Wound healing potential of a formula based on Populus nigra L. flower buds extract with anti-inflammatory activity.

ETHNOPHARMACOLOGICAL RELEVANCE: Wound healing is a complex and dysnamic process supported by a myriad of cellular events that are tightly coordinated to repair efficiently damaged tissue. Populus nigra L. (Salicaceae) flower buds are traditionally used in the treatment of dermatitis, upper respiratory tract infections, rheumatism and wounds. AIM OF THE STUDY: The aim of this study was to assess the wound healing potential of black poplar ointment containing 10 or 20 % of Populus nigra ethanolic flower buds extract using the excision model in rats. MATERIALS AND METHODS: Two ointments (10 and 20 %) were prepared from Populus nigra flower buds ethanolic extract and topically applied on the area of excised skin of the rats for either 14 or 20 days. Morphological, macroscopic, histological and biochemical parameters were evaluated. RESULTS: The results showed that the extract contained high amounts of total phenols (89.5 ± 7.7 mg caffeic acid equivalent/g of extract) and hydrolysable tannins (142.05 ± 2.55 mg tannic acid equivalent/g of extract), in correlation with strong DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity and beta-carotene bleaching with values of 96.31 ± 3.42 and 85.27 ± 1.79 %, respectively. Anti-inflammatory potential was illustrated by lipoxygenase and cyclooxygenase inhibition (52.80 ± 0.2 and 53.88 ± 2.55 %, respectively). Treatment with Populus nigra ointment (10 and 20 %) promoted wound contraction of 97.37 ± 1.19 and 97.28 ± 0.91 %, respectively. The antioxidant marker enzymes, catalase (0.10 ± 0.001; 0.08 ± 0.003 U/mg protein) and superoxide dismutase (363.34 ± 24.37; 317.82 ± 53.83 U/mg protein) activities in the granulation tissues were upgraded with respective treatments of 10 or 20 % ointment. Concurrently, the myeloperoxidase activity (2.21 ± 1.01; 2.13 ± 0.75 U/mg protein) was repressed, indicating anti-inflammatory potential, when compared to untreated, standard and excipient groups. Moreover, a significant increase in respective levels of hydroxyproline (p < 0.001) (28.05 ± 1.20; 25.29 ± 1.17 µg/mg tissue) and hexosamine (p < 0.05) (20.18 ± 1.21; 18.95 ± 1.98 µg/mg tissue) was triggered, reflecting a high regeneration of collagen in the scarred tissue. Histological examination of treated skin tissue revealed higher rates of re-epithelialization, lower neutrophils infiltration and re-vascularization in comparison to the control group. CONCLUSION: Given that the 10 % ointment was the optimal concentration, our findings offer an efficient drug formula for wound healing.

Identification and nanoentrapment of polyphenolic phytocomplex from Fraxinus angustifolia: in vitro and in vivo wound healing potential.

The aim of the present study was to elucidate the polyphenolic composition of Fraxinus angustifolia leaf and bark extracts, and to evaluate their efficacy in wound healing. Quercetin, catechin, rutin and tannic acid were identified as the main components of the extracts. In order to improve their skin bioavailability, the polyphenolic phytocomplexes were incorporated in different nanovesicles, namely ethosomes and phospholipid vesicles containing Transcutol(®) P (Trc) or ethylene glycol (EG). The latter had never been used before as a component of phospholipid vesicles, and it was found to play a key role in improving extract efficacy in wound healing. Results of cryogenic transmission electron microscopy (cryo-TEM), Photon Correlation Spectroscopy (PCS) and Small-Angle X-ray Scattering (SAXS) showed that ethosomes and EG-PEVs were small, monodispersed, unilamellar vesicles, while Trc-PEVs were larger, less homogeneously dispersed and multilamellar, with a large bilayer thickness. Free extracts did not show relevant ability to protect in vitro human keratinocytes from H2O2 damages, while when entrapped in nanovesicles, they significantly inhibited H2O2 stress damages, probably related to a higher level of cell uptake. On the other hand, in vivo results showed that the highest antioxidant and anti-inflammatory effects were provided by the phytocomplexes in EG-PEVs, which favoured wound healing. Moreover, non-entrapped F. angustifolia extracts showed a marginal effect, comparable to that of free quercetin dispersion (control). In conclusion, our results depict that these extracts may find potential applications in biomedicine.