Phytochemical Composition and Bioassay on Iranian Teucrium Polium Extracts against Anopheles Stephensi (Diptera: Culicidae)

Anopheles stephensi is an important malaria vector mosquito in Iran and other western Asian countries. In many human communities, plant products have been used traditionally instead of synthetic pesticides for mosquito control due to their minimal hazardous effects. Teucrium polium, known popularly as felty germander, has been introduced in Persian Medicine (PM) as an insect repellent from a long time ago.

The present study was undertaken to evaluate repellent and larvicidal activity of dichloromethane (DCMETP) and ethanolic extracts (EE-TP) of T. polium against An. stephensi under laboratory conditions. The possible chemical components of the extracts were also investigated through gas chromatography/mass spectrometry (GC-MS) technique.

Based on the results, DCME-TP showed better repellent activity than EE-TP with 56.67 and 28.33 % protection, respectively. Larvicidal activity of DCME-TP with 49.41% mortality was also higher than EE-TP (20.24%). The main identified constituents of DCME-TP were long chain alkanes, phenol, aromatic ester, oxaspiro and triterpenoid. While phenolic and aliphatic acid were only the identified components in EE-TP. It is notable that lupeol was detected in DCME of T. polium for the first time.

DCME-TP can be considered as a new herbal candidate to control An. stephensi mosquitoes. Further studies are required on this extract for the fractionation and identification of the active compounds, and the evaluation of their bioactivity in the laboratory and field.