Metabolite profiling for caffeic acid oligomers in Satureja biflora

Satureja biflora, known as “lemon savory”, grows widely in Southern and Eastern parts of Africa. The plant has been used in Kenyan and Tanzanian traditional medicine as an antimicrobial, spasmolytic, diuretic, analgesic, and cicatrizing herb. Except for the composition of the essential oil no phytochemical data have been reported. Phytochemical profiling of the methanolic extract by a combination of chromatographic methods afforded nine phenolic compounds. Their structures were established by means of extensive 1D- and 2D-NMR, HRESI–MS, and electronic circular dichroism (ECD). One new and eight known natural products were isolated and identified, namely luteolin 7-O-β-d-glucuronide (1), 2″-caffeoyl-luteolin 7-O-β-d-glucuronide (2) rosmarinic acid (3), melitric acid A (4), methyl melitric acid A (5), clinopodic acid I (6), clinopodic acid K (7), clinopodic acid O (8) and clinopodic acid P (9). Quantitative analysis of compounds showed that S. biflora is a rich source of caffeic acid oligomers. Such compounds were also found in other Satureja species, but at significantly lower concentrations.