This study presents a multivariate assessment of the qualitative and quantitative composition of polyphenolic compounds across six Origanum species, including wild and commercial O. majorana, the three other species of section Majorana (O. dubium, O. syriacum and O. onites), and the more distantly related O. minutiflorum and O. vulgare. Methanolic extracts from 657 plants representing 59 populations were analysed by HPLC. A total of 122 constituents were consistently detected, 20 major peaks were selected for detailed evaluation, and eight key constituents were quantified using external standards. Wild O. majorana was characterised by high proportions of arbutin, apigenin 6,8-di-glucopyranoside, luteolin 7-glucuronide, apigenin 7-glucuronide, rosmarinic acid, salvianolic acid B, blumeatin, and two additional flavonoid-like constituents requiring further structural elucidation. Principal component analysis separated wild and commercial O. majorana and distinguished O. majorana, the three overlapping clusters of O. onites, O. dubium and O. syriacum, as well as O. minutiflorum and O. vulgare, reflecting marked interspecific differences in dominant compound classes. Origanum majorana and O. vulgare were richer in phenolic acids, whereas O. dubium, O. syriacum, and O. onites contained higher levels of flavonoid glycosides. Several genotypes accumulated exceptionally high concentrations of arbutin, apigenin 6,8-di-glucopyranoside, rosmarinic acid, or salvianolic acid B. These results establish a robust chemotaxonomic framework for distinguishing Origanum species and pinpoint high polyphenol genotypes as candidates for breeding, quality standardisation, and targeted follow-up studies on antioxidant and other bioactivities.
Lukas et al. (Tue,) studied this question.