Coconut antimicrobial peptide-1 (CnAMP1) is a naturally occurring bioactive peptide from green coconut water ( Cocos nucifera L.). Although biological activities have been reported, the physiological relevance of these reports remains elusive as it is unknown if CnAMP1 is taken up into intestinal cells. To address this open question, we investigated the cytotoxicity of CnAMP1 in intestinal cells and its cellular uptake into human intestinal cells. Considering the importance of the P-glycoprotein (P-gp) to the intestinal metabolism of xenobiotics, we also investigated the influence of CnAMP1 on P-gp activity and expression. Both cell lines showed intracellular fluorescence after incubation with fluorescein labelled CnAMP1, indicating cellular uptake of the intact or fragmented peptide. CnAMP1 (12.5–400 μmol/L) showed no signs of cytotoxicity in LS180 and differentiated Caco-2 cells and did not affect P-gp expression and activity. Further research is required to investigate the identity of CnAMP1 hydrolysis fragments and their potential biological activities.

中文翻译：

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椰子水抗菌肽 CnAMP1 被肠道细胞吸收，但不会改变 P-糖蛋白的表达和活性

椰子抗菌肽-1 (CnAMP1) 是一种来自绿色椰子水 (Cocos nucifera L.) 的天然生物活性肽。尽管已经报道了生物活性，但这些报道的生理相关性仍然难以捉摸，因为 CnAMP1 是否被吸收到肠细胞中尚不清楚。为了解决这个悬而未决的问题，我们研究了 CnAMP1 在肠细胞中的细胞毒性及其对人肠细胞的细胞摄取。考虑到 P-糖蛋白 (P-gp) 对外源性肠道代谢的重要性，我们还研究了 CnAMP1 对 P-gp 活性和表达的影响。两种细胞系在与荧光素标记的 CnAMP1 孵育后都显示出细胞内荧光，表明细胞摄取了完整或片段化的肽。CnAMP1 (12. 5–400 μmol/L) 在 LS180 和分化的 Caco-2 细胞中没有显示细胞毒性迹象，并且不影响 P-gp 的表达和活性。需要进一步的研究来调查 CnAMP1 水解片段的身份及其潜在的生物活性。