scholarly journals PHYTOCHEMICAL EVALUATION AND ANTIMICROBIAL ACTIVITY OF GRACILARIA OPUNTIA: AN IMPORTANT ANTI-DIABETIC RED MARINE MACROALGAE

Author(s):  
Lavanya Rayapu ◽  
Fazina Makkar ◽  
Kajal Chakraborty ◽  
Lokanatha Valluru

Objective: Microorganisms have developed resistance to existing available antibiotics, thereby thriving to anemerging need for new generation of antibiotics. Since seaweeds provide a rich source of bioactive molecules,the present study aimed to investigate its anti-microbial potential against clinically important microorganism.Methods: Redseaweed namelyGracilaria opuntia collected from different coastal regions of Gulf of Mannar and Rameswaram, India was used. For microbiological testing of the seaweed extracts, agar disc diffusion methodwas used.Results: The zone of inhibition was measured for all the different crude algal extracts against strains ofmicroorganisms such as Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia and Pseudomonasputidathat cause diseases in diabetic patients. Crude extracts prepared from aqueous, ethanol and methanol extraction procedures revealed that aqueous extraction procedure have a wide range of antimicrobial activity against all thetest pathogens.Conclusion: The overall antibacterial activity assessed from the above results indicates the presence of activeconstituents in the extractions of seaweeds which can be explored for the production of significant moleculeswhich could be used in pharmaceutical industry.

2021 ◽  
Vol 18 ◽  
Author(s):  
S. Jagadeesan ◽  
S. Karpagam

: Bismuth (III) nitrate pentahydrate (BN) was found to be a mild and efficient catalyst for the electrophilic condensation of 5-nitroindazole with a wide range of aldehydes to obtain Bis (5-nitro indazolyl) methanes 3 (a-h) at ambient temperature. This was structurally confirmed from FTIR, NMR, and HR-MS technique. Molecular docking studies of all compounds was carried out using breast cancer-causing human estrogen receptor (ER) from Molegro Virtual Docker software. Hydroxy Bis (nitro indazolyl) methanes (3b) were shown better binding affinities and the score obtained was -150.146 Kcal/mol compared with Tamoxifen drug. The major H-bond interactions were observed with the compound 3f and the value was -5.679. The antimicrobial activity results revealed that compounds 3b and 3d showed promising activity against bacteria Escherichia coli, Klebsiella pneumonia, Staphylococcus aureus, and Pseudomonas aeruginosa and maximum inhibition against Aspergillus niger and Aspergillus flavus. Methoxy derivatives of Bis (nitro indazolyl methanes) (3e) have shown better antioxidant activity and low MIC (6.25 µg/ml) observed for the compounds 3a and 3b. The synthesized compounds have a very promising starting point for the development and improvement of anti-breast cancer drugs.


2021 ◽  
Author(s):  
Patricia Yumi Hayashida ◽  
Pedro Ismael Silva Junior

Background: Snails and slugs were used as a treatment for many health problems therefore ancient times. Since the antimicrobial resistance became a major global thread, antimicrobial peptides have been considered as a potential source for development of new drugs, especially for drug-resistant bacteria. Nowadays reports confirm that the mucous secretions have antimicrobial, antiviral and antifungal properties. Methods: The present study has the objective to characterize and evaluate antimicrobial peptides of Limacus flavus mucus. The mucus was obtained by thermal shock and submitted to RP-HPLC. Fractions were used to perform the antimicrobial activity and hemolytic assays, electrophoresis (SDS-Page Gel) and submitted to mass spectrometry (LC-MS / MS). Identification and characterization was performed by PeaksX+ software. The physicochemical parameters were evaluated with bioinformatics tools, which predicted water solubility, iso-electric point, charge net and its primary structure. Results: Three fractions were isolated from the mucus of L. flavus and presented antifungal and antibacterial activity. The mucus showed greater inhibition for filamentous fungi (Aspergillus niger), yeast (Cryptococcus neoformans), Gram positive bacteria (Bacillus subtilis, Micrococcus luteus) and Gram negative bacteria (Enterobacter cloacae). These fractions also did not show hemolytic activity for human blood cells (erythrocytes). Fractions sequences were identified and presents Mw <3kDa, WLGH, DLQW, YLRW, respectively. Conclusion: This study revealed three antimicrobial peptides of L. flavus mucus with a wide range of antimicrobial activity and its physic-chemical characterization. Keywords: Limacus flavus, mucus, slug, antimicrobial peptide, bioactive molecules, resistance, microorganisms.


Toxins ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 511 ◽  
Author(s):  
Bruno Casciaro ◽  
Andrea Calcaterra ◽  
Floriana Cappiello ◽  
Mattia Mori ◽  
Maria Loffredo ◽  
...  

Staphylococcus aureus is a major human pathogen causing a wide range of nosocomial infections including pulmonary, urinary, and skin infections. Notably, the emergence of bacterial strains resistant to conventional antibiotics has prompted researchers to find new compounds capable of killing these pathogens. Nature is undoubtedly an invaluable source of bioactive molecules characterized by an ample chemical diversity. They can act as unique platform providing new scaffolds for further chemical modifications in order to obtain compounds with optimized biological activity. A class of natural compounds with a variety of biological activities is represented by alkaloids, important secondary metabolites produced by a large number of organisms including bacteria, fungi, plants, and animals. In this work, starting from the screening of 39 alkaloids retrieved from a unique in-house library, we identified a heterodimer β-carboline alkaloid, nigritanine, with a potent anti-Staphylococcus action. Nigritanine, isolated from Strychnos nigritana, was characterized for its antimicrobial activity against a reference and three clinical isolates of S. aureus. Its potential cytotoxicity was also evaluated at short and long term against mammalian red blood cells and human keratinocytes, respectively. Nigritanine showed a remarkable antimicrobial activity (minimum inhibitory concentration of 128 µM) without being toxic in vitro to both tested cells. The analysis of the antibacterial activity related to the nigritanine scaffold furnished new insights in the structure–activity relationships (SARs) of β-carboline, confirming that dimerization improves its antibacterial activity. Taking into account these interesting results, nigritanine can be considered as a promising candidate for the development of new antimicrobial molecules for the treatment of S. aureus-induced infections.


2021 ◽  
Vol 83 (1) ◽  
pp. 49-57
Author(s):  
M.Ya. Vortman ◽  
◽  
Yu.B. Pysmenna ◽  
A.I. Chuenko ◽  
A.V. Rudenko ◽  
...  

There is information in the literature about the salts of polyhexamethylene guanidine (PGMG), which are effective biocidal and sterilizing drugs and disinfectants due to the wide range of their antimicrobial activity against gram-positive and gram-negative bacteria (including Mycobacterium tuberculosis), viruses, and fungi. The aim of this work is to study the bactericidal and fungicidal activity of the synthesized polyetherguanidinium chloride against a number of bacteria and microscopic fungi. Methods. Cultivation of microorganisms. Bacteria were grown on meat-peptone agar for 48 hours at a temperature of 28±2°C. Test cultures of micromycetes were cultured on beer wort agar (6°B), incubated for 14 days in a thermostat at a temperature of 28±2°C. Antimicrobial activity of newly synthesized polyetherguanidinium chloride was determined by standard disco-diffusion method, and fungicidal activity was determined by agar diffusion method. Results. The synthesis of polyetherguanidinium chloride was carried out in two stages. The first stage was the synthesis of a guanidinium-containing oligoether with terminal guanidine moieties by the reaction between an aromatic oligoepoxide and guanidine. The second stage was the synthesis of polyetherguanidinium chloride by the reaction between a guanidinium-containing oligoether with terminal guanidine moieties and oligooxyethylenediamine. The bactericidal and fungicidal activity of polyetherguanidinium chloride against various heterotrophic bacteria and microscopic fungi has been shown. It was found that polyetherguanidinium chloride at concentrations of 1–3% inhibited the growth of gram-negative (Escherichia coli 475, Klebsiella pneumonia 479) and gram-positive (Staphylococcus aureus 451) bacteria. The proposed 1% solution of polyetherguanidinium chloride shows a 1.5 times higher antimicrobial activity than the polymeric disinfectant polyhexamethyleneguanidinium chloride for E. coli 475 and K. pneumoniae 479 bacteria and lower antimicrobial activity for S. aureus 451 bacteria. According to the obtained data, it was noted that polyetherguanidinium chloride at a concentration of 1% had a high fungicidal activity against almost all investigated isolates: Aspergillus versicolor F-41250, Acremoneum humicola F-41252, Acremoneum roseum F-41251, Cladosporium sphaerospermum F-41255, Paecilomyces lilacinus F-41256 and Scopulariopsis candida F-41257. Conclusions. Received polyetherguanidinium chloride at a concentration of 1% showed bactericidal activity against S. aureus 451, E. coli 475, K. pneumoniae 479 and fungicidal effect to all fungi studied by us, and so can be used as a disinfectant for building materials.


2021 ◽  
Vol 45 (1) ◽  
pp. 59-71
Author(s):  
Md Abdul Alim ◽  
Md Farzanoor Rahman ◽  
Tamim Ahsan ◽  
Toufiqul Islam ◽  
Md Morshedul Alam ◽  
...  

The objective of the present study was to explore the phytochemical profiling, antioxidant and antimicrobial activity of 50% ethanolic extract of Rosenvingea sp. found in the Bay of Bengal of Bangladesh. Seven phytochemicals were tested from the ethanolic extract of Rosenvingea, where four phytochemicals, namely steroid, glycosides, alkaloids, and tannins were present. However, ethanol extract exhibited low antioxidant activity compared to standard ascorbic acid as measured by DPPH-Free radical scavenging assay. In Brine Shrimp lethality bioassay, 50% ethanolic extract showed an LC50 value of 10.88 mg/mL, whereas positive control (K2Cr2O7) showed LC50 59.97 µg/mL suggesting the less toxic property of the ethanolic extract. In-vitro antimicrobial activity of ethanolic extract of Rosenvingea sp. was investigated against gram-positive and gram-negative bacteria species (Staphylococcus, Bacillus, Pseudomonas, Salmonella, and Klebsiella) by agar disc diffusion method. The highest antibacterial activity was noticed against Klebsiella pneumonia, Pseudomonas aeruginosa, Staphylococcus hominis with a zone of inhibition of 5.00±1.00 mm, 3.66±0.57 mm, and 3.33±0.57 mm, respectively. This is the first study on Rosenvingea sp. from the Bay of Bengal, reporting its phytochemical, antioxidant, and antimicrobial potentiality. However, more study is required to elucidate its commercial viability in the food and medicine industries. J. Bangladesh Acad. Sci. 45(1); 59-71: June 2021


2020 ◽  
Vol 24 (8) ◽  
pp. 900-908
Author(s):  
Ram Naresh Yadav ◽  
Amrendra K Singh ◽  
Bimal Banik

Numerous O (oxa)- and S (thia)-glycosyl esters and their analogous glycosyl acids have been accomplished through stereoselective glycosylation of various peracetylated bromo sugar with benzyl glycolate using InBr3 as a glycosyl promotor followed by in situ hydrogenolysis of resulting glycosyl ester. A tandem glycosylating and hydrogenolytic activity of InBr3 has been successfully investigated in a one-pot procedure. The resulting synthetically valuable and virtually unexplored class of β-CMGL (glycosyl acids) could serve as an excellent potential chiral auxiliary in the asymmetric synthesis of a wide range of enantiomerically pure medicinally prevalent β-lactams and other bioactive molecules of diverse medicinal interest.


Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4672
Author(s):  
Mohamed H. Hassan ◽  
Cian Vyas ◽  
Bruce Grieve ◽  
Paulo Bartolo

The detection of glucose is crucial in the management of diabetes and other medical conditions but also crucial in a wide range of industries such as food and beverages. The development of glucose sensors in the past century has allowed diabetic patients to effectively manage their disease and has saved lives. First-generation glucose sensors have considerable limitations in sensitivity and selectivity which has spurred the development of more advanced approaches for both the medical and industrial sectors. The wide range of application areas has resulted in a range of materials and fabrication techniques to produce novel glucose sensors that have higher sensitivity and selectivity, lower cost, and are simpler to use. A major focus has been on the development of enzymatic electrochemical sensors, typically using glucose oxidase. However, non-enzymatic approaches using direct electrochemistry of glucose on noble metals are now a viable approach in glucose biosensor design. This review discusses the mechanisms of electrochemical glucose sensing with a focus on the different generations of enzymatic-based sensors, their recent advances, and provides an overview of the next generation of non-enzymatic sensors. Advancements in manufacturing techniques and materials are key in propelling the field of glucose sensing, however, significant limitations remain which are highlighted in this review and requires addressing to obtain a more stable, sensitive, selective, cost efficient, and real-time glucose sensor.


Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2930
Author(s):  
Jelena Šuran ◽  
Ivica Cepanec ◽  
Tomislav Mašek ◽  
Božo Radić ◽  
Saša Radić ◽  
...  

Propolis is a honeybee product known for its antioxidant, anti-inflammatory, anticancer, and antimicrobial effects. It is rich in bioactive molecules whose content varies depending on the botanical and geographical origin of propolis. These bioactive molecules have been studied individually and as a part of propolis extracts, as they can be used as representative markers for propolis standardization. Here, we compare the pharmacological effects of representative polyphenols and whole propolis extracts. Based on the literature data, polyphenols and extracts act by suppressing similar targets, from pro-inflammatory TNF/NF-κB to the pro-proliferative MAPK/ERK pathway. In addition, they activate similar antioxidant mechanisms of action, like Nrf2-ARE intracellular antioxidant pathway, and they all have antimicrobial activity. These similarities do not imply that we should attribute the action of propolis solely to the most representative compounds. Moreover, its pharmacological effects will depend on the efficacy of these compounds’ extraction. Thus, we also give an overview of different propolis extraction technologies, from traditional to modern ones, which are environmentally friendlier. These technologies belong to an open research area that needs further effective solutions in terms of well-standardized liquid and solid extracts, which would be reliable in their pharmacological effects, environmentally friendly, and sustainable for production.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shi Cao ◽  
Wei Hong ◽  
Ziqi Ye ◽  
Lei Gong

AbstractThe direct and selective C(sp3)-H functionalization of cycloalkanes and alkanes is a highly useful process in organic synthesis owing to the low-cost starting materials, the high step and atom economy. Its application to asymmetric catalysis, however, has been scarcely explored. Herein, we disclose our effort toward this goal by incorporation of dual asymmetric photocatalysis by a chiral nickel catalyst and a commercially available organophotocatalyst with a radical relay strategy through sulfur dioxide insertion. Such design leads to the development of three-component asymmetric sulfonylation involving direct functionalization of cycloalkanes, alkanes, toluene derivatives or ethers. The photochemical reaction of a C(sp3)-H precursor, a SO2 surrogate and a common α,β-unsaturated carbonyl compound proceeds smoothly under mild conditions, delivering a wide range of biologically interesting α-C chiral sulfones with high regio- and enantioselectivity (>50 examples, up to >50:1 rr and 95% ee). This method is applicable to late-stage functionalization of bioactive molecules, and provides an appealing access to enantioenriched compounds starting from the abundant hydrocarbon compounds.


Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1027
Author(s):  
Vincenzo De Leo ◽  
Francesco Milano ◽  
Angela Agostiano ◽  
Lucia Catucci

Liposomes are consolidated and attractive biomimetic nanocarriers widely used in the field of drug delivery. The structural versatility of liposomes has been exploited for the development of various carriers for the topical or systemic delivery of drugs and bioactive molecules, with the possibility of increasing their bioavailability and stability, and modulating and directing their release, while limiting the side effects at the same time. Nevertheless, first-generation vesicles suffer from some limitations including physical instability, short in vivo circulation lifetime, reduced payload, uncontrolled release properties, and low targeting abilities. Therefore, liposome preparation technology soon took advantage of the possibility of improving vesicle performance using both natural and synthetic polymers. Polymers can easily be synthesized in a controlled manner over a wide range of molecular weights and in a low dispersity range. Their properties are widely tunable and therefore allow the low chemical versatility typical of lipids to be overcome. Moreover, depending on their structure, polymers can be used to create a simple covering on the liposome surface or to intercalate in the phospholipid bilayer to give rise to real hybrid structures. This review illustrates the main strategies implemented in the field of polymer/liposome assembly for drug delivery, with a look at the most recent publications without neglecting basic concepts for a simple and complete understanding by the reader.


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