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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]

Chemical investigation of the root wood of Erythrina livingstoniana led to the isolation of one previously undescribed isoflavan (3S,3″R)-7-hydroxy-2′-methoxy-[3″-hydroxy-2″,2″-dimethylpyrano (3′,4′)] isoflavan 1, together with eleven known compounds 2-12. The structure of compound 1 was elucidated on the basis of extensive spectroscopic and spectrometric analyses (1 D and 2 D-NMR and APCI-HRMS), with absolute configurations established by comparison of experimental and DFT calculated ECD data. The assignment of the absolute configurations of C-3 and C-3″ of compounds 2 and 3, respectively, were reported for the first time. Compounds 1 − 4 were evaluated for their antibacterial activities in vitro against E. coli ATCC 25922 and S. aureus ATCC 25923. Compound 1 exhibited moderate antibacterial activity with MIC value of 0.063 mg/mL against the clinically relevant risk-group 2 (RG-2) bacterium S. aureus. [ABSTRACT FROM AUTHOR]

In the present study, a new series of nine Thiazolo[3,2-α] pyrimidine analogs were synthesized in good to excellent yields (87.9–96.9%) and improved reaction time using a ZnO nanoparticle-assisted protocol. All the synthesized compounds were characterized using a combination of physicochemical parameters, UV-visible, 1H-NMR, and 13C-NMR spectroscopic methods. Among the synthesized compounds, the in vitro antibacterial activity displayed by compound 16 was higher (14.67 ± 0.58 mm at 500 μg/mL) against P. aeruginosa compared to amoxicillin (12.33 ± 0.58 mm at 500 μg/mL), whereas compounds 14 and 18 showed comparable activity (12.00 ± 0.00 mm and 12.33 ± 0.58 mm at 500 μg/mL and 250 μg/mL, respectively) against the same strain. The activities displayed by compounds 14, 16, 18, and 20 were comparable (12.33 ± 1.15 mm, 12.65 ± 0.58 mm, 12.33 ± 0.58 mm, and 12.00 ± 1.00 mm, respectively, at 500 μg/mL) to amoxicillin (13.33 ± 1.15 mm at the same concentration) against E. coli. Compound 19 showed good activity (12.00 ± 1.72 mm at 500 μg/mL) against S. aureus compared to amoxicillin (16.33 ± 0.58 mm at the same concentration). Compound 19 displayed the highest percent inhibition of DPPH with an IC50 value of 9.48 g/mL using the DPPH free radical scavenging assay compared to ascorbic acid (3.21 g/mL) and promising inhibition of peroxide formation (76.28 ± 0.12%), demonstrating its potential in preventing the formation of lipid peroxides. Thus, according to our findings, both the biological activities and in silico computational results revealed that compounds 14, 16, and 18 are good antibacterial agents against P. aeruginosa and E. coli, whereas compound 19 was found to be a promising antibacterial agent against S. aureus and an antioxidant agent. The present study revealed that the synthesized compounds appear to be lead compounds for rational drug design. [ABSTRACT FROM AUTHOR]

Background: Cyphostemma cyphopetalum is a medicinal plant traditionally used to treat various ailments. Limited studies on C. cyphopetalum inspired us to investigate the chemical nature and therapeutic potential of the plant. Methods: Silica gel column chromatographic separation was used for isolation. 1D and 2D NMR spectroscopic analysis and literature data were used for structural elucidation. Agar well diffusion assay was used for evaluation of antibacterial activity against E. coli, P. aeruginosa, and S. aureus. DPPH assay was used to evaluate radical scavenging activities. Molecular docking was done by AutoDock Vina 4.2 open-source program. DFT calculations were performed using the Gaussian 16 program package. Results: Dichloromethane/methanol (1:1) roots extract afforded a new hydroxyl-spongiane diterpenoid lactone derivative, 3-hydroxyisoagatholactone (1), along with β-sitosterol (2) and ϵ-viniferin (3) whereas methanol extract afforded trans-resveratrol (4), gnetin H (5), tricuspidatol A (6), ϵ-viniferin-diol (7) and parthenostilbenin B (8). At 50 μg/mL, compound 3 recorded the highest inhibition against E. coli (8.55 ± 0.45 mm) and S. aureus (9.30 ± 1.39 mm). Against P. aeruginosa, compound 5 consistently outperformed chloramphenicol (11.76 ± 0.77 mm, at 30 g/mL). Maximum binding affinity were observed by compound 3 against DNA gyrase B (-7.6 kcal/mol) where as compound 5 displayed maximum binding against PqsA (-8.8 kcal/mol) and S. aureus PK (-5.8 kcal/mol). Compounds 1, 3 and 4 satisfy Lipinski's rule of five. Trans-resveratrol (4) demonstrated strong DPPH scavenging activity at 12.5 g/mL, with IC50 values of 0.052 μg/mL, compared to ascorbic acid (IC50 value of 0.0012 μg/mL). Conclusion: In this work, eight compounds were identified from the roots extracts of C. cyphopetalum including a new hydroxyl-spongiane diterpenoid lactone, 3-hydroxyisoagatholactone (1). Compounds 3 and 5 exhibited good antibacterial activity and binding affinities. The docking result is in agreement with the invitro antibacterial study. Overall, the study result suggests that the isolated compounds have the potential to be used as therapeutic agents, which supports the traditional uses of C. cyphpetalum roots. [ABSTRACT FROM AUTHOR]

Thiazole-pyrazoline Schiff base hybrids have a broad range of pharmacological potential with an ability to control the activity of numerous metabolic enzymes. In this work, a greener and more efficient approach has been developed to synthesize a novel series of thiazole-pyrazoline Schiff base hybrids using ZnO nanoparticle-assisted protocol in good to excellent yields (78.3–96.9%) and examined their antibacterial activity against Gram-positive and Gram-negative bacteria, as well as their antioxidant activity. Compound 24 (IZD = 18.67 ± 0.58) displayed better activity against P. aeruginosa compared with amoxicillin (IZD = 14.33 ± 2.52) at 250 μg/mL, whereas compounds 22 and 24 (IZD = 13.33 ± 0.58 mm and 17.00 ± 1.00 mm, respectively) showed better activity against E. coli compared with amoxicillin (IZD = 14.67 ± 0.58 mm) at 500 μg/mL. The remaining compounds showed moderate to weak activity against the tested bacterial strains. Compound 21 displayed significant inhibition of DPPH (IC50 = 4.63 μg/mL) compared with ascorbic acid (IC50 = 3.21 μg/mL). Compound 21 displayed 80.01 ± 0.07% inhibition of peroxide formation, suggesting its potential in preventing the formation of lipid peroxides. The results of the ADMET study showed that all synthesized compounds obeyed Lipinski's rule of five. In silico pharmacokinetic study demonstrated that compound 24 had superior intestinal absorption compared with amoxicillin. In silico molecular docking analysis revealed a binding affinity of −9.9 Kcal/mol for compound 24 against PqsA compared with amoxicillin (−7.3 Kcal/mol), whereas compounds 22 and 24 displayed higher binding affinity (−8.5 and −7.9 Kcal/mol, respectively) with DNA gyrase B compared with amoxicillin (-7.1 Kcal/mol), in good agreement with in vitro antibacterial activity against P. aeruginosa and E. coli. In silico toxicity study showed that all synthesized compounds had LD50 (mg/kg) values ranging from 800 to 1,000 putting them in ProTox-II class 4. The in vitro antibacterial activity and molecular docking analysis showed that compound 24 is a promising antibacterial therapeutic agent against P. aeruginosa and E. coli and compound 22 is a promising antibacterial agent against E. coli, whereas compound 21 is found to be a potential natural antioxidant agent. Moreover, the green synthesis approach using ZnO nanoparticle as catalyst was found to be a very efficient method to synthesize biologically active thiazole-pyrazoline Schiff base hybrids compared with the conventional method. [ABSTRACT FROM AUTHOR]