Phytochemical analysis of Clinopodium candidissimum (Munby) Kuntze growing in Algeria by an integrated HS-SPME-GC-MS, NMR and HPLC-DAD-MSn approach: valorisation of an endemic natural source of bioactive compounds.

Clinopodium candidissimum (Munby) Kuntze (Lamiaceae) is used in traditional medicine and as a food condiment in Algeria, where it is known as Zaater cheleuh and Nabta elbida. Here, we report the comprehensive characterisation of non-volatile polar constituents extracted from C. candidissimum aerial parts (a mixture of inflorescences, stems and leaves), and their aroma profile. Qualitative 1H-NMR and quali-quantitative HPLC-MSn analyses of fractions obtained with solvents at different polarity revealed the presence of aglyconic and glycosylated flavonoids (3.1%), phenylpropanoids (3.6%), gallic acid derivatives (0.76%), and triterpenoids (0.62%), among the others. On the other hand, HS-SPME-GC-MS allowed to identify 38 volatile constituents, among which the oxygenated monoterpenes pulegone (44.8%), piperitenone (6.6%), isopulegone (5.8%) and neo-menthol (3.8%), and the sesquiterpene hydrocarbons germacrene D (16.2%) and bicyclogermacrene (3.0%) were the most abundant. Overall, results indicate that C. candidissimum represents an endemic natural source of antioxidants and bioactive compounds, and they will be useful for further studies on this species.

Composition and profiling of essential oil, volatile and crude extract constituents of Micromeria inodora growing in western Algeria.

The chemical constituents of the aerial parts of Micromeria inodora (Desf.) Benth. (Lamiaceae) collected in western Algeria, an aromatic shrub traditionally consumed as an herbal remedy, have been characterized. Secondary metabolites were extracted using sequential extractions with solvents at different polarity, and they were determined using an integrated nuclear magnetic resonance (NMR) and high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) approach. The composition of the essential oil obtained by hydrodistillation was characterized by gas chromatography-mass spectrometry (GC-MS), and the aroma profile was analysed by head-space solid phase micro extraction (HS-SPME) coupled with GC-MS. NMR and LC-MSn analyses revealed the presence of aglyconic and glycosylated flavonoids, phenylpropanoid derivatives and triterpenoid acids, mainly in the methanol, dichloromethane and n-hexane extracts. The analysis of the essential oil allowed to identify 66 components, mainly oxygenated mono- and sesquiterpenes (38.2 % and 32.0 %, respectively) and sesquiterpene hydrocarbons (10.8 %). The aroma profile revealed by HS-SPME-GC-MS was characterized by 45 volatile compounds, among which oxygenated monoterpenes appeared to be the most abundant (65.8 %), followed by sesquiterpene hydrocarbons (16.4 %) and monoterpene hydrocarbons (10.6 %). Overall, these data indicate that M. inodora could be a potential source of antioxidants and bioactive compounds, and they represent a starting point for further research on this plant species.