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Myricasalicifolia A Rich (Myricaceae) is a tree growing in Central and East Africa. Traditionally, the plant is used to treat malaria, respiratory disorders, inflammations, and infections. A new compound, 3β-O-trans-caffeoylisomyricadiol (7), was isolated from MeOH : CHCl3 (2 : 1) extract of the stem bark of Myrica salicifolia along with seven known compounds, namely, myricanone (1), myricanol (2), myricanol-11-O-β-D-xylopyranoside (3), taraxerone (4), taraxerol (5), myricadiol (6), and methyl-β-D-glucopyranoside (8). This is the first report of the isolation of taraxerene-type triterpenes from this plant. The structures were determined by a comprehensive analysis of 1D/2D NMR spectroscopy, HR-MS, and by comparison with literature data. The compounds showed a wide range of DPPH scavenging activities from very weak (IC50 value = 282.61 μM) to very strong (IC50 = 13.48 μM). Antibacterial activities of the compounds were evaluated using the disk diffusion agar method, where some of the compounds showed modest antibacterial activities against S. pyogenes and S. aureus at 250 μg/mL. Compounds 2, 3, and 7 were assessed for their in silico molecular docking analysis. The lowest binding affinity for compound 7 was found to be −7.26 to −10.35 kcal/mol against PqsA protein of P. aeruginosa, pyruvate kinase (PK) enzyme of S. aureus, LuxS protein of S. pyogenes, and DNA gyrase B of E. coli, which showed better binding affinity compared to the standard drug ampicillin (−7.36 to −8.03 kcal/mol) and ciprofloxacin (−6.19 to −6.83 kcal/mol). In silico ADMET predictions revealed that compounds 3 and 8 met all the requirements for pharmacokinetic properties. [ABSTRACT FROM AUTHOR]

The chemical study of Erythrina livingstoniana has led to the isolation of three new flavanones namely 5,7,3′-trihydroxy-4′-methoxy-5′-formylflavanone (erylivingstone A) ( 1 ), 5,7,3′-trihydroxy-5′-(2-hydroxy-3-methylbut-3-enyl)-4′-methoxyflavanone (erylivingstone B) ( 2 ) and 5,7,3′-trihydroxy-5′-(3-hydroxy-3-methyl- trans -but-1-enyl)-4′-methoxyflavanone (erylivingstone C) ( 3 ) together with three known compounds ( 4 – 6 ). Their structures were elucidated on the basis of NMR data, HRMS n fragmentation pathway and by comparison with literature data. We evaluated the antibacterial efficacies and free-radical scavenging potential of the isolated compounds ( 1 – 6 ). The typical environmental strains of Gram-positive Bacillus subtilis , Gram-negative Escherichia coli , as well as against the clinically important Staphylococcus aureus , Streptococcus pyogenes and E. coli (risk-group 2) were used for the antibacterial assay. Compounds 5 and 6 exhibited the most pronounced efficacy against tested environmental bacteria as well as against the pathogenic strain of E. coli . Compound 3 was also quite active against these three bacterial strains. The isolated compounds showed weak radical scavenging properties with compound 6 being the most active, followed by compounds 2 , 3 and 5 . [ABSTRACT FROM AUTHOR]

Abstract Phytochemical studies of the seeds of the Cameroonian medicinal plant, Salacia staudtiana , resulted in the isolation and identification of five new cardenolides (1 – 5) as well as a new dihydro-β-agarofuran (9), along with eight known compounds. The structures of all compounds were elucidated by 1D/2D NMR, ESI-HRMS data and comparison with literature data. The relative configurations of the new compounds were defined by X-ray crystallography analysis, NOESY correlations and coupling constants. We evaluated their antibacterial efficacy against two commonly dispersed environmental strains of Escherichia coli and Bacillus subtilis , and two pathogenic strains of Staphylococcus aureus and Pseudomonas aeruginosa , compared to the standard antibiotics, streptomycin and gentamicin. Moreover, we assessed the antibacterial activity of the crude extract of the seeds in parallel to evaluate the plausible synergistic effects of the compounds in chemical defense of the seeds during germination and plant reproduction. The isolated compounds showed moderate antibacterial activities against the tested organisms. Compounds 1 and 3 and the crude extract exhibited distinct antibacterial activities against B. subtilis and S. aureus. The isolated compounds showed weak DPPH radical scavenging properties compared to the reference standard (Trolox). Our study lends evidence to the antibacterial chemical defense of S. staudtiana seeds by seed-borne compounds. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

Seven new cardenolides, staudtianoside A−F ( 1−6 ) and staudtianogenin A ( 8 ), were isolated along with six known compounds from the stem bark of the Cameroonian medicinal plant Salacia staudtiana Loes. ex Fritsch. The structures were elucidated by means of ESI-HRMS and NMR spectroscopic methods and by comparison with literature data. The relative configurations of the new compounds were determined by X-ray diffraction analysis, NOESY correlation and coupling constants. We evaluated the antibacterial efficacy of the isolated compounds against two commonly dispersed environmental strains of Escherichia coli and Bacillus subtilis , as well as against two human pathogenic clinical strains of Staphylococcus aureus and Pseudomonas aeruginosa . Compounds 1 , 2 and 8 exhibited marked antibacterial potencies against the clinically relevant P. aeruginosa that were comparable to the standard antibiotics. Compound 2 was also active against S. aureus and E. coli . Further, compounds 5 and 8 demonstrated efficacy against E. coli as well as B. subtilis . The structure-activity relationship of the tested compounds is discussed. [ABSTRACT FROM AUTHOR]