Phenolic composition, in vitro antioxidant effects and tyrosinase inhibitory activity of three Algerian Mentha species: M. spicata (L.), M. pulegium (L.) and M. rotundifolia (L.) Huds (Lamiaceae)

Abstract

International audienceThe leaves of three Mentha species harvested in Algeria, Mentha spicata L. (MS), Mentha pulegium L. (MP) and Mentha rotundifolia (L.) Huds (MR) were examined for their content in polyphenols and for some activities-linked biological properties these could impart. The contents in total phenolics (TPC) and flavonoids (TFC) were evaluated by the Folin–Ciocalteu and the aluminum chloride methods, respectively. Whereas MS showed the highest TPC (12.0 ± 0.3 mg gallic acid equivalents/g of dry weight), MR had the highest content in TFC (3.3 ± 0.1 mg quercetin equivalents of dry weight). The pharmacological properties of these extracts were evaluated by assessing in vitro their antioxidant and antityrosinase activities. The modulation of mushroom tyrosinase activity was measured by colorimetry of the melanins formed in the presence of tyrosine. MS exhibited the strongest radical scavenging activity (RSA) in all assays: (i) the IC50s values to neutralize the 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) cation radicals (ABTS+) and the 2,2′-diphenyl-1-picrylhydrazyl radicals (DPPH) were 10.3 ± 0.9 and 16.2 ± 0.2 μg/mL, respectively; and (ii) its original electrochemically measured superoxide quenching index value is 188 ± 37 μg/mL (AI50). MR however showed the highest tyrosinase inhibitory activity (IC50 = 108 ± 20 μg/mL). A silica gel thin-layer chromatography (TLC) technique revealed the presence of caffeic and rosmarinic acids and diosmin in all extracts. These results were confirmed by high performance liquid chromatography with diode array detection (HPLC/DAD

Biophenols of mints: Antioxidant, acetylcholinesterase, butyrylcholinesterase and histone deacetylase inhibition activities targeting Alzheimer’s disease treatment

“…Mints showed strong antioxidant capacity consistent with previous reports (Fatiha et al, 2015;Stagos et al, 2012). One of the Australian native mints, M. australis, showed higher antioxidant capacity than recently reported by Tang, Konczak, and Zhao (2016), who found values of 0.398 and 1.932 mM TE/g DW in TEAC and FRAP assays, respectively.…”

“…The strong correlation between TPC and the antioxidant capacity of mints indicates that biophenols may be responsible for antioxidant activity (Fatiha et al, 2015;Stagos et al, 2012). Phenolic compounds are widely known to act as free radical scavengers by their reducing properties, acting as hydrogen or electron donating agents, singlet oxygen quenchers and metal chelators (Riachi & De Maria, 2015).…”

Mentha spicata L. infusions as sources of antioxidant phenolic compounds: emerging reserve lots with special harvest requirements

“…u; loss of a deoxyhexosyl-hexoside residue), which allowed its assignment as chrysoeriol-7-O-rutinoside, taking into account its previous identification in another Mentha species, such as Mentha × villosa. 21 The presence of luteolin-7-O-glucoside and luteolin has been reported in M. spicata, 7,8,13,14,22 although, to the best of our knowledge, the two compounds detected herein have not been reported in M. spicata. The M. spicata reserve lot presented a higher concentration of all the identified compounds than the standard lot, and both types of samples presented rosmarinic acid as the most abundant phenolic compound.…”

“…With the exception of luteolin-7-O-rutinoside, these compounds were previously identified in several studies regarding this species. 7,8,11 Compound 1…”

“…, accompanied by a secondary fragment ion at m/z 179 with approximately 75% abundance of the base peak, which allowed identifying it as 4-O-caffeoylquinic acid according to the fragmentation pattern described by Clifford et al 12 To the best of our knowledge these compounds have never been reported as such in M. spicata, although many researchers 8,11,[13][14][15] describe the presence of chlorogenic acid in this plant without indicating the particular caffeoylquinic acid they are referring to. Compound 2 presented a UV spectrum and product ions similar to p-coumaric acid.…”