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

Abstract

<strong>Background and objectives: </strong><em>Phlomis olivieri </em>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. <br /><strong>Methods: </strong>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<em> P. olivieri </em>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. <br /><strong>Results: </strong>One caffeoylquinic acid derivative, chlorogenic acid (<strong>1</strong>), one iridoid glycoside, ipolamiide (<strong>2</strong>), two phenylethanoid glycosides, phlinoside C (<strong>3</strong>) and verbascoside (<strong>5</strong>), along with two flavonoids, isoquercetin (<strong>4</strong>) and naringenin (<strong>6</strong>) 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). <br /><strong>Conclusion: </strong>the results of the present study introduce <em>P. olivieri</em> as a medicinal plant with valuable biological and pharmacological potentials.