S3A Fig.

BackgroundColorectal cancer (CRC) is the third most common cancer worldwide, with rising incidence linked to unhealthy lifestyle habits. Although 5-fluorouracil (5-FU) remains a standard therapy, its efficacy is often limited by resistance and adverse effects. These limitations have driven interest in plant-derived bioactive compounds as complementary or alternative therapies. This study investigated the potential anticancer effects of Swertiamarin (SWT), a seco-iridoid glycoside with reported anti-inflammatory and antioxidant properties.MethodsThree human CRC cell lines (HT-29, HCT-116, and Caco-2) and a non-cancerous (Vero E6) cell line were treated with SWT sourced from three independent suppliers to ensure reproducibility. Cell viability was evaluated using Trypan blue exclusion and MTT assays, while scratch assay and microscopic analyses were used to assess migration and morphological changes. The antioxidant capacity of SWT was measured using hydrogen peroxide scavenging assays, and its antimicrobial activity was tested against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus).ResultsSWT exhibited minimal or no effect on cell proliferation across all cell lines, concentrations, and time points, while 5-FU significantly reduced cell viability. Co-treatment with SWT and 5-FU did not enhance cytotoxicity, indicating no synergistic effect. SWT also had no impact on cell migration or morphology. However, it demonstrated strong antioxidant activity comparable to ascorbic acid and displayed antimicrobial effects, transiently inhibiting E. coli and persistently suppressing S. aureus.ConclusionSWT does not exert direct cytotoxic or antimigratory effects in CRC models but possesses potent antioxidant and antimicrobial activities. These findings suggest a possible chemopreventive or protective role for SWT rather than a therapeutic one. This study underscores the importance of rigorous and reproducible evaluation of pure natural products to accurately define their biological and therapeutic potential.背景 结直肠癌（Colorectal cancer, CRC）是全球第三大常见恶性肿瘤，其发病率上升与不健康生活方式密切相关。尽管5-氟尿嘧啶（5-fluorouracil, 5-FU）仍是临床标准治疗方案，但其疗效常受耐药性与不良反应的限制。这些局限性促使学界对植物来源生物活性化合物作为辅助或替代治疗方案产生研究兴趣。本研究针对獐牙菜苦苷（Swertiamarin, SWT）——一种已被报道具有抗炎与抗氧化特性的裂环环烯醚萜苷（seco-iridoid glycoside）——的潜在抗癌效应展开探究。 方法 本研究使用3株人CRC细胞系（HT-29、HCT-116与Caco-2）以及1株非癌性细胞系（Vero E6），采用3家独立供应商提供的SWT进行处理，以确保实验可重复性。采用台盼蓝排斥试验（Trypan blue exclusion）与MTT法（MTT assay）检测细胞活力，通过划痕实验（scratch assay）与显微镜分析评估细胞迁移能力与形态学变化。通过过氧化氢清除实验（hydrogen peroxide scavenging assays）检测SWT的抗氧化能力，并针对大肠杆菌（Escherichia coli, E. coli）与金黄色葡萄球菌（Staphylococcus aureus, S. aureus）检测其抗菌活性。 结果 在所有细胞系、浓度与时间点下，SWT对细胞增殖仅表现出极微弱或无影响，而5-FU可显著降低细胞活力。SWT与5-FU联合给药未增强细胞毒性，提示二者无协同效应。SWT对细胞迁移与形态亦无显著影响。但SWT表现出可与抗坏血酸（ascorbic acid）媲美的强抗氧化活性，同时具备抗菌效应：可短暂抑制大肠杆菌，并持续抑制金黄色葡萄球菌。 结论 SWT在CRC模型中未表现出直接细胞毒性或抗迁移效应，但具备强效抗氧化与抗菌活性。上述结果提示SWT或可发挥化学预防或机体保护作用，而非治疗功效。本研究强调了对纯天然产物开展严谨且可重复的评估，以精准明确其生物学与治疗潜力的重要性。