Antibacterial activity and phytochemical characterisation of aerial parts of Cedrus atlantica

Cedrus atlantica (Endl.) G.Manetti ex Carrière is a species endemic to the mountains of North Africa. It‘s a coniferous tree that tolerates drought and cold and can grow on clay and loam soils, highly estimated for its technological, ecological, and biogeographical values [ 1 ]. In particular, its essential oils are known for their antifungal, antimicrobial, antiviral, and anti-inflammatory properties [ 2 ] [ 3 ] and are used as perfumes and medicines [ 4 ]. The aim of this study was to identify antimicrobial compounds from the aerial parts of C. atlantica. The air-dried plant material (350 g) was macerated with n -hexane, CHCl 3 , and CHCl 3 -MeOH(9:1) to yield 8.26, 11.46, and 26.43 g of the respective residue. The chloroform extract at 125 μg/mL (MIC100) showed an interesting antimicrobial activity against Acinetobacter baumannii , a highly pathogenic, multidrug-resistant bacterium that have a significant threat to public health, making it a critical target for antimicrobial research. The chloroform extract, the most active, was then separated by column chromatography on silica gel, yielding eight fractions, which were used to assess their effect on bacterial growth. Two fractions rich in abietane diterpenes affected bacterial growth by prolonging the lag phase. This suggests an effect on bacterial virulence as the bacteria require a longer adaptation time. The active fractions were therefore separated by RP-HPLC, yielding two new diterpenoids (1-2), two new megastigmane glycosides (3-4) ([ Fig. 1 ]) and several known abietanes, whose structures were elucidated by 1D and 2D NMR spectroscopy and HRMS experiments. The evaluation of the antibacterial activity of the isolates is currently under investigation. Fig. 1 Structure of compounds 1 - 4 isolated from Cedrus atlantica aerial parts Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany