What Do We Know about Antimicrobial Activity of Astaxanthin and Fucoxanthin?

Astaxanthin (AST) and fucoxanthin (FUC) are natural xanthophylls, having multidirectional activity, including antioxidant, anti-inflammatory, and anticancer. Both compounds also show antimicrobial activity, which is presented in this review article. There are few papers that have presented the antimicrobial activity of AST. Obtained antimicrobial concentrations of AST (200–4000 µg/mL) are much higher than recommended by the European Food Safety Authority for consumption (2 mg daily). Therefore, we suggest that AST is unlikely to be of use in the clinical treatment of infections. Our knowledge about the antimicrobial activity of FUC is better and this compound acts against many bacteria already in low concentrations 10–250 µg/mL. Toxicological studies on animals present the safety of FUC application in doses 200 mg/kg body weight and higher. Taking available research into consideration, a clinical application of FUC as the antimicrobial substance is real and can be successful. However, this aspect requires further investigation. In this review, we also present potential mechanisms of antibacterial activity of carotenoids, to which AST and FUC belong.

Production, purification, and identification of Glycine, N-(m-anisoyl)-methyl ester from Pseudomonas aeruginosa with antimicrobial and anticancer activities.

The present research is a trial to extract antimicrobial and anticancer substance(s) from Pseudomonas aeruginosa. The bacterial isolate S1B20 exhibited the highest antimicrobial activity that was identified based on 16S rRNA gene sequence as Pseudomonas aeruginosa MG429777. Extraction of various antimicrobial substance(s) (both proteinous and nonproteinous substances) were carried out. Chloroform was established to be the strongest solvent for extraction of the antimicrobial substance, while the 60% ammonium sulfate saturation stage was the brightest to obtain active bacteriocin fraction. The molecular weight of the refined bacteriocins estimated as 124 kDa. Qualitative and quantitative results of GC-mass spectral analysis and IR spectroscopy of non-proteinous and proteinous antimicrobial agents were Oxime methoxyphenyl and Glycine, N-(m-anisoyl)-methyl ester. The research concerned the proteinous compound and proved to have a distinct antibacterial and antitumor force against three carcinoma cell lines.

INVESTIGATION OF ANTIMICROBIAL PROPERTIES OF AQUEOUS EXTRACT OF LEMONGRASS (CYMBOPOGON CITRATUS) UNDER SOME PARAMETERS

The antimicrobial effect of aqueous extract of lemongrass (Cymbopogon citratus) on some isolated microorganisms under varying parameters was investigated. Aqueous extract of lemongrass was prepared and its antimicrobial effect was evaluated against isolated bacteria (Staphylococcus aureus, Escherichia coli and Bacillus cereus) and fungi (Aspergillus flavus and Candida albicans) at varying temperature (40, 60 and 800C) and concentration (10-1, 10-2, 10-4, 10-8 and 10-16 mol/L) of the lemongrass aqueous extract shows that the extract was resisted by Escherichia coli, Bacillus cereus, Aspergillus flavus and Candida albicans. The aqueous C. citratus was able to inhibit the growth of Staphylococcus aureus and this inhibition increases as the concentration of the aqueous extract increase irrespective of the temperature of extraction. The aqueous extract of C. citratus is a tremendous antimicrobial substance especially towards Staphylococcus aureus.

Isolation and Characterization of Fengycins Produced by Bacillus amyloliquefaciens JFL21 and Its Broad-Spectrum Antimicrobial Potential Against Multidrug-Resistant Foodborne Pathogens

The continuing emergence and development of pathogenic microorganisms that are resistant to antibiotics constitute an increasing global concern, and the effort in new antimicrobials discovery will remain relevant until a lasting solution is found. A new bacterial strain, designated JFL21, was isolated from seafood and identified as B. amyloliquefaciens. The antimicrobial substance produced by B. amyloliquefaciens JFL21 showed low toxicity to most probiotics but exhibited strong antimicrobial activities against multidrug-resistant foodborne pathogens. The partially purified antimicrobial substance, Anti-JFL21, was characterized to be a multiple lipopeptides mixture comprising the families of surfactin, fengycin, and iturin. Compared with commercially available polymyxin B and Nisin, Anti-JFL21 not only could exhibit a wider and stronger antibacterial activity toward Gram-positive pathogens but also inhibit the growth of a majority of fungal pathogens. After further separation through gel filtration chromatography (GFC), the family of surfactin, fengycin, and iturin were obtained, respectively. The results of the antimicrobial test pointed out that only fengycin family presented marked antimicrobial properties against the indicators of L. monocytogenes, A. hydrophila, and C. gloeosporioides, which demonstrated that fengycins might play a major role in the antibacterial and antifungal activity of Anti-JFL21. Additionally, the current study also showed that the fengycins produced by B. amyloliquefaciens JFL21 not only maintained stable anti-Listeria activity over a broad pH and temperature range, but also remained active after treatment with ultraviolet sterilization, chemical reagents, and proteolytic enzymes. Therefore, the results of this study suggest the new strain and its antimicrobials are potentially useful in food preservation for the biological control of the multidrug-resistant foodborne pathogens.

Optimization of Mycological Media Using Agro Waste for the Production of Antimicrobial Substance

Aim: This present study was conducted to optimize mycological media using agro waste for the production of antimicrobial substance. Place and Duration of Study: Agro waste (sugarcane and sweet potato, sugarcane and jack fruit) collected within Anambra state between February- August 2019. Methodology: Sugarcane and sweet potato (AMSSP), sugarcane and jack fruit (AMSJ) were peeled and the peels were air-dried and then ground into powdered form. 10 g each of the agro waste samples was weighed into 400 ml of distilled water in 1000 ml Erlenmeyer flask and allowed for 7 days, after which the mixture was filtered. Then 200 ml of the filtrate was used. The experimental conditions were optimized by using agro wastes (20/80 and 50/50 concentrations) as a culture medium, altering the temperature (30ºC and 37ºC), pH (5, 6, 7, 8, and 9), as well as the carbon and nitrogen source (glucose and NaNO3). The fungi used were Aspergillus niger, Aspergillus fischeri, Aspergillus aculeatus and Aspergillus fumigatus. Results: Various agro wastes medium AMSSP and AMSJ were formulated as mycological media and the growth and nutritional conditions were optimized to ascertain antimicrobial substance production using some fungal isolates. Based on different concentrations Aspergillus fumigatus showed a promising zone of inhibition on AMSSP at a concentration of 20/80 while in AMSJ the concentration the 50/50 showed a maximum zone of inhibition on Aspergillus fumigatus ascertaining the presence of antimicrobial substance. AMSSP was able to produce maximum antimicrobial substance when supplemented with 1.0% glucose, 1.0% NaNO3 at pH 7 and at temperature of 30 ± 2ºC. Conclusion: Agro wastes from AMSSP as well as from AMSJ contain nutrients that may support fungal growth. Maximum antimicrobial substance production is enhanced when supplemented with 1.0% of the carbon and nitrogen source at a pH of 7 and at a temperature of 30 ± 2ºC.

Integration of antimicrobial substances in 3-D printed plastics

The risk of healthcare associated infections (HAI) is rising with the utilization of more complex medical devices. Cleaning and disinfecting measures of such devices are often insufficient leading to an increased microbiological contamination on these devices. Recent studies imply that antimicrobial coatings could present a solution for this topic. In this work a novel approach for the introduction of an antimicrobial technology into plastic granulate was tested. After 3-D printing the antimicrobial activity of the test samples was analysed. Our results show that the integration of an antimicrobial substance to ABS plastic is feasible only with sophisticated plastic processing technologies. Simple heating or mixing of the substance did not allow integration of the antimicrobial substance into the 3-D printed sample, but it was possible to integrate the antimicrobial ingredient into the raw material by compounding. The printed test samples showed strong antimicrobial activity in the standardized test procedures.