基于甘草酸为载体的紫杉醇-甘草酸纳米胶束的构建和口服生物利用度的评价

目的：构建紫杉醇-甘草酸纳米胶束（paclitaxel-loaded glycyrrhizic acid micelles）并对其理化性质及口服生物利用度进行考察。方法：所制备纳米胶束的包封率和载药量通过高效液相色谱法检测并计算;采用动态光散射仪测定其粒径分布;以紫杉醇溶液作为对照组,考察纳米胶束口服给药后药动学的变化;采用在体in-situ肠封闭法考察不同肠道对紫杉醇的吸收差异。结果：采用超声分散法制备载紫杉醇-甘草酸纳米胶束大小均匀,平均粒径为（245.42±5.62） nm;药物胶束的包封率为90.22%±0.27% （n=3）,载药量为7.90%±0.10%（n=3）;与对照组相比,纳米胶束口服生物利用度提高约6倍,很大程度上是由于紫杉醇在空肠以及结肠上吸收的增加引起。结论：该方法所制备的纳米胶束制剂能有效提高紫杉醇口服生物利用度,发挥甘草酸药物载体的特点以及药用安全性的优点,该纳米胶束可作为紫杉醇新的药物传递系统,具有临床应用前景。     

One new triterpenoid from biotransformation product of glycyrrhizic acid

A new triterpenoid compound (1) and a known compound (2) were isolated from the product of biotransformation of glycyrrhizic acid by Aspergillus niger. On the basis of the 1D and 2D NMR ((1)H-(1)H COSY, HSQC, HMBC and NOESY) and MS spectrometry, their structures were established as 7beta, 15alpha-dihydroxy-3,11-dioxo-oleana-12-en-30-oic acid (1) and 15alpha-hydroxy-3,11-dione-oleana-12-en-30-oic acid (2), respectively.     

Synthesis of new hetero- and carbocyclic aromatic amides of glycyrrhizic acid as potential anti-HIV agents

Members of a new group of di- and trisubstituted amides of glycyrrhizic acid (GA), the major component of licorice root extract, were synthesized; derivatives contained fragments of heterocyclic and aromatic amines (2-aminopyridine, 4-aminopyridine, 5-aminouracil, sulfadimezine, sulfapyridazine, and L-histidine methyl ester) using the dicyclohexylcarbodiimide method. Amides of GA containing 2-aminopyridine and 5-aminopurine residues had anti-HIV-1 activity in MT-4 cell cultures. The index of selectivity (IS) of the amide of GA with 5-aminouracil was, using various parameters, from 27.73 to 277.32, exceeding values for GA (from 4.45 to 24.0).     

Brominated extracts as source of bioactive compounds

The chemical composition and the biomolecular properties of a crude plant extract were altered through bromination leading to the discovery of an acetylcholinesterase inhibitor.     

Homologation as a lead modification approach en route to a series of lactone-based muscarinic ligands

Previous work identified the lactone ring as a useful scaffold for the design of muscarinic ligands and reported a lactone-based ligand with an IC₅₀ of 340 nM. Using homologation as a lead modification approach, a new series of lactone-based compounds have been designed, synthesized, and screened in muscarinic binding assays. The approach provided a series of compounds with improved % inhibition values and identified the highest affinity lactone-based ligand reported to date. The results of these efforts and the structure–activity relationship for this series of lactones-based ligands are discussed.     

Sea buckthorn as a source of important bioactive compounds in cardiovascular diseases

Hippophae rhamnoides (sea buckthorn) offers many health benefits. It has significant cardioprotective activity and exerts many positive healing effects on the cardiovascular system, including inhibiting blood platelet activation (especially platelet aggregation), lowering cholesterol concentration and blood pressure, and providing antioxidant activity. In addition, sea buckthorn has antibacterial and antiviral properties. The leaves and fruits of the plant, and its oils, are sources of many bioactive substances including vitamins (A, C and E), unsaturated fatty acids, phenolic compounds, especially flavonoids, and phytosterols, which bestow positive effects on the cardiovascular system. This review article summarizes the current knowledge of the biological roles of sea buckthorn in cardiovascular diseases.     

Immunoenzyme test-system for detection of glycyrrhizic acid]

An experimental enzyme immunoassay test kit was developed for detecting glycyrrhizic acid (GA) during pharmacokinetic investigations. This method was used to determine the GA content in the blood plasma of mice and guinea pigs after intraperitoneal and intravenous injections. The results of the GA determination using the new test kit agree with the data obtained by HPLC.     

Biodegradable nano- and microparticles as carriers of bioactive compounds

This review presents examples of polymeric carriers that may be used for design of clinically aplicable drug delivery systems. In particular, there are discussed methods suitable for protein and oligopeptide modification in a way making these molecules "invisible" for immune system of an organism into which they are introduced. Presented are methods of synthesis of block copolymers suitable for self-assembly into nanoparticles loaded with bioactive compounds. There are discussed also strategies used for obtaining microparticles loaded with bioactive compounds either from earlier synthesized polymers or from monomers, directly during polymerization.     

Molecularly imprinted polymers as drug delivery systems for the sustained release of glycyrrhizic acid

Objectives The aim was to synthesize molecularly imprinted polymers (MIPs) with high recognition properties towards glycyrrhizic acid and to evaluate the performance of these materials to act as base excipients in glycyrrhizic acid sustained release in gastrointestinal simulating fluids. Methods MIPs were synthesized using methacrylic acid (MAA) as acidic, 2‐(dimethylamino)ethyl methacrylate (DMAEMA) as basic, and 2‐hydroxyethylmethacrylate (HEMA) as neutral functional monomers, while ethylene glycol dimethacrylate (EGDMA) was chosen as a crosslinking agent. The imprinting effect was evaluated by binding experiments using glycyrrhizic acid and glycyrrhetic acid (analogue molecule) solutions and in‐vitro release studies were performed in gastrointestinal simulating fluids. Key findings Good recognition and selectivity properties were found in all the synthesized materials in both ethanol and ethanol–water mixture. The release from non‐imprinted polymers was indeed higher at acidic pH, while a slower release was observed in MIPs' case, because of the presence of imprinted cavities in the polymeric structure. The stronger capacity of MAA to interact by hydrogen bonds with the template makes MAA‐containing MIPs the most effective materials in both rebinding and release experiments. Conclusions The release tests confirm the applicability of imprinted polymer for glycyrrhizic acid sustained release in gastrointestinal simulating fluids.     

糖类对先导化合物的化学修饰及其在药学中的应用

1996年 ,孙昌俊等[1 6] 用相转移催化法 ,使木糖和葡萄糖的衍生物与含呋喃环的化合物反应得到有抗肿瘤活性的糖酯化合物( 1 1 )。此类化合物经 HL- 6 0细胞的体外癌细胞杀伤实验 ,表明部分化合物具有较高的抑瘤活性。(11)果糖糖酯化合物的合成。糖酯类化合物具有广泛的抗菌、抗肿瘤等的生理活性 ,而糖基磷酸酯还有抗病毒的活性。陈茹玉等 [1 7]对果糖与磷酰胺合成糖酯做了研究。磷酰胺是临床上广泛应用的抗癌药物—环磷酰胺的开环类似物 ,在体内具有选择性细胞毒作用。作者以 2 ,3,4 ,5-二 - O-亚异丙基果糖的 1位羟基与三氯氧磷经一系列…     

糖类对先导化合物的化学修饰及其在药学中的应用

概述了国内外有关糖类对先导化合物化学修饰的研究,从单糖,二糖和寡糖,多糖三个层面,分别对糖及其省生物与先导化合物的键合方式,经过结构修饰的先导化合物的生物活性变化作了综述,结果表明,修饰过的先导化合物能有效地降低毒副作用,增强药效,所以,利用糖类对先导化合物进行化学饰是很有前途的研究领域。     

Bioavailability of bioactive food compounds: a challenging journey to bioefficacy

Bioavailability is a key step in ensuring bioefficacy of bioactive food compounds or oral drugs. Bioavailability is a complex process involving several different stages: liberation, absorption, distribution, metabolism and elimination phases (LADME). Bioactive food compounds, whether derived from various plant or animal sources, need to be bioavailable in order to exert any beneficial effects. Through a better understanding of the digestive fate of bioactive food compounds we can impact the promotion of health and improvement of performance. Many varying factors affect bioavailability, such as bioaccessibility, food matrix effect, transporters, molecular structures and metabolizing enzymes. Bioefficacy may be improved through enhanced bioavailability. Therefore, several technologies have been developed to improve the bioavailability of xenobiotics, including structural modifications, nanotechnology and colloidal systems. Due to the complex nature of food bioactive compounds and also to the different mechanisms of absorption of hydrophilic and lipophilic bioactive compounds, unravelling the bioavailability of food constituents is challenging. Among the food sources discussed during this review, coffee, tea, citrus fruit and fish oil were included as sources of food bioactive compounds (e.g. (poly)phenols and polyunsaturated fatty acids (PUFAs)) since they are examples of important ingredients for the food industry. Although there are many studies reporting on bioavailability and bioefficacy of these bioactive food components, understanding their interactions, metabolism and mechanism of action still requires extensive work. This review focuses on some of the major factors affecting the bioavailability of the aforementioned bioactive food compounds.     

Prospects for the creation of new antiviral drugs based on glycyrrhizic acid and its derivatives (a review)

The review is devoted to the problem of creating new antiviral drugs based on glycyrrhizic acid (GA), the major triterpene glycoside extracted from roots of common and Ural licorice (Glycyrrhiza glabra L. and G. uralensis Fisher, respectively). Published data on the natural GA sources, antiviral activity of GA and its derivatives, clinical applications of GA-based drugs, and the properties of GA-containing biologically active nutrient additives are summarized. Possible mechanisms of the antiviral activity of GA and its derivatives are examined. It is shown that chemical modification of GA is a promising way of designing new highly active antiviral drugs for the prophylaxis and treatment of HIV, hepatitis B and C, corona-virus, and herpes simplex virus infections.     

Study on myxomycetes as a new source of bioactive natural products

The Myxomycetes (true slime molds) are an unusual group of primitive organisms that may be assigned to one of the lowest classes of eukaryotes. As their fruit bodies are very small and it is very difficult to collect much quantity, few studies have been made on the chemistry of myxomycetes. We studied spore germination experiments of hundreds of field-collected myxomycetes collected in Japan, and succeeded in laboratory culture of plasmodia of several myxomycetes in a practical scale for natural products chemistry studies. Pyrroloiminoquinones, polyene yellow pigments, and a peptide lactone were isolated from cultured plasmodia of myxomycetes, while new naphthoquinone pigments, cycloanthranilylprolines, tyrosine-kinase inhibitory bisindoles, a cytotoxic triterpenoid aldehyde lactone, a dibenzofuran glycoside, and sterols possessing an unprecedented 2,6-dioxabicyclo[2.2.2] octan-3-one ring system, were also isolated from field-collected fruit bodies of myxomycetes.     

The use of marine-derived bioactive compounds as potential hepatoprotective agents

The marine environment may be explored as a rich source for novel drugs. A number of marine-derived compounds have been isolated and identified, and their therapeutic effects and pharmacological profiles are characterized. In the present review, we highlight the recent studies using marine compounds as potential hepatoprotective agents for the treatment of liver fibrotic diseases and discuss the proposed mechanisms of their activities. In addition, we discuss the significance of similar studies in Oman, where the rich marine life provides a potential for the isolation of novel natural, bioactive products that display therapeutic effects on liver diseases.     

Cobalt compounds as antidotes for hydrocyanic acid

The antidotal potency of a cobalt salt (acetate), of dicobalt edetate, of hydroxocobalamin and of cobinamide against hydrocyanic acid was examined mainly on mice and rabbits. All the compounds were active antidotes for up to twice the LD50; under some conditions for larger doses. The most successful was cobalt acetate for rabbits (5×LD50), which was effective at a molar cyanide/cobalt (CN/Co) ratio of 5, but had as a side-effect intense purgation. Hydroxocobalamin was irregular in action, but on the whole was most effective for mice (4.5×LD50 at a molar ratio of 1), and had no apparent side effects. Dicobalt edetate, at molar ratios of up to 2, was more effective for rabbits (3×LD50) than for mice (2×LD50), but had fewer side effects than cobalt acetate. The effect of thiosulphate was to augment the efficacy of dicobalt edetate and, in mice, that of hydroxocobalamin; but, apparently, in rabbits, to reduce that of hydroxocobalamin. Cobinamide, at a molar ratio of 1, was slightly more effective than hydroxocobalamin on rabbits and also less irregular in its action. Cobalt acetate by mouth was effective against orally administered hydrocyanic acid. The oxygen uptake of the body, reduced by cyanide, is rapidly reinstated when one of the cobalt antidotes has been successfully administered.     

D-氨基葡萄糖的化学修饰及其在生物医药领域的应用

D-氨基葡萄糖具有一定的生物活性，对其进行化学修饰后可广泛应用于生物医药领域。     

拉肖皂苷元新合成路线研究

目的改进植物激素拉肖皂苷元(25R)-3β-羟基-6-酮-5α-螺甾烷的制备方法。方法以薯蓣皂素异螺环-5-烯-3β-醇为原料,经过氯铬酸吡啶(PCC)氧化、硼氢化钠还原共两步反应得到目标产物。结果目标化合物的结构经NMR、IR谱确认,其熔点、1H-NMR谱数据与文献报道一致,总收率为67.8%(以薯蓣皂素计)。结论与文献报道的方法相比,改进后的工艺路线更短、后处理更简单、收率更高,有利于工业化生产。