Obtenção de nanoemulsão contendo extrato da espécie vegetal Jatropha gossypiifolia e avaliação da atividade antidermonecrótica frente a peçonha de Bothrops erythromelas

Abstract

Snakebite is a Neglected Tropical Disease of category A, which affects around 2.7 million people per year worldwide. In Brazil, the genus Bothrops has the greatest clinical relevance, with the species Bothrops erythromelas standing out in the Northeast region. Tissue necrosis is one of the most relevant local damages caused by this genus, given the possibility of loss of function of the bitten limb and even amputation, impacting the victim's quality of life. The ineffectiveness of antivenom in combating local damage caused by envenomation encourages the search for new complementary therapies, especially medicinal plants. The species Jatropha gossypiifolia (Jg) is used in popular culture for inflammation, wounds and snakebites. Therefore, this study aimed to develop a topical nanoemulsion containing the hydroethanolic extract of Jg leaves, to evaluate the healing and antidermonecrotic activity. The phytochemical characterization of the Jg extract was performed using High Performance Liquid Chromatography coupled to a photodiode array detector (HPLC-DAD), which detected the presence of the flavonoids vitexin, luteolin derivates and apigenin derivatives, and quantification of the phenolic content and flavonoids, with 95.08 ± 5.46 mg of gallic acid/g of extract and 137.92 ± 0.99 mg of quercetin/g of extract, respectively. Next, a nanoemulsion containing Jg extract (NJg) was developed and physicochemical characterization was performed, in which NJg (n=2) presented an average size of 164.96 ± 9.487 nm, PDI of 0.217 ± 0.026, pH of 5.89 ± 0.0281 and phenolic content of 32.039 ± 14.628 mg of gallic acid/g of extract, showing no color variation or phase separation. Over the course of 4 weeks, the characteristics were maintained. To evaluate in vitro cytotoxicity, the hemolytic and crystal violet assay was performed, in which the extract and NJg did not show toxicity at the concentrations tested (32.25-250 μg/mL) for human erythrocytes and murine fibroblasts (NHI/3T3). Furthermore, the antioxidant activity of the extract and NJg was performed, reaching an IC50 of 0.2999 and 0.4646 μg/μL for the ABTS∙+ radical, respectively, and of 0.2899 and 0.4374 μg/μL for the radical DPPH, respectively. Next, the skin irritation of the NJg was evaluated, demonstrating the absence of irritation. In the evaluation of healing activity in vivo, NJg presented significant wound closure from the 5th day of treatment, when compared to the no treatment group, being 45% for NJg and 21% for the no treatment group, and on the 8th day reaching 58%. Besides, NJg promoted the reduction of nitrite, myeloperoxidase activity and cytokines. An evaluation of the in vitro inhibition of phospholipase A2 (PLA2) and hyaluronidase from Bothrops erythromelas venom (BeV) was also carried out, with maximum inhibition of 23% (1:100; BeV:NJg) and 24% (1:0.25; BeV:NJg), respectively. Finally, the in vivo inhibition of the dermonecrotic halo caused by Pbe was evaluated, demonstrating that NJg was able to reduce the formation of this halo from 24h after induction. Therefore, it can be suggested the participation of the extract's compounds in the pharmacological action, especially the flavonoids, which mainly have antioxidant and anti-inflammatory actions. In conclusion, the results suggest that the developed NJg is promising and may be contributing to the treatment of local damage from snakebite.