Antioxidant and antimicrobial activities of ethanol and aqueous extracts from Urtica urens

Figures & data

Table 1. Extract yield and total flavonoids, phenolic and tannin contents from Urtica urens extracts.

Sample	Yield (%)	Flavonoids (mg quercetin/g DW)	Phenolics (mg GAE/g DW)	Tannins (mg GAE/g DW)
Ethanol	4.768	6.81 ± 1.72	31.41 ± 0.31	8.29 ± 0.3
Aqueous	0.87	5.34 ± 0.21*	29.56 ± 1.56*	4.05 ± 0.52*

Values are expressed as mean ± SEM of three independent determinations. *p < 0.05.

DW: dry weight.

Figure 1. Antioxidant capacity of ethanol and aqueous extracts of Urtica urens by the DPPH• method at different concentrations. BHT and ascorbic acid (Vitamin C) were used as positive control. Values are means ± SEM (n = 3).

Table 2. Antioxidant activity of Urtica urens extracts (ABTS^•+, DPPH^•).

Sample	DPPH^• scavenging (IC50, μg/mL)	ABTS^•+ scavenging (IC50, μg/mL)	DPPH^• scavenging (mg TE/g extract)	ABTS^•+ scavenging (mg TE/g extract)
Ethanol	245.65 ± 10.2	30.88 ± 3.03	65.33 ± 10.72	560.33 ± 29.45
Aqueous	142.94 ± 10.54***	14.65 ± 1.09***	45.67 ± 10.21***	350.33 ± 18.73***

Values are expressed as mean ± SEM of three independent determinations. ***p < 0.001.

TE: Trolox equivalents; IC: Inhibition Concentration.

Figure 2. ABTS (TEAC) activities of Urtica urens extracts. Values are means ± SEM (n = 3). ***p < 0.001.

Figure 3. β-Carotene bleaching percentage of Urtica urens extracts. Values are means ± SEM (n = 3). ***p < 0.001. α: compared to BHT (control); β: compared to Ascorbic Acid; £: compared to Ethanol.

Figure 4. FRAP activities in ethanol and water extracts of Urtica urens. Values represent means ± SEM (n = 3). ***p < 0.001. α: compared to BHT; β: compared to Ethanol.

Table 3. Rapport MBC/MIC.

		Ethanol		Aqueous
	Stains	MBC/MIC		MBC/MIC
Gram+	Bacillus subtilis	2	bactericidal	–
	Staphylococcus aureus	2	bactericidal	–
	Micrococcus luteus	2.01	bactericidal	–
	Staphylococcus epidermidis	2	bactericidal	–
	Enterococcus faecalis	–	–	–
Gram−	Escherichia coli	–	–	–
	Salmonella enteritidis	1.93	bactericidal	–
	Pseudomonas aeruginosa	2	bactericidal	–
Rapport MBC/MIC Canillac & Mourey 2001		MBC/MIC ≥4		bacteriostatic
		MBC/MIC <4		bactericidal

Table 4. Levels of vitamins D, C and E in Urtica urens leaves.

Sample	Vitamin D (mg/100 g)	Vitamin C (mg/100 g)	Vitamin E (mg/100 g)
Ethanol	1.45 ± 0.14	238 ± 2.95	356 ± 0.15
Aqueous	0.23 ± 0.04	160.55 ± 3.09^α***	2.3 ± 0.01^α***

Values are expressed as mean ± SEM of three independent determinations. ***p < 0.001.

α: compared to Ethanol.

Canillac N, Mourey A. 2001. Antibacterial activity of the essential oil of Picea excelsa on Listeria, Staphylococcus aureus and coliform bacteria. Food Microbiol. 18:261–268.

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