Abstract：
Although rare, amoebic keratitis (AK) is a disease caused by Acanthamoeba spp. that can lead to blindness. The drugs currently available for its treatment are very toxic, which has motivated the investigation for more effective and safe therapeutic options. In this study, the in vitro activity of ß-caryophyllene (BCP) was exploited taking into account its action against other protozoans as well as its well-known healing and anti-inflammatory properties (aspects relevant for the AK pathogenesis). On the other hand, high volatilization and oxidation phenomena are found for this compound, which led to its incorporation into nanoemulsions (NEs). Two emulsifying agents were tested, resulting in monodisperse systems with reduced droplet size (<265 nm) and high surface charge (positive and negative for NEs prepared with cetrimonium bromide -CTAB and Phosal® 50+, respectively). NEs prepared with CTAB were shown to be more stable after long-term storage at 4 and 25 °C than those prepared with Phosal®. Pure BCP, at the highest concentration (500 µM), resulted in a level of inhibition of Acanthamoeba trophozoites equivalent to that of reference drug (chlorhexidine). This activity was even greater after oil nanoencapsulation. The reduced droplet size could improve the interaction of the oil with the microorganism, justifying this finding. Changes in surface charge did not impact the activity. Positively charged NEs improved the interaction and retention of BCP in the cornea and thus should be prioritized for further studies.
摘要：
虽然罕见，阿米巴角膜炎（AK）是一种由棘阿米巴引起的疾病。会导致失明.目前可用于治疗的药物毒性很大，这促使研究更有效和安全的治疗方案。在这项研究中,β-石竹烯(BCP)的体外活性被考虑到其对其他原生动物的作用以及其众所周知的愈合和抗炎特性(与AK发病机制相关的方面).另一方面,该化合物存在高度挥发和氧化现象，这导致其掺入纳米乳液（NEs）。测试了两种乳化剂，产生具有减小的液滴尺寸(<265nm)和高表面电荷的单分散系统(对于用西曲溴铵-CTAB和Posal®50+制备的NEs为正和负,分别)。与用Posal®制备的那些相比,用CTAB制备的NE在4和25°C下对长期储存更稳定。纯BCP,在最高浓度(500µM)下，导致对棘阿米巴滋养体的抑制水平与参考药物（氯己定）相同。这种活性在油纳米封装后甚至更大。减小的液滴尺寸可以改善油与微生物的相互作用，为这一发现辩护。表面电荷的变化不影响活性。带正电荷的NE改善了BCP在角膜中的相互作用和保留，因此应优先进行进一步研究。
