Abstract

Medicinal plants are used by rural Guatemalan villagers to treat a variety of ailments, and a better understanding of their effectiveness against common diseases is warranted. Acetone and methanol extracts of 73 medicinal plant species from 44 families were bio-assayed against breast, cervical, skin, and tongue cancers, and Staphylococcus aureus, Escherichia coli, Streptococcus mutans, Lactobacillus acidophilus, and Candida albicans. Half-maximum inhibitory concentrations (IC₅₀) and half-maximum cytotoxicity concentrations (CC₅₀) were determined against cancerous and non-cancerous cell lines, respectively. Minimum inhibitory concentrations (MIC) were determined for active extracts. Bursera simaruba (L.) Sarg. (Burseraceae), Byrsonima crassifolia (L.) Kunth (Malpighiaceae), Guazuma ulmifolia Lam. (Malvaceae), and Quercus acatenangensis Trel. (Fagaceae) were inhibitory to one or more cancer cell lines and yielded promising IC₅₀ and CC₅₀ values. Eucalyptus globulus Labill. (Myrtaceae), Liquidambar styraciflua L. (Altingiaceae), Pelargonium hortorum L.H. Bailey (Geraniaceae), and Psidium guajava L. (Myrtaceae) were inhibitory to one or more microbes and had MIC’s of 250 µg/ml or less against one or more microbes. The activity of these species against cancer and pathogenic microbes indicates that they are valuable resources that should be conserved and considered for future research.

Key words: Anticancer, antimicrobial, IC₅₀, CC₅₀, minimum inhibitory concentrations (MIC), Guatemala.