Synthesis and antioxidant activity of monoterpene nitrobenzylidenesulfenimines

GC-MS analysis, phytochemical composition of Hertia cheirifolia L. essential oil with pharmacological assessments: antioxidant, antibacterial, and antifungal activities

The genus Hertia, which belongs to the Asteraceae family, is a flowering genus with 12 species found in Africa, North and South. Among the species present in Algeria, Hertia cheirifolia L. is distributed in the eastern regions of Algeria. The aim of this study is to evaluate its phytochemical composition with following pharmacological assessments: the antioxidant, antibacterial, and antifungal activities of Hertia cheirifolia L. essential oil (EO). GC-MS analysis was used to analyze the chemical constituents of H. cheirifolia essential oil. The antioxidant capacity was assessed using DPPH, FRAP, and H2O2 tests. The EO was also tested for its ability to inhibit six strains of microorganisms, including two Gram (+) and four Gram (-) strains. The antifungal activity was tested by analyzing the effect of the EO on the mycelial growth of Fusarium oxysporum f.sp. lycopersici (FOL) fungi. Results showed that primary volatile components were α-pinene (32.59%), 2-(1-cyclopent-1-enyl-1-methylethyl) cyclopentanone (14.62%), (-)-germacrene D (11.37%), and bakkenolide A (9.57%). H. cheirifolia EO showed inhibitory effects against DPPH, H2O2, and FRAP (IC50 = 0.34 ± 0.1, 0.053 ± 0.1, and 0.047 ± 0.01 mg mL-1, respectively). The EO also exhibited moderate antibacterial effects against Staphylococcus aureus ATCC 25923 (S. aureus), Streptococcus pneumoniae ATCC 49619 (S. pneumoniae), and Enterobacter aerogenes ATCC 13048 (E. aerogenes), as well as significant antioxidant potential and varied antifungal activity based on dosage and fungal strain. To our knowledge, no previous research has examined the antifungal capacity of H. cheirifolia oil and oil-mycelial development of the FOL relationship. To fully explore the benefits of H. cheirifolia EO, more in vivo research is necessary, along with more testing on other bacterial and fungal strains.

Bioactivity assays and phytochemical analysis upon Alcea glabrata; focusing on xanthine oxidase inhibitory and antimalarial properties

Alcea glabrata from the family Malvaceae, was selected for evaluating its xanthine oxidase inhibitory, anti-malarial, and antioxidant activities. In addition, some phytochemical analysis upon different extracts of A. glabrata were performed. Aerial parts of the collected A. glabrata plant material were dried and solvent extracted via soxhlet apparatus using different solvents. Various chromatographic techniques were used for extra fractionation of the achieved extracts. Xanthine oxidase (XO) inhibitory, antimalarial and antioxidant activity assays upon different A. glabrata extracts and fractions were carried out and reported in terms of IC_50s. Total phenolic and flavonoid contents of the A. glabrata methanol extract (MeOH) were determined using the 2,2-Di Phenyl-1-Picryl Hydrazyl (DPPH) assay, aluminum chloride colorimetric, and Folin-Ciocalteu reagents, respectively. In addition, A. glabrata essential oil was obtained through hydrodistillation by a Clevenger apparatus. Analysis and identification of essential oil compounds were carried out through gas chromatography mass spectrometry (GC-MS) analysis. MeOH extract showed the highest XO inhibitory activity with the IC₅₀ of 0.37 ± 0.12 μg/mL antioxidant activity with the RC₅₀ of 0.24 ± 0.06 μg/mL. While, chloroform extract revealed the strongest antimalarial activity with the IC₅₀ of 0.4 ± 0.05 μg/mL. The total flavonoid and phenolic contents of the A. glabrata methanol extract were 39.8 mg quercetin equivalent and 6.1 g gallic acid equivalent per 100 g of dry plant material, respectively. GC-MS analysis showed that the monoterpenes were prevailing in A. glabrata essential oil where the major constituents: octacosane (30.7%), eugenol (12.3%), and anethole (12.0%). Concerning the results of this study, A. glabrata extracts and its ingredients could be considered as a novel promising herbal medicine in the design and also treatment of new drugs for the relief of gout and malaria diseases.

Synthesis and Antimicrobial Activity of Sulfenimines Based on Pinane Hydroxythiols

The widespread presence of multidrug-resistant pathogenic microorganisms challenges the development of novel chemotype antimicrobials, insensitive to microbial tools of resistance. To date, various monoterpenoids have been shown as potential antimicrobials. Among many classes of molecules with antimicrobial activity, terpenes and terpenoids are an attractive basis for the design of antimicrobials because of their low toxicity and availability for various modifications. In this work, we report on the synthesis of sulfenimines from chiral trifluoromethylated and non-fluorinated pinane-type thiols. Final compounds were obtained with yields of up to 81%. Among the 13 sulfenimines obtained, 3 compounds were able to repress the growth of both bacteria (S. aureus, both MSSA and MRSA; P. aeruginosa) and fungi (C. albicans) with an MIC of 8-32 µg/mL. Although compounds exhibited relatively high cytotoxicity (the therapeutic index of 3), their chemotype can be used as a starter point for the development of disinfectants and antiseptics for targeting multidrug-resistant pathogens.

Thioterpenoids as Potential Antithrombotic Drugs: Molecular Docking, Antiaggregant, Anticoagulant and Antioxidant Activities

Natural monoterpenes and their derivatives are widely considered as effective ingredients for the design and production of new biologically active compounds with high antioxidant, antimicrobial and anti-protozoa properties. In this study, we synthesized two series of thiotherpenoids "sulfide-sulfoxide-sulfone", with different bicyclic monoterpene skeleton (bornane and pinane) structures. The effect of the obtained compounds on platelet aggregation was investigated by using the molecular docking technique. The obtained data revealed that all the synthesized compounds may act as potential inhibitors of platelet aggregation. Moreover, the studied sulfides have shown high antioxidant activity as revealed by lipid peroxidation (LPO) process inhibition in a non-cellular substrate containing animal lipids. The sulfides were able to inhibit erythrocyte oxidative hemolysis, to reduce the accumulation of secondary LPO products in cells and to prevent the oxidation of native oxyhemoglobin. Additionally, the corresponding sulfones and sulfoxides exhibited insignificant antioxidant activity. However, the sulfides were found to exhibit significant antiaggregant and anticoagulant effects. These findings suggest as well that the sulfides could serve as a leader compound for future research and possible practical applications.

Ceylon cinnamon and clove essential oils as promising free radical scavengers for skin care products

Due to adverse effects of free radicals on human skin and increasing consumer demand for natural ingredients, essential oils from basil, Ceylon cinnamon bark, clove, juniper, lavender, oregano, rosemary, tea tree, thyme, and ylang-ylang were assessed for their antiradical activity. The oils were evaluated in the concentration range of 5—0.1 mg·mL−1, in which the three reference synthetic antioxidants are most often added to mass-produced cosmetics. Among all examined samples, C. cinnamon oil at a concentration of 5 mg·mL−1 showed the strongest DPPH radical scavenging activity (0.41 mg·mL−1 IC50), followed by clove oil, BHA, α-tocopherol, and BHT (0.82, 0.84, 0.88 and 0.93 mg·mL−1 IC50), respectively. At the same concentration, the reduction power of C. cinnamon oil was higher (1.64 mg·mL−1 Trolox Eq.) than that of α-tocopherol and BHT (1.42 and 0.80 mmol·L−1 Trolox Eq., respectively) but lower than that of BHA (1.81 mmol·L–1 Trolox Eq.). Antiradical activity of the other eight essential oils was low or negligible. C. cinnamon oil and clove oil are promising antiradical agents for skin care but according to our GC-MS analysis, these oils contain 0.29 % of cinnamaldehyde, 0.03 % of linalool, 0.02 % of D-limonene, and 0.02 % of eugenol or 0.41 % of eugenol and 0.002 % of linalool, respectively, which are monitored contact allergens in cosmetics. Such a product is not be suitable for consumers allergic to these substances but for the vast majority of consumers it does not pose a risk in terms of allergic manifestations.

Synthesis and Antioxidant Capacity of Some Derivatives of Sesamol at the C-6 Position

Several synthetic approaches (aminomethylation, alkylation, condensation, etc.) have been used to synthesize derivatives based on the sesamol (1), natural phenol. The set of methods, including the study of antioxidant activity (AOA) by the ability to inhibit the initiated oxidation of animal lipids, radical scavenging activity, Fe²⁺ -chelation ability, as well as a comparative assessment of membrane-protective activity under the conditions of H₂ O₂ -induced hemolysis of mice red blood cells (RBCs), was used to analyze the antioxidant potential of the synthesized compounds. The synthesized derivatives have demonstrated different activity in the listed test systems, and we have identified compounds which appear to be most promising for a detailed study of their pharmacological properties.