Ethnobotany: Saltgrass, Distichlis spicata, Can Inhibit Bacterial Growth

For centuries, plants have been used by many cultures to treat a variety of infections. Since the discovery of penicillin, exploration of antimicrobials has focused on microbial origins. As bacteria become increasingly resistant to antibiotics, alternative antimicrobials are needed to treat such infections. Plants can provide new antimicrobials. Saltgrass, Distichlis spicata, was used by Native Americans to treat genitourinary and respiratory infections. We screened D. spicata for antibacterial compounds. D. spicata leaves and stems were ground in acetone, ethanol, ethyl alcohol, and distilled water to final concentrations of 0.20-0.67 g/mL. We tested each extract against Pseudomonas aeruginosa, Staphylococcus cerevisiae, and Staphylococcus aureus bacteria in agar diffusion assays. In the preliminary trials, ethanolic extracts of D. spicata stems and leaves inhibited growth of P. aeruginosa, Sac. cerevisiae, and Sta. aureus. The ethanolic extract produced zones of inhibition of 1 mm to 3 mm. Paper chromatography will be used to separate and characterize antimicrobial components of the plant extract. The effect of sublethal concentrations of the ethanolic extract on P. aeruginosa will be determined. These results suggest that D. spicata may have the potential to treat a broad range of infections.