A Synthetic Curcuminoid Analog, (2E,6E)-2,6-bis(2-(trifluoromethyl)benzylidene)cyclohexanone, Ameliorates Impaired Wound Healing in Streptozotocin-Induced Diabetic Mice by Increasing miR-146a

The impairment in diabetic wound healing represents a significant clinical problem, with no efficient targeted treatments for these wound disorders. Curcumin is well confirmed to improve diabetic wound healing, however, its low bioavailability and poor solubility severely limit its clinical application. This study aims to provide the pharmacological basis for the use of (2E,6E)-2,6-bis(2-(trifluoromethyl)benzylidene)cyclohexanone (C66). The results showed that topically applied C66 improved cutaneous wound healing in vivo. Further studies showed that C66 treatment increased the level of microRNA-146a (miR-146a) in the wounds in streptozotocin (STZ)-induced diabetic mice, downregulated the expression of interleukin-1 receptor-associated kinase 1 (IRAK1) and phosphorylated nuclear factor-κB (NF-κB) p65 subunit (p-p65) (both p < 0.05), and suppressed the mRNA expression of inflammation-related cytokines, tumor necrosis factor-α (TNF-α), interleukin-8 (IL-8), and interleukin-6 (IL-6). The in vitro data obtained in human umbilical vein endothelial cells (HUVECs) showed that C66 could reverse high glucose (HG)-induced NF-κB activation due to upregulation of miR-146a expression, which matched the in vivo findings. In conclusion, the present study indicates that C66 exerts anti-inflammation activity and accelerates skin wound healing of diabetic mice, probably via increasing miR-146a and inhibiting the NF-κB-mediated inflammation pathway. Therefore, C66 may be a promising alternative for the treatment of diabetic wounds.

Anti-Edematogenic and Anti-Granuloma Activity of a Synthetic Curcuminoid Analog, 5-(3,4-Dihydroxyphenyl)-3-hydroxy-1-(2-hydroxyphenyl)penta-2,4-dien-1-one, in Mouse Models of Inflammation

Curcumin, derived from the rhizome Curcuma longa, has been scientifically proven to possess anti-inflammatory activity but is of limited clinical and veterinary use owing to its low bioavailability and poor solubility. Hence, analogs of curcuminoids with improved biological properties have been synthesized to overcome these limitations. This study aims to provide the pharmacological basis for the use of 5-(3,4-dihydroxyphenyl)-3-hydroxy-1-(2-hydroxyphenyl)penta-2,4-dien-1-one (DHHPD), a synthetic curcuminoid analog, as an anti-edematogenic and anti-granuloma agent. The carrageenan-induced paw edema and the cotton pellet-induced granuloma assays were used to assess the anti-inflammatory activity of DHHPD in mice. The effects of DHHPD on the histaminergic, serotonergic, and bradykininergic systems were determined by the histamine-, serotonin-, and bradykinin-induced paw edema tests, respectively. DHHPD (0.1, 0.3, 1, and 3 mg/kg, intraperitoneal) evoked significant reductions (p < 0.05) in carrageenan-induced paw edema at different time intervals and granuloma formation (p < 0.0001) by 22.08, 32.57, 37.20, and 49.25%, respectively. Furthermore, DHHPD significantly reduced paw edema (p < 0.05) induced by histamine, serotonin, and bradykinin. The present study suggests that DHHPD exerts anti-edematogenic activity, possibly by inhibiting the synthesis or release of autacoid mediators of inflammation through the histaminergic, serotonergic, and bradykininergic systems. The anti-granuloma effect may be attributed to the suppression of transudative, exudative, and proliferative activities associated with inflammation.

In vitro and in vivo antimicrobial activity of two alpha-helical cathelicidin peptides and of their synthetic analogs

Two alpha-helical antimicrobial peptides (BMAP-27 and -28) and four synthetic analogs were compared for in vitro and in vivo antimicrobial efficacy. All peptides proved active in vitro at micromolar concentrations against a range of clinical isolates, including antibiotic-resistant strains. BMAP-27 and two analogs were more effective towards Gram-negative, and BMAP-28 towards Gram-positive organisms. In addition, BMAP-28 provided some protection in vitro against human herpes simplex virus type 1 (HSV-1). The parent peptides and mBMAP-28 analog protected mice from lethal i.p. infections in an acute peritonitis model at peptide doses significantly lower than those toxic to the animals, suggesting a satisfactory therapeutic index.