Abstract The ethanolic extract obtained from purple pitanga fruit (Eugenia uniflora – PPE) has been previously described by its potential to reduce lipid accumulation in vitro. In this study, we aimed to study this potential in vivo using Caenorhabditis elegans as animal model. Considering the low pH of the extract, its hydrophilic characteristic, its absorption by the medium where the worms are cultivated and the need of a chronic exposure in the worms solid medium, we have loaded liposomes with PPE and investigated its potential for oral administration. Following 48 h exposure to the PPE-loaded liposomes on worms nematode growth medium, we did not observe any toxic effects of the formulation. Under high cholesterol diet, which increased worms total lipid and also triacylglycerides levels, liposomes containing PPE were able to significantly attenuate these alterations, which could not be observed when worms were treated with free PPE. Furthermore, we could evidence that liposomes were ingested by worms through their labelling to uranin fluorescence dye. Through total phenolic compounds quantification, we estimated an entrapment efficacy of PPE into liposomes of 87.7%. The high levels of phenolic compounds present in PPE, as previously described by our group, indicate that these antioxidants may interfere in worms lipid metabolism, which may occur through many and intricated mechanisms. Although the use of conventional liposomes for human consumption may not be pragmatic, its application for oral delivery of a hydrophilic substance in C. elegans was absolutely critical for our experimental design and has proven to be efficient.

中文翻译：

---

含有紫色皮坦加（Eugenia uniflora）乙醇提取物的脂质体对秀丽隐杆线虫的降脂潜力

摘要 从紫色皮坦加果实 (Eugenia uniflora – PPE) 中提取的乙醇提取物先前已被描述为具有减少体外脂质积累的潜力。在这项研究中，我们旨在使用秀丽隐杆线虫作为动物模型在体内研究这种潜力。考虑到提取物的低 pH 值、其亲水特性、其被培养蠕虫的培养基吸收以及蠕虫固体培养基中长期暴露的需要，我们已将 PPE 装入脂质体并研究其口服给药的潜力。在蠕虫线虫生长培养基上暴露于装载 PPE 的脂质体 48 小时后，我们没有观察到该制剂的任何毒性作用。在高胆固醇饮食下，会增加蠕虫的总脂质和甘油三酯水平，含有 PPE 的脂质体能够显着减弱这些变化，当用游离 PPE 处理蠕虫时无法观察到这些变化。此外，我们可以证明脂质体被蠕虫通过标记为 uranin 荧光染料而摄入。通过总酚类化合物的量化，我们估计 PPE 进入脂质体的效率为 87.7%。正如我们小组先前所描述的，PPE 中存在高水平的酚类化合物表明这些抗氧化剂可能会干扰蠕虫脂质代谢，这可能通过许多复杂的机制发生。尽管使用常规脂质体供人类食用可能不切实际，但其在秀丽隐杆线虫中口服输送亲水性物质的应用对于我们的实验设计绝对至关重要，并且已被证明是有效的。