Investigation of the Functional Groups of Bioactive Compounds, Radical Scavenging Potential, Antimicrobial Activity and Cytotoxic Effect of Callistemon Citrinus Aqueous Extract on Cell Line HT29: A Laboratory Study

Background and Objectives: The extensive use of chemical drugs for the treatment and control of chronic and infectious diseases as well as colorectal cancer, has led to an increased demand for natural and safe drugs and preservatives. Therefore, this study aimed to evaluate the presence of functional groups of constituents, total phenol and flavonoids content, radical scavenging potential, and antimicrobial activity of Callistemon citrinus aqueous extract (CCE). Its interaction with common therapeutic antibiotics and cytotoxic effect on cell line HT29 was also evaluated. Materials and Methods: In this laboratory study, the presence of functional groups of chemical constituents of C. citrinus aqueous extract was evaluated by Fourier transform infrared (FTIR) spectroscopy. Free radical scavenging activity, total phenol and flavonoids content, antimicrobial activity of C. citrinus aqueous extract and its interaction with chloramphenicol and gentamicin antibiotics, and the viability of cell line HT29 (through MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] test) under different concentrations of C. citrinus aqueous extract were investigated. Data were analyzed using one-way ANOVA followed by Duncan’s test. Results: The C. citrinus aqueous extract had a considerable antimicrobial effect on Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus, and Listeria innocua. The free radicals scavenging effect of C. citrinus aqueous extract was in the range of 51.33-71.68%. The presence of C-C and OH groups of phenolic compounds of C. citrinus aqueous extract was confirmed by FTIR. After 24 hours, the different concentrations of C. citrinus aqueous extract reduced the growth of cell line HT29 compared to the control group (p<0.05). Conclusion: The C. citrinus aqueous extract had antimicrobial activity, antioxidant potential and inhibitory effect on cell line HT29. Therefore, the use of C. citrinus aqueous extract could be suggested in pharmaceutical and food industries. Key words: Cytotoxic effect, Minimum inhibitory concentration, In vitro, Callistemon citrinus aqueous extract   Funding: This study was funded by Agricultural Sciences and Natural Resources University of Khuzestan. Conflict of interest: None declared. Ethical approval: This study has been approved by the Research Deputy of Agricultural Science and Natural Resources of University of Khuzestan and Iranian Research Institute for Information Science and Technology (IR.AC.IRANDOC. SABT.1520449). How to cite this article: Sosani Gharibvand  Z, Alizadeh Behbahani B, Noshad  M, Jooyandeh H. Investigation of the Functional Groups of Bioactive Compounds, Radical Scavenging Potential, Antimicrobial Activity and Cytotoxic Effect of Callistemon Citrinus Aqueous Extract on Cell Line HT29: A Laboratory Study. J Rafsanjan Univ Med Sci 2020; 19 (5): 463-84. [Farsi]