Phenolic compounds of herbal infusions obtained from some species of the Lamiaceae family

The present investigation was to estimate the total phenolic content and composition of flavonoids and hydroxycinnamic acids in herbal infusions obtained from aerial parts of three Lamiaceae species (Dracocephalum moldavica, Ocimum americanum and Satureja hortensis). The total phenolic content of herbal infusions was determined using a spectrophotometric method, whereas the individual phenolics were assessed by high-performance liquid chromatography (HPLC). The HPLC method was developed and validated. The total phenolic content was measured by applying the Folin-Ciocalteu method with reference to gallic acid. Results were in the range from 29.39 to 65.38 mg estimated as gallic acid equivalents per gram of dry herb. The phenolic profile was, in turn, analysed by HPLC and consisted of gallic acid, hydroxycinnamic acids (caffeic, chlorogenic, ferulic, and rosmarinic) and flavonoids (rutin, hyperoside, quercitrin, quercetin, apigenin, apigenin-7-glucoside and catechin) in different concentrations. Rosmarinic acid was the predominant component among the hydroxycinnamic acids in herbal infusions of all three plants. This was found to be in the range of 3.64 to 5.28 mg per gram of dry herb. Apigenin-7-glucoside, quercitrin and hyperoside were the prevailing flavonoid components of the infusions.