Jean Legault

• Professeur titulaire
• Université du Québec à Chicoutimi

A visible-light-mediated chlorotrifluoromethylation catalyzed by Copper-based photoredox catalyst of internal alkenes is depicted. The reaction proceeds with total regioselectivity under mild reaction conditions using commercially available F3CSO2Cl as both the...

Methotrexate is successfully used as the gold standard for managing moderate‐to‐severe psoriasis. However, the low bioavailability and short half‐life of the oral pills and the invasiveness of the parenteral injections make these suboptimal therapeutic options. Microneedles, bridging the advantages of the former forms, are successfully used to deli...

Background The genus Teucrium L. is frequently employed in traditional medicine, primarily for addressing disorders of the digestive and respiratory systems. Biological investigations focused on essential oils have substantiated their antibacterial, antioxidant, anti-tumor, anti-diabetic, and anti-rheumatic properties. Objective The aim of the stu...

Plaque psoriasis is a chronic inflammatory skin disease causing red inflamed lesions covered by scales. Leukocytes, including dendritic cells and T cells, participate in the inflammation of the skin by producing multiple cytokines, thus contributing to the hyperproliferation of keratinocytes. Lack of effectiveness and toxic side effects are the mai...

Exploration of the hydroethanolic extracts from the halophyte Limonium densiflorum, led to the isolation of seven phenolic compounds: gallic acid, epigallocatechin gallate (EGCG), quercitrin, a mixture of myricetin 3-O-α-rhamnopyranoside + myricetin 3-O-L-arabinofuranoside, dihydrokaempferol, pinoresinol, and trans-N-ferulolyl tyramine. These compo...

A study of the chemical composition of the essential oil obtained from the aerial parts of Thymus collinus Bieb., collected in Kvemo Kartli floristic area (Georgia), endemic to caucasus, was carried out. The percentage of terpenic components was determined by gas chromatography. The major components of essential oil are nerolidol (43.42 %) and carv...

The goal of presented research was a study on tropane group alkaloids from the above-ground and underground organs of Atropa caucasica Kreyer (Solanaceae) grown in Georgia, and evaluation of their cytotoxic activity. Alkaloid-containing total substances were obtained by liquid-demand extraction from the air-dried comminuted of the above-ground and...

Three original derivatives of the cytotoxic betulinic acid 3-O-α-l-rhamnopyranoside featuring a monomethylated rhamnoside residue were synthesized. An improved catalytic procedure was involved to functionalize the O-3 position of the monosaccharide in a site-selective fashion. The cytotoxicity of the novel compounds was evaluated in vitro to highli...

The current study aimed to evaluate Tunisian Tamarix africana Poir biological activities. In this study, novel biological activities of the shoot extracts related to their phenolics investigated. Secondary metabolite contents, antioxidant, anti-inflammatory and cytotoxic activities of four extracts (hexane, dichloromethane, methanol and water) were...

This study examined the antioxidant, anticancer and antiviral properties of the methanolic extracts from bigarade (Citrus aurantium L.) leaves at two development stages. Ferulic acid, naringin and naringenin were the principal phenolic components of young and old leaves. The highest total antioxidant capacity was obtained in young leaf extracts (YL...

The aim of the research was to study chemical composition and anti-inflammatory effect of essential oil from Salvia sclarea aerial parts growing in Georgia. It is well known that essential oils of Salvia possesses anti-inflammatory, antifungal, antioxidant, antimicrobial, cytotoxic and anti-diabetic activities. Essential oil (EO) was obtained by hy...

The objects of the study were Ephedra procera Fisch (Fam. Ephedraceae), Taxus baccata L. (Fam. Taxaceae) and Mahonia aquifolium (Pursh) Nutt (Fam. Berberidaceae) growing or introduced in Georgia. Biologically active alkaloid-containing substances were obtained by liquid-liquid extraction. In all studied species, the dominant alkaloids belong to the...

The aim of this study was to investigate the antioxidant, anti-inflammatory, and anticancer properties of Tunisian Suaeda mollis specie after fractionation by increasing polarity of several extracts (Hexane, Dichloromerthane, Methanol and water). Water and methanol extracts of S. mollis exhibited the best in vitro antioxidant ability (2.92±0.19 and...

Biosynthesis of metallic nanoparticles is simple, effective, eco-friendly and inexpensive way. It is a non-toxic method. Biosynthesized nanoparticles are primarily biocompatible and can be used in biomedical applications. Silver nanoparticles (AgNPs) are known to have strong antibacterial effects against pathogenic bacteria and have shown antifunga...

Lycium europaeum is used as a medicinal herb in many countries. In this study, cyclohexane, dichloromethane, ethyl acetate, methanol and water were used as solvents in the extraction of L. europaeum fruits. The contents of total phenolics, total flavonoids, total tannins and condensed tannins as well as the biological activities of these extracts w...

Thymelaea microphylla is an edible and medicinal species that exhibits high antioxidant activity and phenolic content. Moreover, four fractions (hexane, dichloromethane, methanol and water) were tested towards their ex-vivo antioxidant, anticancer, anti-inflammatory and antiviral effects. Dichloromethane fraction had marked protection against cell...

Of the various methods available for the synthesis of metal nanoparticles, the green approach is the most in-teresting and promising. It is known that silver nanoparticles (AgNPs) have a strong antibacterial effect against pathogenic bacteria and have antifungal and antiviral activity, so they can be useful not only for fighting bacte-ria. They can...

Dirchromone is a bioactive vinyl sulfoxide-bearing chromone first isolated from the shrub Dirca palustris. Altogether, 32 of its derivatives were prepared to assess the effect of substitution of its chromone core upon activities against cancer cell lines, Gram-positive bacteria, and fungi (such as Candida albicans). All compounds were synthesized f...

The fractionation of the methanolic extract (MeOH-E) of Retama raetam (Forssk.) Webb & Berthel and further analysis by thin layer chromatography resulted in four fractions (F1, F2, F3 and F4) that, in parallel with the MeOH-E, were screened for antioxidant, cytotoxic, antidiabetic and antibacterial properties. In addition, chemical characterization...

Skin aging is the most visible element of the aging process, giving rise to a major concern for many people. Plants from the Ericaceae family generally have antioxidant and anti-inflammatory properties, making them potential anti-aging active ingredients. This study aimed to evaluate the safety and anti-aging efficacy of a Kalmia angustifolia extra...

UV-B and IR-A radiation are important inducers of biological changes in skin involving ROS generation. The overloading of antioxidant defense mechanisms by ROS production could lead to photoaging and photocarcinogenesis processes. Various traditional usages are reported for Aralia nudicaulis L. extracts, including treatment of dermatological disord...

The use of growth-promoting antibiotics in livestock faces increasing scrutiny and opposition due to concerns about the increased occurrence of antibiotic-resistant bacteria. Alternative solutions are being sought, and plants of Lamiaceae may provide an alternative to synthetic antibiotics in animal nutrition. In this study, we extracted essential...

Three new oleanolic glycosides (1–3), along with seven known saponins from various plants (4–10) were isolated for the first time from the leaves of Aralia nudicaulis. Their structures were elucidated on the basis of spectroscopic evidence, including 1D and 2D NMR, and HRESIMS. Nudicauloside A and B (1–2) have shown moderate anti-inflammatory activ...

Several families of naturally occurring C-alkylated dihydrochalcones display a broad range of biological activities, including antimicrobial and cytotoxic properties, depending on their alkylation sidechain. The catalytic Friedel–Crafts alkylation of the readily available aglycon moiety of neohesperidin dihydrochalcone was performed using cinnamyl,...

Rhamnolipids are a specific class of microbial surfactants, which hold great biotechnological and therapeutic potential. However, their exploitation at the industrial level is hampered because they are mainly produced by the opportunistic pathogen Pseudomonas aeruginosa . The non-human pathogenic bacterium Pantoea ananatis is an alternative produce...

The peculiar vinylsulfoxide side chain of dirchromone plays a pivotal role in the bioactivity of this novel pharmacophore.

Five batches of resin from the Pili tree (Canarium ovatum Engl.) were distilled and their essential oils and hydrosols analyzed by gas chromatography. The oils, obtained in yields of 13.4‐19.7% v/m, featured α‐phellandrene in high proportions (50‐65%), alongside limonene, β‐phellandrene and para‐cymene. Chiral GC analysis confirmed that both phella...

Steroidal hydrazones include compounds with a variety of biological activities, e.g., antiproliferative and cytotoxic [1-6]. Adamantane derivatives are used as medicines. Several adamantane-containing steroids were synthesized and observed to exhibit a prolonged androgenic effect and sometimes enhancement of a certain specific activity [7, 8]. Prev...

During the last few years, various strategies for cancer therapy have emerged where l-rhamnose interacts with either an anti-rhamnose antibody or a hypothetically over-expressed l-rhamnose-binding lectin. These studies have led to promising results in cancer immunotherapy and the design of selective cytotoxic rhamnosides, respectively. We have synt...

The aim of the study was to determine the stable diagnostic traits and the biological activity of the stems and leaves of Daphne albowiana Woronow ex Pobed., a plant native to Georgia. Biological assays of the methanol, chloroform and hexane extracts show the plant to possess cytotoxic and antioxidant activities, but no noteworthy antibacterial or...

Psoriasis is a skin disorder characterized by epidermal hyperplasia, hyperkeratosis, and inflammation. The treatments currently available on the market only improve patients’ quality of life and are associated with undesirable side effects. Thus, research leading to the development of new, effective, and safer therapeutic agents is still relevant....

Betulinic acid and ursolic acid are ubiquitous, naturally-occurring triterpenoids exhibiting various pharmacological activities including cytotoxic and anti-inflammatory activities. However, these triterpenoids display unfavorable pharmacokinetic properties as well as low aqueous solubility. It has been shown that the presence of α-L-rhamnose moiet...

New options are urgently needed for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. Balsacone C is a new dihydrochalcone extracted from Populus balsamifera that has been reported previously as being active against Staphylococcus aureus. Here, we evaluate the antibacterial activity of balsacone C against MRSA. Thirty-...

The essential oil of Hedyosmum arborescens Sw. (Chloranthaceae), a native plant of the Caribbean archipelago, was extracted by hydrodistillation. The chemical composition of the volatile fraction was determined by GC and GC-MS analyses and 50 components were identified. The major components are α-phellandrene (11.4%), bicyclogermacrene (10.6%) and...

Leaf volatile components of Bursera simaruba (L.) Sarg., a native tree from tropical America used in traditional medicine, were extracted by hydrodistillation. The essential oil was analyzed by GC-MS. We have identified 38 compounds in this oil, of which limonene (46.7%), β-caryophyllene (14.7%), α-humulene (13.2%) and germacrene D (7.6%) are the m...

A seven-step total synthesis of the original scaffold of cytotoxic dirchromones involving an unprecedented soft-enolization Baker-Venkataraman rearrangement was designed. The methodology enabled access to naturally occurring dirchromone 1 (21% overall yield) at gram-scale, which was screened for cytotoxicity against 13 cancer cell lines. The scope...

The chemical composition of Tussilago farfara L. essential oil from the Saguenay-Lac-St-Jean region of Quebec, Canada was analyzed by gas chromatography–flame ionisation detector (GC-FID) and gas chromatography–mass spectrometry (GC-MS), and the antibacterial activity of the oil was tested against Escherichia coli and Staphylococcus aureus. Forty-f...

Steroidal hydrazones and pyrazolines were synthesized via condensation of a series of 5α-steroidal ketones with several hydrazines. Their cytotoxic activity against cancer cultures (A549 lung cancer, DLD-1 colorectal cancer, and WS1 normal skin fibroblasts) and antibacterial activity against E. coli and S. aureus strains were studied. The structure...

Aerial parts of northern bayberry (Morella pensylvanica (Mirbel) Kartesz) from the Magdalen Islands were submitted to steam distillation to evaluate both yield and composition of essential oil and hydrosol. It yielded 0.15% (m/m) of a pleasantly scented essential oil featuring a different composition than that reported in Connecticut. This oil appe...

Betulin has a wide range of biological and pharmacological properties with its anticancer activity attracting most of the attention as it offers a possible alternative treatment to chemotherapy. However, betulin’s in vivo biological effectiveness is limited by its poor solubility. As such, we synthesized polar glycosylated derivatives to increase i...

Common scab is one of the most important diseases affecting potato crops worldwide. Using fresh residues and/or bio-products of Canadian goldenrod (Solidago canadensis) may offer an alternative to harmful conventional fumigants. In this study, we aimed to: i) conduct a preliminary investigation of the utilization of S. canadensis to reduce common s...

Background: Tanacetum vulgare L. (Asteraceae) is a perennial herb that has been used to treat multiple ailments. Regional variability of the chemical composition of T. vulgare essential oils is well-known. Despite these regional chemotypes, most relevant studies did not analyze the complete chemical composition of the T. vulgare essential oil and i...

Background Many plants of boreal forest of Quebec have been used by Native Americans to treat a variety of microbial infections. However, the antiviral activities of these plants have been seldom evaluated on cellular models to validate their in vitro efficiencies. In this study, Cornus canadensis L. (Cornaceae), a plant used in Native American tra...

Bellis perennis L. is a medicinal plant in the family Compositae. It has been used as a remedy for wounds, rheumatism, eczema, eye diseases, inflammation and tonsillitis in folk medicine. In the present study, 19 different extracts and two fractions were obtained from wild-grown flowers, leaves and/or in vitro-grown leaves of common daisy by using...

Ethnopharmacological relevance: Oleoresin of Abies balsamea (L.) Mill. was used by Aboriginal people of the boreal forest of Canada and French Canadians to treat various infections, suggesting that oleoresin has antibacterial properties. Aim of the study: In this study, the antibacterial activity of whole oleoresin from A. balsamea was investiga...

There is nowadays an urgent need for developing novel generations of antibiotic agents due to the increased resistance of pathogenic bacteria. As a rich reservoir of structurally diverse compounds, plant species hold promise in this regard. Within this framework, we isolated a unique series of antibacterial flavonoids, named balsacones N-U, featuri...

Reaumuria vermiculata is a xero-halophytic specie widely distributed in the south of Tunisia. In the current study, antioxidant, anti-inflammatory and anticancer activities of Reaumuria vermiculata shoot extracts as well as its phenolic compounds were investigated in different solvent extracts (hexane, dichloromethane, methanol and water). Results...

A preliminary antiviral plate assay of the green solvent (hydro-ethanolic) shoot extract of Limonium densiflorum showed a potent activity against the herpes simplex virus type 1 (HSV-1). In order to isolate the active compounds, an in vitro bio-guided fractionation was undertaken by preparative chromatographic techniques. On the basis of nuclear ma...

Eight non-carotenoid tetraterpenoids, abibalsamins C-J (3-10), were isolated from the oleoresin of Abies balsamea. Their chemical structures were determined based on analysis of 1D/2D NMR and MS data. The assignment of their relative configurations was accomplished using homonuclear coupling constants in tandem with ROESY data. However, the presenc...

Although the genus Limonium was widely used in traditional medicine, few studies have focused on the biological capacities of different species of this group. In this study, biological activities of hexanic, dichloromethane, ethanolic, and methanolic extracts, related to their phenolic contents, and HPLC phytochemical analysis of the halophyte Limo...

Eight novel organic sulfur compounds featuring an unprecedented structure among natural organosulfur molecules are reported. The identified compounds, named dirchromones (1–8), were isolated from a dichloromethane extract of the roots, bark, and wood of Dirca palustris, an endemic shrub of eastern North America. Their identification was based on th...

A phytochemical investigation of buds from the hardwood tree Populus balsamifera led to the isolation of six new cinnamoylated dihydrochalcones as pairs of racemates and one as a racemic mixture along with the known compound iryantherin-D (2), the absolute configuration of which was determined for the first time. The structures of balsacones J (1),...

Inflammation plays a crucial role in many types of cancer and is known to be involved in their initiation and promotion. As such, it is presently recognized as an important risk factor for several types of cancers such as bladder, prostate and breast cancers. The discovery of novel anti-inflammatory compounds can have a huge implication not only fo...

The electrosynthesis of new 2,4-dialkylcarbonotrithioates, in satisfactory yields, starting from arylthiols and carbon disulfide using an electrogenerated base (EGB) that is reported to promote the reaction is reported. The EGB was prepared by pro-base-free electrolysis of acetonitrile under galvanostatic conditions using a sacrificial magnesium an...

This study investigates the polyphenol content of Diplotaxis simplex extract and the biological activities of the main organ. The analysed extracts showed that polyphenol contents varied considerably as a function of organs. Furthermore, novel biological activities of this species were assessed. Flower extracts exhibit a potent in vitro antioxidant...

Hellecaucaside A, a new disaccharide nucleoside featuring a 2'-O-alpha-D-ribofuranosyluridine skeleton and a 4-hydroxybenzoyl group at the 50 position, was isolated from the underground part of Helleborus caucasicus. The structure of the compound was elucidated by means of chemical degradation and spectroscopic analyses, such as 1D/2D NMR, chiral-G...

Oxidative stress and advanced glycation end products (AGEs) are known as key factors for the development of diabetic complications such as retinopathy, cataract as well as atherosclerosis and neurodegenerative diseases, including Alzheimer’s diseases. In this context, natural products have been previously identified as promising sources for antioxi...

A new flavonol glycoside, namely 3-(α-rhamnopyranosyl-(1 → 2)-[β-xylopyranosyl-(1 → 6)]-β-glucopyranosyloxy) isorhamnetin was reported from methanol extracts of aerial parts of Suaeda fruticosa for the first time. In this work, liquid chromatography coupled to atmospheric pressure chemical ionisation mass spectrometry, high-resolution mass spectrom...

Viral infections remain a major threat to humans and animals and there is a crucial need for new antiviral agents especially with the development of resistant viruses. Several Limonium genus members (Plumbaginacea) have been widely used in traditional medicine for the treatment of infections. In this study, we investigated the antiviral activities...

Goldenseal has a long history of use in North American folk medicine and today has emerged as one of the 20 most popular herbal supplements used worldwide. The alkaloids present in goldenseal are believed to be the main bioactive compounds with various pharmacological effects including antibacterial, antifungal, and anticancer activities. The most...

The chemical composition of Populus balsamifera essential oils obtained from spring buds, fall buds, and young leaves were determined by GC and GC-MS analyses. The major constituent, (+)-alpha-bisabolol, a rare sesquiterpene, was isolated from spring oil using reverse-phase preparative HPLC. The cytotoxic activity of balsam poplar oils and isolated...

A phytochemical investigation of an ethanolic extract from Populus balsamifera L. buds resulted in the isolation and characterization of twelve new flavan derivatives consisting of six pairs of enantiomers. Structures of (+) and (-)-balsacones D-I were elucidated based on spectroscopic data (1D and 2D NMR, MS) and their absolute configurations were...

The bark of boreal forest conifers has been traditionally used by Native Americans to treat various ailments and diseases. Some of these diseases involve reactive oxygen species (ROS) that can be prevented by the consumption of antioxidants such as phenolic compounds that can be found in medicinal plants. In this study, ultrasonic assisted extracti...

Iso-caryophyllene, a sesquiterpene, is present in several essential oils from vegetable species. In previous work, iso-caryophyllene was found cytotoxic against in vitro culture cell lines but its mechanism of action is still unknown. Reactive oxygen species (ROS) and lipid oxidation induced by iso-caryophyllene were assessed using DCFH-DA and BODI...

Phytochemical analysis of A. balsamea oleoresin led to the isolation of three new 3,4-seco-lanostane triterpenoids 1-3, one new cycloartane triterpenoid 4 along with fourteen known terpenoids. Structure determinations were based on extensive 1D/2D NMR, IR and MS spectroscopic analyses, and comparison with literature data. The isolated compounds wer...

Three new dihydrochalcone derivatives, balsacones A, B, and C, along with seven known compounds, were isolated from the buds of Populus balsamifera. The structures of the new compounds were elucidated by the analysis of spectroscopic data. Only balsacone A, B, and C were significantly active against Staphylococcus aureus with MIC values ranging fro...

The aim of this study was to investigate the chemical composition and bioactivity of Amomum biflorum Jack harvested in the region of Petchaboon, Thailand. The essential oil of the fresh whole plant obtained by hydrodistillation was analyzed by gas chromatography (GC) (Kovats index) and gas chromatography coupled with mass spectrometry (GC/MS). The...

Three new diterpenoids, namely 7α-hydroxyabieta-8,11,13,15-tetraen-18-oic acid, 7β,15,18-trihydroxyabieta-8,11,13-triene, 13,15-dihydroxypodocarpa-8,11,13-triene, and 12 other known compounds were isolated from buds of Pinus banksiana Lamb. All these compounds, except for 7-oxodehydroabietinol, were isolated for the first time from this plant. Thei...

Nigella sativa is a one of the most commonly found aromatics in the Mediterranean kitchen. This plant is traditionally used for the treatment of several pathologies. In this study, the antioxidant, anti-inflammatory, anticancer and antibacterial activities of the shoots, roots and seeds methanol extracts from N. sativa were studied. The three organ...

Among consumers, heat-treated wood recently gained more importance due its attractive darker color along with several other advantages such as improved biological resistance, dimensional stability, and thermal insulating properties. However, exposure to the exterior environment drastically changes the attractive darker color of this product. From d...

A new series of betulinic acid and betulin derivatives were synthesized by introducing a D-glycerol moiety at the C-3 and/or C-28 positions of the lupane skeleton. The resulting glyceryl esters were evaluated in vitro for their cytotoxic activity against A549, DLD-1 and WS1 human cell lines. The structure-activity relationships study revealed that...

Suaeda fruticosa is an edible and medicinal halophyte known for its hypoglycaemic and hypolipidaemic activities. In this study, novel biological activities of the shoot extracts related to their phenolics were investigated. Results showed an appreciable total phenolic (31.8 mg GAE/g DW) in shoot extracts. The estimation of antioxidant capacities us...

Abibalsamins A (1) and B (2), two unprecedented tetraterpenoids featuring a 3,4-seco-rearranged lanostane system fused with a β-myrcene lateral chain via a [4 + 2] Diels-Alder cycloaddition, were isolated from the oleoresin of Abies balsamea. Their structures were elucidated by means of extensive 2D NMR, IR, and MS spectroscopy analyses. The absolu...

Antioxidants are the chemical substances that reduce or prevent oxidation. The present study aimed to assess in vitro and ex vivo antioxidant activities of four acetonic extracts Tunisian halophytes (Suaeda fruticosa, Suaeda pruinosa, Suaeda mollis and Suaeda maritima). Various experimental models were used for characterization of antioxidant activ...

Fractionation of the essential oil from the seeds of Nigella sativa (Ranunculaceae) led to the isolation of four terpenoids: trans- (1), cis-sabinene hydrate methyl ether (2), 1,2-epoxy-menth-4-ene (3) and 1,2-epoxy-menth-4(8)-ene (4). Structure elucidation was performed using NMR (1D and 2D NMR) experiments and mass spectral data. Compounds 3 and...

Lupeol, betulin and betulinic acid are members of the so-called lupane-type triterpenoids. These natural products found worldwide in quite of lot of vegetables, fruits and plant species exhibit promising pharmacological activities including anti-inflammatory, anti-HIV and antitumor activities. Nevertheless, the poor pharmacokinetic properties of th...

Brasenia schreberi Gmel. (Cabombaceae) is an aquatic plant that grows in eastern Asia, Australia, Africa, and North and Central America. B. schreberi leaf extracts were obtained by sequential solvent extraction with dichloromethane, methanol, and water. The antioxidant potential of each extract was assessed by using the oxygen radical absorbance ca...

Withanolide-type steroids, withametelin Q (1) and 12α-hydroxydaturametelin B (2) along with three known withanolides, were isolated from leaves of Datura metel L. (Solanaceae). The respective structures, characterized mainly by NMR spectroscopy, were identified as (20R,22R,24R)-21,24-epoxy-1α,3β-dihydroxywitha-5,25(27)-dienolide-3-O-β-D-glucopyrano...

Carthamus tinctorius L. (Asteraceae) is an aromatic and folkloric medicinal plant thanks to its multiple virtues. However, few scientific studies investigated its biological activities. For that, this study aimed to investigate antioxidant, antibacterial, anti-inflammatory and anticancer activities of methanolic flower extracts of Carthamus tinctor...

Extremophile plants are remarkable plants that tolerate severe environmental constraints which may trigger in plants an oxidative stress Able to overcome oxidative stress, these species have developed potent antioxidant systems. Among them, polyphenols constitute the main powerful compounds, owing to their strong biological activity. Therefore, the...