(R)-(-)-carvone and (1R, 4R)-trans-(+)-dihydrocarvone from poiretia latifolia vogel

The comparative perspective of phytochemistry and biological properties of the Apiaceae family plants

Despite the availability of numerous reports on the discovery of medicinal plant compounds and their properties, one may encounter contradictory results released by these reports at the level of plant families and even within species. To establish an accurate perspective of the Apiaceae family, this study examined the fruit essential oil and methanolic extract of wild and common species of this family. According to the measurement of the antioxidant property in the methanolic extract of the fruits using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, Ferula gummosa, Pimpinella anisum and Cuminum cyminum have high power in inhibiting free radicals. However, Bunium persicum had the strongest DPPH radicals inhibitory potential among all essential oils. The results of antimicrobial tests and their classification analysis showed that C. cyminum and B. persicum fruit essential oil with a high amount of cuminaldehyde had the most antibacterial properties. At the same time, the antifungal properties of H. persicum essential oil (rich in aliphatic ester) were stronger than those of the all the studied plants. Also, the essential oils of F. gummosa and Kelussia odoratissima had favourable antimicrobial properties compared to other studied plants. The investigation of the bacterial structure by scanning electron microscope confirmed the effect of the applied essential oils dose and their antibacterial potential. In general, for the first time, this paper determined the biological values of the fruit essential oil of some wild plants, such as K. odoratissima and H. persicum. Besides, in vitro examination and the mathematical models provided a suitable classification, which makes a comprehensive view in terms of the properties of the Apiaceae family.

GC-MS Profiling, Vibriocidal, Antioxidant, Antibiofilm, and Anti-Quorum Sensing Properties of Carum carvi L. Essential Oil: In Vitro and In Silico Approaches

The main objectives of the present study were to investigate anti-Vibrio spp., antibiofilms, and anti-quorum-sensing (anti-QS) properties of caraway essential oil in relation to their phytochemical composition. The results obtained show the identification of twelve compounds, with carvone (58.2%) and limonene (38.5%) being the main ones. The obtained essential oil (EO) is particularly active against all Vibrio spp. species, with bacteriostatic action against all tested strains (MBC/MIC ratio ≥ 4) and with inhibition zones with high diameters of growth, ranging from 8.66 ± 0.58 mm for V. furnisii ATCC 35016 to 37.33 ± 0.58 mm for V. alginolyticus ATCC 17749. Caraway essential oil (Carvone/limonene chemotype) exhibits antioxidant activities by using four tests (DPPH = 15 ± 0.23 mg/mL; reducing power = 7.8 ± 0.01 mg/mL; β-carotene = 3.9 ± 0.025 mg/mL; chelating power = 6.8 ± 0.05 mg/mL). This oil is particularly able to prevent cell-to-cell communication by inhibiting swarming motility, production of elastase and protease in Pseudomonas aeruginosa PAO1, and violacein production in C. violaceum in a concentration-dependent manner. A molecular docking approach shows good interaction of the identified bioactive molecules in caraway EO, with known target enzymes involved in antioxidant, antibacterial, and anti-QS activities having high binding energy. Overall, the obtained results highlight the possible use of caraway essential oil against pathogenic Vibrio species and to attenuate the secretion of virulence-related factors controlled by QS systems in Gram-negative bacteria. Therefore, this oil can be used by food industries to prevent biofilm formation on abiotic surfaces by Vibrio strains.

Bioactive properties of the aromatic molecules of spearmint (Mentha spicata L.) essential oil: a review

Spearmint belongs to the genus Mentha in the family Labiateae (Lamiaceae), which is wildly cultivated worldwide for its remarkable aroma and commercial value. The aromatic molecules of spearmint essential oil,...

In Vitro Antifungal Activity and Toxicity of Dihydrocarvone-Hybrid Derivatives against Monilinia fructicola

The aim of this study was to synthesize a series of novel and known dihydrocarvone-hybrid derivatives (2–9) and to evaluate mycelial growth activity of hybrid molecules against two strains of Monilinia fructicola, as well as their toxicity. Dihydrocarvone-hybrid derivatives have been synthesized under sonication conditions and characterized by FTIR, NMR, and HRMS. Antifungal efficacy against both strains of M. fructicola was determined by half maximal effective concentration (EC₅₀) and toxicity using the brine shrimp lethality test (BSLT). Among the synthesized compounds, 7 and 8 showed the best activity against both strains of M. fructicola with EC₅₀ values of 148.1 and 145.9 µg/mL for strain 1 and 18.1 and 15.7 µg/mL for strain 2, respectively, compared to BC 1000^® (commercial organic fungicide) but lower than Mystic^® 520 SC. However, these compounds showed low toxicity values, 910 and 890 µg/mL, respectively, compared to Mystic^® 520 SC, which was highly toxic. Based on the results, these hybrid compounds could be considered for the development of more active, less toxic, and environmentally friendly antifungal agents against phytopathogenic fungi.

A new isoflavone glucoside and other compounds from Poiretia bahiana C. Mueller: Chemophenetics, fragmentation pattern and biogenetic implications

The genus Poiretia belongs to the Fabaceae (Leguminosae) family and it encompasses twelve species of flowering plants. The chemistry of this genus is scarcely investigated, although some studies have demonstrated the potential of Poiretia species to produce important bioactive compounds. Herein, we describe the phytochemical investigation of P. bahiana C. Mueller leaves. A new isoflavone glucoside named as 2',4',5'-trimethoxyisoflavone-7-O-β-D-glucopyranoside (1), along with six known isoflavones (2-7), two rotenones (8-9), cyclitol 3-O-methyl-chiro-inositol (10), the amino acid proline (11), a mixture of sitosterol (12) and stigmasterol (13), and a mixture of the triterpenes lupeol (14) and β-amirine (15) were obtained from P. bahiana leaves. The structures were established by extensive analysis of their spectroscopic data, which included ¹H NMR, ¹³C NMR, DEPT, and 2D-NMR (¹³C¹H HETCOR and ¹³C¹H COLOC). Two isoflavones (3 and 5) and two rotenones (8-9) exhibited antifungal activity against the plant pathogenic fungus Cladosporium sphaerospermum. Furthermore, the biogenetic implications of the oxygenation pattern of the B-ring of the isoflavones, and the chemophenetics and fragmentation pattern of the isoflavones and rotenones are discussed.

Screening a Strain of Klebsiella sp. O852 and the Optimization of Fermentation Conditions for Trans-Dihydrocarvone Production

Flavors and fragrances have high commercial value in the food, cosmetic, chemical and pharmaceutical industries. It is interesting to investigate the isolation and characterization of new microorganisms with the ability to produce flavor compounds. In this study, a new strain of Klebsiella sp. O852 (accession number CCTCC M2020509) was isolated from decayed navel orange (Citrus sinensis (L.) Osbeck), which was proved to be capable of converting limonene to trans-dihydrocarvone. Besides, the optimization of various reaction parameters to enhance the trans-dihydrocarvone production in shake flask was performed for Klebsiella sp. O852. The results showed that the yield of trans-dihydrocarvone reached up to 1 058 mg/L when Klebsiella sp. O852 was incubated using LB-M medium for 4 h at 36 °C and 150 rpm, and the biotransformation process was monitored for 36 h after adding 1680 mg/L limonene/ethanol (final ethanol concentration of 0.8% (v/v)). The content of trans-dihydrocarvone increased 16 times after optimization. This study provided a basis and reference for producing trans-dihydrocarvone by biotransformation.

Polyvinyl alcohol modification with sustainable ketones

Water-degradable polyvinyl ketals with high glass transition temperatures (78–127 °C) were made via ketalization of polyvinyl alcohol (PVA) with sustainable ketones.

Production of flavours and fragrances via bioreduction of (4R)-(-)-carvone and (1R)-(-)-myrtenal by non-conventional yeast whole-cells

As part of a program aiming at the selection of yeast strains which might be of interest as sources of natural flavours and fragrances, the bioreduction of (4R)-(-)-carvone and (1R)-(-)-myrtenal by whole-cells of non-conventional yeasts (NCYs) belonging to the genera Candida, Cryptococcus, Debaryomyces, Hanseniaspora, Kazachstania, Kluyveromyces, Lindnera, Nakaseomyces, Vanderwaltozyma and Wickerhamomyces was studied. Volatiles produced were sampled by means of headspace solid-phase microextraction (SPME) and the compounds were analysed and identified by gas chromatography-mass spectroscopy (GC-MS). Yields (expressed as % of biotransformation) varied in dependence of the strain. The reduction of both (4R)-(-)-carvone and (1R)-(-)-myrtenal were catalyzed by some ene-reductases (ERs) and/or carbonyl reductases (CRs), which determined the formation of (1R,4R)-dihydrocarvone and (1R)-myrtenol respectively, as main flavouring products. The potential of NCYs as novel whole-cell biocatalysts for selective biotransformation of electron-poor alkenes for producing flavours and fragrances of industrial interest is discussed.

Biochemical characterization and substrate profiling of a new NADH-dependent enoate reductase from Lactobacillus casei

Carbon-carbon double bond of α,β-unsaturated carbonyl compounds can be reduced by enoate reductase (ER), which is an important reaction in fine chemical synthesis. A putative enoate reductase gene from Lactobacillus casei str. Zhang was cloned into pET-21a+ and expressed in Escherichia coli BL21 (DE3) host cells. The encoded enzyme (LacER) was purified by ammonium sulfate precipitation and treatment in an acidic buffer. This enzyme was identified as a NADH-dependent enoate reductase, which had a K(m) of 0.034 ± 0.006 mM and k(cat) of (3.2 ± 0.2) × 10³ s⁻¹ toward NADH using 2-cyclohexen-1-one as the substrate. Its K(m) and k(cat) toward substrate 2-cyclohexen-1-one were 1.94 ± 0.04 mM and (8.4 ± 0.2) × 10³ s⁻¹, respectively. The enzyme showed a maximum activity at pH 8.0-9.0. The optimum temperature of the enzyme was 50-55°C, and LacER was relatively stable below 60 °C. The enzyme was active toward aliphatic alkenyl aldehyde, ketones and some cyclic anhydrides. Substituted groups of cyclic α,β-unsaturated ketones and its ring size have positive or negative effects on activity. (R)-(-)-Carvone was reduced to (2R,5R)-dihydrocarvone with 99% conversion and 98% (diasteromeric excess: de) stereoselectivity, indicating a high synthetic potential of LacER in asymmetric synthesis.