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

Triumfettamide B, a New Ceramide from the Twigs of Triumfetta rhomboidea

International audienceA new ceramide (1) along with lupeol (2) and a mixture of β-sitosterol and stigmasterol, oleanolic acid (4), maslinic acid (5), β-sitosterol glucopyranoside (6), and trans-tiliroside (7) were isolated from Triumfetta rhomboidea (Tiliaceae). Their structures were determined on the basis of spectroscopic methods and mass spectrometry analysis, as well as by comparison of their physical and spectral data with those reported in the literature. The cytotoxic activity of crude extract, fractions, and some compounds were evaluated against human fibrosarcoma cancer cell line HT1080 using flow cytometry. The ethyl acetate fraction showed weak activity while the crude extract and the hexane and n-butanol fractions presented less than 50% of cell growth inhibition

O-Prenylated Acridone Alkaloids from the Stems of Balsamocitrus paniculata (Rutaceae)

Happi EN, Waffo AFK, Wansi JD, Ngadjui BT, Sewald N. O-Prenylated Acridone Alkaloids from the Stems of Balsamocitrus paniculata (Rutaceae). Planta Medica. 2011;77(09):934-938.Two new O-prenylated acridone alkaloids, balsacridone A (1) and B (2), together with eighteen known compounds were isolated from the methanol extract from the stems of Balsamocitrus paniculata, a Cameroonian medicinal plant. The structures of all compounds were determined by comprehensive analyses of their 1D and 2D NMR, mass spectral (EI and ESI) data, and chemical reactions. N-methyl-6-methoxybenzoxazolinone (16) was isolated for the first time from a natural source while compounds 13, 14, and 15 for the first time from this genus. Pure compounds were tested for their activity against bacteria, fungi, and plant pathogen oomycetes, using the paper disk agar diffusion assay. The agar diffusion test delivered low to missing antimicrobial activities, corresponding to MICs > 1 mg/mL. However, compounds 1-15 exhibited a strong suppressive effect on phagocytosis response upon activation with serum opsonized zymosan in the range of IC(50) = 0.5-7.2 mu M, and the acridone alkaloids (1-5), N-trans- p-coumaroyltyramine (13), and N-trans-p-coumaroyloctopamine (14) displayed weak cytotoxic activity against the human Caucasian prostate adenocarcinoma cell line PC-3, with IC(50) values ranging from 69.8 to 99.0 mu M

(−)-Brunneusine, a new phenolic compound with antibacterial properties in aqueous medium from the leaves of Agelanthus brunneus (Engl.) Tiegh (LORANTHACEAE)

Agelanthus brunneus (Loranthaceae) is a hemiparasitic plant growing on Senna siamea (Fabaceae). The chemical investigation of its leaves and flowers led to the isolation of one new phenolic compound namely (-)-brunneusine (1), together with 13 known compounds. The crude leaves and flowers extracts (CLE and CFLE) with their ethyl acetate fractions (EAFL and EAFFL) and some isolated compounds (1-3; 8-9 and 11-14) have been tested on four bacterial species of sanitary importance isolated in an aquatic environment. All the samples except compound 3 showed antibacterial activity with MICs ranging from 0.43 to 8.88.103 μg/mL and MBCs from 0.43 to 3.55.103 μg/mL. Compounds 9 and 14 showed better activity on all bacterial species tested with MICs ranging from 0.43 to 27.77 μg/mL. Only CLE, EAFL and compounds 14, 2, 8 and 9 showed bactericidal effects on all bacterial species tested

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