Anticancer, antioxidant, and antibacterial effects of nanoemulsion of Origanum majorana essential oil.

Background and Objectives: This study aimed to develop a natural nanoemulsion with antibacterial and anticancer properties. Materials and Methods: The chemical composition of the Origanum majorana essential oil was investigated using GC-MS analysis. Besides, the successful loading of the essential oil in the nanoemulsion was confirmed using ATR-FTIR analysis. Moreover, nanoemulsion's anticancer, antioxidant, and antibacterial activities were investigated. Results: Terpinen-4-o1 (46.90%) was identified as the major compound in the essential oil. The nanoemulsion with a 149 ± 5 nm droplet size and zeta potential of -11 ± 1 mV was prepared. The cytotoxic effect of the nanoemulsion against A-375 human melanoma cells (IC50 = 139 µg/mL) showed significantly more potency than A-549 human lung cancer cells (IC50 = 318 µg/mL). Interestingly, growth of Staphylococcus aureus (Gram-positive) and E. coli (Gram-negative) bacteria after treatment with 4800 µg/mL of nanoemulsion were obtained at 12 ± 2 and 6 ± 1%, respectively. However, the IC50 value of nanoemulsion against E. coli (580 µg/mL) was not significantly different (P > 0.05) from S. aureus (611 µg/mL). Conclusion: A straightforward preparation method, high stability, and multi-biological effects are the main advantages of the prepared nanoemulsion. Therefore it could be considered for further investigation in vivo studies or complementary medicine.

Finding and engineering the newly found bacterial superoxide dismutase enzyme to increase its thermostability and decrease the immunogenicity: a computational and experimental research.

Superoxide dismutase (SOD) is one of the most important antioxidant enzymes that can reduce oxidative stress in the cell environment. Nowadays, bacterial sources of enzyme are commercially applicable in the cosmetics and pharmaceutical industries, but the allergenic effect of proteins from non-human sources has been mentioned as disadvantage of these kinds of enzymes. In this study, to find the suitable bacterial SOD candidate for decreasing immunogenicity, the sequences of five thermophilic bacteria were selected as reference species. Then, linear and conformational B-cell epitopes of the SOD were analyzed by different servers. The stability and immunogenicity of mutant positions were also evaluated. The mutant gene was inserted into the pET-23a expression vector and transformed into E. Coli BL21 (DE3) for expression of the recombinant enzyme. Afterward, the expression of the mutant enzyme was evaluated by SDS-PAGE analysis and the recombinant enzyme activity was assessed. Anoxybacillus gonensis was selected as a reasonable SOD source according to BLAST search, physicochemical properties analysis, and prediction of allergenic features. Regarding our results, five residues including E84, E142, K144, G147, and M148 were predicted as candidates for mutagenesis. Finally, the K144A was chosen as the final modification due to the increase in the stability of the enzyme and decreased immunogenicity of the enzyme as well. The enzyme activity was 240 U/ml at room temperature. Alternation in K144 to alanine caused increased stability of the enzyme. In silico studies confirmed non-antigenic protein after mutation.

A Nanoliposomal Gel Containing Cinnamomum zeylanicum Essential Oil with Effective Repellent against the Main Malaria Vector Anopheles stephensi.

Malaria is the most important vector-borne disease; however, mosquito repellents are still a practical approach for controlling malaria, especially in endemic regions. Due to the side effects of synthetic repellents such as N, N-diethyl-meta-toluamide (DEET), the development of natural repellents has received much attention. In this study, nanoliposomes containing 0.5 and 2.5% w/v Cinnamomum zeylanicum essential oil were firstly prepared with particle sizes of 119 ± 6 and 195 ± 9 nm. Their morphologies and loading of the essential oil in the particles were then investigated using transmission electron microscopy (TEM) and attenuated total reflection-Fourier transform infrared (ATR-FTIR) analyses. The nanoliposomes were finally jellified to increase their viscosity and facilitate topical usage. The complete protection time of the nanoliposomal gel containing 2.5% C. zeylanicum essential oil was significantly longer than that of 2.5% DEET against Anopheles stephensi: 303 ± 10 > 242 ± 12 min, p < 0.001. Moreover, the prepared nanoformulation was stable for at least six months at 4 and 26°C. Therefore, the prepared prototype could be considered a natural repellent against the main malaria mosquito vector in field conditions. In addition, it is suggested to be investigated against other important factors mosquitoes.