Hepatoprotective effects of flexirubin, a novel pigment from Chryseobacterium artocarpi, against carbon tetrachloride-induced liver injury: An in vivo study and molecular modeling.

Liver injuries caused by various industrial chemicals represent a serious health concern worldwide. Flexirubins are a novel class of naturally occurring bacterial pigments whose bioactivity remains largely unexplored. The present study evaluated the hepatoprotective effects of flexirubin pigment extracted from the bacterium Chryseobacterium artocarpi against CCl4-induced acute liver injury in mice. Flexirubin was applied at three different oral doses, 125, 250 and 500 mg/kg bw/d for seven consecutive days. Treatment of animals with flexirubin before exposure to CCl4 (10 mL/kg bw dissolved in olive oil, 1:1 v/v) significantly decreased the elevated serum levels of ALT, AST, ALP, LDH and TBL. Flexirubin pretreatment showed a great capability for attenuating the CCl4-induced oxidative stress by decreasing the level of liver MDA, and increasing the antioxidant enzyme activities of liver SOD and CAT, and the levels of GSH and TAC. Flexirubin also alleviated the histopathological alterations in liver by prohibiting steatosis, ballooning degeneration, leukocytic infiltration and necrosis. Immunohistochemical analysis demonstrated that flexirubin has a significant anti-apoptotic activity against CCl4 via upregulation of Bcl-2, and downregulation of Bax, Caspase-3 and TGF-ß1. Flexirubin also exhibited a remarkable anti-inflammatory activity against CCl4 through its suppressive action on TNF-α, COX-2 and CD-45. Flexirubin could trigger upregulation of the Nrf2/HO-1 signaling pathway mediating protection against CCl4. In silico molecular docking revealed flexirubin as a potential inhibitor against two target proteins, TGF-ß1 and TACE. The results proved the effectiveness of flexirubin as a significant source of natural compounds for its use in drug formulation strategies to offer protection against hepatotoxins.

Antioxidant Activity Evaluation of FlexirubinType Pigment from Chryseobacterium artocarpi CECT 8497 and Related Docking Study.

The current research is focused on studying the biological efficacy of flexirubin, a pigment extracted from Chryseobacterium artocarpi CECT 8497.Different methods such as DPPH, H2O2, NO•, O2•-, •OH, lipid peroxidation inhibition by FTC and TBA, ferric reducing and ferrous chelating activity were carried out to evaluate the antioxidant activity of flexirubin. Molecular docking was also carried out, seeking the molecular interactions of flexirubin and a standard antioxidant compound with SOD enzyme to figure out the possible flexirubin activity mechanism. The new findings revealed that the highest level of flexirubin exhibited similar antioxidant activity as that of the standard compound according to the H2O2, •OH, O2•-, FTC and TBA methods. On the other hand, flexirubin at the highest level has shown lower antioxidant activity than the positive control according to the DPPH and NO• and even much lower when measured by the FRAP method. Molecular docking showed that the interaction of flexirubin was in the binding cavity of the SOD enzyme and did not affect its metal-binding site. These results revealed that flexirubin has antioxidant properties and can be a useful therapeutic compound in preventing or treating free radical-related diseases.