Research on the relationship between diet and human health provided information on prophylactic and auxiliary treatment of many diseases, nutrients and non-food components of plant-origin products. However the content of compounds with health-promoting effects in plants varies and depends on many factors among others: genotype, geographical area, agrotechnical practices, climatic and soil conditions. The subject of the study were fruits of cherry cv. ‘Łutówka’, cherry cv. ‘Vanda’, sea buckthorn cv. ‘Sirola’, and Japanese knotweed leaves as potential source of resveratrol and tryptophan in human diet. The plants was grew at the Agricultural Experimental Station in Lipnik (53°20′35″N 14°58′10″E, altitude 7 m.a.s.l.), in north Poland. The soil on which the experiment was conducted belongs to the typical rusty soil group and is classified as Haplic Cambisol. In the Ap level (arable-humus horizon), it has a granulometric composition of clay with a slightly acidic pH. Content analysis of soil minerals showed moderate levels of magnesium and potassium and high levels of phosphorus. No fertilization or supplementary irrigation was used. The fruits were collected from representative trees (avoiding the edge trees). The leaves were collected from four plants - from each plant of the four shoots.  Analysis of tryptophan content in the study material was performed according to the methodology described by AOAC (2012). The UHPLC Thermo Ultimate 3000 RS system was used for analysis resveratrol in plant material. In this study, the content of free resveratrol in the fruit of sea buckthorn leaves and Japanese knotweed leaves has not been demonstrated. It was also not found in the fruit of cherries and sweet cherries. Leaves of Japanese knotweed contained derivatives of resveratrol, piceids. Fruits of cherry, and above all, sweet cherry and sea buckthorn, were characterized by a high content of tryptophan