Detailed chemical composition was determined in 7 tea samples, i.e., infusions prepared from the dried aerial herba of St. John’s wort (Hypericum perforatum L.) commercially available or collected, from locations in the east and south-east Serbia. In addition, quantitative analysis for five selected major constituents in the samples, neochlorogenic acid, isoquercitrin, quercetin, hyperforin and hypericin, was performed. Qualitative and quantitative analyses were done by Ultra-high-performance liquid chromatography–diode array detector–electrospray mass spectrometry (UHPLC–DAD–ESI–MS/MS) method. The aims of this work were to detect and identify as well as quantitative analysis of phytochemicals in the infusions prepared in a traditional way and to compare obtained results with the corresponding available literature. Over fifty compounds from wide range of polyphenols were detected in the infusions: acids and phenolic acids, flavonoids, phloroglucinols, naphthodianthrones and xanthones. Some of them such as 4- and 5-O-p-coumaroyl-quinic and 4-O-feruloyl-quinic acids, or some quercetin and dihydroquercetin derivatives were for first time detected in the St. John’s wort infusions. Among them, high concentrations of major quantified phenolics determined in infusions (nechlorogenic acid, isoquercitrin, quercetin, hyperforin and hypericin) can contribute to a higher quality of St. John’s wort teas from Serbia origin. Their concentrations vary through the samples: concentration of neochlorogenic acid is in the range of 51.8–103.7 mg/dm3, isoquercitrin 17.4–35.3 mg/dm3, quercetin 22.0–54.1 mg/dm3, hyperforin 0.13–0.92 mg/dm3 and hypericin 0.5–4.9 mg/dm3.
Graphic abstract
Keywords: Hypericum perforatum; UHPLC; Mass spectrometry; Polyphenols; Infusions