Determination of Chemical Composition and Investigation of Biological Activities of Ocimum basilicum L.

This study aimed to determine the chemical composition of the essential oils (EOs) of Ocimum basilicum L., as well as to evaluate the antibacterial, antidiabetic, dermatoprotective, and anti-inflammatory properties, and the EOs and aqueous extracts of O. basilicum. The antibacterial activity was evaluated against bacterial strains, Gram-positive and Gram-negative, using the well diffusion and microdilution methods, whereas the antidiabetic activity was assessed in vitro using two enzymes involved in carbohydrate digestion, α-amylase and α-glucosidase. On the other hand, the dermatoprotective and anti-inflammatory activities were studied by testing tyrosinase and lipoxygenase inhibition activity, respectively. The results showed that the chemical composition of O. basilicum EO (OBEO) is dominated by methyl chavicol (86%) and trans-anethol (8%). OBEO exhibited significant antibacterial effects against Gram-negative and Gram-positive strains, demonstrated by considerable diameters of the inhibition zones and lower MIC and MBC values. In addition, OBEO exhibited significant inhibition of α-amylase (IC50 = 50.51 ± 0.32 µg/mL) and α-glucosidase (IC50 = 39.84 ± 1.2 µg/mL). Concerning the anti-inflammatory activity, OBEO significantly inhibited lipoxygenase activity (IC50 = 18.28 ± 0.03 µg/mL) compared to the aqueous extract (IC50 = 24.8 ± 0.01 µg/mL). Moreover, tyrosinase was considerably inhibited by OBEO (IC50 = 68.58 ± 0.03 µg/mL) compared to the aqueous extract (IC50 = 118.37 ± 0.05 µg/mL). The toxicological investigations revealed the safety of O. basilicum in acute and chronic toxicity. The finding of in silico analysis showed that methyl chavicol and trans-anethole (main compounds of OBEO) validate the pharmacokinetics of these compounds and decipher some antibacterial targets.

Determination of Chemical Compounds and Investigation of Biological Properties of Matricaria chamomilla Essential Oils, Honey, and Their Mixture.

This exploratory investigation aimed to determine the chemical composition and evaluate some biological properties, such as antioxidant, anti-inflammatory, antidiabetic, and antimicrobial activities, of Matricaria chamomilla L. essential oils (EOs). EOs of M. chamomilla were obtained by hydrodistillation and phytochemical screening was performed by gas chromatography-mass spectrophotometry (GC-MS). The antimicrobial activities were tested against different pathogenic strains of microorganisms by using disc diffusion assay, the minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) methods. The antidiabetic activity was performed in vitro using the enzyme inhibition test. The antioxidant activity of EOs was tested using the free radical scavenging ability (DPPH method), ferrous ion chelating (FIC) ability, and ß-carotene bleaching assay. The anti-inflammatory effects were tested in vivo using the carrageenan-induced paw edema method and in vitro using the inhibition of the lipoxygenase test. The analysis of the phytochemical composition by GC-MS revealed that camphor (16.42%) was the major compound of EOs, followed by 3-carene (9.95%), ß-myrcene (8.01%), and chamazulene (6.54%). MCEO, honey, and their mixture exhibited antioxidant activity against the DPPH assay (IC50 ranging from 533.89 ± 15.05 µg/mL to 1945.38 ± 12.71 µg/mL). The mixture exhibited the best radical scavenging activity, with an IC50 of 533.89 ± 15.05 µg/mL. As antidiabetic effect, EO presented the best values against α-glucosidase (265.57 ± 0.03 µg/mL) and α-amylase (121.44 ± 0.05 µg/mL). The EOs and honey mixture at a dose of 100 mg/kg exhibited a high anti-inflammatory effect, with 63.75% edema inhibition after 3 h. The impact of EOs on the studied species showed an excellent antimicrobial (Staphylococcus aureus ATCC 29213 (22.97 ± 0.16 mm)), antifungal (Aspergillus niger (18.13 ± 0.18 mm)) and anti-yeast (Candida albicans (21.07 ± 0.24 mm) effect against all the tested strains. The results obtained indicate that the EOs of M. chamomilla could be a potential drug target against diabetes, inflammation and microbial infections; however, further investigations to assess their bioactive molecules individually and in combination are greatly required.

Chemical Profiling and Biological Activities of Pelargonium graveolens Essential Oils at Three Different Phenological Stages.

The aim of this work was the determination of Pelargonium graveolens (aerial parts) volatile compounds at three developmental stages and the evaluation of their antioxidant, antidiabetic, dermaprotective, anti-inflammatory, and antibacterial effects. The aerial parts of Pelargonium graveolens were collected at three stages, namely the vegetative, beginning, and full flowering. Pelargonium graveolens essential oils were extracted from the dried materials of these aerial parts by hydrodistillation. The volatiles were analyzed by Gas Chromatography-Mass Spectrometry GC-MS, and the antioxidant activity was assessed by DPPH, ABTS, H2O2, and FRAP assays. The in vitro antidiabetic effect was evaluated by the inhibition of α-amylase, α-glucosidase, and lipase enzymes, while the antibacterial activity was assessed against six bacterial strains using an agar well diffusion assay and a microdilution method. The main constituents were menthol, menthene, eremophilene, isoborneol, isogeraniol, α-pinene, linalyl acetate, and 3-carene, with quantitative differences at the three phenological stages. The essential oil at the full flowering stage showed the best antioxidant activity, with IC50 values of 83.26 ± 0.01, 116.42 ± 0.07, 132.25 ± 0.11, and 48.67 ± 0.04 µg/mL for DPPH, FRAP, ABTS, and H2O2 assays, respectively. This oil also exhibited significant effects against α-amylase (IC50 = 43.33 ± 0.01 µg/mL), α-glucosidase (IC50 = 19.04 ± 0.01 µg/mL), lipase (IC50 = 24.33 ± 0.05 µg/mL), 5-lipoxygenase (IC50 = 39.31 ± 0.01 µg/mL), and tyrosinase (IC50 = 124.49 ± 0.07 µg/mL). The essential oil extracted at the full flowering stage showed the best antibacterial effect against a panel of microorganisms with diameter inhibition zones ranging between 11.00 ± 0.17 mm and 17.30 ± 0.17 mm and MIC values from 0.25% to 2% v/v. Overall, the results presented here suggest that the full flowering stage is the best optimal harvest time of Pelargonium graveolens for food and pharmaceutical applications.