In this study, methoxylated flavonoids and volatile constitutions of Agrostis gigantea Roth (Poaceae) were investigated for the first time. The flavonoids were identified by spectroscopic methods (1H-NMR, 13C-NMR, COSY, NOSEY, TCOSY, and HMBC). The volatile constitutions of aerial parts and seeds were analyzed by gas chromatography-mass spectrometry (GC-MS). Two methoxylated flavonoids, luteolin 5-methyl ether (1), and cirsilineol (2) were isolated from the aerial parts of this plant. According to the GC-MS data the main constitutions of these volatile oils belong to the simple phenolic category which include coniferyl alcohol (18.80%) and eugenol (12.19%) in aerial parts and seeds, respectively. By using the computer- aided molecular modeling approaches, the binding affinity of these compounds was predicted in the catalytic domains of aryl hydrocarbon receptor (AhR). These two isolated flavonoids were investigated in-vitro for their inhibitory activity on 4T1 breast carcinoma cells. It was predicted that these compounds could be well-matched in aryl hydrocarbon receptor (3H82) active site, but based on the in-vitro assay, the IC50 values on cytotoxicity were 428.24 ±3.21 and 412.7±3.02 μg/mL for luteolin 5-methyl ether and cirsilineol, respectively. Thus, it can be concluded that these flavonoids exhibit low cytotoxicity against 4T1 breast carcinoma cell line.
Keywords: 4T1 breast carcinoma cell; Agrostis gigantea Roth; Aryl hydrocarbon receptor; Methoxylated flavonoids.