No abstract

The combination of essential oils (EOs) is a novel alternative to improve their preservative effects and to reduce their organoleptic impact in food. In this context, this work aims to investigate the antibacterial combined effect of two EOs combinations through the calculation of the fractional inhibitory concentration index. The combinations tested consists of Lavandula dentata/Origanum majorana EOs and Thymus serpyllum/Origanum majorana EOs. Their chemical compositions were identified by CG/MS analyses. The main compounds of O. majorana EO were (-)-terpinene-4-ol and trans-4-thujanol. Those of L. dentata EO were β-pinene and 1,8-cineole, and those of T. serpyllum EO were p-cymene and γ-terpinene. Regarding the outcomes, results highlighted partial synergistic and additive interactions. Two combinations of marjoram and thyme EOs had antibacterial activities against S. aureus. The first one corresponded to the quarter of the minimum inhibitory concentration of marjoram and half that of thyme. The second one was the mix of half and quarter of the minimum inhibitory concentration of respectively marjoram and thyme EOs. This last combination also showed an antibacterial effect against E. coli. The quarter and the half of their minimum inhibitory concentration of marjoram and lavender combination, respectively, gave a partial synergy against both strains. Henceforth, these findings could be largely exploited in food preservation through the use of minimal doses of these plant products without affecting the antibacterial and the organoleptic properties in foods.

Phytopharmaceuticals play an essential role in medicine, since the need to investigate highly effective and safe drugs for the treatment of diabetes mellitus disease remains a significant challenge for modern medicine. Arbutus unedo L. root has various therapeutic properties, and has been used widely in the traditional medicine as an antidiabetic agent. The current study aimed to isolate the pharmacologically active compound from A. unedo roots using accelerated solvent extraction technology, to determine its chemical structure using different instrumental analytical methods, and also to evaluate the α-glucosidase inhibitory activity. The roots of A. unedo were exhaustively extracted by high-pressure static extraction using the Zippertex® technology (Dionex-ASE, Paris, France), and the extract was mixed with XAD-16 resin to reach quantifiable amounts of active compounds which were identified by high-pressure liquid chromatography (HPLC), 1H NMR (300 MHz), and 13C NMR. The antidiabetic activity of the isolated compound was evaluated using the α-glucosidase inhibitory assay. The active compound was isolated, and its structure was identified as catechin using instrumental analysis.The results revealed that the isolated compound has potential α-glucosidase inhibitory activity with an IC50 value of 87.55 ± 2.23 μg/mL greater than acarbose. This was used as a positive control, which has an IC50 value of 199.53 ± 1.12 μg/mL. According to the results achieved, the roots of A. unedo were considered the best source of catechin and the Zippertex® technology method of extraction is the best method for isolation of this therapeutic active compound. In addition, the α-glucosidase inhibitory activity results confirmed the traditional use of A. unedo roots as an antidiabetic agent. Future clinical trials and investigations of antidiabetic and other pharmacological effects such as anticancer are required.

In this work, the chemical composition, the antioxidant, and the antibacterial activities of two Moroccan essential oils less studied, extracted from Pelargonium asperum and Ormenis mixta, were investigated. According to the gas chromatography coupled to mass spectrometry analysis, citronellol (25.07%), citronellyl ester (10.52%), geraniol (10.46%), and buthyl anthranilate (5.93%) were found to be the major components of P. asperum, while O. mixta was mainly composed of D-germacrene (11.46%), 1,8-cineole (10.28%), and cis-methyl isoeugenol (9.04%). Moreover, O. mixta essential oil exhibited an important antioxidant activity being significantly higher than that exhibited by P. asperum oil (P < 0.001). As regards the antimicrobial activity of both essential oils, the zones of growth inhibition and the minimum inhibitory concentration values showed that P. asperum essential oil was more active than that of O. mixta. Thereafter, the impact of the binary combination of essential oils on their antimicrobial effect was investigated against Staphylococcus aureus using the fractional inhibitory concentration index calculation. The results showed a promising synergistic antibacterial interaction between essential oils studied.

Flavonoids are a class of natural chemicals with variable phenolic structures that have long been recognized for their health advantages, they have recently attracted researchers’ attention for treating diabetes and hyperglycemia. The goal of this research is to develop a novel antihyperglycemic formulation using a combination of three plant flavonoids: Linum usitatissimum L. seeds (FLU), Coriandrum sativum L. seeds (FCS), and Olea europaea var. sylvestris leaves (FOE) based on a mixture design experiment approach which generates the most effective ratio of each component in a mixture instead of the trial-and-error method. Prior to the test, sub-acute toxicity research was conducted to establish a safe and effective dosage. The Oral Glucose Tolerance Test (OGTT) was used to assess the antihyperglycemic impact of these extracts and their combinations in Swiss albino mice. The dose that showed efficacy and safety was 25 mg/kg, which was utilized in all formulations. According to the results, the binary and ternary combinations showed the most significant synergetic effects. The optimum combination with the most potent effect was 37% FLU, 20% FCS, and 43% FOE. This study’s mixture design and prediction model for glycemic variation (GV) may be utilized at an industrial level to develop a novel antidiabetic and antihyperglycemic formulation that is safe and effective.