Phthalic anhydride esterified chicha gum: characterization and antibacterial activity.

The objective of this research was to modify chicha gum with phthalic anhydride to obtain a new biologically active material. The chemical modification of the gum structure was proven through FTIR, elemental analysis, XRD, TG, and DSC. The derived materials demonstrated excellent inhibitory effect against P. aeruginosa and K. pneumoniae species (rating 100% inhibition) and could also inhibit Escherichia coli growth. The best antimicrobial activity observed for the derivatives suggests that chicha gum hydrophobization due to the addition of phthalic groups improved the interaction of these derivatives with bacterial cell wall components. On the other hand, the derivatives increased CC50 in macrophages but did not present acute toxicity or hemolytic activity, indicating that they are promising for use in prophylaxis or treatment of infections caused by Gram-negative bacteria.

Modified chicha gum by acetylation for antimicrobial and antiparasitic applications: Characterization and biological properties.

It was developed a material to act as an antimicrobial and antiparasitic agent through a modification reaction in the gum structure extracted from the plant Sterculia striata. This material was characterized, the oxidant activity was evaluated and the antimicrobial activity against Candida albicans, Escherichia coli, Pseudomonas aeruginosa, Salmonella Typhimurium and Klebsiella pneumoniae was investigated, in addition to the effect against Leishmania amazonensis, testing its acute toxicity and its cytotoxicity in human cells. Characterization techniques proved the success of chemical modification. The modification led to an increase in antioxidant activity, with excellent antibacterial activity, reaching almost 100% inhibition for P. aeruginosa and S. Typhimurium, and inhibitory effect above 70% against L. amazonensis, with an affinity far superior to the parasite than macrophages. The derivative showed no acute toxicity, it was non-hemolytic, increased cell viability in macrophages and fibroblasts, and stimulated cell proliferation of keratinocytes, thus being a strong candidate to be used as an antimicrobial and antiparasitic agent in biomedical applications.

Silver nanoparticle stabilized by hydrolyzed collagen and natural polymers: Synthesis, characterization and antibacterial-antifungal evaluation.

In synthesis of silver nanoparticles (AgNPs), the composition of the stabilizer used can be closely related to the effectiveness of the synthesis and to the shape of the final nanoparticles. Recently, the use of collagen as an effective nanoparticle stabilization agent was reported. In this work, synthesis of silver nanoparticles using mixed capping agents is reported. The capping agents used were cashew gum-hydrolyzed collagen; kappa carrageenan-hydrolyzed collagen, and agar-hydrolyzed collagen. We evaluated antibacterial action against Gram-positive and Gram-negative bacteria, as well as antifungal activity and cytotoxicity. Homogenized mixtures of collagen and aqueous cashew gum, carrageenan or agar respectively were used to produce the nanoparticles AgNPcolCashew, AgNPcolCarr and AgNPcolAgar. AgNP characterization was performed using Uv-vis, XRD, TEM and DLS and the biological activities were assayed using MIC and MBC analyses for both antibacterial and antifungal application. Results showed that the AgNPcollcar sample showed the strongest bacterial inhibition with MIC values of 62.5 and 31.25 µM/mL Ag against E. coli and P. aeruginosa respectively. Interestingly, AgNPcollAgar also presented the lowest cytotoxicity when compared with other AgNPs and AgNO3.