关键词: 中国野生葡萄, 株系, 果皮, 黄烷-3-醇

Abstract: 【Objective】China is one of the countries rich in resources of Vitis germplasm in the world, most of their berries are little in size, with thick dark-red peels, thus they are expected to be utilized for high quality wine production. While as a critical component to wine quality, flavan-3-ols in peel of Chinese wild grapes seldomly has been researched. In the present paper, the difference of the composition and concentration of flavan-3-ols in berry peel of different Chinese wild grape species was evaluated, with the aim of leading to better choice of raw materials for wine making and evaluation of Chinese wild grape germplasm.【Method】 Ninety-eight cultivars or clones of eleven Chinese wild species were selected, including Vitis piasezkii, V. davidii, V. pseudoreticulata, V. betulifolia, V. heyneana, V. romanetii, V. heyneana subsp. ficifolia, V. amurensis, V. adenoclada, V. amurensis var. yanshanensis and V. adsticta. Vitis. vinifera L.‘Cabernet Sauvignon’ was chosen as control. Mature berries were collected from the National Grape Germplasm Repository in Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences in 2015. The composition and concentration of flavan-3-ols in berry peel of selected samples were determined by reversed-phase UPLC after acetone extraction and acid-catalysis in the presence of excessive phloroglucinol. 【Result】 The results are as follows: The contents of flavan-3-ols from different species were different. Among the eleven species, the contents of flavar-3-ols in V. heyneana subsp. ficifolia were much higher in berry peel than the control and the other detected species, while that in V. betulifolia and V. piasezkii were the lowest in berry peel, only 64% of the control. The compositions of falvan-3-ols in berry peel of Chinese wild grapes was similar to that of the control, and composed by catechin (C), epicatechin (EC), epigallocatechin (EGC) and epicatechin-3-O-gallate (ECG). In berry peel, EGC was the major constituent representing around 60% of total flavan-3-ols, with EC accounting for around 35% of total flvan-3-ols, while C and ECG represented less than 5%. These four constitutional units can not only being as terminal subunits but also as extension subunits of polymeric flavan-3-ols. The flavan-3-ols in berry peel of Chinese wild species was mainly existed as polymers, and representing above 90% of total flavan-3-ols. The mean degree of polymerization (mDP) of different species was different, among the detected species, V. amurensis had the highest level of mDP above 50, while V. betulifolia was only 25 and the other species were between 25 and 45. Of these flavan-3-ol compounds, EGC is synthesized from the F3′5′H-mediated branch pathway and so is grouped into the 3′,4′,5′-substituted flavan-3-ols, whereas C, EC and ECG are from the F3′H-mediated branch and are grouped into 3′,4′-substitued flavan-3-ols. Compared with the other species, V. heyneana and V. romanetii had a much lower percentage of total 3′,4′-substituted flavan-3-ols (C, EC and ECG) and a significantly higher percentage of 3′,4′,5′-substituted flavan-3-ols (EGC). Principle component analysis revealed that there was a certain distinction among the wild species, while V. davidii was notably from the other species.【Conclusion】 Compared with the V. vinifera L.‘Cabernet Sauvignon’, some special cultivars or clones of the V. davidii, V. betulifolia, V. heyneana subsp. ficifolia, V. amurensis and V. adenoclada possess much higher flavan-3-ols content in berry peel, which hold a great potential be used for breeding new materials with high level of flavan-3-ols. Besides, the content of flavan-3-ols varied among different species, which would act as an additional index to evaluate the quality of Chinese wild grape germplasm.

Key words: Chinese wild grapes, cultivars or clones, berry skin, flavan-3-ols