物理化学学报 >> 2022, Vol. 38 >> Issue (12): 2205053.doi: 10.3866/PKU.WHXB202205053

所属专题: 纪念傅鹰先生诞辰120周年

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香茅油纳米乳剂的构建、表征、抗菌性能和细胞毒性

陈志洋, 唐雅婷, 吕泽, 孟霄汉, 梁前伟, 冯建国()   

  • 收稿日期:2022-05-27 录用日期:2022-06-21 发布日期:2022-06-27
  • 通讯作者: 冯建国 E-mail:jgfeng@yzu.edu.cn
  • 基金资助:
    江苏省研究生实践创新计划项目(SJCX21_1613)

Citronella Oil Nanoemulsion: Formulation, Characterization, Antibacterial Activity, and Cytotoxicity

Zhiyang Chen, Yating Tang, Ze Lü, Xiaohan Meng, Qianwei Liang, Jianguo Feng()   

  • Received:2022-05-27 Accepted:2022-06-21 Published:2022-06-27
  • Contact: Jianguo Feng E-mail:jgfeng@yzu.edu.cn
  • About author:Jianguo Feng, Email: jgfeng@yzu.edu.cn
  • Supported by:
    the Postgraduate Research & Practice Innovation Program of Jiangsu Province(SJCX21_1613)

摘要:

化学合成杀菌剂的大量、不合理使用对人类健康造成危害的同时也会导致严重的环境污染。因此,迫切需要寻找低毒、高效、无残留的天然杀菌剂。植物精油因其优良的杀菌活性、良好的生物相容性和丰富的来源,已成为农业病害防控领域的研究热点。香茅油是一种具有趋避、杀虫和抗菌活性的天然植物精油,主要包括香茅醛、香叶醇和香茅醇。目前,关于香茅油的研究主要集中于卫生害虫的驱避和防治,而用于农业致病菌防治的相关报道相对较少。在实际应用中,香茅油的疏水性和挥发性导致其生物利用度低,不能充分发挥生物活性。因此,构建一种改善香茅油疏水性、降低挥发性的递送系统十分必要。纳米乳剂因具有液滴细微均匀、物理稳定性好、渗透能力强以及生物利用度高等优点,已成为疏水农药的重要递送系统。本研究通过观察样品的外观和微观结构,并且测量样品液滴大小,考察了乳化剂种类(亲水亲油平衡值,HLB)、用量和乳化时间对纳米乳剂形成及稳定的影响,在此基础上筛选了香茅油纳米乳剂的优化配方。同时本研究还调查了香茅油纳米乳剂的生物活性和生物安全性。结果表明,以蓖麻油聚氧乙烯醚EL-40 (HLB = 13.5)为乳化剂的纳米乳剂性能最佳,且乳化剂用量从3%增加到7% (w,质量分数)时,纳米乳剂稳定性提高。此外,高速剪切3 min获得的纳米乳剂稳定性最高。基于此,确定了香茅油纳米乳剂的优化配方为:5% (w)香茅油,6% (w)乳化剂(EL-40),89% (w)去离子水,高速剪切3 min。香茅油纳米乳剂对菠萝泛菌(Pantoea ananatis)具有良好的抑制作用,抑制中浓度(EC50)为74.85 mg·L−1。纳米乳剂(低于100 mg·L−1)处理人体正常肝细胞(L02) 24 h后,细胞存活率仍高于83%,凋亡率仅为6.93%,表明香茅油纳米乳剂具有较低的细胞毒性。本研究有助于设计和构建稳定、高效、安全的农业纳米乳剂,同时为植物精油作为农业杀菌剂提供了切实可行的解决方案。

关键词: 香茅油, 纳米乳剂, 稳定性, 杀菌剂, 细胞毒性, 环境友好

Abstract:

The excessive and unreasonable use of synthetic bactericides in the agricultural field has caused many serious problems, including toxic effects on human health and environmental pollution. Therefore, searching for low toxicity, highly efficient, and no-residue natural bactericides is urgently needed. Plant essential oil has become an emerging and hot topic in the agricultural field because of its excellent bactericidal activity, good biocompatibility, and abundant sources. Citronella oil is a natural plant essential oil with insect repellent, insecticidal, and antibacterial activities, which mainly includes citronellal, geraniol, and citronellol. At present, the major of research on citronella oil focuses on the repellency and control of sanitary pests, but there are relatively few reports on the control of agricultural pathogenic bacteria. In addition, the hydrophobicity and volatility of citronella oil lead to its low bioavailability and hinder its full biological activity. Therefore, constructing a delivery system for improving the hydrophobicity and reducing the volatility of citronella oil is urgently needed. Nanoemulsions have the advantages of fine and uniform droplets, better physical stability, efficient permeation ability, and enhanced bioavailability. Therefore, nanoemulsions are important drug delivery systems for hydrophobic pesticides. In this study, the influences of emulsifier type (hydrophilic-lipophilic balance (HLB)), dosage, and emulsifying time on the formation and stability of citronella oil nanoemulsions were investigated by observing the appearances and microstructures of samples and measuring droplet size, thereby the optimized formula of the citronella oil nanoemulsions was determined. Furthermore, the bioactivity and biosafety of citronella oil nanoemulsions were also investigated. The results showed that nanoemulsions using castor oil polyoxyethylene ethers EL-40 (hydrophilic-lipophilic balance = 13.5) as an emulsifier had the best performance, and the stability of nanoemulsions improved as the emulsifier dosage increased from 3% to 7% (w, mass fraction). In addition, the nanoemulsion prepared through high speed shearing for 3 min was the most stable. The optimal formula for citronella oil nanoemulsions was determined to contain 5% (w) citronella oil, 6% (w) emulsifier (EL-40), and 89% (w) deionized water, upon high speed shearing for 3 min. Then, the inhibitory effect of citronella oil nanoemulsions against the growth of Pantoea ananatis was studied. The concentration for 50% of maximal effect (EC50) of citronella oil nanoemulsions against Pantoea ananatis was 74.85 mg·L−1. The cell viability of L02 cells treated with the citronella oil nanoemulsions (below 100 mg·L−1) was above 83% after 24 h, and the apoptosis rate was 6.93%, indicating that the citronella oil nanoemulsions had low cytotoxicity. This research facilitated the design and fabrication of stable, efficient, and safe agricultural nanoemulsions, and it provides a practical solution for using plant essential oils as agricultural bactericides.

Key words: Citronella oil, Nanoemulsion, Stability, Bactericide, Cytotoxicity, Environment-friendliness

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