Antibacterial, Antifungal, and Anticancer Effects of Camel Milk Exosomes: An In Vitro Study

Simple Summary Camel milk (CM) and its exosomes (CM-EXO) have many health-promoting effects due to their antibacterial, antifungal, and anticancer effects. Herein, we investigated the CM-EXO antimicrobial effect on Gram-positive bacteria (Staphylococcus aureus, Micrococcus luteus, and Enterococcus feacalis), Gram-negative strains (Escherichia coli, Pseudomonas aeruginosa, and Proteus mirabilis), and Candida albicans and found only bacteriostatic effects against Gram-negative strains, and fungistatic effect. To the best of our knowledge, this is the first study to report a selective apoptotic effect of CM-EXOs on HepG2 and CaCo2 cells, but not on normal Vero cells. CM-EXOs also induced the elevation of intracellular reactive oxygen species and reduced antioxidant status in cancer cells but not in normal cells. Camel milk (CM) has potent antibacterial and antifungal effects and camel milk exosomes (CM-EXO) have been shown to inhibit the proliferation of a large variety of cancer cells including HepaRG, MCF7, Hl60, and PANC1. However, little is known regarding the effects of CM-EXO on bacteria, fungi, HepG2, CaCo2, and Vero cells. Therefore, this study aimed to evaluate the antibacterial, antifungal, and anticancer effects of CM-EXO. EXOs were isolated from CM by ultracentrifugation and characterized by transmission electron microscope and flow cytometry. Unlike CM, CM-EXO (6 mg/mL) had no bactericidal effects on Gram-positive bacteria (Staphylococcus aureus, Micrococcus luteus, and Enterococcus feacalis) but they had bacteriostatic effects, especially against Gram-negative strains (Escherichia coli, Pseudomonas aeruginosa, and Proteus mirabilis), and fungistatic effects on Candida albicans. HepG2, CaCo2, and Vero cells were respectively treated with CM-EXOs at low (6.17, 3.60, 75.35 mu g/mL), moderate (12.34, 7.20, 150.70 mu g/mL), and high (24.68, 14.40, 301.40 mu g/mL) doses and the results revealed that CM-EXOs triggered apoptosis in HepG2 and CaCo2 cells, but not in normal Vero cells, as revealed by high Bax expression and caspase 3 activities and lower expression of Bcl2. Interestingly, CM-EXOs also induced the elevation of intracellular reactive oxygen species and downregulated the expression of antioxidant-related genes (NrF2 and HO-1) in cancer cells but not in normal cells. CM-EXOs have antibacterial and antifungal effects as well as a selective anticancer effect against HepG2 and CaCo2 cells with a higher safety margin on normal cells.

Automated summary

Camel milk exosomes (CM-EXOs) from camel milk have antimicrobial and anticancer effects, exhibiting bacteriostatic and fungistatic effects on certain bacteria and fungi, while selectively inducing apoptosis in cancer cells but not normal cells. CM-EXOs also promote the production of reactive oxygen species and reduce antioxidant status in cancer cells. Overall, CM-EXOs have significant health-promoting effects.