Phenolic profile and biological activities ofMicromeria graeca(L.) Benth. ex Rchb

Phytochemical analysis and in vitro biological activity assessment of extracts from Micromeria myrtifolia

In this study, the antioxidant capacity, the effect on anti-acetylcholinesterase and anti-urease enzyme inhibition, and kidney stone-reducing effects of different extracts from M.myrtifolia. In addition, the phytochemical content of the bioactive methanol extract was analyzed by HPLC-DAD. The methanol extract showed strong DPPH (IC50:0.036 mg/mL) radical scavenging, Cu (II) ion (6.535 mmTroloxE) and Fe3+ (6.476 FeSO4) ion reducing antioxidant activity compared to other extracts. The methanol extract contained the highest amount of phenolic (400 mgGAE) and flavonoid (2.519 QuE) compounds. Moreover, the methanol extract had significant anticholinesterase (78.935%), anti-urease (71.014%) and calcium oxalate anti-crystallization (18.22%, 37.427%) activities. The findings show that all extracts exhibited varying amounts of antibacterial activity against Staphylococcus aureus. The bioactive methanol extract contained rosmarinic acid (31.35 µg), quercetin (12.99 µg) and chlorogenic acid (3.55 µg). The analyzed compounds are thought to contribute significantly to the pharmacological effect of the methanol extract.

Effects of Different Solvents on the Total Phenol Content, Total Flavonoid Content, Antioxidant, and Antifungal Activities of Micromeria graeca L. from Middle Atlas of Morocco

Micromeria graeca L. is a dense chemical source of bioactive compounds such as phenolic compounds, which have various health-related properties. The current study aimed to investigate the impact of different extractor solvents on phenol and flavonoid contents, as well as the antioxidant and antifungal activities of different extracts. Initially, three extractor solvents (methanol, ethyl acetate, and water) were used to prepare the Soxhlet extracts, which were then examined for their polyphenolic content, flavonoid content, and antioxidant potential using three complementary assays (DPPH, FRAP, and TAC). The antifungal capacity against the two fungal strains (Candida albicans and Aspergillus niger) was performed using the method of diffusion on disc. The dosage of phytochemical compounds revealed that the highest values were established in water extract with values of 360 ± 22.1 mg GAE/g dry weight plant and 81.3 ± 21.2 mg RE/g dry weight plant for TPC and TFC, respectively. In addition, the strongest antioxidant activity measured by DPPH and FRAP assays was established in water extract with IC50 values of 0.33 ± 0.23 and 0.23 ± 0.12 mg/mL, respectively, while the methanol extract showed the best antioxidant activity as measured by TAC with an IC50 of 483 ± 17.6 mg GAEq/g dry weight plant. The water extract recorded the most important antifungal activity against Candida albicans with an inhibition zone of 16 ± 1.6 mm and MFC = 500 μg/mL, whereas ethyl acetate extract showed the lowest activity against both studied fungi strains. Micromeria graeca L. contains considerable amounts of bioactive contents with high antioxidant and antifungal potentials, which may make it a promising source of antioxidants and natural antifungal agents.

Metabolic profiling and biological activities of the aerial parts of Micromeria imbricata Forssk. growing in Saudi Arabia

The hydroalcoholic extract (MIT) of Micromeria imbricata (Forssk.) growing in Saudi Arabia in addition to the chloroform (MIC) and n-butanol (MIB) fractions were investigated for the first time using UPLC-ESI-MS/MS. The analysis revealed the tentative identification of fifty-eight compounds including three organic acids, twenty-five phenolic compounds, three coumarins, two anthocyanins, twenty-one flavonoids, three terpenes, and one miscellaneous. Moreover, the therapeutic potential of M. imbricata (MIT) and its fractions (MIC and MIB) were determined by in vitro evaluation of their cytotoxic, antioxidant, and anti-obesity characteristics. The MIT extract showed the highest phenolic (125.23 ± 0.87 mg gallic acid equivalent/100 gm extract) and flavonoid (112.24 ± 2.45 mg quercetin equivalent/100 gm extract) contents followed by n-butanol and chloroform fractions. The MIT extract revealed a potent cytotoxic activity against HepG-2 (Hepatocellular carcinoma) and MCF-7 (Breast carcinoma) with IC₅₀ 28.5 ± 2.0 and 35.2 ± 1.2 µg/mL, respectively. Additionally, the tested hydroalcoholic extract exhibited a significant DPPH scavenging activity with SC₅₀ 28.4 ± 1.2 µg/mL and a remarkable lipase inhibitory activity with IC₅₀ 54.2 ± 1.2 µg/mL. In conclusion, the current study presents the first insights into the phytochemical constituents and pharmacological properties of M. imbricata extract and its chloroform and n-butanol fractions. The results revealed that M. imbricata hydroalcoholic extract might be a prolific source of bioactive constituents with potent antioxidant, cytotoxic and anti-obesity potential. It might be a natural alternative therapy and nutritional strategy for obesity treatment.

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.

Phytochemical composition and biological activities of native and in vitro-propagated Micromeria croatica (Pers.) Schott (Lamiaceae)

In vitro culture conditions and kinetin induced quantitative modifications in the production of the major volatile constituents in Micromeria croatica plantlets. Antimicrobial activity of methanolic extracts obtained from micropropagated and wild-growing plants was evaluated. Micromeria spp. are aromatic plants, many of which were shown to exhibit various biological effects. The present study aimed to determine the content and the composition of the essential oil of in vitro-cultured Micromeria croatica (Pers.) Schott and to evaluate the in vitro antimicrobial activity of its methanolic extract, in order to compare its phytochemical profile and biological activity with wild-growing plants. Shoots regenerated on MS medium without plant growth regulators (PGRs) or supplemented with kinetin were used for phytochemical analysis. Essential oils from both native plant material and in vitro-cultivated M. croatica plants, with a total of 44 identified constituents, were dominated by oxygenated monoterpenes. Borneol was the main component detected in wild-growing plants (25.28%) and micropropagated plants grown on PGR-free medium (20.30%). Kinetin treatment led to increased oil yield and favored the production of oxygenated monoterpenes, dominated by geranial (33.53%) and cis-p-mentha-1(7),8-dien-ol (23.69%). The percentage of total sesquiterpenoids in micropropagated plant material was considerably lower than in wild-growing plants. In vitro culture conditions and PGRs affected the production of essential oils, inducing quantitative modifications in the production of the major volatile constituents in M. croatica plantlets. The antimicrobial activity of M. croatica methanolic extracts was investigated using the broth microdilution method. Extracts obtained from in vitro cultures generally exhibited greater antibacterial potential, compared to wild-growing plants. Among six bacterial strains tested, Bacillus cereus and Staphylococcus aureus were the most sensitive microorganisms. The present study provided evidence that in vitro culture conditions might favorably affect the antimicrobial activity of M. croatica methanolic extracts.