Chemical composition and molluscicidal activities of the essential oils from Cotula cinerea a saharan medicinal plant

Abstract

Schistosomiasis is one of the 20 neglected tropical diseases (NTDs) recognized by the World Health Organization and remains a major public health problem in many developing countries. Natural molluscicides derived from medicinal and aromatic plants (MAPs) offer a promising and eco-friendly alternative. Sahara, with its vast botanical diversity and rich traditional knowledge, represents a valuable reservoir for the identification of new bioactive natural products for schistosomiasis control. The essential oil derived from the Saharan medicinal plant Cotula cinerea (Asteraceae), growing in Tindouf (Algeria), was analyzed for its chemical composition using gas chromatography/ mass spectrometry (GC/MS) and evaluated for its molluscicidal properties. Thirty-six compounds, representing 93.4% of the essential oil, revealed that the major constituents were trans-Thujone (34.8%), Camphor (11.9%), Santolinatriene (10.2%), 1,8-Cineol (7.4%), and Cis-Verbenyl acetate (6.4%). The essential oil is characterized by the presence of high content of oxygenated monoterpenes. The molluscicidal activity tested against adult Lymnaea stagnalis snails using WHO-recommended bioassay protocols showed that the essential oil of C. cinerea exhibited significant molluscicidal effects with the 24-h LC50 of 95.8 μg/mL and achieving 90% mortality at 114.2 μg/mL within 24 hours and 90% mortality at 87.3 μg/mL within 48 hours. The results support the potential use of essential oils from the Saharan medicinal plant as natural alternatives to synthetic molluscicides that cause serious environmental hazards.

KEY WORDS: Natural products; Lymnaea stagnalis; Oxygenated monoterpenes; Schistosomiasis; Algerian Sahara.