Phytochemical constituents, antioxidant activity and toxicity potential of Phlomis olivieri Benth.

Phlomis olivieri Benth. (Lamiaceae) is a medicinal plant widely distributed in Iran. In the present study, we have investigated the phytochemical constituents, antioxidant activity and general toxicity potential of the aerial parts of this species.

Silica gel (normal and reversed phases) and Sephadex LH-20 column chromatographies were used for isolation of compounds from methanol-soluble portion (MSP) of the total extract obtained from P. olivieri aerial parts. The structures of isolated compounds were elucidated using 1H-NMR, 13C-NMR and UV spectral analyses. Antioxidant activity and general toxicity potential of MSP were also evaluated in DPPH free radical-scavenging assay and brine shrimp lethality test (BSLT), respectively.

One caffeoylquinic acid derivative, chlorogenic acid (1), one iridoid glycoside, ipolamiide (2), two phenylethanoid glycosides, phlinoside C (3) and verbascoside (5), along with two flavonoids, isoquercetin (4) and naringenin (6) were isolated and identified from MSP. The MSP exhibited considerable antioxidant activity in DPPH method (IC50; 50.4 ± 4.6 µg/mL), compared to BHT (IC50; 18.7 ± 2.1 µg/mL), without any toxic effect in BSLT at the highest tested dose (1000 µg/mL).

the results of the present study introduce P. olivieri as a medicinal plant with valuable biological and pharmacological potentials.