Antibacterial Activity and Phytochemical Screening of Erythrina fusca Lour. Leaf Extract (Fabaceae)

Erythrina fusca Lour. (family Fabaceae) is a flowering tree that is locally known as ‘chengkering’. The plant is traditionally used in treatment of some symptoms related to bacterial infections such as wound infections, inflammations, and skin itching. This work reports for the first time in vitro antibacterial screening of the E. fusca Lour. methanolic leaf extract against some common Gram-negative and Gram-positive bacteria such as Klebsiella pneumonia, Proteus vulgaris, Pseudomonas aeruginosa, Bacillus cereus, Bacillus subtilis, and Staphylococcus aureus. The in vitro antibacterial assay was carried out using agar diffusion method with the extract concentration of 3 mg/well and vancomycin 30 µg/well as the positive control. It was found that the extract exhibits antibacterial effects in range of 10.5 – 14 mm of zone of inhibition (ZOI) against all tested bacteria except for K. pneumoniae. P. aeruginosa showing ZOI of 14 mm was the most sensitive bacterium while P. vulgaris (ZOI of 10.5 mm) was the least sensitive strain to the extract. Based on the preliminary phytochemical screening of using standard qualitative phytochemical tests, this species contains significant amount of alkaloids, flavonoids, terpenoids, and tannins, which might contribute to the antibacterial activity of the extract. Both antibacterial potential and presence of various phytochemicals in the extract could support the traditional uses of E. fusca , and the obtained results would serve as a basis for further exploration of antibacterial properties of the plant’s leaves.

Discovery of gargantulides B and C, new 52-membered macrolactones from Amycolatopsis sp. Complete absolute stereochemistry of the gargantulide family

Gargantulides B and C, two new and highly complex 52-membered glycosylated macrolactones, were isolated from Amycolatopsis sp. strain CA-230715 during an antibacterial screening campaign. The structures of these giant macrolides...

Phytochemical and antibacterial screening of leaf extracts from Cassia singueana Del.(Fabaceae)

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Photocatalytic Remediation of Methylene Blue and Antibacterial Activity Study Using Schiff Base - Cu Complexes

Photocatalytic degradation of organic dyes under visible light and ultraviolet radiation is an efficient strategy for effluent treatment. This work describes the design of novel Cu(II) complexes using the ligand N'-(3-hydroxy-4-methoxybenzylidene)nicotinohydrazide and their application in the photocatalytic degradation of the organic dye, methylene blue (MB). The photocatalytic degradation of MB follows pseudo first-order kinetics with high correlation coefficient values (R2> 0.95), making them useful as simple and low-cost organic dye degradation agents. The antibacterial screening studies of the ligand and the Cu(II) complexes by disc diffusion method show the systems to exhibit activity against Escherichia coli (gram negative) and Bacillus circulans (gram positive).

One-pot synthesis of N-benzyl-2-aminobenzoic acid, via ring opening of isatoic anhydride derivative, and its antibacterial screening

2-(N-Benzyl) amino benzoic acid is a bifunctional molecule that could be produced from the reaction between isatoic anhydride and aryl halide. Analogues and derivatives of isatoic anhydride have wide application in pharmaceuticalsincluding antibacterial activity. The aim of this study is to synthesize, characterize and screen N-benzyl isatoic anhydride and 2-(N-benzyl) amino benzoic acid for antibacterial activity. The reaction of isatoic anhydride and benzyl bromide in the presence of potassium carbonate in DMSO at room temperature yielded N-benzyl isatoic anhydride, which under hydrolysis yielded 2-(N-benzyl) amino benzoic acid in which the anhydride ring is opened up. This compound was screened against Gram positive and negative bacteria. Moderate yield of 2-(N-benzyl) amino benzoic acid, a yellow crystal (melting point of 160-162oC, percentage yield 65 %, Rf 0.19) formed by ring opening of N-benzyl isatoic anhydride. The compound showed no antibacterial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas pyocyanea, Salmonella typhimurium, Klebsiella aeruginosa and Bacillus subtilis. 2-(N-benzyl)amino benzoic was synthesized, characterized and showed no activity against bacteria.

Mass Spectrometric Identification of Antimicrobial Peptides from Medicinal Seeds

Traditional medicinal plants contain a variety of bioactive natural products including cysteine-rich (Cys-rich) antimicrobial peptides (AMPs). Cys-rich AMPs are often crosslinked by multiple disulfide bonds which increase their resistance to chemical and enzymatic degradation. However, this class of molecules is relatively underexplored. Herein, in silico analysis predicted 80–100 Cys-rich AMPs per species from three edible traditional medicinal plants: Linum usitatissimum (flax), Trifolium pratense (red clover), and Sesamum indicum (sesame). Bottom-up proteomic analysis of seed peptide extracts revealed direct evidence for the translation of 3–10 Cys-rich AMPs per species, including lipid transfer proteins, defensins, α-hairpinins, and snakins. Negative activity revealed by antibacterial screening highlights the importance of employing a multi-pronged approach for AMP discovery. Further, this study demonstrates that flax, red clover, and sesame are promising sources for further AMP discovery and characterization.

Uncovering the potential of actinobacterium BLH 1-22 isolated from marine sediment as a producer of antibiotics

Actinobacteria have been known as producers of many bioactive compounds. The present study examines ten marine Actinobacterial isolates, aiming to investigate their potential as producers of antimicrobial compounds. The secondary metabolites were extracted from these Actinobacteria using ethyl acetate, and the crude extracts were tested for their bioactivity against Escherichia coli, Bacillus subtilis, and Micrococcus luteus. The antibacterial screening showed that the crude extracts of these Actinobacteria inhibit the growth of indicator strains. The extracts of isolate BLH 1-22 were further analysed using high-performance liquid chromatography (HPLC), which showed potential compounds with peak and retention time similar to the antibiotic standards (i.e., erythromycin, ampicillin, tetracycline, and penicillin). In addition to the HPLC profile, molecular identification showed that the isolate BLH 1-22 was similar to Micromonospora chalcea (99.6%). Further genome characterization of the strain, as well as purification and fractionation of the metabolite extracts, are important to obtain a comprehensive study on the potential of isolate BLH 1-22 as antibiotic compound producers. This study reported the potential of Micromonospora BLH 1-22 isolated from marine sediment. Hence, it also highlighted the potential of Actinobacteria isolated from Indonesian environments for bioprospecting studies.

Towards Property Profiling: SYNTHESIS and SAR Probing of New Tetracyclic Diazaphenothiazine Analogues

A series of new tertiary phenothiazine derivatives containing a quinoline and a pyridine fragment was synthesized by the reaction of 1-methyl-3-benzoylthio-4-butylthioquinolinium chloride with 3-aminopyridine derivatives bearing various substituents on the pyridine ring. The direction and mechanism of the cyclization reaction of intermediates with the structure of 1-methyl-4-(3-pyridyl)aminoquinolinium-3-thiolate was related to the substituents in the 2- and 4-pyridine position. The structures of the compounds were analyzed using 1H, 13C NMR (COSY, HSQC, HMBC) and X-ray analysis, respectively. Moreover, the antiproliferative activity against tumor cells (A549, T47D, SNB-19) and a normal cell line (NHDF) was tested. The antibacterial screening of all the compounds was conducted against the reference and quality control strain Staphylococcus aureus ATCC 29213, three clinical isolates of methicillin-resistant S. aureus (MRSA). In silico computation of the intermolecular similarity was performed using principal component analysis (PCA) and hierarchical clustering analysis (HCA) on the pool of structure/property-related descriptors calculated for the novel tetracyclic diazaphenothiazine derivatives. The distance-oriented property evaluation was correlated with the experimental anticancer activities and empirical lipophilicity as well. The quantitative shape-based comparison was conducted using the CoMSA method in order to indicate the potentially valid steric, electronic and lipophilic properties. Finally, the numerical sampling of similarity-related activity landscape (SALI) provided a subtle picture of the SAR trends.

Antibacterial Screening of Endophytic Fungus Xylaria sp. derived from Andrographis paniculata (Sambiloto)

AIM: The purpose of this research is to evaluate the antibacterial activity of endophytic fungi derived from the flowers of Andrographis paniculata (Sambiloto). METHODS: The endophytic fungi were obtained following the dilution method with potato dextrose agar as media. Four isolates of fungi have been obtained and then fermented with rice media for 3 weeks. The fermented fungi were extracted with ethyl acetate (EtOAc) and evaporated to yield the EtOAc extract. All EtOAc extracts were evaluated for their antibacterial activity using agar diffusion method. RESULTS: The results indicated that the EtOAc extract from fungus RG-2 was the potential source of antibacterial compounds. Molecular identification showing fungus RG-2 was Xylaria sp. CONCLUSION: Further investigation of the antibacterial compounds produced by fungus Xylaria sp. derived from the flowers of A. paniculata will be performed in the future. To the best of our knowledge, endophytic fungal Xylaria sp. is firstly isolated from A. paniculata.