Antiprotozoal activity of diterpenoids isolated from Zhumeria majdae- absolute configuration by circular dichroism

PurposeZhumeria majdae, a unique species of the Zhumeria genus, is an endemic Iranian plant in the Lamiaceae family. Phytochemical investigation and biological activity of this plant are rarely reported. The current study aimed to find new antiprotozoal compounds from the roots of Z. majdae and to determine the absolute configuration of isolated compounds by circular dichroism.MethodsThe extraction process from roots and aerial parts of Z. majdae was carried out by hexane, ethyl acetate and methanol followed by testing their antiprotozoal effects against Leishmania donovani, Trypanosoma brucei rhodesiense, T. cruzi, and Plasmodium falciparum, respectively. Structure elucidation was done using 1D and 2D NMR spectroscopy and HREIMS spectrometry. In addition, experimental and theoretical circular dichroism spectroscopy was used to establish absolute configuration.ResultsIn comparison with aerial parts, the hexane extract from roots showed superior activity against T. b. rhodesiense, L. donovani and P. falciparum with IC₅₀ values of 5.4, 1.6 and 2.1 μg/ml, respectively. From eight abietane-type diterpenoids identified in roots, six were reported for the first time in the genus Zhumeria. 11,14-dihydroxy-8,11,13-abietatrien-7-one (6) exhibited a promising biological activity against P. falciparum (IC₅₀ 8.65 μM), with a selectivity index (SI) of 4.6, and lanugon Q (8) showed an IC₅₀ value of 0.13 μM and SI of 15.4 against T. b. rhodesiense.ConclusionAltogether, according to the results, of 8 isolated compounds, dihydroxy-8,11,13-abietatrien-7-one (6) and lanugon Q (8) exhibited a promising activity against T. b. rhodesiense and P. falciparum. In conclusion, these compounds could be potential candidates for further analysis and may serve as lead compounds for the synthesis of antiprotozoal agents. Open in a separate windowGraphical abstractElectronic supplementary materialThe online version of this article (10.1007/s40199-020-00345-w) contains supplementary material, which is available to authorized users.