Rearranged abietane diterpenoids from roots of Teucrium hircanicum L.

Medicinal plants play a significant role in preventing and treating diseases due to their traditional uses.

The aim of the study was to isolate, purify and identify phytochemicals from the n-hexane extract of Teucrium hircanicum L. roots and evaluate the antioxidant activity of the extract and its purified compounds.

The n-hexane extract (2.27 g) was extracted from the roots of this plant. The extract was fractionated by column chromatography with normal phase by eluting with n-hexane-EtOAc and following with EtOAc-Methanol. Fractions with similar phytochemical fingerprints combined to produce 23 main fractions. Final purification was carried out by preparative reversed-phase HPLC-UV. The structures of isolated were secured by different spectroscopic methods such as 1D, 2D NMR, and mass spectroscopy methods and comparing of these data with literature reported values. The antioxidant activity of the n-hexane extract of T. hircanicum roots and its purified diterpenoids was evaluated in DPPH assay and radical scavenging activity was calculated.

Extraction and isolation methods were used to purify three rearranged abietane-type diterpenoids villosin A (1), teuvincenone B (2) and 5, 8, 11, 13, 15-abietapentaen-7-one (3), a phenethyl ester namely 4-hydroxyphenethyl pentacosanoate (4) and one sterol namely 22-dehydroclerosterol (5).

The n-hexane extract from roots of T. hircanicum and three rearranged abietane type diterpenoids were showed good antioxidant activities ranged from 3.5-4.3 μg/ml compared with the reference value (BHT = 16.5 μg/ml).