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Table 1 Antimicrobial activity of methanolic extracts of R. californica and U. californica analyzed by Kirby-Bauer disc-diffusion assay

From: Antibacterial activity of native California medicinal plant extracts isolated from Rhamnus californica and Umbellularia californica

Bacterial Strains
Diameter of Zone of Inhibition (mm)
Plants Dose (mg) B. cereus ATCC® 14579 E. coli ATCC® 25922 P. aeruginosa ATCC® 10145 S. aureus ATCC® 25923 MRSA 1 ATCC® BAA-1683 S. pyogenes 1 ATCC® 10782
R. californica        
Leaves 1 10.0 ± 2.1 -- -- -- 10.0 9.0
  5 12.3 ± 0.5 -- -- 11.0 ± 1.2** 15.0 12.0
  10 13.0 ± 0.0 -- -- 12.5 ± 2.1Ψ 16.0 14.0
  25 14.3 ± 0.5 -- -- 14.0 ± 1.4** n.t. n.t.
U. californica        
Leaves 1 9.0 ± 0.0 -- -- -- 8.0 8.0
  5 9.5 ± 0.5 -- -- 9.3 ± 1.0** 9.0 11.0
  10 9.3 ± 0.5 -- -- 10.5 ± 1.4Ψ 10.0 15.0
  25 10.0 ± 0.0 -- -- 10.9 ± 2.0** n.t. n.t.
Bark 1 -- -- -- 8.0 ± 0.0Ψ -- --
  5 9.3 ± 0.5 -- -- 12.8 ± 2.6** 9.0 8.0
  10 10.3 ± 0.5 -- -- 17.5 ± 1.4Ψ 10.0 11.0
  25 11.7 ± 0.5 -- -- 16.0 ± 1.2** n.t. n.t.
Streptomycin 0.01 23.8 ± 1.2 19.8 ± 0.2 10.4 ± 0.3 18.9 ± 1.0 17.0 ± 0.0 18.0 ± 0.0
Methanol 100 % -- -- -- -- -- --
  1. Data represented as averages ± SD. --, no significant zone of inhibition; n.t., not tested; 1, n = 1; Ψ, n = 2; **, n = 4; remaining data (B. cereus, E. coli, and P. aeruginosa) represent sample size of 3 (n = 3)