Antioxidant, Antibacterial Activities and General Toxicity of Alnus glutinosa, Fraxinus excelsior and Papaver rhoeas

Alnus glutinosa, Fraxinus excelsior and Papaver rhoeas have long been used in folkloric medicine for the treatment of various ailments. As part of our continuing screening of plant extracts for biological activities, the extracts of A. glutinosa, F. excelsior and P. rhoeas have been screened for their antioxidant and antibacterial activities, as well as their general toxicity towards brine shrimps. Among the extracts, the methanol (MeOH) extract of F. excelsior displayed the highest level of antioxidant activity (RC 50 =1.35x10 -2 mg/mL) and the dichloromethane (DCM) extract of P. rhoeas was the most toxic extract towards brine shrimps (LD 50 =2.4x10 -2 mg/mL). The n-hexane and DCM extracts of F. excelsior and the MeOH extract of A. glutinosa were active (MIC values were within 1.25x10 -1 and 1.00 mg/mL) against all 8 bacterial species tested, including methicillin-resistant Staphylococcus aureus (MRSA).