Ethnobotanical study and valorization of bioactive compounds of food interest of some native Lamiaceae of western Algeria: case of Calamintha candidissima (Munby) Benth. and Micromeria inodora (Desf.) Benth.

Abstract

The purpose of this study was to characterize Clinopodium candidissimum (Munby) Kuntze and Micromeria inodora (Desf.) Benth. (Lamiaceae) natives of western Algeria by the investigation of ethno-medicinal uses by ethnobotanical investigations, phytochemistry by the quantification of minerals, the rate of polyphenols and flavonoids, the composition of essential oils obtained by hydrodistillation by gas chromatography - mass spectrometry (GC-MS), the aromatic profile by solid phase micro-extraction in the headspace (HS-SPME) coupled with GC-MS, also NMR and LC-MSn and HPLC-DAD-MSn were performed for polar fractions. The in vitro bioactivity of different extracts was evaluated by several tests, namely: antioxidant potential by three methods (DPPH, ABTS and CUPRAC); enzymatic inhibition potential by cholinesterases, α-glucosidase and α-amylase, In addition, our extracts were examined for their possible antimicrobial activity using the method of disk diffusion against several strains. Informants reported no traditional knowledge of M. inodora, while for C. candidissimum, therapeutic and culinary uses were recorded for traditional uses of Nepeta albida, which is morphologically similar to our plant. A high level of minerals, particularly iron, manganese, zinc, boron, copper, calcium and potassium has been confirmed. Levels of phenolic compounds and flavonoids in the methanolic extracts were 63.33 (μg GAeq.mg-1Ext) and 11.19 (μg Qeq.mg-1Ext) for M. inodora; 58.79 (μg eq AG/mg Ext) and 40.93 (μg eq Q/mg Ext) for C. candidissimum. For M. inodora, NMR and LC-MSn analyses revealed the presence of aglyconic and glycosylated flavonoids, phenylpropanoid derivatives and acids triterpenoids. Analysis of the oil identified 66 components, primarily oxygenated mono- and sesquiterpenes (38.2% and 32.0%, respectively). The aromatic profile by HS-SPME-GC-MS revealed 45 compounds, among which oxygenated monoterpenes appeared to be the most abundant (65.8%). For C. candidissima, qualitative analyses by 1H-NMR and qualitative analyses by HPLC-MSn revealed the presence of aglyconic and glycosylated flavonoids (3.1%), phenyl propanoids (3.6%), and other compounds. On the other hand, HS-SPME-GC-MS identified 38 volatile constituents, among which the oxygenated, pulegone monoterpenes (44.8%) was the most abundant. Analyses of antioxidant activity showed moderate capacity. The potential for enzymatic inhibition indicates a lack of activity. Antimicrobial activity has shown that all strains tested are sensitive to our extracts. Overall, these data indicate that C. candidissimum and M. inodora may be a potential source of antimicrobial and bioactive compounds and a starting point for further research on these plant species.