Background: Many Tunisian medicinal plants are widespread and are used in modern ethnomedecin
due to their interesting biological activities. Considering natural products of plant origin, this
study was conceived to evaluate the allelopathic effect of leaf and stem extracts of Erica arborea and
Viburnum tinus on the seed germination and seedling development of Avena sativa. We identified the
secondary metabolites that were responsible.
Methods: Total phenols, flavonoids, tannins contents and antioxidant activity were evaluated using the
Folin ciocalteux, Aluminum trichloride, vanillin and scavenging activity on 2, 2-diphenyl-
1picrylhydrazyl (DPPH) radicals methods, respectively. Leaf powders (5, 20, 40, 60 and 100 g) were
macerated each with 1000 ml of distilled water for 24 h. The extracts were filtered through Whatman
N°1 filter paper, pooled and concentrated under vacuum. Allelopathic bioassays were conducted using
the obtained supernatant.
Results: The obtained results indicated that acetonic extracts of the Viburnum leaves had the highest
levels of total phenols (36.82 mg / g), flavonoïds (11.99 mg / g) and tannins (7.93 mg / g) and recorded
a high antioxidant activity (0.054 mg / ml). Both test species showed that all organs had significant
inhibitory effect on the development of Avena sativa. The leaves of Viburnum are best from the point of
view inhibition of root length (-85.45%) and height of the aerial part (-78.95%).
Conclusion: The inhibitory effects of these extracts were manifested much more on the development of
seedlings. Extracts from Viburnum tinus leaves were the best inhibitors and could be regarded as promising
candidates for natural plant source of antioxidant and herbicide agents.