Antimicrobial, anticancer, and antioxidant compounds from Premna resinosa growing in Saudi Arabia

Figures & data

Figure 1. Chemical structures of the isolated flavonoids.

Figure 2. Minimum inhibitory concentrations (mg/mL) of the isolated compounds P. resinosa. Qu: Quercetin; 3-Me: 3-Methoxy quercetin; Ka: Kaempferol; 3-Met: 3-Methoxy kaempferol; Myr: Myricetin 3,7,3′-trimethyl ether; Lu: Lupeol and Sti: Stigmasterol.

Table 1. Minimum inhibitory concentrations (mg/mL) of the P. resinosa crude methanol extract and its fractions.

Organism tested	Crude methanol Ex.	n-Hexane Fr.	Dichloromethane Fr.	EtOAc. Fr.	n-Butanol Fr.
S. aureus^a	0.06	0.01	0.25	0.06	1
S. aureus^b	0.25	0.12	0.25	0.5	0
B. subtilis	0.25	0.06	0.25	0.12	1
E. faecalis	0.03	0.01	0.01	0.03	0.5
A. baumannii	1	0.25	0.25	0.5	1
E. coli	0.12	0.03	0.25	0.06	1
S. typhimurium	1	0.5	1	1	2
S. flexneri	0.12	0.01	0.01	0.03	0.12

Staphylococcus aureus ^aATCC 29312, Staphylococcus aureus ^bATCC-25923, Bacillus subtilis NCTC 10400, Acinetobacter baumannii BM 4436, Escherichia coli 469-3 (O21: H^-), Salmonella typhimurium ATCC 14028, Shigella flexneri ATCC 12022.

Table 2. Cytotoxic activity of methanol extract of P. resinosa, its fractions and isolated compounds.

Tested samples	Daoy		HepG2		SK-MEL28
	% Inhibition25 (μg/mL)	IC50 (μg/mL)	% Inhibition25 (μg/mL)	IC50 (μg/mL)	% Inhibition 50(μg/mL)	IC50 (μg/mL)
	Crud extract and its fractions
Crude methanol ext.	62.1	5.2 ± 2.8	40.1	NT	0	NT
n-Hexane fr.	64.5	9.0 ± 1.9	83.9	8.5 ± 2.2	70.4	13.2 ± 4.1
Dichloromethane/ethyl acetate fr.	62.9	17.8 ± 3.5	81.4	9.8 ± 3.1	38.0	NT
n-Butanol fr.	0	–	0	NT	1.48	NT
Isolated compounds
Quercetin	62.40	10.5 ± 2.4	23.31	>25*	0	>25*
3-Methoxy quercetin	51.07	19.6 ± 4.3	30.21	>25*	44	>25*
Kaempferol	54.84	21.1 ± 3.1	36.56	>25*	4.86	>25*
3-Methoxy kaempferol	14.94	>25	33.25	>25*	65.76	18.8 ± 3.8
Myricetin 3,7,3′-trimethyl ether	65.0	7.0 ± 1.2a	40.72	>25*	22.15	>25*
Lupeol	36.89	>25*	0	>25*	0.045	>25*
Stigmasterol	45	>25*	39.77	>25*	37.05	>25*
Dasatinib	76.60	7.3 ± 1.6a	72.03	8.2 ± 2.1	51.95	23.8 ± 4.6

Percent inhibition of cell survival at a concentration of 25 (μg/mL), relative to control (DMSO-treated cells), Daoy: Medulloblastoma cell line, HepG2: hepatocellular carcinoma cell line, SK-MEL28: melanoma cell line, NT: Not tested. In the column of IC₅₀, means ± SD with same letter notification are not significantly different at (p < 0.05) (n = 3). *Not included in statistical analysis.

Table 3. Antioxidant and free radical scavenging activity of the fractions and isolated compounds of P. resinosa.

Fractions and isolated compounds	*Total antioxidant activityin %(1000 μg/mL)	Free radical scavenging activity % (DPPH) assay
		Concentration (μg/mL)
		10	50	100	500	1000
		Fractions
n-Hexane	61.4 ± 6.1	2.3 ± 1.2	9 ± 2.3	37.1 ± 3.9	67.6 ± 3.2d	77.5 ± 2.7
Dichloromethane	90.6 ± 5.6a	25.5 ± 4.3	69 ± 3.0	90.8 ± 4.2a	97.1 ± 2.1a	96.5 ± 1.9
Ethyl acetate	86.1 ± 4.5b	18.1 ± 2.9a	48.3 ± 5.5	81.9 ± 3.1c	92.5 ± 2.6a	92.9 ± 2.3a
n-Butanol	72.0 ± 5.2	12.5 ± 2.3	21.4 ± 4.7	48.8 ± 5.0	72.2 ± 3.8cd	85.7 ± 4.1
Isolated compounds
Quercetin	94.4 ± 3.8	29.2 ± 4.1	81.1 ± 2.8	91.2 ± 1.9a	91.5 ± 1.6ab	95.8 ± 2.3b
3-Methoxy quercetin	90.5 ± 4.3a	16 ± 3.2	55.1 ± 5.1	86.1 ± 3.4b	91.0 ± 2.1a	92.1 ± 1.9bc
Kaempferol	91.2 ± 4.1a	22.4 ± 5.1	74.8 ± 3.2	82.0 ± 3.0c	90.0 ± 2.5a	92.9 ± 1.6d
3-Methoxy kaempferol	86.2 ± 3.9b	18.8 ± 4.0a	49.6 ± 4.6	82.8 ± 5.1c	90.5 ± 3.3a	91.0 ± 2.8cd
Myricetin 3,7,3′-trimethyl ether	80.9 ± 5.3	15.4 ± 3.3	41.6 ± 2.8	63.5 ± 3.2	78.1 ± 4.1bc	87.1 ± 3.0
Rutin	93.1 ± 3.0	NT	NT	NT	NT	NT
Ascorbic acid	NT	33.5 ± 3.1	71.2 ± 4.9	85.5 ± 2.8b	92.7 ± 2.4a	94.1 ± 2.1a

* β-carotene-linoleic acid assay. NT: not tested. In a column, means ± SD with same letter notification are not significantly different at (p < 0.05) (n = 3).