Biochemical analysis of the TPS-a subfamily in Medicago truncatula

Terpenes are important mediators of plant chemical response to environmental cues. Here, we describe the genome-wide identification and biochemical characterization of TPS-a members in Medicago truncatula, a model legume crop. Genome mining identified thirty-nine full-length terpene synthases with a significant number predicted to produce monoterpenes and sesquiterpenes. Biochemical characterization of the TPS-a subfamily associated with sesquiterpene biosynthesis revealed such compounds, that exhibit substantial biological activity in other plants. Gene expression analysis using qPCR and the Medicago gene atlas illustrated distinct tissue and time-based variation in expression in leaves and roots. Together our work establishes the gene-to-metabolite relationships for sesquiterpene synthases in M. truncatula. Understanding the biosynthetic capacity is a foundational step to defining the ecological roles of this important family of compounds

Synthesis of novel stilbene–coumarin derivatives and antifungal screening of monotes kerstingii-specialized metabolites against fusarium oxysporum

Fusarium is one of the most toxigenic phytopathogens causing diseases and reduced agricultural productivity worldwide. Current chemical fungicides exhibit toxicity against non-target organisms, triggering negative environmental impact, and are a danger to consumers. In order to explore the chemical diversity of plants for potential antifungal applications, crude extract and fractions from Monotes kerstingii were screened for their activity against two multi-resistant Fusarium oxysporum strains: Fo32931 and Fo4287. Antifungal activity was evaluated by the determination of minimum inhibitory concentration (MIC) by broth dilution of fermentative yeasts using kinetic OD600 nm reading by a spectrophotometer. The n-butanol fraction showed the best activity against Fo4287. We screened eleven previously reported natural compounds isolated from different fractions, and a stilbene–coumarin 5-[(1E)-2-(4-hydroxyphenyl)ethenyl]-4,7-dimethoxy-3-methyl-2H-1-benzopyran-2-one (1) was the most active compound against both strains. Compound 1 was employed as a nucleophile with a selection of electrophilic derivatizing agents to synthesize five novel stilbene–coumarin analogues. These semisynthetic derivatives showed moderate activity against Fo32931 with only prenylated derivative exhibiting activity comparable to the natural stilbene–coumarin (1), demonstrating the key role of the phenolic group

Phytochemical analysis and antifungal property of Mallotus oppositifolius (Geiseler) Müll.Arg. (Euphorbiaceae)

The emergence of resistant fungi to available drugs highlights the need for new antifungal drugs. The present study aimed to evaluate the antifungal activity of the isolated compounds, fractions and crude extract from the leaf of Mallotus oppositifolius (Geiseler) Müll. Arg. Three pure compounds labelled 1-3 were isolated from the methylene chloride / methanol (1/1) extract of the leaf of this plant using chromatography techniques. These compounds were identified using analytical spectroscopic methods as betulinic acid (1), quercetine (2) and quercitin (3). The crude extract, fractions and compounds were tested against pathogenic yeasts (Candida albicans, Candida glabrata, Candida krusei) and dermatophytes (Trichophyton rubrum, Trichophyton soudanense, Microsporum audouinii, Microsporum langeronii) using agar well diffusion and dilution methods. The safety of the crude extract was studied on Wistar rats according to the WHO guidelines. The minimal inhibitory concentration (MIC) values ranged from 48 to 781 μg/ml against yeasts for crude extract and fractions, and 1.86 to 25000 μg/ml against dermatophytes for pure compounds, fractions and crude extract. The antifungal activity of pure compounds was not determined against yeasts. The crude extract of leaf was found to be safe in rat at up to 12 g/kg. The results achieved supported the traditional use of Mallotus oppositifolius leaf for the treatment of fungal infections.Keywords: Mallotus oppositifolius, antifungal activity, safety, phytochemical screening

DataSheet_1_Biochemical analysis of the TPS-a subfamily in Medicago truncatula.pdf

Terpenes are important mediators of plant chemical response to environmental cues. Here, we describe the genome-wide identification and biochemical characterization of TPS-a members in Medicago truncatula, a model legume crop. Genome mining identified thirty-nine full-length terpene synthases with a significant number predicted to produce monoterpenes and sesquiterpenes. Biochemical characterization of the TPS-a subfamily associated with sesquiterpene biosynthesis revealed such compounds, that exhibit substantial biological activity in other plants. Gene expression analysis using qPCR and the Medicago gene atlas illustrated distinct tissue and time-based variation in expression in leaves and roots. Together our work establishes the gene-to-metabolite relationships for sesquiterpene synthases in M. truncatula. Understanding the biosynthetic capacity is a foundational step to defining the ecological roles of this important family of compounds.</p

Mesomeric form of quaternary indoloquinazoline alkaloid and other constituents from the Cameroonian Rutaceae Araliopsis soyauxii Engl.

Noulala CGT, Fotso GW, Rennert R, et al. Mesomeric form of quaternary indoloquinazoline alkaloid and other constituents from the Cameroonian Rutaceae Araliopsis soyauxii Engl. BIOCHEMICAL SYSTEMATICS AND ECOLOGY. 2020;91: UNSP 104050.A mesomeric form of quaternary indoloquinazoline alkaloid, soyauxinium chloride (1) was obtained through the chemical investigation of stem bark and roots of Araliopsis soyauxii Engl. [syn. Vepris soyauxii (Engl.) Mziray] (Rutaceae) together with fifteen known compounds, including three furoquinoline alkaloids, three 2-quinolones, two limonoids, two triterpenes, two steroids, a coumarin, an acridone alkaloid, and a flavonoid glycoside. Their structures were established by comprehensive spectroscopic and spectrometric analyses (1D and 2D NMR, ESI-HR-MS) and by comparison with previously reported data. C-13 NMR data of araliopsinine are also reported here for the first time. The isolated compounds were screened in vitro for their effects on the viability of two different human cancer cell lines, namely prostate PC-3 adenocarcinoma cells and colorectal HT-29 adenocarcinoma cells. However, none of the tested compounds exhibited strong anti-proliferative or cytotoxic activities, to either prostate PC-3 cells or colon HT-29 cells. At 100 mu M, the furoquinoline maculine showed a slightly increased anti-proliferative effect, however, exclusively on HT-29 cells. The chemotaxonomic significance of the isolated compounds has also been discussed

Bruceadysentoside A, a new pregnane glycoside and others secondary metabolites with cytotoxic activity from brucea antidysenterica J. F. Mill. (simaroubaceae).

Makong YS, Fotso GW, Mouthe GH, et al. Bruceadysentoside A, a new pregnane glycoside and others secondary metabolites with cytotoxic activity from brucea antidysenterica J. F. Mill. (simaroubaceae). Natural product research. 2019:1-7.The chemical investigation of the root barks leaves and stem barks of Brucea antidysenterica J. F. Mill. (Simaroubaceae) led to the isolation of a new pregnane glycoside, named Bruceadysentoside A or 3-O-beta-L-arabinopyranosyl-pregn-5-en-20-one (1) together with seventeen known compounds. Their structures were established from spectral data, mainly HRESIMS, 1D and 2D NMR and by comparison with literature data. Compounds 1, 2, 5, 6, 8, 10, 12 and 13 were tested in vitro for their effects on the viability of two different human cancer cell lines, namely prostate PC-3 adenocarcinoma cells and colorectal HT-29 adenocarcinoma cells. No substantial activities were recorded for 2, 10, 12 and 13 (up to 10muM concentration). 1, 5 and 8 did not show strong anti-proliferative effects up to 100muM, however, 6 exhibited a stronger anti-proliferative effect with IC50 values of 100muM against PC-3 and 200muM against HT-29

Chemical Constituents of Macaranga occidentalis, Antimicrobial and Chemophenetic Studies

Kamso VFK, Simo Fotso CC, Kanko Mbekou IM, et al. Chemical Constituents of Macaranga occidentalis, Antimicrobial and Chemophenetic Studies. Molecules. 2022;27(24): 8820.Medicinal plants are known as sources of potential antimicrobial compounds belonging to different classes. The aim of the present work was to evaluate the antimicrobial potential of the crude extract, fractions, and some isolated secondary metabolites from the leaves of Macaranga occidentalis, a Cameroonian medicinal plant traditionally used for the treatment of microbial infections. Repeated column chromatography of the ethyl acetate and n-butanol fractions led to the isolation of seventeen previously known compounds (1−17), among which three steroids (1−3), one triterpene (4), four flavonoids (5−8), two stilbenoids (9 and 10) four ellagic acid derivatives (11−14), one geraniinic acid derivative (15), one coumarine (16), and one glyceride (17). Their structures were elucidated mainly by means of extensive spectroscopic and spectrometric (1D and 2D NMR and, MS) analysis and comparison with the published data. The crude extract, fractions, and isolated compounds were all screened for their antimicrobial activity. None of the natural compounds was active against Candida strains. However, the crude extract, fractions, and compounds showed varying levels of antibacterial properties against at least one of the tested bacterial strains, with minimal inhibitory concentrations (MICs) ranging from 250 to 1000 μg/mL. The n-butanol (n-BuOH) fraction was the most active against Escherichia coli ATCC 25922, with an MIC value of 250 μg/mL. Among the isolated compounds, schweinfurthin B (10) exhibited the best activity against Staphylococcus aureus NR 46003 with a MIC value of 62.5 μg/mL. In addition, schweinfurthin O (9) and isomacarangin (6) also exhibited moderate activity against the same strain with a MIC value of 125 μg/mL. Therefore, pharmacomodulation was performed on compound 6 and three new semisynthetic derivatives (6a–c) were prepared by allylation and acetylation reactions and screened for their in vitro antimicrobial activity. None of the semisynthetic derivatives showed antimicrobial activity against the same tested strains. The chemophenetic significance of the isolated compounds is also discussed in this paper

Chemical constituents of two Cameroonian medicinal plants: Sida rhombifolia L. and Sida acuta Burm. f. (Malvaceae) and their antiplasmodial activity

Kamdoum BC, Simo I, Wouamba SCN, et al. Chemical constituents of two Cameroonian medicinal plants: Sida rhombifolia L. and Sida acuta Burm. f. (Malvaceae) and their antiplasmodial activity. Natural product research. 2021.An extensive phytochemical investigation of the EtOH/H2O (7:3) extracts of Sida rhombifolia L. and Sida acuta Burm. f., yielded a previously undescribed ceramide named rhombifoliamide (1) and a xylitol dimer (2), naturally isolated here for the first time, as well as the thirteen known compounds viz, oleanolic acid (3), beta-amyrin glucoside (4), ursolic acid (5), beta-sitosterol glucoside (6), tiliroside (7), 1,6-dihydroxyxanthone (8), a mixture of stigmasterol (9) and beta-sitosterol (10), cryptolepine (11), 20-Hydroxyecdysone (12), (E)-suberenol (13), thamnosmonin (14) and xanthyletin (15). Their structures were elucidated by the analyses of their spectroscopic and spectrometric data (1D and 2D NMR, and HRESI-MS) and by comparison with the previously reported data. The crude extracts, fractions, and some isolated compounds were tested against chloroquine-sensitive (3D7) and chloroquine-resistant (Dd2) Plasmodium falciparum strains. All the tested samples demonstrated moderate and/or significant activities against 3D7 (IC50 values: 0.18-20.11g/mL) and Dd2 (IC50 values: 0.74-63.09g/mL)

Soyauxinine, a New Indolopyridoquinazoline Alkaloid from the Stem Bark of Araliopsis soyauxii Engl. (Rutaceae)

Noulala CGT, Ouete JLN, Atangana AF, et al. Soyauxinine, a New Indolopyridoquinazoline Alkaloid from the Stem Bark of Araliopsis soyauxii Engl. (Rutaceae). Molecules. 2022;27(3): 1104.The chemical investigation of the total alkaloid extract (TAE) of the stem bark of Araliopsis soyauxii (Rutaceae) afforded an unreported indolopyridoquinazoline (compound 1) along with nine previously known alkaloids 2–10. In addition, six semi-synthetic derivatives 3a–c, 4b, 5a and 6a were prepared by allylation and acetonidation of soyauxinium nitrate (5), edulinine (3), ribalinine (4) and arborinine (6). The structures and spectroscopic data of five of them are reported herein for the first time. The suggested mechanism for the formation of the new N-allylindolopyridoquinazoline 5a is presented. The structures of natural and derived compounds were determined employing extensive NMR and MS techniques. The absolute configuration of stereogenic centers in compounds 2–4 were determined using NOESY technique and confirmed by the single-crystal X-ray diffraction (SC-XRD) technique. The use of SC-XRD further enabled us to carry out a structural revision of soyauxinium chloride recently isolated from the same plant to soyauxinium nitrate (5). The TAE, fractions, compounds 1–7 and 9, and semi-synthetic derivatives 3a–c, 4b, 5a and 6a were evaluated for their cytotoxic activity towards the cervix carcinoma cell line KB-3-1. No significant activity was recorded for most of the compounds except for 9, which showed moderate activity against the tested cancer cell lines