Conflict of interest

The authors declare that there is no conflict of interest.

Flavonoids and Phenolic Acids as Potential Natural Antioxidants DOI: http://dx.doi.org/10.5772/intechopen.83731

some flavonoids is based on their ability to chelate transition metal ions, thereby preventing the formation of radicals (initiators of LP), catching radical initiators of LP (ROS), scavenging lipid alkoxyl and lipid peroxyl radicals, and regenerating α-tocopherol by reduction of α-tocopherol radicals. Different metals have different binding affinities of the flavonoids. Thus, for example, iron has the highest binding affinity for 3-OH group of ring C, then catechol group ring B, and at the end of 5-OH group of ring A, while the copper ions bind to the first ring catechol group B [70]. Also, in the previous investigation, on L. nobilis, different groups of chemicals

were isolated (luteolin, apigenin, alkaloids, monoterpene, and germacrane

One of the paradoxes of life on Earth is that, on the one hand, oxygen is necessary for the life of aerobic organisms. On the other hand, increased concentrations of oxygen and especially its reactive metabolites (reactive oxygen species) may lead to the development of numerous diseases. A major source of free radicals in biological systems is molecular oxygen (O2). The results of our in vitro assays of examined five different extracts of Laurus nobilis leaves expressed significant

be correlated to different compounds. HPLC-DAD analysis indicates a significant presence of flavonoids and phenolic in the EtOAc and n-BuOH extracts. Quercetin glycosides and flavonoids (e.g., kaempferol-3-O-Glc) were detected in EtOAc extract. In addition, the presence of phenolic acids (such as caffeic acid) and flavonoids (rutin and kaempferol) was proven in the H2O extract. The amount of flavonoids in extracts plays a significant role in their antioxidant capacity, and it can be concluded that ethyl acetate proved to be the best solvent for extraction of plant material. Furthermore, it can be concluded that these extracts can be used in the

This work was supported by the Ministry of Science and Environmental Protec-

•, NO, and OH radicals), which was found to

alcohols) [71].

Antioxidants

5. Conclusions

protective effects on ROS (DPPH, O2

preparation of various herbal medicines.

tion of the Republic of Serbia (Project No. 172058).

The authors declare that there is no conflict of interest.

Acknowledgements

Conflict of interest

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