An examination of the medicinal potential of Planchonella queenslandica: toxicity, antibacterial, and antiviral activities
Planchonella queenslandica (family Sapotaceae) is an Australian native plant which has a history of usage in indigenous Australian medicinal systems. The antimicrobial activity of P. queenslandica was investigated by disc diffusion assays against a panel of 13 bacteria (4 Gram-positive and 9 Gram-negative). Antiviral activity was determined using an MS2 bacteriophage plaque reduction model system. Toxicity was determined using the Artemia franciscana nauplii bioassay. The methanol, water, and ethyl acetate P. queenslandica leaf extracts all displayed antibacterial activity in the disc diffusion assay. The methanol and ethyl acetate extracts proved to have the broadest activity, inhibiting the growth of 9 of the 14 bacteria tested (64%). The water extract also had broad-spectrum antibacterial activity, inhibiting the growth of 6 of the 14 bacteria tested (43%). All extracts that displayed antibacterial activity were more effective against Gram-positive than Gram-negative bacteria. The methanol and ethyl acetate extracts each inhibited the growth of all five of the Gram-positive species tested and 5 of the 9 (56%) Gram-negative bacteria. The water extract inhibited 3 of the 4 (75%) Gram-positive bacteria and 3 of the 9 (33%) of the Gram-negative bacteria tested. The methanol, water, and ethyl acetate extracts also displayed antiviral activity in the MS2 plaque reduction assay, inhibiting 90.8±2.4, 50.7±5.8 and 71.7±4.4% of MS2 plaque formation, respectively. All P. queenslandica extracts were also non-toxic or of low toxicity in the Artemia fransiscana bioassay. The low toxicity of the P. queenslandica extracts and their inhibitory bioactivity in the MS2 bacteriophage reduction bioassay and against a panel of bacteria validate Australian Aboriginal usage of this plant as an antiseptic agent and confirms its medicinal potential.
Kalt, F.R. and Cock, I.E. (2016). An examination of the medicinal potential of Planchonella queenslandica: toxicity, antibacterial, and antiviral activities. Acta Hortic. 1125, 269-282
Sapotaceae, Planchonella queenslandica, Blush Condoo, Australian medicinal plants, MS2 bacteriophage, antiviral