Abstract

Context

Traditionally, Inula racemosa Hook. f. (Asteraceae) has been reported to be effective in cancer treatment which motivated the authors to explore the plant for novel anticancer compounds.

Objective

To isolate and characterize new cytotoxic phytoconstituents from I. racemosa roots.

Materials and methods

The column chromatography of I. racemosa ethyl acetate extract furnished a novel sesquiterpene lactone whose structure was established by NMR (1D/2D), ES-MS and its cytotoxic properties were assessed on HeLa, MDAMB-231, and A549 cell lines using MTT and LDH (lactate dehydrogenase) assays. Further, morphological changes were analyzed by flow cytometry, mitochondrial membrane potential, AO-EtBr dual staining, and comet assay. Molecular docking and simulation were performed using Glide and Desmond softwares, respectively, to validate the mechanism of action.

Results

The isolated compound was identified as racemolactone I (compound 1). Amongst the cell lines tested, considerable changes were observed in HeLa cells. Compound 1 (IC₅₀ = 0.9 µg/mL) significantly decreased cell viability (82%) concomitantly with high LDH release (76%) at 15 µg/mL. Diverse morphological alterations along with significant increase (9.23%) in apoptotic cells and decrease in viable cells were observed. AO-EtBr dual staining also confirmed the presence of 20% apoptotic cells. A gradual decrease in mitochondrial membrane potential was observed. HeLa cells showed significantly increased comet tail length (48.4 µm), indicating broken DNA strands. In silico studies exhibited that compound 1 binds to the active site of Polo-like kinase-1 and forms a stable complex.

Conclusions

Racemolactone I was identified as potential anticancer agent, which can further be confirmed by in vivo investigations.

中文翻译：

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从总状旋覆花中分离出的一种新的倍半萜内酯 racemolactone I 的细胞毒性和分子对接分析

摘要

语境

传统上，总状旋覆花Hook。F。据报道（菊科）可有效治疗癌症，这促使作者探索该植物以寻找新型抗癌化合物。

客观的

从I. racemosa根中分离和表征新的细胞毒性植物成分。

材料和方法

I. racemosa乙酸乙酯提取物的柱层析提供了一种新型倍半萜内酯，其结构通过 NMR (1D/2D)、ES-MS 确定，并使用 MTT和LDH（乳酸脱氢酶）测定。此外，通过流式细胞术、线粒体膜电位、AO-EtBr 双染色和彗星试验分析形态学变化。分别使用Glide和Desmond软件进行分子对接和模拟，以验证作用机制。

结果

分离出的化合物被鉴定为外消旋内酯 I（化合物1）。在测试的细胞系中，在 HeLa 细胞中观察到相当大的变化。化合物1 (IC ₅₀ = 0.9 µg/mL) 在 15 µg/mL 时显着降低细胞活力 (82%) 并伴有高 LDH 释放 (76%)。观察到多种形态学改变以及凋亡细胞显着增加 (9.23%) 和活细胞减少。AO-EtBr 双染色也证实了 20% 凋亡细胞的存在。观察到线粒体膜电位逐渐降低。HeLa 细胞的彗尾长度显着增加 (48.4 µm)，表明 DNA 链断裂。计算机研究表明，化合物1与 Polo 样激酶 1 的活性位点结合并形成稳定的复合物。

结论

Racemolactone I 被确定为潜在的抗癌剂，这可以通过体内研究进一步证实。