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Background: Colistin (Cst) is one of the antimicrobial peptides and is reserved for use against multi‐drug‐resistant Gram‐negative bacteria. However, the clinical value of Cst is limited by its nephrotoxic adverse effects. Caffeic acid phenethyl ester (CAPE) is a honeybee propolis flavonoid recognised for its diverse pharmacological potential. It has demonstrated d antioxidant and anti‐inflammatory properties, as well as protective effects against chemically induced toxicity in variuos biological systems. This study aimed to investigate the impact of CAPE on nephrotoxicity induced in rats by Cst. Methods: Animals were randomly divided into five groups. Group 1 served as control, group 2 received CAPE (10 mg/kg) orally, group 3 received Cst IP, group 4 received Cst + CAPE (5 mg/kg) and group 5 received Cst + CAPE (10 mg/kg). All treatments were given daily for 10 consecutive days. Results: CAPE notably attenuated Cst‐inducednephrotoxicity as shown by reducing urea serum levels, creatinine, cystatin C, urinary protein contents and urinary N‐acetyl‐β‐D‐glucosaminidase (NAG). This was confirmed by histological investigations that indicated amelioration of histopathological changes in the kidney architecture as well as the deposition of collagen in renal tissues. CAPE exhibited antioxidant effects supported by the prevention of rise in Cst‐induced lipid peroxidation and depletion of superoxide dismutase and catalase enzymatic activities. In addition, CAPE inhibited the expression of the inflammatory markers including tumour necrosis factor‐α, nuclear factor kappa B and interleukin‐6. These actions were associated with modulation of messenger ribonucleic acid (mRNA) expression of Bax and Bcl‐2 in favour of anti‐apoptosis. CAPE inhibited Cst‐induced rise in forkhead box O1 (FOXO1) expression and downregulation of nuclear factor erythroid 2–related factor 2 (Nrf2) and Sirtuin 1 (Sirt1) immune‐expression. Conclusion: CAPE protects against nephrotoxicity induced by Cst in ratsprimarily through its antioxidant, antiinflammatory and antiapoptotic activities. These pritective effects are mediated via modulation of FOXO1/Nrf2/Sirt1 axis. [ABSTRACT FROM AUTHOR]

Syzygium aqueum is widely used in folk medicine. A polyphenol-rich extract from its leaves demonstrated a plethora of substantial pharmacological properties. The extract showed solid antioxidant properties in vitro and protected human keratinocytes (HaCaT cells) against UVA damage. The extract also reduced the elevated levels of ALT, AST, total bilirubin (TB), total cholesterol (TC) and triglycerides (TG) in rats with acute CCl4 intoxication. In addition to reducing the high MDA level, the extract noticeably restored GSH and SOD to the normal control levels in liver tissue homogenates and counteracted the deleterious histopathologic changes in liver after CCl4 injection. Additionally, the extract exhibited promising anti-inflammatory activities in vitro where it inhibited LOX, COX-1, and COX-2 with a higher COX-2 selectivity than that of indomethacin and diclofenac and reduced the extent of lysis of erythrocytes upon incubation with hypotonic buffer solution. S. aqueum extract also markedly reduced leukocyte numbers with similar activities to diclofenac in rats challenged with carrageenan. Additionally, administration of the extract abolished writhes induced by acetic acid in mice and prolonged the response latency in hot plate test. Meanwhile, the identified polyphenolics from the extract showed a certain affinity for the active pockets of 5-lipoxygenase (5-LOX), cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) explaining the observed anti-inflammatory activities. Finally, 87 secondary metabolites (mostly phenolics) were tentatively identified in the extract based on LC-MS/MS analyses. Syzygium aqueum displays good protection against oxidative stress, free radicals, and could be a good candidate for treating oxidative stress related diseases. [ABSTRACT FROM AUTHOR]

Objective: Inflammation is the initial physiological reaction of the immune system to infection or irritation, leading significant risk factors for several forms of cancer. The genus Asteriscus has been observed to possess a notable abundance of sesquiterpenes with anti-inflammatory properties. This study was designed to assess the anti-inflammatory activity of the sesquiterpenoids isolated from Asteriscus graveolens. Methods: The organic extract of the Asteraceae plant A. graveolens was subjected to different chromatographic and spectroscopic techniques for isolation, purification, and identification of sesquiterpenoid contents. The isolated compounds were screened for antiinflammatory activities in two animal models: rat paw edema and rat ear edema. Histopathological examinations as well as biochemical markers of inflammation were assessed. This was followed by in silico screening for anti-inflammatory activity. Results: Four known sesquiterpenoids were isolated from A. graveolens, including two humulene derivatives, namely, 9-oxohumula-4-en-6,15-olide (1), and 9-oxohumula-1(10)(Z),4,7(E)-trien-6,15-olide (2) and two bisabolene derivatives, identified as bisabola-2,10-dien-1-one (3) and 6-hydroxybisabola-2,10-dien-1-one (4) described. In the rat paw edema model, compound 2 showed highest activity in preventing formation carrageenan-induced paw edema. This was confirmed by histopathological examinations that indicated partial preservation of the epidermal and dermal layers. Further, the compound significantly inhibited cyclooxygenase-2 (COX-2) and tumor necrosis factor-a (TNF-a) release. In the croton oil indued rat ear edema, compounds 2 and 4 significantly inhibited ear edema and protected against histopathological alterations. This was associated with prevention of myeloperoxidase (MPO) concentration in ear tissues. Molecular docking and molecular dynamic simulation indicated the affinity and docking stability of compounds 1-4 to the selected inflammatory protein. Conclusion: Phytochemical investigation of A. graveolens resulted in the isolation and characterization of four sesquiterpenes. In particular, compound 2 showed potent anti-inflammatory activity in carrageenan rat paw edema and croton oil ear edema. [ABSTRACT FROM AUTHOR]