ANTIOXIDANT ACTIVITY OF VEGETATIVE ORGANS OF DENDROBIUM PARISHII RCHB.F. IN THE MUSCLE TISSUE OF RAINBOW TROUT (ONCORHYNCHUS MYKISS WALBAUM): IN VITRO MODEL STUDY

This research aimed to evaluate the in vitro effect of buffer extract obtained from leaves and pseudobulbs (modified shoots) of Dendrobium parishii Rchb. f. on the 2-thiobarbituric acid reactive substances (TBARS) as lipid peroxidation biomarker, aldehydic and ketonic derivatives of oxidatively modified proteins, and total antioxidant capacity (TAC) in the muscle tissue of the rainbow trout (Oncorhynchus mykiss Walbaum). The shoots (pseudobulbs) with leaves of Dendrobium parishii cultivated under glasshouse conditions were sampled at M.M. Gryshko National Botanic Garden (NBG) (Kyiv, Ukraine). Since 1999, the whole collection of tropical and subtropical plants (including orchids) has had the status of a National Heritage Collection of Ukraine and is supported through State funding. Besides, NBG’s collection of tropical orchids was registered at the Administrative Organ of CITES in Ukraine (Ministry of Environment Protection, registration No. 6939/19/1-10 of 23 June 2004). The collected pseudobulbs and leaves were brought into the laboratory for biochemical studies. Freshly collected leaves were washed, weighed, crushed, and homogenized in 0.1M phosphate buffer (pH 7.4) (in proportion 1:19, w/w) at room temperature. The extract was then filtered and investigated for its antioxidant capacity. The extract was stored at -20°C until use. The increase in TBARS level in the muscle tissue exposed to extracts derived from leaves and pseudobulbs of D. parishii was insignificant. The level of ketonic derivatives of oxidatively modified proteins was non-significantly decreased both for leaf and pseudobulb extracts compared to the untreated samples. The extracts obtained from leaves and pseudobulbs of D. parishii significantly increased the TAC level in muscle tissue due to inhibited the Fe2+/ascorbate-induced oxidation of Tween 80. Overall, these findings demonstrate that aqueous extracts of vegetative organs of Dendrobium parishii can enhance the total antioxidant capacity in the muscle tissue of the rainbow trout. Moreover, this antioxidant effect was more intensive for pseudobulb extracts.