Department of Chemistry, Federal University of Espírito Santo (UFES), Avenida Fernando Ferrari, 514, 29.075-910, Vitória, Espírito Santo, Brazil.
Pharmaceutical Science Undergraduate Program, Universidade Vila Velha (UVV), Rua José Dantas de Melo, 21, 29.102-770, Vila Velha, Espírito Santo, Brazil.
Anticancer Agents Med Chem. 2019;19(5):707-717. doi: 10.2174/1871520619666190118122523.
Amaryllidaceae plants are known to be a great source of alkaloids, which are considered an extensive group of compounds encompassing a wide range of biological activities. The remarkable cytotoxic activities observed in most of the Amaryllidaceae alkaloids derivatives have prompt the chemical and biological investigations in unexplored species from Brazil.
To evaluate the cytotoxic and genotoxic properties of alkaloids of Griffinia gardneriana and Habranthus itaobinus bulbs and study the role of caspase-3 as a molecular apoptosis mediator.
Methanolic crude extracts of Griffinia gardneriana and Habranthus itaobinus bulbs were submitted to acid-base extraction to obtain alkaloid-enriched fractions. The obtained fractions were fractionated using chromatographic techniques leading to isolation and identification of some alkaloids accomplished via HPLC and 1H-NMR, respectively. Molecular docking studies assessed the amount of free binding energy between the isolated alkaloids with the caspase-3 protein and also calculated the theoretical value of Ki. Studies have also been developed to evaluate in vitro cytotoxicity and genotoxicity in such alkaloids and apoptosis activation via the caspase pathway using both tumor and normal cell lines.
Seven alkaloids were isolated and identified. Among these, 11-hydroxyvittatine and 2-α-7- dimethoxyhomolycorine were not cytotoxic, whereas tazettine, trisphaeridine, and sanguinine only showed activity against the fibroblast lineage. Lycorine and pretazettine were 10 to 30 folds more cytotoxic than the other alkaloids, including cancerous lines, and were genotoxic and capable of promoting apoptosis via the caspase-3 pathway. This result supports data obtained in docking studies wherein these two compounds exhibited the highest free energy values.
The cytotoxicity assay revealed that, among the seven alkaloids isolated, only lycorine and pretazettine were active against different cell lines, exhibiting concentration- and time-dependent cytotoxic actions alongside genotoxic action and the ability to induce apoptosis by caspase-3, a result consistent with those obtained in docking studies.
石蒜科植物是生物碱的重要来源，生物碱被认为是一组广泛的化合物，具有广泛的生物活性。大多数石蒜科生物碱衍生物具有显著的细胞毒性活性，这促使人们对来自巴西的未开发物种进行了化学和生物学研究。
评估 Griffinia gardneriana 和 Habranthus itaobinus 鳞茎中的生物碱的细胞毒性和遗传毒性，并研究 caspase-3 作为分子凋亡介体的作用。
Griffinia gardneriana 和 Habranthus itaobinus 鳞茎的甲醇粗提取物经酸碱提取得到富含生物碱的馏分。用色谱技术对获得的馏分进行分离，得到一些生物碱的分离和鉴定，分别通过 HPLC 和 1H-NMR 完成。分子对接研究评估了分离的生物碱与 caspase-3 蛋白之间的游离结合能的数量，并计算了 Ki 的理论值。还进行了研究以评估这些生物碱的体外细胞毒性和遗传毒性，以及通过 caspase 途径激活凋亡。
分离并鉴定了 7 种生物碱。其中，11-羟基维替汀和 2-α-7-二甲氧基霍罗辛没有细胞毒性，而塔泽汀、三尖杉碱和血根碱仅对成纤维细胞系有活性。石蒜碱和前塔泽汀比其他生物碱（包括癌细胞系）的细胞毒性高 10 到 30 倍，具有遗传毒性，并能通过 caspase-3 途径促进凋亡。这一结果支持对接研究中获得的数据，其中这两种化合物表现出最高的自由能值。
细胞毒性测定表明，在所分离的 7 种生物碱中，只有石蒜碱和前塔泽汀对不同细胞系具有活性，表现出浓度和时间依赖性的细胞毒性作用以及遗传毒性作用，并能通过 caspase-3 诱导凋亡，这与对接研究的结果一致。
