鱼腥草总生物碱的大孔吸附树脂纯化工艺

目的:优选鱼腥草总生物碱大孔吸附树脂的分离纯化工艺.方法:以盐酸小檗碱、胡椒内酰胺及马兜铃内酰胺B含量为指标,比较不同型号树脂和不同工艺条件对鱼腥草总生物碱的分离纯化能力.结果:HPD-100型大孔树脂对鱼腥草总生物碱有良好的吸附分离性能,最佳工艺条件为药液质量浓度20 g?L-1,pH 3,吸附流速0.5 mL? min -1,洗脱溶剂为氨水乙醇溶液(氨水浓度0.5 mol?L-1,乙醇体积分数80％),洗脱剂用量4 BV,洗脱速度3.0mL?min -1.结论:HPD-100型大孔树脂可用于鱼腥草总生物碱的提取纯化.     

马钱子总生物碱复合磷脂脂质体的抗肿瘤作用研究

目的: 通过比较马钱子总生物碱溶液和3种不同磷脂组成的马钱子总生物碱脂质体对H22荷瘤小鼠的抑瘤率,评价马钱子总生物碱复合磷脂脂质体的抗肿瘤作用。方法: 采用硫酸铵梯度法和隐形脂质体技术制备了3种不同磷脂组成的马钱子总生物碱脂质体。ICR小鼠接种H22肝癌瘤株造成移植性肝癌H22小鼠模型,测定马钱子总生物碱溶液、马钱子总生物碱大豆磷脂(SPC)脂质体、氢化大豆磷脂(HSPC)脂质体和复合磷脂脂质体各ip 1 mg ·kg^-1,连续10 d,观察对H22肝癌小鼠的抑瘤效果,比较给药后各组H22荷瘤小鼠的体重、免疫器官(脾和胸腺)指数和生命延长率。结果: 1 mg ·kg^-1剂量下的马钱子总生物碱溶液、SPC脂质体、HSPC脂质体和复合磷脂脂质体的抑瘤率分别为29.05%,29.29%,45.11%,37.23%;3种马钱子总生物碱脂质体未发现对免疫器官有明显的抑制作用;与对照组相比体重也无明显变化。结论: 复合磷脂脂质体是抗肿瘤中药有效部位马钱子总生物碱具有开发前景的新型载体。     

In vitro antiplasmodial activity of indole alkaloids from the stem bark of Geissospermum vellosii

Ethnopharmacological relevance

The stem bark of Geissospermum vellosii has been traditionally used by the native population of northern South America to treat malaria. Indole alkaloids have been previously isolated from this plant, but the antiplasmodial constituents have not yet been described. As part of our ongoing investigations of new bioactive compounds with activity against malaria parasites, we tested the in vitro antiplasmodial activity of isolated fractions and purified alkaloids from Geissospermum vellosii.

Materials and methods

Indole alkaloids were isolated and identified from a methanolic crude extract of Geissospermum vellosii bark using a combination of high performance counter current chromatography, mass spectrometry and nuclear magnetic resonance technologies. The methanolic extract, the crude alkaloid fractions and the purified compounds were tested for in vitro antiplasmodial activity against the chloroquine-sensitive strain of Plasmodium falciparum (D10).

Results

An indole alkaloid (4) along with four known indole alkaloids, geissolosimine (1), geissospermine (2), geissoschizoline (3), and vellosiminol (5) were isolated and structure elucidated. The antiplasmodial activity (IC₅₀) of the methanolic crude extract was 2.22 μg/mL, while for the isolated compounds it ranged from 0.96 μM to 13.96 μM except for (5) which showed a low activity (157 μM). Geissolosimine (1) showed the highest antiplasmodial activity (0.96 μM).

Conclusions

This study provides evidence to support the use of Geissospermum vellosii as an antimalarial agent, as used by the native populations. Geissolosimine (1) is a lead molecular structure for possible antimalarial drug development.     

Acute toxicity, antinociceptive activity and indole alkaloids of aqueous extract from bark of Aspidosperma cuspa (Kunth) Blake

Etnopharmacological relevance

Aspidosperma cuspa (Kunth) Blake (Apocynaceae) is popularly known as “amargosa” or “cuspa”, and its bark is used in folk medicine primarily for pain.

Aim of the study

In the present study the acute toxicity, antinociceptive effect and alkaloids of the aqueous decoction extract of the Aspidosperma cuspa bark in mice was investigated.

Materials and methods

Acute toxicity was tested using a variation of the method described by Lichfield and Wilcoxon. The antinociceptive activity was evaluated using the acetic acid induced writhing and tail-flick tests. The phytochemical analysis was performed.

Results and conclusion

Oral administration of the extract did not cause animal death (LD₅₀>4 g/kg), and the histological analysis showed an absence of alterations in all organs examined. TD₅₀ of the extract was 0.5521 g/kg for male mice and 1.1565 g/kg for females. The aqueous extract at doses 276 mg/kg (p.o.) did not produce a significant inhibition of acetic acid-induced writhes, but showed a significant effect in tail-flick test. Naloxone, an opioid receptor antagonist, pretreatment inhibited significantly the antinociceptive activity of the extract. It is suggested that the aqueous decoction extract of the bark of Aspidosperma cuspa has an antinociceptive effect, and this may be mediated by opioid receptors. Three indole alkaloids (aspidocarpine, 11-methoxytubotaiwine and picraline) were isolated from the aqueous extract. The antinociceptive activity of the extract is presumed to be due to these compounds.     

小飞蓬化学成分的研究

目的 对小飞蓬Erigeron canadensis的化学成分进行研究.方法 采用硅胶柱色谱及其他多种色谱方法对小飞蓬化学成分进行分离,应用MS、1H-NMR、3C-NMR等技术鉴定化合物的结构.结果 从小飞蓬95％乙醇提取物中分离并鉴定了 12个化合物,其中8个生物碱类:对羟基苯甲酰胺(1)、carbamic acid,N,N'-(4-methyl-1,3-phenylene) bis-C,C'-dimethyl ester (2)、硫酸阿托品(3)、3,4-二羟基苯甲酰胺(4)、4-羟基-3,5-二甲氧基苯甲酰胺(5)、2-羟基-5-甲氧基苯甲酰胺(6)、甜菜碱(7)、盐酸小檗碱(8);4个五环三萜类:α-香树脂醇(9)、β-谷甾醇(10)、齐墩果酸(11)、β-胡萝卜苷(12).结论 8个生物碱类化合物均为首次从该植物中分离得到.     

苦参总生物碱及其单体在Caco-2细胞模型的吸收特征研究

目的 建立同时测定Caco-2细胞模型中苦参碱、氧化槐果碱和氧化苦参碱的HPLC方法,探讨苦参总生物碱在Caco-2细胞模型的吸收机制.方法 利用人源结肠腺癌细胞系Caco-2细胞单层模型,研究苦参碱、氧化槐果碱和氧化苦参碱由细胞绒毛膜面供给侧(AP)→基底外侧(BL)和BL→AP侧两个方向的转运过程;HPLC-UV法测定上述3个生物碱的量;计算转运参数和表观渗透系数(Papp).结果 苦参总碱给药后,苦参碱、氧化槐果碱和氧化苦参碱由AP→BL侧的Papp分别为(1.098±0.092)×10-5、(1.434±0.098)×10-5、(3.87±0.64)×10-6cm/s,由BL→AP侧的Papp分别为(1.104±0.098)×10-5、(1.034±0.079)×10-5、(2.75±0.33)×10-6 cm/s,与文献报道的单体化合物给药相比,氧化槐果碱和氧化苦参碱双向转运的Papp明显增大.苦参碱、氧化槐果碱和氧化苦参碱的表观渗透率值分别为1.01、0.72、0.71.结论 苦参总生物碱中苦参碱、氧化槐果碱和氧化苦参碱仍主要以被动吸收方式进入体内,但比各单体给药吸收更好.     

附子总生物碱对乳腺癌小鼠的抗肿瘤作用

目的 观察附子总生物碱对二甲基苯葸诱导的乳腺癌小鼠体征、部分血液学指标及肿瘤的影响.方法 小鼠分为对照组、模型组、附子总生物碱组.模型组小鼠每天sc二甲基苯蒽橄榄油溶液50 mg/kg,每周2次、连续5周,建立乳腺癌模型,给药组在每天给予二甲基苯蒽的同时,给予附子总生物碱2 mg/kg,观察实验期间各组小鼠乳腺肿瘤的潜伏期、发生率、外观、体温和外耳微循环变化,检测血清中雌二醇和孕酮水平、红细胞Na+,K+-ATP酶和Ca2+,Mg2+-ATP酶活性及血液流变学指标,综合评价附子总生物碱对小鼠乳腺癌的影响.结果 模型组小鼠随给药时间的延长逐渐出现畏寒喜暖、蜷缩少动、体温下降、外耳微循环受阻状况,同时血中雌二醇和孕酮水平升高,红细胞ATP酶活性降低,全血黏度及红细胞聚集指数增高;附子总生物碱可以显著改善上述指标变化,阻止肿瘤生长.结论 二甲基苯葸诱导的乳腺癌小鼠表现为体寒血瘀体征,附子总生物碱能改善这些症状,阻止肿瘤进展.     

Endothelial vascular toxicity from chemotherapeutic agents: preclinical evidence and clinical implications

In cancer biology angiogenesis plays a vital role in tumour growth and its subsequent metastatic potential. By targeting the angiogenic process, a new treatment strategy was added in the clinician's therapeutic armamentarium. On the other hand, numerous classic cytotoxic agents are currently considered as potential angiogenesis inhibitors, although they were not originally developed as such, representing the so-called "accidental" anti-angiogenic drugs. The discovery of these new properties of classic cytotoxic agents led to the re-evaluation of their effect on vascular cells, rendering thus the endothelium an appealing target for therapeutic intervention, either with chemotherapy alone or with combination of cytotoxics with molecular angiogenesis inhibitors. Moreover, current evidence supports that chemotherapy-induced endothelial dysfunction constitutes an integrating predictive marker of future cardiovascular events and correlates well with traditional cardiovascular risk factors. It has therefore been suggested that evaluation of endothelial function may be useful in identifying asymptomatic subjects at high risk for cardiovascular events as well as for risk stratification of patients with established cardiovascular disease. Integration of the assessment of endothelial function in the clinical setting will thus enable effective intervention strategies to prevent or minimize the impact of these late adverse effects and design accurate follow-up protocols focused on cardiovascular complications. In the current review we provide a comprehensive overview of the effects of cytotoxic chemotherapeutic agents on endothelial function and the clinical implications of chemotherapy-associated endothelial toxicity in patients with cancer.     

Metabolic Activation of Pyrrolizidine Alkaloids Leading to Phototoxicity and Photogenotoxicity in Human HaCaT Keratinocytes

Pyrrolizidine alkaloids, produced by a large number of poisonous plants with wide global distribution, are associated with genotoxicity, tumorigenicity, and hepatotoxicity in animals and humans. Mammalian metabolism converts pyrrolizidine alkaloids to reactive pyrrolic metabolites (dehydropyrrolizidine alkaloids) that form covalent protein and DNA adducts. Although a mechanistic understanding is currently unclear, pyrrolizidine alkaloids can cause secondary (hepatogenous) photosensitization and induce skin cancer. In this study, the phototoxicity of monocrotaline, riddelliine, dehydromonocrotaline, dehydroriddelliine, and dehydroretronecine (DHR) in human HaCaT keratinocytes under ultraviolet A (UVA) irradiation was determined. UVA irradiation of HaCaT cells treated with dehydromonocrotaline, dehydroriddelline, and DHR resulted in increased release of lactate dehydrogenase and enhanced photocytotoxicity proportional to the UVA doses. UVA-induced photochemical DNA damage also increased proportionally with dehydromonocrotaline and dehydroriddelline. UVA treatment potentiated the formation of 8-hydroxy-2′-deoxyguanosine DNA adducts induced by dehydromonocrotaline in HaCaT skin keratinocytes. Using electron spin resistance trapping, we found that UVA irradiation of dehydromonocrotaline and dehydroriddelliine generates reactive oxygen species (ROS), including hydroxyl radical, singlet oxygen, and superoxide, and electron transfer reactions, indicating that cytotoxicity and genotoxicity of these compounds could be mediated by ROS. Our results suggest that dehydropyrrolizidine alkaloids formed or delivered to the skin cause pyrrolizidine alkaloid-induced secondary photosensitization and possible skin cancer.