The CK signal is recognised by histidine kinases that are found in the membrane of the cell and conveyed by a two-component system (TCS) that is unique to plants and is found only in higher eukaryotes. Numerous plant-interacting microorganisms, including pathogenic and non-pathogenic bacteria, fungi, nematodes, and animal pathogens such as Mycobacterium tuberculosis, have been demonstrated to produce CK.
However, despite the promising future of CKs in applied research, the presence of CKs, the signalling circuitry that they activate, and the biological activities that they perform in mammalian cells are still poorly understood. Kinetin was employed in our work as a synthetic CK, but it was also found in the endosperm liquid of fresh young coconut fruits, in plant cell extracts, in human urine, and in a variety of other biological extracts in addition to our study. Plant tissue culture systems have made considerable use of kinetin as a growth promoter, but the potential consequences of kinetin on human health are still being investigated. Several researches found that kinetin has a positive effect on human illnesses or diseases.
Examples include the prevention of age-related changes in human skin, presumably through the protection of skin cells’ DNA from damage as well as the reduction of water loss in skin, as well as kinetin’s therapeutic potential in the treatment of the human splicing disease familial dysautonomia, which is a genetic disorder affecting the nervous system. Also noted is that kinetin has an effect on oxidative stress parameters in human fibroblasts in vitro, which is consistent with previous findings. Despite the numerous fragmented reports on the application of CKs, the physiological effects of CKs on mammalian cells have not been thoroughly investigated. It is possible to examine the protective effects of kinetin in mammalian cells in a dose-dependent manner, with greater concentrations of kinetin having toxic and DNA-damaging effects while lower concentrations of kinetin have protective benefits.
Oxidative stress
It is a condition in which there is an imbalance between the generation of oxidants and the antioxidant defence capacity of a cell. Several human disorders, such as atherosclerosis, cancer, neurological diseases, and the ageing process, as well as different pathogenic processes, have been associated with it. A cell’s DNA can be attacked by reactive oxygen species (ROS), which can cause oxidative DNA damage, which may eventually result in mutation.
Aside from that, reactive oxygen species (ROS) have an effect on protein and lipid molecules in the cell, impairing their function and leading to the generation of hazardous lipid peroxidation products.
Cells have been protected against ROS by antioxidants, and natural antioxidants have been explored for their potential application as preventative and therapeutic agents in medicine.
The intrinsic features of kinetin, as well as the diverse protective effects of kinetin, were investigated in mammalian cells such as HL60 cells, HaCaT human keratinocyte cells, NRK rat epithelial kidney cells, and human peripheral lymphocytes.
Also investigated was kinetin’s intrinsic antioxidant activity in a cell-free system using the FRAP assay and in cells using dihydroethidium (DHE) staining, as well as its potential to act as an antioxidant against NQO, which is a mediator of oxidative stress in the presence of kinetin.
NRK, an epithelial rat kidney cell line, was obtained from the American Type Culture Collection (ECACC, Salisbury, UK) and cultured at 37°C with 5 percent (v/v) CO2 in DMEM high glucose (4.5 g/l) with 10.0 percent (v/v) FCS, 1.0 percent (v/v) L-glutamine, 1.0 % (w/v) non-essential amino acids, and 1.0 percent They were subjected to subculture twice a week.
Isolation of lymphocytes
The isolation of lymphocytes was accomplished by layering 7 mL of blood from healthy human volunteers over Histopaque-1077 in a one-to-one ratio. Using a centrifuge at 400 g for 30 minutes at room temperature, we were able to separate the layers from which mononuclear cells were recovered from the plasma/Histopaque junction. It was necessary to wash them twice with lymphocyte media (250 x g; 1300 rpm; room temperature for 10 min each time), and then resuspended in 3 ml of lymphocyte medium after that. The comet experiment was carried out after lymphocytes had been treated for 24 hours with 100 nM kinetin and for 30 minutes with 0.6 mM NQO.
Conclusion
Kinetin’s potential to cause DNA damage by itself was also investigated using the comet test, which was then followed by an evaluation of its antigenotoxic action against oxidative stress, which is known to cause DNA damage in the first place. In future investigations, we will investigate the possibility that CKs binding proteins found in mammalian sera could serve as essential cellular targets for CK-mediated protection against oxidative stress. Following the thorough examination of the complicated kinetin effects, a solid foundation for further research in human cells has been laid.