Table 5.

Antibacterial activities of ethanolic extract of G. thoracica, H. itama, and T. binghami propolis along with the two standard antibiotics, rifampicin and streptomycin, for comparison. Negative control (water) did not show any inhibition zone as expected. R and S denote significant difference (p < 0.05) between the inhibition zones of the propolis and that of rifampicin (RIF) and streptomycin (STR), respectively.

Bacterial strain	Inhibition zone (mm)
	G. thoracica propolis	H. itama propolis	T. binghami propolis	Antibiotics
				RIF	STR
B. subtilis	10.8 ± 1.0	13.0 ± 4.6	11.0 ± 2.7	14.0 ± 4.4	14.0 ± 4.1
S. aureus	7.8 ± 0.5S	9.7 ± 4.6S	7.0 ± 0.8RS	12.9 ± 4.6	16.8 ± 4.2
E. coli	11.3 ± 1.0	10.8 ± 1.0	10.0 ± 4.4	13.8 ± 4.6	12.4 ± 4.0
P. aeruginosa	9.0 ± 1.2RS	9.8 ± 1.3S	8.8 ± 1.3S	14.0 ± 5.1	14.8 ± 2.6