# Effects of Epigallocatechin-3-O-Gallate on Bone Health
## 1 Introduction
Clinical studies indicate that EGCG consumption reduces tumour incidence and multiplicity in the liver, stomach, skin, lung, mammary gland, and colon [2; 3]. EGCG is also considered a potential therapeutic agent able to prevent the carcinogenesis of oral potentially malignant disorders (OPMDs) that most often precede the diagnosis of oral squamous cell carcinoma. EGCG may block the progression of cancer by disrupting the cell cycle and precancerous lesions of the oral cavity [13]. EGCG also exhibits neuroprotective abilities, as it is assumed to diffuse and localise in the brain. Additionally, EGCG shows potential for the prevention of [PERSON]'s disease to reduce the amino acid form of \(\beta\)-amyloid A\(\beta\) and T (tau) protein toxicity and inhibit apoptosis. Moreover, ECGG may be a promising natural neuroprotective agent for the treatment of [PERSON]'s disease by reducing and preventing dopamine loss as well as inhibiting oxidative stress [15]. In addition, EGCG seems to be a promising therapeutic for reducing neuroinflammation and preventing nerve damage after intracerebral haemorrhage (ICH). [PERSON] et al. 2023 [16] investigated the effects of EGCG pretreatment on neuroinflammation-mediated neuronal pyproptosis in experimental ICH in mice. They observed the alleviation of microglial pyproptosis and neuroinflammation and an improvement in neurological function [16]. EGCG has also been reported to inhibit high glucose-induced senescence in H9C2 cardiomyocytes, as well as inflammation, and oxidative stress response and to trigger peroxisome proliferatorator-activated receptor gamma-dependent signalling pathways, thereby preventing diabetic cardiomyopathy [17]. The advantageous effects of EGCG on bone condition have been widely researched [1,11]. Based on the results of many studies, EGCG has been shown to play a significant regulatory role in the immune response in osteoporosis, fracture healing, and periodontitis [18, 19, 20]. Moreover, green tea phytochemicals were found to improve various bone loss models associated with ageing, estrogen deficiency, and chronic inflammation [21, 22]. The regular consumption of green tea is associated with improved bone health. Although a higher bone mineral density (BMD) and a lower hip fracture rate are associated with a higher consumption of green tea, the relationship remains unclear [18,23]. EGCG can suppress receptors for advanced glycation end product (RAGE) expression by epigenetic regulation, which leads to chondrocyte protection against osteoarthritis [24]. Interestingly, EGCG, as a substance capable of regulating bone metabolism, also affects periodontal remodelling during orthodontics, which was studied by [PERSON] et al. [25]. In a study on rats, it reduced orthodontic tooth movement and orthodontic-induced root resorption. Furthermore, EGCG impaired osteoclastsgenesis on the pressure side and promoted osteogenesis on the tension side. Summarising, EGCG is a non-toxic, naturally occurring compound with diverse and promising biological properties and a diversity of beneficial health effects, which is worth discussing in more detail. Considering the aforementioned properties of EGCG, this review explores the current state of research, emphasising its effects on bone density, mineralisation, and the regulation of bone metabolism, from two perspectives: functional and biochemical effects. It aims to clarify the connection between EGCG and bone health, while highlighting key areas for future research and potential clinical applications. The literature search was performed using the following databases: PubMed and Google Scholar. Searches were carried out using combinations of the following keywords: \"epigallocatechin-3-gallate\", \"EGCG\", \"green tea polyphenols\", \"bone health\", \"bone metabolism\", \"osteoblast\", \"osteoclast\", \"osteoporosis\", \"bone regeneration\", and \"bone density\". The authors have included scientific publications from 1 January 1985 to 30 March 2025. In the first stage of the review, the titles of the articles were carefully checked.