Cytotoxic stilbenes and canthinone alkaloids from Brucea antidysenterica (Simaroubaceae)

Phytochemical study of the root and bark of Brucea antidysenterica J. F. Mill. (Simaroubaceae) afforded three new compounds including a stilbene glycoside bruceanoside A (1), and two canthinone alkaloids bruceacanthinones A (3) and B (4), as well as ten known secondary metabolites, rhaponticin (2), 1,11-dimethoxycanthin-6-one (5), canthin-6-one (6), 1-methoxycanthin-6-one (7), 2-methoxycanthin-6-one (8), 2-hydroxy-1,11-dimethoxycanthin-6-one (9), β-carboline-1-propionic acid (10), cleomiscosin C (11), cleomiscosin A (12) and hydnocarpin (13). The structures of all the compounds were determined using spectrometric and spectroscopic methods including 1D and 2D NMR, and HRSEIMS. The identity of the known compounds was further confirmed by comparison of their data with those reported in the literature. The root and bark methanolic extracts, the dichloromethane and ethyl acetate soluble fractions, as well as the isolated compounds (3–13), were assessed for their cytotoxicity against the cancer cell lines A-549, MCF-7 and PC-3. The results suggested that compounds in the extracts might possess a synergic action in their cytotoxicity

Antimicrobial Furoquinoline Alkaloids from Vepris lecomteana (Pierre) Cheek & T. Heller (Rutaceae)

Three new prenylated furoquinoline alkaloids named lecomtequinoline A (1), B (2), and C (3), together with the known compounds anhydroevoxine (4), evoxine (5), dictamnine (6), N-methylflindersine (7), evoxanthine (8), hesperidin, lupeol, β-sitosterol, stigmasterol, β-sitosterol-3-O-β-d-glucopyranoside, stearic acid, and myristyl alcohol, were isolated by bioassay-guided fractionation of the methanolic extracts of leaves and stem of Vepris lecomteana. The structures of compounds were determined by spectroscopic methods (NMR, MS, UV, and IR) and by comparison with previously reported data. Crude extracts of leaves and stem displayed high antimicrobial activity, with Minimum Inhibitory Concentration (MIC) (values of 10.1–16.5 and 10.2–20.5 µg/mL, respectively, against Escherichia coli, Bacillus subtilis, Pseudomonas agarici, Micrococcus luteus, and Staphylococcus warneri, while compounds 1–6 showed values ranging from 11.1 to 18.7 µg/mL or were inactive, suggesting synergistic effect. The extracts may find application in crude drug preparations in Western Africa where Vepris lecomteana is endemic, subject to negative toxicity results in vivo

Antimycobacterial cycloartane derivatives from the roots of Trichilia welwistchii C. DC (Meliaceae).

Chemical investigation of the roots of yielded a cycloartane type terpenoid 28,29-bis-norcycloart-24-en-3 ,4 ,6 -triol ( ), isolated as pure compound for the first time, three coumarins and three sterols. New cycloartane derivatives ( ) and ( + ) were obtained by hemi-synthetic reaction of compound . The structures of – were established by spectroscopic methods including 1D and 2D-NMR analysis, HR-EIMS, chemical transformations and by comparison of these data with those of related compounds. Evaluated for their antimycobacterial potential, compound and + were determined to show significant activities against MIC values of 6.25 μg mL while compound displayed weak activity showing MIC > 100 μg mL . Compounds – displayed moderate activity with MIC values range from 12.5 to 50 μg mL

Oxidative burst inhibition, cytotoxicity and antibacterial acriquinoline alkaloids from Citrus reticulate (Blanco)

Fomani M, Ngeufa Happi E, Nouga Bisoue A, et al. Oxidative burst inhibition, cytotoxicity and antibacterial acriquinoline alkaloids from Citrus reticulate (Blanco). Bioorganic & Medicinal Chemistry Letters. 2015;26(2):306-309

A New Antimicrobial Phenylpropanol from the Leaves of Tabernaemontana inconspicua Stapf. (Apocynaceae) Inhibits Pathogenic Gram-Negative Bacteria.

A chemical investigation of the leaves of Tabernaemontana inconspicua Stapf. led to the isolation of a new phenylpropanol derivative, namely irisdichototin G (1), together with nine known compounds, including one polyol derivative, dambonitol (2); three alkaloids, 10-hydroxycoronaridine (3), voacristine (4) and vobasine (5); two triterpenes lupeol (6), betulinic acid (7) and three sterols, sitosterol (8), sitosterol-3-O-β-D-glucopyranoside (9) and stigmasterol (10). The structure of the new compound, as well as those of the known ones, was established by means of spectroscopic methods: NMR analysis (1H and 13C NMR, 1H-1H-COSY, HSQC, HMBC and NOESY), high-resolution mass spectrometry (HR-ESI-MS) and comparisons with previously reported data. Among the known compounds, compound 2 was firstly reported from the family Apocynaceae. Compounds 1–5 were tested for their antimicrobial effects against three Gram-negative organisms associated with human wound and systemic infections, namely Haemophilus influenzae 9435337A, Klebsiella pneumoniae 17102005 and Pseudomonas aeruginosa 2137659B. Compounds 1, 3, and 5 showed significant antimicrobial effects with minimum inhibitory concentrations (MIC) of 62.5 μg/mL, 62.5 μg/mL and 7.81 μg/mL, respectively, against Haemophilus influenzae, whereas compounds 1 and 5 showed significant antimicrobial effects, with a MIC value of 31.25 μg/mL against Pseudomonas aeruginosa. In addition, compound 3 showed significant antimicrobial activity, with a MIC value of 31.25 μg/mL against Klebsiella pneumoniae

Chemical constituents from Penianthus camerounensis Dekker (Menispermaceae)

The phytochemical study of the roots, leaves and twigs of Penianthus camerounensis Dekker (Menispermaceae) has led to the isolation and the characterization of 20 compounds. A ceramide, camerounamide (1), and a furoclerodanediterpenoid, camerounin (2), have not been described previously, while the compounds xylopic acid (3), syringaresinol (4), iso-propylmethylcyclohexa-1,4-diol (5), 1-(28-hydroxyoctacosanoyl)glycerol (6), scoparone (7), friedelin (8), friedelanol (9) and betulinic acid (10) are being reported for the first time from the genus Penianthus alongside 10 known compounds (11–20). Chemical structures were determined using 1D- and 2D-NMR spectroscopy, MS and chemical analysis. Their chemotaxonomic importance is discussed

Chemical Composition and Synergistic Antimicrobial Effects of a Vegetatively Propagated Cameroonian Lemon, Citrus x limon (L.) Osbeck

Nsangou MF, Happi EN, Fannang SV, et al. Chemical Composition and Synergistic Antimicrobial Effects of a Vegetatively Propagated Cameroonian Lemon, Citrus x limon (L.) Osbeck. ACS Food Science & Technology. 2021.This study analyzed the antimicrobial effects of compounds present in the roots and leaves of Citrus x limon (L.) Osbeck to help understand how this plant (1) ecologically modulates microbial defense in the rhizosphere and (2) protects against food-borne bacterial pathogens. Antimicrobial effects of C. limon collected from a farm in Foumban in Cameroon are reported against Salmonella typhi, Salmonella typhimurium, Salmonella enteritidis, Escherichia coli, Shigella flexineri, and Saccharomyces cerevisiae. The study modeled synergistic antifungal effects of an essential oil from the roots of C. limon or E-caryophyllene when combined with the isolated compounds against S. cerevisiae. Twenty-four compounds were identified from the methanol extracts of the roots and leaves: 10 prenylated coumarins (1–10), six methoxylated flavones (11–16), two limonoids (18 and 19), a phenylalanine derivative (20), lupeol, stigmasterol, sitosterol, and sitosterol-3-O-β-d-glucoside. Major compound 16, atalantoflavone, was esterified using lauric acid to yield the undescribed 5,4′-dilaureate atalantoflavone (16a). The essential oil from the roots contained methyl esters of hexadecanoic acid (39%) and 9-octadecenoic acid (9.3%) and sesquiterpenes β-bisabolene (10.1%) and α-santalene (8.0%). The antimicrobial effects of the root extract, leaf extract, compounds 1, 2, 4, 7–9, 11, 12, 14, 16, 16a, and 18 were evaluated against S. typhi, S. typhimurium, S. enteritidis, E. coli, S. flexineri, and S. cerevisiae. Compounds 11, 16, and 18 from the root extract of C. x limon showed significant antimicrobial effects with a minimum inhibitory concentration (MIC) of 62.5 μg/mL against S. flexineri, whereas compounds 5, 7, 11, and 18 showed significant antimicrobial effects with a MIC of 62.5 μg/mL against S. typhi. The essential oil from the roots synergized compounds 11–14 against S. cerevisiae. A synergistic MIC of 7.8 μg/mL was registered by combining 12 and E-caryophyllene

Antibacterial constituents from the roots, stem bark and leaves of Manilkara obovata (Sabine & G. Don) J. H. Hemsl. (Sapotaceae)

Akosung E, Djouaka Bavoua JL, Tabekoueng GB, et al. Antibacterial constituents from the roots, stem bark and leaves of Manilkara obovata (Sabine &amp; G. Don) J. H. Hemsl. (Sapotaceae). Phytochemistry Letters. 2021;44:55-61.The investigation of the methanolic extracts of the roots, stem bark and leaves of Manilkara obovata (Sabine & G. Don) J. H. Hemsl. (Sapotaceae), synonym Manilkara argentea Pierre ex Dubard, has led to the isolation and characterization of a new 4-phenylcoumarin derivative, in form of a racemic mixture of obovacoumaric acid (1a) and the previously reported callophyllic acid (1b) as well as a new taraxerane type triterpene named obovatol (2), alongside twenty-five known compounds. In addition, ethylcanophyllate (3a), obtained by esterification of canophyllic acid (3) is reported here for the first time. The structures of compounds were determined by comprehensive spectroscopic analyses of their 1D and 2D NMR, EI/ESI-MS and single crystal X-ray diffraction (SC-XRD) analysis for 1a and 1b, accompanied by comparison with reported records. In addition, the antibacterial activity of crude extracts, fractions and some of the isolated compounds including the hemi-synthesized ethylcanophyllate (3a) was determined against Salmonella typhi, Staphylococcus aureus ATCC4330, Enterobacter cloacae, Pseudomonas aeruginosa HM801, Streptococcus pneumoniae ATCC491619 and Escherichia coli ATCC25322 applying the broth microdilution method. While the methanolic stem bark extract showed good to significant activity against all bacterial test strains with MICs between 7.8 and 62.5 μg/mL, its fractions A and B were less active, indicating synergistic effects. This effect was also observed for the methanolic root extract, which gave a significant MIC against Staphylococcus aureus ATCC4330 with MIC < 3.9 μg/mL, but only MICs of 31.2 and 7.8 μg/mL for its fractions D and E. Likewise, though fractions F3 and F4 of the methanolic leaf extract displayed good MICs of 31.2 and 15.6 μg/mL, respectively, against Staphylococcus aureus ATCC4330, tested compounds were not stronger active. Interestingly, the hemi-synthesized ethylcanophyllate (3a) based on the completely antibacterial inactive canophyllic acid (3) displayed a good MIC of 15.6 μg/mL against Staphylococcus aureus ATCC4330, pointing here to a dominant role of the ester function in compound 3a in the structure-activity relationship

The chemistry and biological activities of Citrus clementina Hort. Ex Tanaka (Rutaceae), a vegetatively propagated species

We report the chemistry and biological activities of a Cameroonian Citrus clementina Hort. Ex Tanaka, a vegetatively propagated species. The compounds isolated from this plant were determined to be the known 5-hydroxy-6,7,8,3’,4’-pentamethoxyflavone (1), tangerine (3), nobilletin (4), 5,7,8,4’-tetramethoxyflavone (5), citracridone I (6), 5-hydroxynoracronycine (7), citracridone III (8), xanthyletin (10), suberosin (9), E-suberenol (11), E-methoxysuberenol (13), 6-formylumbelliferone (12), aurantiamide acetate (2), limonin (14), stigmasterol, β-sitosterol and β-sitosterol-3-O-β-D-glucoside. The structures of the compounds were established on the basis of their NMR spectroscopic data and comparison with published data. Methanol leaf extract and compounds 1, 2, 4, 6, 7 and 10 were evaluated for their anti-inflammatory, antioxidant, urease and anti-diabetic effects. Compound 10 showed antioxidant activity, anti-inflammatory effect, urease activity and anti-diabetic activity with IC50 values of 47.3 µM, 33.5 µM, 25.2 µM and 33.9 µM respectively, values that were comparable to the respective positive standards

The chemistry of the West and Central African Penianthus zenkeri Diels (Menispermaceae)

A phytochemical investigation of the roots and twigs of Penianthus zenkeri Diels led to the identification of twenty four compounds including one previously undescribed C-28 ecdysteroid (1) and previously described phytosteroids (2–5, 20, 22, 23), phenolic compounds (6–8, 12), diterpenoids (9–11), alkaloids (13,14, 18, 19), a dipeptide (15), ursane type triterpenoids (16–17), a carbohydrate (21) and a fatty alcohol (24). Three semi-synthetic derivatives (5b, 5a, 17a) obtained from acetylation and acetonidation of rubrosterone (5), and allylation of ursolic acid (17), respectively, are also reported. The chemical structures of the compounds were determined using 1D and 2D NMR spectral data, mass spectrometry and by comparison with the data reported in the literature. The absolute configuration of compound 9 was established using X-Ray and ECD analysis. Different extracts of the twigs and roots, compounds 2–4, 6–11, 15, and 17–21 were evaluated for their antibacterial, and cytotoxic activities. The twigs extract showed an antibacterial activity with an MIC of 62.5 μg/mol against Staphylococcus aureus ATCC 4300, while ursolic acid exhibited a moderate cytotoxicity with an IC50 of 50.9 μM. The chemotaxonomic relevance of the isolated compounds is discussed