Comparative Evaluation of Oxidatively Modified Proteins in the Equine Plasma after Treatment with Extracts Derived from Leaves of Various Camellia japonica L. Cultivars

Abstract

The main goal of the current study was to determine the antioxidant activity of leaf extracts of six Camellia japonica L. cultivars, using the biomarkers of protein oxidation [aldehydic and ketonic derivatives content] in the in vitro equine erythrocyte model. The leaves of Camellia japonica cultivars Kramer’s Supreme, C.M. Wilson, La Pace, Mrs. Lyman Clarke, Benikarako, Fanny Bolis plants cultivated under glasshouse conditions, were sampled at M.M. Gryshko National Botanic Garden (Kyiv, Ukraine). Freshly collected leaves were washed, weighed, crushed, and homogenized in 0.1 M phosphate buffer (pH 7.4) (in proportion 1 : 19, w/w) for 2 min at room temperature. The extracts were then filtered and used for analysis after two weeks. A volume of 0.1 ml of the plant extracts was added to 1.9 ml of equine plasma. Phosphate buffer was used for positive control. After incubation of the mixture at 37 °C for 60 min with continuous stirring, it was centrifuged and plasma aliquots were used in the study. The aldehydic and ketonic derivatives content as a biomarker of protein oxidation was non-significantly altered after in vitro incubation with extracts obtained from the selected Camellia japonica cultivars. The percent of the increase had oscillated from 0.2 % (cv. Benikarako) to 2.4 % (cv. C.M. Wilson). Of the six plant extracts screened, C. japonica cv. La Pace exhibited the highest increase of the level of ketonic derivatives of oxidatively modified proteins (OMP) (by 15.3 %, p >0.05). Cultivars C.M. Wilson, Kramer’s Supreme, Benikarako, Mrs. Lyman Clarke, and Fanny Bolis exhibited a non-significant increase of ketonic derivatives’ level by 10.8 %, 10.8 %, 7.6 %, 6.6 %, and 6.3 %, respectively. Some fluctuations in the protein oxidation profile in the plasma across different cultivars were found. Such differences could be related to the plant‘s metabolic state. Screening of Camellia species and their cultivars for other biological activities including antioxidant and anti-inflammatory activities is essential and may be effective for searching the preventive agents in the pathogenesis of some metabolic diseases.