FLAVONOID COMPOUNDS AND ANTIOXIDANT ACTIVITY OF BULGARIAN SPECIES OF MICROMERIA
MILENA NIKOLOVA1, INA ANEVA1*, PETER ZHELEV2, MARINA DIMITROVA1
1-Institute of Biodiversity and Ecosystem Research, 1113 Sofia, Bulgaria
2-University of Forestry, 10 Kliment Ohridski blvd., 1797 Sofia, Bulgaria
* Corresponding author: ina.aneva@abv.bg
Keywords: Thin-layer chromatography (TLC), DPPH, chemotaxonomy
Abstract: Four Micromeria species, naturally distributed in Bulgaria were examined: Micromeria dalmatica Benth, Micromeria frivaldszkyana (Degen) Velen., Micromeria juliana (L.) Rchb. and Micromeria cristata (Hampe) Griseb. Acetone exudates and methanolic extracts of the species were studied for flavonoid compounds by TLC and HPTLC. Sixteen flavonoid compounds were detected by screening in different TLC systems (different sorbents and mobile phases). Flavonoid aglycones – apigenin, luteolin, apigenin 4’-methyl ether, quercetagetin 3,6,7-trimethyl ether – were identified in acetone exudates of the examined species. Flavonoid glycosides – kaempferol 3-rutinoside, quercetin 3-rutinoside (rutin), quercetin 3-glucoside/hyperoside, luteolin 7-0-glucoside as well as chlorogenic acid – were determined in the methanolic extracts. The methanolic extract of studied species were evaluated also for free radical scavenging activity using DPPH assay. All extracts showed significant antioxidant activity, and the ones of M. dalmatica and M. frivaldszkyana exhibited the highest activity.