Potencial cicatrizante de Colocasia esculenta (L.) Schott: caracterização química, avaliação biológica e desenvolvimento de filmes para uso como coberturas

Abstract

Colocasia esculenta is a plant popularly recognized for its nutritional value and healing effect. Its purpose was to evaluate the healing activity of its aerial parts extracts (EPA) and rhizomes extracts (ER) and to develop films for use in wound dressings, using poly(vinyl alcohol) (PVA) and ER blends. The extracts were chemically characterized, checking phenolic compounds (1.04% EPA; 0.71% ER), flavonoids (0.24%, EPA) and polysaccharides (ER). The healing activity in rats was evaluated in the control groups: negative (C-), vehicle (VC), positive (C+); as well as in ER and EPA. The areas of lesions were registered at 0, 7, 14 and 21 days, and the Ulcer Healing Index (UCI) was calculated. There was no significant effect of the extracts on ICU, but it was observed a tendency of higher ICU in C+, ER and EPA, in 14 days. The qualitative and quantitative histological analysis showed greater regeneration, tissue quality and fibroblastic proliferation in C+ (12 ± 0), ER (12 ± 0) and EPA (12 ± 0) at 21 days; modulation of inflammation at 14 days in EPA, with lower polymorphonuclear infiltrate in C+ (3.5 ± 1) and EPA (3.2 ± 1.79); greater reepithelialization in CV (1.8 ± 0.45) and ER (1.75 ± 0.5) at 7 days. Therefore, the extracts produced beneficial effects to healing. Films were prepared by casting-solving using blends of PVA 8% with ER at 10%, 20%, 30%, 40%. Colourless, transparent, flexible, resistant to handling films were obtained, with good interaction between the polymers, without phase separation. The addition of ER resulted in films with lower thickness, higher swelling capacity and partially wettable by water. The increase of the ER content in the blends interfered with the solubility and permeability to water vapor. Joint analysis of the parameters suggests that PVA film containing a higher percentage of natural polymer (40% ER) is potentially useful for the preparation of bioactive wound dressings.