Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Debrecen, Debrecen, 4032, Hungary.
Department of Medical Microbiology, Faculty of Medicine, University of Debrecen, Debrecen, 4032, Hungary.
Eur J Pharm Sci. 2020 Feb 15;143:105162. doi: 10.1016/j.ejps.2019.105162. Epub 2019 Nov 20.
Nowadays, the sorbates are the third largest group of antimicrobial preservatives in food and pharmaceutical industries, following the parabens and benzoates whose safety is questioned by recent publications. A disadvantage of sorbates is their pH dependence, as their antimicrobial effect is greatly reduced in alkaline environment. The main, widely used sorbate derivatives are sorbic acid and potassium sorbate, no sorbic acid esters are involved in current industrial application. We aimed to test whether the esters of sorbic acid are capable to extend the antimicrobial spectrum of the original molecule while maintaining its advantageous biocompatibility profile. A comparative biocompatibility study of different derivatives (sorbic acid, potassium sorbate, isopropyl sorbate and ethyl sorbate) was carried out. In vitro cell viability assays of MTT (2-(4,5-dimethyl-2-thiazolyl)-3,5-diphenyl-2H-tetrazolium bromide), Neutral Red (3-amino-7-dimethylamino-2-methylphenazine hydrochloride) and flow cytometry with propidium iodide and annexin were performed on Caco-2 cells. In case of in vivo toxicity study, G. mellonella larvae were injected with different concentrations of the test compounds. Time-kill tests were executed on reference strains of C. albicans, E. coli, and S. aureus. According to the MTT-assay, the IC values were the following: ethyl sorbate, sorbic acid <0.045% /, isopropyl sorbate 0.32% /, potassium sorbate >0.75% /, while Neutral Red values were >0.75% / for the esters and potassium sorbate and 0.66% / for sorbic acid. Flow cytometry results indicated the higher cell damage in case of isopropyl sorbate. However, the cytotoxic results of isopropyl sorbate, in vivo toxicity study on G. mellonella larvae did not show significant mortality. It was found, that the antimicrobial properties of isopropyl sorbate were outstanding compared to sorbic acid and potassium sorbate. These results indicate, that the use of sorbate esters can be advantageous, hence, further toxicity studies are needed to prove their safety.
现如今，山梨酸盐是继对羟基苯甲酸酯和苯甲酸酯之后，在食品和制药行业中使用的第三大类抗菌防腐剂。由于其抗菌效果在碱性环境中大大降低，山梨酸盐的一个缺点是其 pH 值依赖性。山梨酸盐的主要衍生物是山梨酸和山梨酸钾，目前工业应用中不涉及山梨酸酯。我们旨在测试山梨酸酯是否能够在保持其有利的生物相容性的同时，扩大原始分子的抗菌谱。对不同衍生物（山梨酸、山梨酸钾、异山梨酸钾和乙基山梨酸酯）进行了比较生物相容性研究。通过 MTT（2-(4,5-二甲基-2-噻唑基)-3,5-二苯基-2H-四唑溴盐）、中性红（3-氨基-7-二甲基氨基-2-甲基吩嗪盐酸盐）和碘化丙啶和 Annexin 的流式细胞术，对 Caco-2 细胞进行了体外细胞活力测定。在体内毒性研究中，用不同浓度的测试化合物注射 G. mellonella 幼虫。对参考菌株白色念珠菌、大肠杆菌和金黄色葡萄球菌进行了时间杀伤试验。根据 MTT 测定，IC 值如下：乙基山梨酸酯、山梨酸 <0.045%/，异山梨酸钾 0.32%/，山梨酸钾 >0.75%/，而中性红值 >0.75%/的酯和山梨酸钾和 0.66%/的山梨酸。流式细胞术结果表明，异山梨酸钾的细胞损伤更高。然而，异山梨酸钾的细胞毒性结果、G. mellonella 幼虫的体内毒性研究并未显示出显著的死亡率。研究发现，与山梨酸和山梨酸钾相比，异山梨酸钾具有出色的抗菌性能。这些结果表明，使用山梨酸酯可以带来优势，因此需要进一步的毒性研究来证明其安全性。
