Biological screening of various medicinal plant extracts for antibacterial and antitumor activities

Abstract

Bioassays of 2 types (antibacterial and antitumor) were performed to show the biological activities of 16 different plants grown in Bolu, Turkey: Clinopodium vulgare L. subsp. vulgare L., Salvia verticillata L. subsp. amasiaca (Frey & Bornm.) Bornm., Salvia tomentosa Mill., Mentha pulegium L., Melilotus officinalis (L.) Desr., Melilotus alba Desr., Medicago lupulina L., Galega officinalis L., Xeranthemum annuum L., Cichorium intybus L., Plantago lanceolata L., Plantago major L. subsp. major, Fumaria officinalis L., Galium palustre L., Echium vulgare L., and Sambucus nigra L. For each plant, 3 different extracts (aqueous, ethanol, and methanol) were obtained, and a total of 48 extracts were evaluated. Antibacterial activity was evaluated with 10 bacteria, including Streptococcus pyogenes, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Serratia marcescens, Proteus vulgaris, Enterobacter cloacae, and Klebsiella pneumoniae by disk diffusion method. All plants except M. alba, M. lupulina, X. annuum, G. palustre, and S. nigra showed inhibitory activity against both gram-positive and gram-negative bacteria. The best inhibitory activity was observed with aqueous extract of M. officinalis (22.5 mm); it performed better than all positive controls (erythromycin, ampicillin, carbenicillin, tetracycline, and chloramphenicol; 7-20 mm) against P. aeruginosa. Antitumor activity was evaluated with Agrobacterium tumefaciens-induced potato disk tumor assay. The best antitumor activity was obtained with the methanolic extract of M. alba and aqueous extract of F. officinalis (100% tumor inhibition).