Oxyphytosterol Generated by Ozone

1Igor R. Martins, 2Sayuri Miyamoto, 3Janice Onuki, 1*Miriam Uemi

1Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Departamento de Química, Universidade Federal de São Paulo, campus Diadema, Diadema, SP, Brasil.
2Instituto de Química, Departamento Bioquímica, Universidade de São Paulo, Campus São Paulo, São Paulo, SP, Brasil
3Laboratório de Biologia Molecular, Instituto Butantan, São Paulo, SP, Brasil
Rua São Niclolau, 210, CEP 09913-030 Centro, Diadema, São Paulo
*e-mail: [email protected]

Ozone is one of the most reactive oxygen species, generated in the troposphere by photochemical reactions between Volatile Organic Compounds (VOCs) and Nitrogen Oxides (NOx) in the presence of solar radiation1. Damage caused by ozone can affect human and agricultural crops, leading to development of diseases or economic losses 2.
Phytosterols are sterols found in plants, which play an important role as regulators of the fluidity and stability of cell membrane and as plant hormone precursors3. Studies showed that phytosterols ingestion decreases the concentration of low-density lipoprotein (LDL) in blood, reducing the risk of cardiovascular diseases. Besides, phytosterols seems to have a relationship with the inhibition of carcinogenic process and induction of apoptosis4.
β-sitosterol is the most abundant phytosterol present in vegetable oils, nuts, seeds, cereals and fruits. Due to its benefits, it is a common food additive, as in margarine. β-sitosterol has one insaturation, becoming susceptible to oxidation by ozone, generating compounds (oxyphytosterols) that can be harmful to biological system.
In this context, β-sitosterol was exposed to ozone atmosphere and three novel oxyphytosterols were synthesized and characterized. The cytotoxicity was evaluated by MTT assay in hepatocarcinoma HepG2 cell lines and the results demonstrated an inhibition of cell viability.

References

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