Flavonol glycosides were identified in potato flowers and seeds, including kampferol and quercetin derivatives, and luteolin in a wild species. A gene controlling glucose transfer to quercetin 3-rhamnosylglucoside was found. A biosynthesis pathway for flavonol glycosides and anthocyanins in potatoes was proposed. The 7-hydroxyl group of flavonols requires a separate enzyme for synthesis. A method for determining ester sulphate content in sulphated polysaccharides was developed. The method involves hydrolysis followed by turbidimetric measurement of liberated sulphate. The method was adapted to account for ultraviolet-absorbing products formed during hydrolysis. The method was tested on various polysaccharide sulphates, including chondroitin sulphates, charonin sulphate, porphyran, and heparin. The results agreed closely with those obtained by gravimetric methods. The method is efficient, requires small amounts of starting material, and is suitable for various polysaccharide sulphates. The study highlights the importance of hydrolysis conditions in minimizing the formation of ultraviolet-absorbing materials. The method is applicable to a wide range of polysaccharide sulphates, including those with different sulphate linkages. The study also discusses the structures of these compounds and the possible involvement of various functional groups in sulphate binding. The method is suitable for the analysis of ester sulphate contents of plant and animal origin.Flavonol glycosides were identified in potato flowers and seeds, including kampferol and quercetin derivatives, and luteolin in a wild species. A gene controlling glucose transfer to quercetin 3-rhamnosylglucoside was found. A biosynthesis pathway for flavonol glycosides and anthocyanins in potatoes was proposed. The 7-hydroxyl group of flavonols requires a separate enzyme for synthesis. A method for determining ester sulphate content in sulphated polysaccharides was developed. The method involves hydrolysis followed by turbidimetric measurement of liberated sulphate. The method was adapted to account for ultraviolet-absorbing products formed during hydrolysis. The method was tested on various polysaccharide sulphates, including chondroitin sulphates, charonin sulphate, porphyran, and heparin. The results agreed closely with those obtained by gravimetric methods. The method is efficient, requires small amounts of starting material, and is suitable for various polysaccharide sulphates. The study highlights the importance of hydrolysis conditions in minimizing the formation of ultraviolet-absorbing materials. The method is applicable to a wide range of polysaccharide sulphates, including those with different sulphate linkages. The study also discusses the structures of these compounds and the possible involvement of various functional groups in sulphate binding. The method is suitable for the analysis of ester sulphate contents of plant and animal origin.