*Considering the Antioxidant Properties of Tea to Improve Human Health DOI: http://dx.doi.org/10.5772/intechopen.107148*

the hydrogen-oxygen bond in the phenolic hydroxyl group. The hydrogen in phenolic hydroxyl groups participates in the increase and scavenging of free radicals that compete for active oxygen and also terminate the auto-oxidation reaction of the free radicals [10, 38]. Second, phenols remove ROS/RNS to promote the initiation of antioxidants relevant to quenching the formation of cold product chains. Wherefore, improve and protect the antioxidant defense system, chelate available metal ions, strengthen co-oxidants, and/or regulate gene expressions [12, 39].

Yan et al. [10] in their research found that ROS could function at low levels as molecular signals to regulate cellular activities, such as adaptive cellular responses and possible cell growth. Once there is an imbalance between ROS accumulation and the antioxidant process in the body, oxidative stress and damage to cells and tissues become the result, leading to several health anomalies. Further corroborative evidence from research suggests an association between free radicals and the development of diseases, such as arterial hardening, malignancies, emphysema, and others.

Bernatoniene and Kopustinskiene [39] detail how catechins can inhibit the actions of oxidant supporting enzymes, such as NADPH, or modulate the interaction of ligands with receptors like TNF; they are also capable of repressing many pathways related to oxidative stress that is responsible for the processes of inflammation. Catechins are suspect in modulating important responses to pathogenesis-related oxidative stress by facilitating the activities of redox-sensitive transcription factors, enhancement of activated B cells, and activator proteins. The interactive ability of Catechins is possible due to penetrative ability into the membranes of lipid bilayers via adsorption or penetration, hydrogen bonding to protein proline residues, and power to bind to the enzyme ATP-binding sites. **Figure 3** partly explains the role of EGCG in the body.

#### **Figure 4.**

*Antioxidant properties of catechins as adopted from http://www.sciencedirect.com › science*

Researchers have also suggested the similar structures and conformational properties of both catechins and transcriptional factors as possible mechanisms for interactions. **Figure 4** illustrates the oxidation mechanism of catechins.

Oz et al. [1] further elucidate how an assortment of reviews has communicated the importance of tea polyphenols as formidable antioxidants in the inactivation of several signaling trails involved in inflammation; down-regulation of Cox-2 and Bcl-2 activities, up-regulation of protective and programmed apoptotic trajectories, and NF-\_B mediated pathways of IKK.
