Raw data for the publication: Polyphenol Diversity and Chemotype Variation in Origanum majorana and Related Species: Implications for Chemotaxonomic Differentiation, Standardisation and Genotype Selection Brigitte Lukas, Johannes Novak, Magdalena Neumüller, Jennifer Romana Valek, Salme Ahmed, Zehra Aytaç, Ahmet Gümüşçü Abstract This study focuses on the qualitative and quantitative composition of non-volatile compounds in wild and commercial O. majorana, the three other species of section Majorana (O. dubium, O. syriacum and O. onites) as well as two more distantly related species, O. minutiflorum (section Chilocalyx) and O. vulgare (section Origanum). Methanolic extracts from 657 individual plants from 59 populations and seed accessions were analysed using high performance liquid chromatography (HPLC). The extracts of wild O. majorana predominantly consisted of arbutin (mean of 9 area percent), apigenin 6,8-di-glucopyranoside (4%), luteolin 7-glucuronide (9%), rosmarinic acid (19%), apigenin 7-glucuronide (7%), salvianolic acid B (8%), two unidentified flavonoids (4 and 7%, respectively) and blumeatin (6%). Differences in the proportions of these compounds enabled the differentiation between wild and commercial O. majorana plants by principal component analysis (PCA). The polyphenol spectrum of O. majorana was remarkable within the section Majorana. Origanum dubium, O. syriacum and O. onites displayed a markedly distinct polyphenol chemotype, with their clusters intersecting centrally between the well-defined clusters of O. majorana, O. minutiflorum and O. vulgare. When considering qualitative and quantitative extract composition of the economically significant Origanum species, O. majorana and O. vulgare are superior sources of phenolic acids while O. dubium, O. syriacum and O. onites are more abundant in flavonoid glycosides. There is high potential for the selection of genotypes exhibiting elevated levels of arbutin (O. majorana wildtype, up to 99 mg/g dry weight), apigenin 6,8-di-glucopyranoside (O. dubium, up to 118 mg/g), rosmarinic acid (commercial O. majorana, up to 53 mg/g; O. vulgare ssp. vulgare up to 62 mg/g) or salvianolic acid B (O. majorana wildtype, up to 37 mg/g).