Evaluation of the Antimicrobial Activity of Leaf Extracts of Acokanthera schimperi against Various Disease-Causing Bacteria

Figures & data

Table 1 Phytochemical Investigation of Solvent Fractions of A. schimperi Leave

Phytochemical Tests	DCM Fractionate	TCM Fraction	PE Fractionate	EA Fraction
Terpenoids	+	+	+	+
Tannin	+	+	+	+
Alkaloid	+	+	+	+
Cardiac glycoside	–	–	+	–
Phenolic compounds	+	+	+	+
Saponin	+	+	+	+
Flavonoids	+	+	+	+

Abbreviations: +, present; –, absent.

Table 2 Zone of Inhibition (in mm) of the Different Concentrations of DCM Fraction of A. schimperi Leave Against the Tested Bacteria

	DCM
	200mg/mL	100mg/mL	50mg/mL	25mg/mL	Vanc	CAF
C. freundii(ATCC 43864)	13.33±0.66^a***b***c*	11.67±0.88^a***b**	9.67±0.88^a***e*	7.67±0.33^a***d**e***	22.33±0.33	22.67±0.33
K. pneumonia (ATCC 700603)	16.67±0.66^a***b***c**	14.33±0.88^a***b***c*	11.00±0.57^a***d*e***	8.67±0.33^a***d***e***	24.00±0.57	21.67±0.66
S. typhi (ATCC 6539)	16.67±0.33^a***b***c***d*	14.00±0.33^a***b***c*e*	11.67±0.33^a***b**d*e***	9.67±0.33^a***c**d***e***	22.67±0.66	22.33±0.33
E. coli (ATCC 25922))	16.67±0.33^a***b***c***d*	15.00±0.00^a***b***c**e*	13.00±0.00^a***b*d**e***	11.33±0.33^a***c*d***e***	24.00±0.57	23.33±0.33
P. aeruginosa(ATCC)	15.67±0.33^a***b***c***	14.00±0.57^a***b***c*	11.67±0.33^a***d*e***	9.67±0.33^a***d***e***	22.33±0.66	22.33±0.66
S. aureus(ATCC 29213)	15.00±0.57^a***b***c***	13.33±0.33^a***b***c**	10.67±0.33^a***b*d*e***	8.67±0.33^a***c*d***e***	19.33±0.33	22.33±0.33

Notes: Values are expressed as Mean ± S.E.M (n=3), analysis was performed with One-Way ANOVA followed by Tukey’s test; ^aCompared to vancomycin, ^bCompared to 25 mg/mL, ^cTo 50 mg/mL, ^dTo 100 mg/mL, ^eTo 200 mg/mL; *P<0.05, **P<0.01, ***P<0.001. The negative control has shown no antibacterial activity.

Abbreviations: CAF, chloramphenicol; Vacho, vancomycin.

Table 3 Zone of Inhibition (in mm) of the Different Concentrations of TCM Fraction of A. schimperi Leave Against the Tested Bacteria

	TCM
	200mg/mL	100mg/mL	50mg/mL	25mg/mL	Vanc	CAF
C. freundii(ATCC 43864)	14.33±0.333^a***b***c***d**	11.67±0.333^a***b***c***e**	8.33±0.333^a***d***e***	6.83±0.167^a***d***e***	22.33±0.33	22.67±0.33
K. pneumonia (ATCC 700603)	15.67±0.667^a***b***c***	14.00±0.577^a***b***c***	9.67±0.333 ^a***d***e***	8.17±0.167^a***d***e***	24.00±0.57	21.67±0.66
S. typhi (ATCC 6539)	18.0±0.00^a***b***c***d***	15.33±0.333^a***b***c***e***	10.33±0.333^a***b***d***e***	8.17±0.167^a***c***d***e***	22.67±0.66	22.33±0.33
E. coli (ATCC 25922))	16.25±0.333^a***b***c***d**	14±0.00^a***b***c**e**	11.33±0.333 ^a***b***d**e***	7.5±0.289^a***c***d***e***	24.00±0.57	23.33±0.33
P. aeruginosa	17.67±0.333^a***b***c***d**	15.33± 0.333^a***b***c***e**	12±0.00 ^a***d***e***	10.67±0.667 ^a***d***e***	22.33±0.66	22.33±0.66
S. aureus(ATCC 29213)	16.25±0.577^a***b***c***d**	15±0.00^a***b***c***e***	10.33±0.333 ^a***b***d***e***	7±0.577^a***c***d***e***	18.33±0.33	22.33±0.33

Notes: Values are expressed as Mean ± S.E.M (n=3), analysis was performed with One-Way ANOVA followed by Tukey’s test; ^aCompared to vancomycin, ^bCompared to 25 mg/mL, ^cTo 50 mg/mL, ^dTo 100 mg/mL, ^eTo 200 mg/mL; **P<0.01, ***P<0.001. The negative control has shown no antibacterial activity.

Abbreviations: CAF, chloramphenicol; Vacho, vancomycin.

Table 4 Zone of Inhibition (in mm) of the Different Concentrations of PE Fraction of A. schimperi Leave Against the Tested Bacteria

	PE
	200mg/mL	100mg/mL	50mg/mL	25mg/mL	Vanc	CAF
C. freundii(ATCC 43864)	13.67±0.33^a***b***c*e**	11.67±0.33^a***b***c*e**	10.00±0.00^a***b*d*e***	8.33±0.33^a***c*d***e***	22.33±0.33	22.67±0.33
K. pneumonia (ATCC 700603)	17.00±0.00^a***b***c***d**	14.67±0.33^a***b***c**e**	12.00±0.00^a***b*d**e***	10.33±0.33^a***c**d***e***	24.00±0.57	21.67±0.66
S. typhi (ATCC 6539)	16.00±0.00^a***b***c***d**	14.00±0.00^a***b***c***e**	11.67±0.33^a***b**d***e***	9.67±0.33^a***c**d***e***	22.67±0.66	22.33±0.33
E. coli (ATCC 25922))	17.67±0.33^a***b***c***d**	15.33±0.33^a***b***e**	13.67±0.33^a***b**e***	11.00±0.57^a***c**d***e***	24.00±0.57	23.33±0.33
P. aeruginosa	17.33± 0.33^a***b***c***d**	14.67±0.33^a***b***c**e**	12.00±0.57^a***b**d**e***	9.33±0.33^a***c**d***e***	22.33±0.66	22.33±0.66
S. aureus(ATCC 29213)	17.33±0.33^a***b***c***d**	15.00±0.00^a***b***c***e**	12.00±0.57^a***b**d**e***	9.67±0.33^a***c**d***e***	18.33±0.33	22.33±0.33

Notes: Values are expressed as Mean ± S.E.M (n=3), analysis was performed with One-Way ANOVA followed by Tukey’s test; ^aCompared to positive control, ^bTo 25 mg/mL, ^cTo 50 mg/mL, ^dTo 100 mg/mL, ^eTo 200 mg/mL; *P<0.05, **P<0.01, ***P<0.001. The negative control has shown no antibacterial activity.

Abbreviations: CAF, chloramphenicol; Vacho, vancomycin.

Table 5 Zone of Inhibition (in mm) of the Different Concentrations of EA Fraction of A. schimperi Leave Against the Tested Bacteria

	EA
	200mg/mL	100mg/mL	50mg/mL	25mg/mL	Vanc	CAF
C. freundii(ATCC 43864)	14.33±0.333^a***b***c***d**	11.67±0.333^a***b***c***e**	8.33±0.333^a***d***e***	6.83± 0.167^a***d***e***	22.33±0.33	22.67±0.33
K. pneumonia (ATCC 700603)	15.67±0.667^a***b***c***	14±0.577^a***b***c***	9.67±0.333^a***d***e***	8.17±0.167^a***d***e***	24.00±0.57	21.67±0.66
S. typhi (ATCC 6539)	18.25± 0.00^a***b***c***d***	15.33±0.333^a***b***c***e***	10.33±0.00^a***b***d***e***	8.18±0.167^a***c***d***e***	22.67±0.66	22.33±0.33
E. coli (ATCC 25922))	16.67±0.333^a***b***c***d**	14.5±0.00^a***b***c***d**	11.88±0.333^a***b***d***e***	7.5±0.289^a***c***d***e***	24.00±0.57	23.33±0.33
P. aeruginosa	17.67± 0.333^a***b***c***d**	15.33± 0.333^a***b***c***e**	12±0.57^a***d***e***	10.67±0.667^a***d***e***	22.33±0.66	22.33±0.66
S. aureus(ATCC 29213)	16.25±0.333^a***b***c***d*	15±0.33^a***b***c***e*	10.33±0.333^a***b***d***e***	7±0.577^a***c***d***e***	18.33±0.33	22.33±0.33

Notes: Values are expressed as Mean ± S.E.M (n=3), analysis was performed with One-Way ANOVA followed by Tukey’s test; ^aCompared to positive control, ^bTo 25 mg/mL, ^cTo 50 mg/mL, ^dTo 100 mg/mL, ^eTo 200 mg/mL; *P<0.05, **P<0.01, ***P<0.001. The negative control has shown no antibacterial activity.

Abbreviations: CAF, chloramphenicol; Vacho, vancomycin.

Figure 1 Zone of inhibition of A. schimperi TCM (A) and EA (B) fraction against S. typhi(+ve CAF disc as a positive control and 5%DMSO as a negative control).

Figure 2 Agar well diffusion test by PE fractionate of the leaves of A. schimperi against K. pneumoniae. (+ve CAF disc as a positive control and 5% DMSO as a negative control).

Table 6 The MIC (in mg/mL) of the Solvent Fractions of the Leaves of A. schimperi Against Tested Bacteria

Bacteria	DCM Fraction		PE Fraction
	MIC	MBC	MIC	MBC
K. pneumoniae	4.17±0.00	6.95±1.39	11.13±2.78	11.13±2.78
S. aureus	13.91±2.78	16.70±0.00	13.91±2.78	19.416±7.34
C. freundii	22.24±5.54	22.24±5.54	33.34±0.00	33.34±0.00
E. coli	11.13±2.78	13.91±2.78	13.91±2.78	16.70.±0.00
P. aeruginosa	13.91±2.78	13.91±2.78	11.13±2.78	13.91±2.78
S. typhi	11.13±2.78	13.91±2.78	11.13±2.78	11.13±2.78

Note: The values are the average of triplicate tests.

Abbreviation: MIC, minimum inhibitory concentration.

Table 7 The MIC (in mg/mL) of the Solvent Fractions of the Leaves of A. schimperi Against Tested Bacteria

	TCM Fraction		EA Fraction
	MIC	MBC	MIC	MBC
E. coli	16.7±0.000	22.24±5.54	22.24±5.54	16.7±0.000
S. typhi	8.35±0.000	8.35±0.000	4.17±0.000	4.17±0.000
S. aureus	27.79±5.54	27.79±5.54	27.79±5.54	33.34±0.00
C. freundii	44.45±11.11	55.56±11.11	44.45±11.11	55.56±11.11
K. pneumoniae	27.79±5.00	33.34±0.00	33.34±0.000	33.34±0.000
P. aeruginosa	11.14±2.79	11.14±2.79	8.35±0.000	11.14±2.79

Note: The values are the average of triplicate tests.

Abbreviation: MIC, minimum inhibitory concentration.