Determination of essential oil composition of Laurencia obtusa and Ceramium spp. in Black Sea and antileishmanial activity

In this study, the chemical compositions of volatile oils obtained via Clevenger distillation from red algae species Laurencia obtusa and Ceramium spp., collected from the coastal areas of Sinop (Black Sea), were analyzed by GC/MS. Additionally, hexane, dichloromethane, chloroform, and methanol extracts were prepared using the Soxhlet extraction method, and their antileishmanial activities were evaluated. As a result, 80.92% and 90.51% of the volatile oil compositions of Laurencia obtusa and Ceramium spp. were identified, respectively, with 20 compounds characterized in each species. Hydrocarbons were the predominant compound class in the essential oils of Laurencia obtusa (79.31%) and Ceramium spp. (72.89%). The leishmanicidal activities of the solvent extracts were tested in vitro against Leishmania infantum promastigotes. The minimum inhibitory concentration (MIC) values for Laurencia obtusa extracts in hexane, dichloromethane, chloroform, and methanol were 5, 2.5, 2.5, and 10 mg/mL, respectively. For Ceramium spp., the MIC values were 2.5, 2.5, 2.5, and 10 mg/mL, respectively. Dichloromethane and chloroform extracts of both species exhibited greater antileishmanial activity compared to methanol and hexane extracts, indicating their higher potential as antileishmanial agents.