scholarly journals Four New Phloroglucinol-Terpene Adducts from the Leaves of Myrciaria cauliflora

Author(s):  
Ming Chen ◽  
Jia-Qing Cao ◽  
Wen-Jing Wang ◽  
Ni-Ping Li ◽  
Yan Wu ◽  
...  

Abstract Myrcauones A–D (1–4), four new phloroglucinol–terpene adducts were isolated from the leaves of Myrciaria cauliflora. Their structures with absolute configurations were elucidated by combination of spectroscopic analysis, single crystal X-ray diffraction, and electronic circular dichroism (ECD) calculations. Compound 1 was a rearranged isobutylphloroglucinol–pinene adduct featuring an unusual 2,3,4,4a,10,11-hexahydro-1H-3,11a-methanodibenzo[b,f]oxepin backbone. Compound 4 showed moderate antibacterial activity against Gram-positive bacteria including multiresistant strains. Graphic Abstract

2020 ◽  
Vol 16 ◽  
pp. 2100-2107
Author(s):  
Ken-ichi Nakashima ◽  
Junko Tomida ◽  
Tomoe Tsuboi ◽  
Yoshiaki Kawamura ◽  
Makoto Inoue

Two new azaphilones, namely muyocopronones A (1) and B (2), were isolated from the cultures of an endophytic fungus Muyocopron laterale ECN279. Their structures were elucidated by extensive spectroscopic analysis. Their absolute configurations were determined using the modified Mosher’s method and through comparisons of experimental and calculated electronic circular dichroism data. In addition, muyocopronone B (2) was found to exhibit a weak antibacterial activity against some Gram-positive bacteria.


1997 ◽  
Vol 50 (8) ◽  
pp. 861 ◽  
Author(s):  
Shaheen Faizi ◽  
Bina Shaheen Siddiqui ◽  
Rubeena Saleem ◽  
Farzana Akhtar ◽  
Khursheed Ali Khan ◽  
...  

Quinolin-8-ol (1) on reaction with 2,6-dichloroaniline and m-nitrobenzaldehyde afforded 7-(α-hydroxy- m-nitrobenzyl)quinolin-8-ol (2), which is an unusual Mannich reaction product. The structure of (2) was determined by spectroscopic and single-crystal X-ray diffraction studies. Preliminary antimicrobial screening showed that (1) and (2) have activity against a large number of Gram-positive and Gram-negative bacteria.


2011 ◽  
Vol 366 ◽  
pp. 404-407
Author(s):  
Li Hua Wang

The block single-crystals of taurine were obtained, and its structure was determined by single-crystal X-ray diffraction. The single-crystal X-ray analysis of taurine reveals that the crystal belongs monoclinic, space group P2(1)/c with a = 0.52824(10) nm, b = 1.1647(8) nm, c = 0.79236(13) nm, ß = 94.0850(10). The magnesium complex with taurine has been synthesized in ethanol. The antibacterial assay of the Mg (II) complex was measureed using a modified version of the 2-fold serial dilution method. The results show that the complex shows considerable antibacterial activity against escherichia coli, bacillus subtilis and staphylococcus white.


Author(s):  
Danyang Zhang ◽  
Xiao-Xia Wang ◽  
Ya-Nan Wang ◽  
Min Wang ◽  
Peng-Yu Zhuang ◽  
...  

Chlorahupetones A-I (1−9), nine sesquiterpenoid dimers, were isolated from Chloranthus henryi var. hupehensis. Their structures were characterized by nuclear magnetic resonance (NMR), electronic circular dichroism (ECD), and X-ray diffraction analysis....


2015 ◽  
Vol 32 ◽  
pp. 71-80
Author(s):  
Mohsen Mehregan ◽  
Hossein Soltaninejad ◽  
Behnaz Toluei Nia ◽  
Hadi Zare-Zardini ◽  
Masoud Zare-Shehneh ◽  
...  

The formation of biofilm (Biofouling) in different surface is the great concern in types of fields, especially in medical and health system as well as in membrane technology. The present study deals with the synthesis and characterization of Al2O3 nanopowders with antibacterial activity which can be a potentially utilized material for biocompatible implants. Nanostructure was synthesized based on sol-gel method and then, crystallite size, and microstructural and morphological characterization of nanostructure were determined by X-ray diffraction, electron-microscopic techniques - scanning electron microscopy (SEM) and transmission electron microscopy (TEM). According to X-ray diffraction, the value of particle size for Al2O3 nanopowders is 20.85 nm. In the following, the antibacterial activity of Al2O3 nanoparticles was assessed on three gram positive and three gram negative bacteria by radial diffusion assay and measurement of minimum inhibitory concentration (MIC). The toxicity of Al2O3 nanopowders on blood cells was also assessed. The results showed that this nanostructure has potent antibacterial activity against gram positive and gram negative bacteria. The synthesized Al2O3 nanopowders showed the antimicrobial activity against antibiotic resistant bacterium, Staphylococcus aureus. Significant antibacterial activity of this nanostructure was seen to have a greatest effect on Bacillus cereus with the MIC value of 9.2 μg/ml; while, among bacterial strains, Salmonellatyphimurium was investigated to be the most resistant one with the MIC of 35.6 μg/ml. Al2O3 nanopowders showed no toxicity on blood cells. according to acquired data in this study, Al2O3 nanopowders may be a good material for inhibition of biofilm formation.


2019 ◽  
Vol 9 (6) ◽  
pp. 425-429 ◽  
Author(s):  
Xiang-Mei Li ◽  
Xian-Jun Jiang ◽  
Guo-Zhu Wei ◽  
Li-Hua Ren ◽  
Li-Xia Wang ◽  
...  

Abstract Two hitherto unknown iboga-type indole alkaloids, namely (3R)-7,19-di-epi-3-methoxytabernoxidine (1) and (3R,19R)-19-hydroxy-3-(2-oxopropyl)voacangine (2), together with eight known alkaloids (3–10), were isolated from the twigs and leaves of Tabernaemontana divaricata. Their structures were established on the basis of spectroscopic data interpretation, single crystal X-ray diffraction analysis and circular dichroism spectrum. Graphic Abstract


2018 ◽  
Vol 10 (6) ◽  
pp. 224 ◽  
Author(s):  
Manyasree D. ◽  
Kiranmayi P. ◽  
Venkata R Kolli

Objective: In the present study the antibacterial activity of zinc oxide (ZnO) nanoparticles was investigated against gram negative (Escherichia coli and Proteus vulgaris) and gram positive (Staphylococcus aureus and Streptococcus mutans) organisms.Methods: The synthesis of ZnO nanoparticles was carried out by co-precipitation method using zinc sulfate and sodium hydroxide as precursors. These nanoparticles were characterized by XRD (X-Ray Diffraction), FTIR (Fourier Transform Infrared Radiation), UV-Visible spectroscopy and SEM (Scanning Electron Microscope) with EDX (Energy Dispersive X-ray analysis). As well as antibacterial activity and minimum inhibitory concentration of the nanoparticles were carried out by agar well diffusion method and broth dilution method respectively against gram negative (Escherichia coli and Proteus vulgaris) and gram positive (Staphylococcus aureus and Streptococcus mutans) bacteria.Results: The average crystallite size of ZnO nanoparticles was found to be 35 nm by X-ray diffraction. The vibration bands at 450 and 603 cm-1 which were assigned for ZnO stretching vibration were observed in FTIR spectrum. The optical absorption band at 383 nm was obtained from UV-Visible spectrum. Spherical shape morphology was observed in SEM studies. The antibacterial assay clearly expressed that E. coli showed a maximum zone of inhibition (32±0.20 mm) followed by Proteus vulgaris (30±0.45 nm) at 50 mg/ml concentration of ZnO nanoparticles.Conclusion: Zinc oxide nanoparticles have exhibited good antibacterial activity with gram negative bacteria when compared to gram positive bacteria.


2016 ◽  
Vol 14 (30) ◽  
pp. 7354-7360 ◽  
Author(s):  
Hong-Xin Liu ◽  
Kai Chen ◽  
Yao Yuan ◽  
Zhi-Fang Xu ◽  
Hai-Bo Tan ◽  
...  

Two novel meroterpenoids were isolated from Rhodomyrtus tomentosa. Their structures with unique NMR characteristics were determined by extensive spectroscopic analysis, single-crystal X-ray diffraction, quantum molecular calculation, chemical transformation as well as total synthesis.


Sign in / Sign up

Export Citation Format

Share Document