Synthesis and Antioxidant Properties of 5,6,7,8-Tetrahydroxyflavone

Influence of bioaugmented fungi on tolerance, growth and phytoremediation ability of Prosopis juliflora Sw. DC in heavy metal-polluted landfill soil

The research aimed to determine the influence of endophytic fungi on tolerance, growth and phytoremediation ability of Prosopis juliflora in heavy metal-polluted landfill soil. A consortium of 13 fungal isolates as well as Prosopis juliflora Sw. DC was used to decontaminate heavy metal-polluted landfill soil. Enhanced plant growth (biomass and root and shoot lengths) and production of carotenoids, chlorophyll and amino acids L-phenylalanine and L-leucine that are known to enhance growth were found in the treated P. juliflora. Better accumulations of heavy metals were observed in fungi-treated P. juliflora over the untreated one. An upregulated activity of peroxidase, catalase and ascorbate peroxidase was recorded in fungi-treated P. juliflora. Additionally, other metabolites, such as glutathione, 3,5,7,2',5'-pentahydroxyflavone, 5,2'-dihydroxyflavone and 5,7,2',3'-tetrahydroxyflavone, and small peptides, which include Lys Gln Ile, Ser Arg Ala, Asp Arg Gly, Arg Ser Ser, His His Arg, Arg Thr Glu, Thr Arg Asp and Ser Pro Arg, were also detected. These provide defence supports to P. juliflora against toxic metals. Inoculating the plant with the fungi improved its growth, metal accumulation as well as tolerance against heavy metal toxicity. Such a combination can be used as an effective strategy for the bioremediation of metal-polluted soil.

Protective effect of 5,6,7,8-Tetrahydroxyflavone on high altitude cerebral edema in rats

High altitude cerebral edema (HACE) is a potentially life-threatening disease encountered at high altitudes. However, effective methods for HACE prophylaxis are limited. Convincing evidence confirms that oxidative stress induced by hypobaric hypoxia (HH) is one of the main factors that account for the development of HACE. 5,6,7,8-Tetrahydroxyflavone (THF), a flavone with four consecutive OH groups in ring A, exhibited excellent antioxidant activity in vitro and could attenuate HH induced injury in vivo. The aim of this study was to investigate the protective effect of THF against HACE and its underlying mechanisms. THF administration significantly suppressed HH induced oxidative stress by reducing the formation of hydrogen peroxide and malondialdehyde, by increasing the levels of glutathione and superoxide dismutase in brain tissue. Simultaneously, THF administration inhibited inflammatory responses by decreasing the levels of tumor necrosis factor-α, interleukin-1β, and interleukin-6 in serum and brain tissue. In addition, THF administration mitigated the energy metabolism disorder induced by HACE as evidenced by decreased levels of lactic acid, lactate dehydrogenase and pyruvate kinase as well as increased ATP levels and ATPase activities. Furthermore, THF administration decreased the expression of matrix metalloproteinase-9, aquaporin 4, hypoxia-inducible factor-1α and vascular endothelial growth factor, which attenuated blood-brain barrier (BBB) disruption and brain edema. Additionally, THF administration improved HACE induced cognitive dysfunction. These results show that THF is a promising agent in the prevention and treatment of HACE.

Antioxidant and anticancer activity of synthesized 4-amino-5-((aryl substituted)-4H-1,2,4-triazole-3-yl)thio-linked hydroxamic acid derivatives

OBJECTIVES

The antioxidant and anticancer activity of twelve 5-substituted-4-amino-1,2,4-triazole-linked hydroxamic acid derivatives were evaluated.

METHODS

Previously synthesized 2-((4-amino-5-substituted-4H-1,2,4-triazol-3-yl)thio)-N-hydroxyacetamide and 3-((4-amino-5-substituted-4H-1,2,4-triazol-3-yl)thio)-N-hydroxypropanamide (6a-6l) were evaluated for in vitro antioxidant and in vivo anticancer activity. MDA-MB-231, MCF-7 and HCT 116 cell lines were used to evaluate IC₅₀ values, in vitro. Ehrlich ascites carcinoma (EAC)-induced mice model was used to evaluate in vivo anticancer potential. Different biological markers were examined for drug-related toxicities.

KEY FINDINGS

Compound 6b revealed more potent antioxidant property among all tested compounds, even than the ascorbic acid. The IC₅₀ values of compound 6b were found to be 5.71 ± 2.29 μg/ml (DPPH assay) and 4.12 ± 0.5 μg/ml (ABTS assay). Histopathology of liver sections of drug-treated mice was evaluated. Survival analysis showed that compound 6b could increase the life span as of the standard drug.

CONCLUSIONS

After the assessment of all in vivo anticancer study related data, it was found that compound 6b possess superior anticancer potency in terms of efficacy and toxicity. From this experimental design, it could be concluded that further modification of this prototypical structure will lead to develop more potent antioxidant as well as an anticancer agent in the future.