Seasonal Variation in Essential Oils Composition and the Biological and Pharmaceutical Protective Effects of Mentha longifolia Leaves Grown in Tunisia

Table 1

Yields extracts, amounts of total flavonoids, total phenolic compounds, and determined IC₅₀ values of the DPPH free radical scavenging assay of M. longifolia leave extracts and essential oil. Ascorbic acid was used as positive control.

Extracts	Yield ()	TPC; mg GAE/g	TF; mg QE/g	DPPH; IC50 (g/ml)	carotene; IC50 (g/ml)
Ml EtOH-H2OE	12.46	59.25±0.38	18.23±0.35	16.23 ± 1.60	66.75± 0.57
Ml HexF	7.35	nd	nd	> 1000	>1000
Ml EtAOcF	2.5	99.72±1.26	20.85 ± 0.94	12.64± 0.21	34.75 ± 0.76
Ml WF	2.61	45.25 ± 0.87	10.75 ± 0.47	47.71± 0.43	56.31± 0.67
E-E	0.5-2.5	-	-	> 100	> 100
Ascorbic acid	-	-	-	3.50	-

TPC: total phenolic content; TF: flavonoid content.
mg GAE /g: mg of gallic acid equivalent per g of dry plant extract.
mg QE/g: mg of quercetin equivalent per g of dry plant extract.
IC₅₀ (μg/ml): the IC₅₀ values corresponding to the amount of extract required to scavenge 50 % of radicals present in the reaction mixture.
nd: not detected.
E: essential oil extracted at winter season; E: spring essential oil.