Royal Jelly's Strong Selective Cytotoxicity Against Lung Malignant Cells and Macromolecular Alterations in Cells Observed by FTIR Spectroscopy

Abstract

Introduction/objective: Several nutraceuticals, food, and cosmetic products can be developed using royal jelly. It is known for its potential health benefits, including its ability to boost the immune system and reduce inflammation. It is rich in vitamins, minerals, and antioxidants, which can improve general health. Royal jelly (RJ) is also being studied as a potential therapeutic agent for cancer and other chronic diseases. It is effective in reducing tumor growth and stimulating immunity.

Methods: In this study, we investigated the effects of royal jelly on cancerous A549 cells and healthy MRC-5 cells at various doses ranging from 1.25 to 10 mg/mL. Royal jelly's anti-proliferative effect was evaluated by MTT and SRB assay for 48 h. The induction of necrosis and apoptosis was assessed by flow cytometry as well. The relative amounts of major molecules in Royal jelly were determined by FTIR spectroscopy to identify key functional groups and molecular structures. In addition, this technique was used for the first time to detect changes in the macromolecular composition of lung cells treated with royal jelly. Thus, it provided insights into the relative abundance of proteins, lipids, and carbohydrates, which could correlate with their bioactive properties.

Results: The antiproliferative effect of Royal jelly was found to be selective on A549 cells in a dose-dependent manner with an IC₅₀ of 9.26 mg/mL, with no cytotoxic effects on normal MRC-5 cells. Moreover, Royal jelly induced predominantly necrotic cell death in A549 cells, %39.10 at 4 mg/mL and %57.88 at 10 mg/mL concentrations. However, the necrosis rate in MRC-5 cells was quite low, at 9.16% and 20.44% at the same doses. Royal jelly showed dose-dependent selective cytotoxicity toward A549 cells, whereas it exhibited no apparent cytotoxicity in MRC-5 cells. In order to identify the biomolecular changes induced by royal jelly, we used two unsupervised chemometric pattern recognition algorithms (PCA and HCA) on the preprocessed sample FTIR spectra to determine the effects of royal jelly on cell biochemistry. According to PCA and HCA results, RJ treatments especially affected biomolecules in A549 cells. The total spectral band variances in the PCA loading spectra were calculated for understanding biomolecular alterations. These plots revealed profound changes in the lipid, protein, and nucleic acid content of RJ-applied lung cells, primarily identifying RJ and H₂O₂ treated groups for A549 cells.

Conclusion: Ultimately, the selective cytotoxicity of royal jelly toward A549 cancerous cells suggests that royal jelly may be a promising therapeutic agent for identifying innovative lung cancer treatment strategies. Additionally, understanding the molecular alterations induced by royal jelly could guide the development of novel cancer treatments that exploit its bioactive properties. This could lead to more effective and safer therapies.

Keywords: FTIR spectroscopy; MTT; Royal jelly; SRB assay; flow cytometry; lung cancer treatment..