Núcleo de Pesquisa em Biodiversidade e Biotecnologia, Biotec, Campus Ministro Reis Velloso, Universidade Federal do Piauí, Parnaíba, PI, Brazil.
Laboratório de Nanobiotecnologia, Instituto de Biologia, Campus Darcy Ribeiro, Universidade de Brasília, Brasília, DF, Brazil.
Food Res Int. 2018 Mar;105:184-196. doi: 10.1016/j.foodres.2017.10.045. Epub 2017 Oct 27.
This study investigated a lycopene-rich extract from red guava (LEG) for its chemical composition using spectrophotometry, mass spectrometry, attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR), and computational studies. The cytotoxic activity of LEG and the underlying mechanism was studied in human breast adenocarcinoma cells (MCF-7), murine fibroblast cells (NIH-3T3), BALB/c murine peritoneal macrophages, and sheep blood erythrocytes by evaluating the cell viability with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method and flow cytometry. Spectrophotometry analysis showed that LEG contained 20% of lycopene per extract dry weight. Experimental and theoretical ATR-FTIR suggests the presence of lycopene, whereas MS/MS spectra obtained after fragmentation of the molecular ion [M] of 536.4364 show fragment ions at m/z 269.2259, 375.3034, 444.3788, and 467.3658, corroborating the presence of lycopene mostly related to all-trans configuration. Treatment with LEG (1600 to 6.25μg/mL) for 24 and 72h significantly affected the viability of MCF-7 cells (mean half maximal inhibitory concentration [IC]=29.85 and 5.964μg/mL, respectively) but not NIH-3T3 cells (IC=1579 and 911.5μg/mL, respectively). Furthermore LEG at concentrations from 800 to 6.25μg/mL presented low cytotoxicity against BALB/c peritoneal macrophages (IC≥800μg/mL) and no hemolytic activity. LEG (400 and 800μg/mL) caused reduction in the cell proliferation and induced cell cycle arrest, DNA fragmentation, modifications in the mitochondrial membrane potential, and morphologic changes related to granularity and size in MCF-7 cells; however, it failed to cause any significant damage to the cell membrane or display necrosis or traditional apoptosis. In conclusion, LEG was able to induce cytostatic and cytotoxic effects on breast cancer cells probably via induction of an apoptotic-like pathway.
本研究使用分光光度法、质谱法、衰减全反射傅里叶变换红外光谱（ATR-FTIR）和计算研究，对富含番茄红素的红番石榴提取物（LEG）进行了化学成分分析。通过 3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴化物（MTT）法和流式细胞术评估细胞活力，研究了 LEG 在人乳腺癌细胞（MCF-7）、小鼠成纤维细胞（NIH-3T3）、BALB/c 小鼠腹腔巨噬细胞和绵羊血红细胞中的细胞毒性作用及其潜在机制。分光光度法分析表明，LEG 提取物每干重含有 20%的番茄红素。实验和理论 ATR-FTIR 表明存在番茄红素，而分子离子 [M] 的 MS/MS 谱在碎裂后获得的碎片离子在 m/z 269.2259、375.3034、444.3788 和 467.3658 处，证实了番茄红素的存在主要与全反式构型有关。用 LEG（1600 至 6.25μg/mL）处理 24 和 72 小时显著影响 MCF-7 细胞的活力（半数最大抑制浓度[IC]分别为 29.85 和 5.964μg/mL），但不影响 NIH-3T3 细胞（IC 分别为 1579 和 911.5μg/mL）。此外，LEG 在 800 至 6.25μg/mL 的浓度下对 BALB/c 腹腔巨噬细胞的细胞毒性较低（IC≥800μg/mL），且无溶血活性。LEG（400 和 800μg/mL）导致 MCF-7 细胞的细胞增殖减少并诱导细胞周期停滞、DNA 片段化、线粒体膜电位改变以及与颗粒度和大小相关的形态变化；然而，它未能对细胞膜造成任何显著损伤，也未显示坏死或传统凋亡。总之，LEG 能够诱导乳腺癌细胞产生细胞停滞和细胞毒性作用，可能是通过诱导类似凋亡的途径。
