Antimicrobial flavonoids as a potential substitute for overcoming antimicrobial resistance

White Tip Silver Needle (Slightly Fermented White Tea) Flavonoids Help Prevent Aging via Antioxidative and Anti-Inflammatory Effects

AIM

White tip silver needle, a slightly fermented white tea, is abundant in flavonoids, and it has great significance in terms of D-galactose/lipopolysaccharide-induced aging in mice.

METHODS

We analyzed the antioxidant capacity of white tip silver needle flavonoids (WTSNF) in vitro, assessed the effects of WTSNF on organ indexes, pathological changes, liver function indexes, biochemical indicators, molecular biological indicators, and genes related to oxidation and inflammation.

RESULTS

Ultra-high performance liquid chromatography-tandem mass spectrometry results showed that WTSNF contained baicalin, kaempferol, kaempferide, quercetin, isorhamnetin, lespenephryl, and rutin. WTSNF showed strong scavenging ability for both 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) free radicals. Pathological analysis results showed that WTSNF reduced liver, kidney, and lung damage in mice with induced aging. In the serum and liver tissue, WTSNF effectively increased the antioxidant-related levels of superoxide dismutase, catalase, glutathione peroxidase, glutathione, and total antioxidant capacity and reduced the levels of aspartate aminotransferase, alanine aminotransferase, malondialdehyde and nitric oxide. WTSNF also reduced the inflammation-related levels of interleukin-6, interleukin-1 beta, tumor necrosis factor alpha (TNFα), and interferon gamma (IFN-γ) and increased the levels of interleukin-10 and interleukin-12. Furthermore, WTSNF upregulated the mRNA expression levels of cupro-zinc superoxide dismutase, manganese superoxide dismutase, catalase, glutathione peroxidase, interleukin-10, neuronal nitric oxide synthase, endothelial nitric oxide synthase, nuclear factor erythroid 2-related factor, heme oxygenase 1, NAD(P)H dehydrogenase [quinone] 1, nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκB-α), and thioredoxin, while it downregulated the mRNA expression levels of interleukin-6, interleukin-18, interleukin-1 beta, TNFα, IFN-γ, inducible nitric oxide synthase, cyclooxygenase-2, and nuclear factor kappa-light chain-enhancer of activated B cells (NF-κB).

CONCLUSION

WTSNF is a high-quality natural product with antioxidative and anti-inflammatory properties that can inhibits D-galactose/lipopolysaccharide-induced aging in mice.

Antibacterial Films Based on Polylactide with the Addition of Quercetin and Poly(Ethylene Glycol)

A series of new films with antibacterial properties has been obtained by means of solvent casting method. Biodegradable materials including polylactide (PLA), quercetin (Q) acting as an antibacterial compound and polyethylene glycol (PEG) acting as a plasticizer have been used in the process. The effect of quercetin as well as the amount of PEG on the structural, thermal, mechanical and antibacterial properties of the obtained materials has been determined. It was found that an addition of quercetin significantly influences thermal stability. It should be stressed that samples containing the studied flavonoid are characterized by a higher Young modulus and elongation at break than materials consisting only of PLA and PEG. Moreover, the introduction of 1% of quercetin grants antibacterial properties to the new materials. Recorded results showed that the amount of plasticizer did not influence the antibacterial properties; it does, however, cause changes in physicochemical properties of the obtained materials. These results prove that quercetin could be used as an antibacterial compound and simultaneously improve mechanical and thermal properties of polylactide-based films.

Propolis from the Monte Region in Argentina: A Potential Phytotherapic and Food Functional Ingredient

The aim of this review is to provide overall information on Argentine propolis and to shed light on its potential, especially the one from the Monte region so as to support future research in the field. Around 1999, the Argentine propolis began to be chemically and functionally characterized to give it greater added value. Because Argentina has a wide plant biodiversity, it is expected that its propolis will have various botanical origins, and consequently, a different chemical composition. To date, five types have been defined. Based on their functionality, several products have been developed for use in human and veterinary medicine and in animal and human food. Because the Argentine propolis with the greatest potential is that of the Monte eco-region, this review will describe the findings of the last 20 years on this propolis, its botanical source (Zuccagnia punctata Cav.), its chemical composition, and a description of markers of chemical quality (chalcones) and functionality. Propolis can regulate the activity of various pro-inflammatory enzymes and carbohydrate and lipid metabolism enzymes, as well as remove reactive oxygen and nitrogen species. Consequently, it can modulate metabolic syndrome and could be used as a functional ingredient in food. Furthermore, hydroalcoholic extracts can act against human and animal pathogenic bacteria and human yeast, and mycelial pathogenic fungi. The ability to stop the growth of post-harvest pathogenic bacteria and fungi was also demonstrated. For this reason, Argentine propolis are natural products capable of protecting crops and increasing the lifespan of harvested fruit and vegetables. Several reports indicate the potential of Argentine propolis to be used in innovative products to improve health, food preservation, and packaging. However, there is still much to learn about these natural products to make a wholesome use of them.

Toxicological Screening of Four Bioactive Citroflavonoids: In Vitro, In Vivo, and In Silico Approaches

Many studies describe different pharmacological effects of flavonoids on experimental animals and humans. Nevertheless, few ones are confirming the safety of these compounds for therapeutic purposes. This study aimed to investigate the preclinical safety of naringenin, naringin, hesperidin, and quercetin by in vivo, in vitro, and in silico approaches. For this, an MTT-based cytotoxicity assay in VERO and MDCK cell lines was performed. In addition, acute toxicity was evaluated on Wistar rats by OECD Guidelines for the Testing of Chemicals (Test No. 423: Acute Oral Toxicity-Class Method). Furthermore, we used the ACD/Tox Suite to predict toxicological parameters such as hERG channel blockade, CYP450 inhibition, and acute toxicity in animals. The results showed that quercetin was slightly more cytotoxic on cell lines (IC₅₀ of 219.44 ± 7.22 mM and 465.41 ± 7.44 mM, respectively) than the other citroflavonoids. All flavonoids exhibited an LD₅₀ value > 2000 mg/kg, which classifies them as low-risk substances as OECD guidelines established. Similarly, predicted LD⁵⁰ was LD₅₀ > 300 to 2000 mg/kg for all flavonoids as acute toxicity assay estimated. Data suggests that all these flavonoids did not show significant toxicological effects, and they were classified as low-risk, useful substances for drug development.