Bioactivities of phytochemicals in Callistemon citrinus against multi-resistant foodborne pathogens, alpha glucosidase inhibition and MCF-7 cancer cell line

Figures & data

Table 1. Simplex lattice design and experimental data for responses from Callistemon extract.

Block	Standard order	Run order	X1	X2	Y1
1	8	1	0.5	0.5	29.049
1	6	2	1	0	14.414
1	2	3	0.5	0.5	18.567
1	4	4	0.75	0.25	28.959
1	1	5	1	0	18.934
1	5	6	0.25	0.75	19.361
1	7	7	0	1	24.644
1	3	8	0	1	15.678

*X₁: Methanol; X₂: Water component; Y1: TPC (mg GAE/g sample).

Figure 1. Comparison of extraction methods with aqueous and organic solvents for extracts from leaf and flower of C. citrinus. CLWA, HPLC grade water leaf extract; CLMT, methanol leaf extract; CLAC, acetone leaf extract; CLET, ethanol leaf extract; CFWA, HPLC grade water flower extract; CFMT, methanol flower extract; CFAC, acetone flower extract; CFET, ethanol flower extract.

Figure 2. FT-IR spectra of extracts from flowers (a) and leaves (b) of C. citrinus.

Table 2. Total phenolic contents, antioxidant capacity and α-glucosidase inhibition potential of extracts from Callistemon leaves and flowers.

Plant samples	TPC (mg GAE/g sample)	EC50 (g sample/g DPPH)	TEAC (mg/TEAC g sample)	IC50 (μg/mL) (α-glucosidase inhibition*)
CL	24.985 ± 7.38^a	0.474 ± 0.03^b	426.604 ± 12.54^a	3.690 ± 0.61^b
CF	23.118 ± 1.57^b	0.787 ± 0.15^a	196.269 ± 6.54^b	4.830 ± 0.01^a

*Values in the same column with ± SD and different superscripts are significantly different (P ˂ 0.05).

Table 3. Antibacterial activity of Callistemon extracts against pathogenic gram-positive and gram-negative bacteria.

		Gram-positive			Gram-negative
Sample	Conc (%)	B. cereus	S. aureus	L. monocytogenes	Y. enterocolitica	S. typhimurium	E. coli O157:H7
CL	10	16.75 ± 0.35^a	19.00 ± 2.83^a	32.50 ± 0.71^a	18.50 ± 0.71^a	ND	ND
	5	15.25 ± 0.35^b	16.50 ± 2.12^a	27.50 ± 2.12^ab	15.75 ± 0.35^b	ND	ND
	2	13.25 ± 0.35^c	15.50 ± 2.12^a	25.25 ± 2.47^ab	14.25 ± 0.35^b	ND	ND
	1	12.75 ± 0.35^c	13.75 ± 1.06^a	21.00 ± 2.83^b	11.75 ± 0.35^c	ND	ND
CF	10	19.50 ± 0.71^a	20.00 ± 0.00^a	35.00 ± 2.83^b	15.50 ± 0.71^a	ND	ND
	5	17.75 ± 0.35^ab	17.75 ± 0.35^ab	31.50 ± 2.12^a	12.50 ± 0.71^b	ND	ND
	2	15.00 ± 1.41^bc	16.25 ± 1.06^b	29.50 ± 0.71^ab	11.50 ± 0.71^bc	ND	ND
	1	14.00 ± 0.71^c	12.50 ± 0.71^c	25.00 ± 1.41^b	9.50 ± 0.71^c	ND	ND

*Conc, concentration; CL, Callistemon leaf extract; CF, Callistemon flower extract; ND, not detected. Values in the same column with ± SEM and different superscripts are significantly different (P ˂ 0.05).

Table 4. Antibacterial activity of Callistemon extracts against non-pathogenic bacteria.

Sample	Concentration (%)	S. carnosus	S. xylosus	L. sakei	L. plantarum
CL	10	18.25 ± 0.35^a	20.75 ± 1.06^a	ND	ND
	5	16.50 ± 0.71^ab	19.00 ± 1.41^a	ND	ND
	2	15.50 ± 0.71^bc	17.50 ± 2.12^a	ND	ND
	1	13.50 ± 0.71^c	16.00 ± 1.41^a	ND	ND
CF	10	18.50 ± 0.71^a	16.75 ± 0.35^a	ND	ND
	5	17.25 ± 0.35^ab	14.50 ± 0.71^ab	ND	ND
	2	14.75 ± 1.06^ab	13.00 ± 1.41^ab	ND	ND
	1	12.75 ± 2.47^b	11.00 ± 1.41^b	ND	ND

*CL, Callistemon leaf extract; CF, Callistemon flower extract; ND, not detected. Values in the same column with ± SEM and different superscripts are significantly different (P ˂ 0.05).

Figure 3. Population and apoptosis profiles for MCF-7 cell treated with leaf (CL) and flower (CF) extracts.

Figure 4. Cell index profiles of fibroblast normal cell line treated with different concentrations of leaf (CL) and flower (CF) extracts from C. citrinus.

Figure 5. Cell index profiles of MCF-7 cell line treated with different concentrations of leaf (CL) and flower (CF) extracts from C. citrinus.

Figure 6. Dose-response curve of MCF-7cell line and IC₅₀ level at 24 h of leaf (CL) and flower (CF) extracts from C. citrinus.

Table 5. MTT cell proliferation rate of MCF-7 cells cultured with and without Callistemon extracts.

CL concentration (µg/mL)	24 h	48 h	72 h
Control	99.9	100	100
1	8.2 ± 0.02^b	5.4 ± 0.06^c	15.2 ± 0.04^a
10	47.5 ± 0.01^a	11.3 ± 0.05^c	22.8 ± 0.01^b
50	29 ± 0.02^b	17 ± 0.04^c	40.7 ± 0.04^a
100	123.7 ± 0.04^a	28.8 ± 0.11^c	70.1 ± 0.02^b
200	374.4 ± 0.1^a	46.1 ± 0.1^c	83.7 ± 0.08^b
400	476.1 ± 0.12^a	70.6 ± 0.2^c	102.6 ± 0.09^b
CF concentration (µg/mL)	24 h	48 h	72 h
Control	100	100	99.9
1	5.4 ± 0.1^c	63.5 ± 0.2^a	40.8 ± 0.08^b
10	11.3 ± 0.07^c	51.4 ± 0.1^a	12.3 ± 0.08^b
50	17 ± 0.05^b	22.8 ± 0.08^a	11.8 ± 0.7^c
100	28.8 ± 0.05^a	26.1 ± 0.08^b	12.8 ± 0.08^a
200	46.1 ± 0.07^a	19.6 ± 0.1^b	10.1 ± 0.09^c
400	70.6 ± 0.09^a	33.8 ± 0.1^b	15.6 ± 0.1^c

*CL, Callistemon leaf extract; CF, Callistemon flower extract’. Values in the same row with ± SEM and different superscripts are significantly different (P ˂ 0.05).