双氢青蒿素抗肿瘤分子生物学机制研究进展

青蒿素作为抗疟特效药在临床应用中存在水溶性小、口服效果差等缺点,因此研究人员开发了保留其母核的多种衍生物。其中双氢青蒿素（DHA）的抗疟活性更强,且具有在体内代谢速度快、水溶性好等优点,同时DHA对肿瘤细胞也有良好的抑制效果,且其分子生物学作用机制与自身结构中的过氧桥密切相关。由于肿瘤细胞比正常细胞需要摄取更多的铁离子,因此肿瘤细胞膜上存在大量的转铁蛋白受体。DHA能在亚铁离子的存在下使过氧桥发生断裂,产生自由基从而对肿瘤细胞发挥杀伤作用,并能使转铁蛋白受体发生内吞,阻止肿瘤细胞从外界摄入必需的铁离子。本文主要从DHA加速细胞氧化损伤、诱导肿瘤细胞凋亡、抑制肿瘤细胞生长增殖和侵袭转移以及逆转肿瘤细胞多药耐药等方面对其抗肿瘤的分子生物学机制进行综述。     

The osteoprotective effects of artemisinin compounds and the possible mechanisms associated with intracellular iron: A review of in vivo and in vitro studies

Osteoporosis is a progressive systemic disease characterized by low bone mineral density and deterioration of bone microarchitecture. The current therapies are effective to prevent further bone loss and fractures but they are accompanied by undesirable side effects and cost issues. The discovery of Chinese herbal medicines with osteoprotective effects provides alternative treatments to prevent bone loss without causing severe side effects. Artemisinin (ARS) and its related compounds have been clinically used as antimalarial agents. Interestingly, their bioactivity is not limited to antimalarial treatment. Experimental evidences indicate that ARS compounds are a potential type of therapeutic alternative medicine for bone loss induced by accelerated osteoclastic bone resorption. The present review intends to summarize the current understandings of ARS compounds and their molecular mechanisms of actions in preventing bone loss. ARS compounds selectively inhibit osteoclast differentiation by downregulation of pathways involved in receptor activator of nuclear factor kappa-B ligand (RANKL) -induced osteoclastogenesis, and have no effect on osteogenic differentiation of osteoblasts. The exact mechanism of activation and action of these anti-resorption effects are not fully elucidated. Considering the characteristic of high levels of intracellular iron in osteoclasts, ARS compounds may inhibit osteoclast differentiation via mechanisms associated with intracellular iron, including the cleavage of endoperoxide bridge, oxidative damage and ferroptosis. The anti-resorptive effects of ARS compounds need to be further investigated in bone loss models caused by different factors, and to be under clinical development.     

Artemisinin and thiabendazole are potent inhibitors of cytochrome P450 1A2 (CYP1A2) activity in humans

Objective To investigate the likelihood of artemisinin and thiabendazole causing pharmacokinetic interactions involving cytochrome P450 (CYP1A2) in humans given their potent inhibitory effects on the isoform in vitro. Methods Ten healthy volunteers received caffeine (136.5 mg), and after a washout period of 48 h, the volunteers were given a caffeine tablet (136.5 mg) together with thiabendazole (500 mg). After an additional 14 days, the volunteers received caffeine together with artemisinin (500 mg). After each treatment, plasma was obtained up to 24 h post-dose. The plasma concentrations of the drugs were measured by HPLC with UV and MS detection. Results Using the ratio of paraxanthine to caffeine after 4 h as an indicator of CYP1A2 activity, thiabendazole and artemisinin inhibited 92 and 66%, respectively, of the enzyme activity in vivo. In addition, the pharmacokinetics of caffeine were altered in the presence of the drugs; increases in AUC_0–24 of 1.6-fold (P<0.01) and 1.3-fold of caffeine in the presence of thiabendazole and artemisinin respectively were measured. The use of in vitro data to predict the effects of thiabendazole on the formation of paraxanthine yielded good results and underestimated the effects of artemisinin when total plasma concentrations were used. Corrections for protein binding resulted in underestimation of inhibitory effects on CYP1A2. Conclusions Co-administration of thiabendazole or artemisinin with CYP1A2 substrates could result in clinically significant effects. Our results highlight the validity of in vitro data in predicting in vivo CYP inhibition. The formation of paraxanthine seems to be a better indicator of in vivo CYP1A2 activity than caffeine levels.     

The history of qing hao in the Chinese materia medica

Artemisinin is currently used for treating drug-resistant malaria. It is found in Artemisia annua and also in A. apiacea and A. lancea. Artemisia annua and A. apiacea were known to the Chinese in antiquity and, since they were easily confused with each other, both provided plant material for the herbal drug qing hao (blue-green hao). This article shows, however, that since at least the eleventh century Chinese scholars recognized the difference between the two species, and advocated the use of A. apiacea, rather than A. annua for 'treating lingering heat in joints and bones' and 'exhaustion due to heat/fevers'. The article furthermore provides a literal translation of the method of preparing qing hao for treating intermittent fever episodes, as advocated by the eminent physician Ge Hong in the fourth century CE. His recommendation was to soak the fresh plant in cold water, wring it out and ingest the expressed juice in its raw state. Both findings may have important practical implications for current traditional usage of the plant as an antimalarial: rather than using the dried leaves of A. annua in warm infusions, it suggests that fresh juice extraction from A. apiacea may improve efficacy.     

Artemisinin–naphthoquine combination: A directly observed treatment option in malaria

Resistance to standard antimalarials has led to the need for newer options. Artemisinin-based combination therapies (ACTs), which require a tedious three-day treatment schedule, have been introduced for the treatment of drug-resistant malaria. Of late, the new generation artemisinin–naphthoquine (ANQ) combination has been developed, which requires a single dose treatment.Artemisinin initiates the action through the cleavage of the endoperoxide bridge while naphtoquine maintains the process by getting concentrated in the digestive vacuole of the parasite.One ANQ tablet contains 50 mg naphthoquine and 125 mg of artemisinin in the ratio of 1:2.5. The optimal dosage in adults is 400 mg of naphthoquine and 1000 mg artemisinin; which amounts to 8 tablets in a single dose. The dosage for children is adjusted based on the body-weight.The combination has been found to be quite effective with and safe. Studies have demonstrated an adequate clinical and parasitologic response of 98.1–100% in both adults and children. However, further trials are required to confirm its non-inferiority with other ACTs. Adverse reactions with ANQ have been mild. Further studies are needed before safety can be established during pregnancy.ANQ increases the compliance rates because of single dosage. It may be administered by the peripheral health workers as a directly observed therapy, which would be of special benefit to troops in the North-Eastern Sector.     

磷酸萘酚喹与青蒿素伍用增效和延缓疟原虫抗药性的研究

本文采用鼠疟模型进行磷酸萘酚喹与青蒿素伍用的药效学研究。用正交设计和4天抑制试验法,研究两药伍用增效的最适配比。采用药物剂量递增培育抗性的方法,连续血传100代,分别培育鼠疟原虫对磷酸萘酚喹、青蒿素及两药伍用的抗药性。结果显示磷酸萘酚喹和青蒿素最适配比为1：50,对鼠疟敏感株和抗氯喹株的增效指数分别为4．2和8．2,杀虫速度和治愈率均优于单药。培育至100代时,磷酸萘酚喹、青蒿素和两药伍用抗性指数分别为200．3、5．6和4．4。结果表明,磷酸萘酚喹与青蒿素配伍具有增效作用,并能明显延缓疟原虫对单药抗性产生的速度,降低抗性水平。     

Design of a New Line in Treatment of Experimental Rheumatoid Arthritis by Artesunate

This study was aimed to evaluate the therapeutic potency of a new antimalarial drug, artesunate, in an experimental model of rheumatoid arthritis. Collagen-induced arthritis (CIA) was induced in Lewis rats.The intraperitoneally administration of artesunate (ARS) and methotrexate (MTX) were started on day 25 postimmunization and continued until final assessment on day 35. During this period, clinical examination was intermittent. The anticollagen type II antibody (CII Ab) and nitric oxide synthesis were measured. The paws and kness were then removed for histopathology and radiography assay. The biocompatibility of ARS and MTX were assessed using fibrosarcoma cell line. Our results showed that i.p. injection of artesunate to arthritic rats induced a significant reduction in paw edema. This beneficial effect was associated with a significant decrease in anti-CII antibody response compared with untreated rats. Histopathological assessment showed reduced inflammatory cells infiltrate in joints of treated rats, and tissue edema and bone erosion in the paws were markedly reduced following ARS therapy. Moreover, our radiographic results paralleled histological findings. Cytotoxicity analysis of ARS showed greater tolerability compared with MTX. Treatment with ARS significantly diminished nitric oxide formation in treated rats compared with untreated controls. Our findings revealed the therapeutic efficacy of artesunate in experimental rheumatoid arthritis compared with a choice drug (methotrexate). This result may recommend it as a second-line drug in the treatment of rheumatoid arthritis.     

青蒿素类化合物专利格局分析

目的：青蒿素及其系列衍生物的抗疟作用已被广泛认可,该类化合物的其他生物活性也受到广泛关注,深入的实验研究产生了大量专利文献。本文对青蒿素、青蒿酸和青蒿乙素的专利申报情况进行了系统梳理,以展示其研发态势,为规划研究路线、制订专利申请策略提供参考。方法：制订检索策略,从多个专利数据库检索和下载题录信息,利用统计学软件对题录中的有效信息进行分析挖掘。结果：获得了青蒿素类化合物专利申请的生命周期、应用功效偏好、优秀申请机构和高价值专利等方面的格局情报。结论：该领域专利技术生命周期整体处于技术成熟期。其中,青蒿素发展空间相对较大,最受关注的应用功效包括抗寄生虫、抗肿瘤和抗感染,而内部引用的核心主题是治疗皮肤病、抑制癌症。     

Sensitivity of human herpesvirus 6 and other human herpesviruses to the broad-spectrum antiinfective drug artesunate

BackgroundAntiviral therapy for HHV-6 infection with conventional anti-herpesviral drugs is problematic so novel drugs are required. Artesunate is a well-tolerated drug approved for malaria therapy which possesses antiviral activity.ObjectiveThe artesunate sensitivity of HHV-6 was analyzed and compared to that of several other human herpesviruses.Study designCultured human cells were productively infected with strains of HHV-6 or other human herpesviruses to measure artesunate inhibition of viral protein synthesis (Western blot analysis) or viral genome replication (qPCR), and to determine IC₅₀ values by immunofluorescence or plaque reduction assays.ResultsSensitivity of HHV-6 to artesunate was demonstrated with an IC₅₀ of 3.80 ± 1.06 μM. This is in a range similar to IC₅₀ values for HCMV and EBV. Artesunate treatment of HHV-6-infected cells significantly reduced viral early and late protein synthesis that occurred in the absence of drug-induced apoptosis or necrotic cytotoxicity. HHV-6A genome replication was markedly reduced by artesunate.ConclusionsArtesunate possesses anti-HHV-6 activity in vitro and may be useful for treatment of HHV-6 infections.     

体外胁迫促进青蒿素在黄花蒿培养细胞中合成的研究

在黄花蒿细胞悬浮培养合成青蒿素的过程中添加微生物刺激剂和微生物胸外酶刺激剂,测定刺激剂对青蒿素合成的影响。采用的微生物刺激剂为霉菌ＡＳ３４,３０９和ＡＳ３,３４６、酵母Ｋluyberomyces fragilis及细菌ＡＳ１,３９８的提取物,微生物胸外酶刺激剂为果胶酶、纤维素酶及半纤维素酶。其中酵母Ｋluyberomyces fragilis提取物和果胶酶对青蒿素生物合成具有明显的刺激作用。用酵母Ｋluyberomyces fragilis提取物（２０％）处理黄花蒿培养细胞３天,青蒿素合成量达到每克黄花蒿干细胞３２０μｇ,比未刺激细胞的青蒿素合成量提高３８％;将果胶酶（０.２％）添加到青蒿素合成培养基中处理黄花蒿培养细胞２天以上,青蒿素合成量达到每克黄花蒿干细胞７４０μｇ,比未刺激细胞的青蒿素合成量提高３.０８倍。