度较低,推广与应用受到制约。因此通过整合现有研究成果,推断岩藻聚糖硫酸酯功能性结构,并对其展开系统性的研究与调查,是岩藻聚糖硫酸酯的药用开发进程中不可或缺的关键步骤。基于以上考虑,该文通过CNKI,Pubmed,Science Direct等数据库对国内外有关褐藻岩藻聚糖硫酸酯结构研究现状、解析方法、结构修饰以及构效关系研究进行整理,并对岩藻聚糖硫酸酯构效关系深入研究进行展望,以期为岩藻聚糖硫酸酯结构功能作用研究、活性作用机制阐明、医药及保健产品开发提供参考。