Diterpenoids from Astrodaucus orientalis (L.) Drude - Antiprotozoal activity

Astrodaucus orientalis (L.) Drude belongs to Apiaceae family. It is called 'Havij-e-kohi' meaning 'mountain carrot' in Iran. The plant has been used as a food additive, vegetable and a salad in Iran and Turkey. The chemical compositions of essential oils from different parts of A. orientalis have been reported previously but there are no reports on nonvolatile phytochemical. Fractionation of an n-hexane extract of Astrodaucus orientalis (L.) Drude petals resulted on isolation, purification and identification of four new diterpenoids (1-4) and two known compounds namely 2-epilaserin (5) and α-Angeloyloxylatifolone (6). Structure elucidation was achieved by 1D and 2D NMR experiments and HRMS spectroscopy. Relative configurations 1 – 4 were established on the basis of ³ J _H-H coupling constants and NOE difference spectra. The absolute configuration of 1 – 4 were achieved by comparison of experimental ECD spectra with simulated ECD data for possible stereoisomers, by using time dependent density function theory (TDDFT). Compounds tested in vitro for antiprotozoal activity against Plasmodium falciparum, Trypanosoma brucei rhodesiense, and Leishmania donovani with IC₅₀ values ranging from 15.9 to 37.4µM, 10.4 to 61.4µM, and 5.8 to 78.5µM respectively. The cytotoxicity of isolated compounds tested against L6- rat myoblast cell line and showed no toxicity.

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