The aim of the study was to investigate the role of the proteolytic fraction from Vasconcellea cundinamarcensis, designated as P1G10, on healing of chronic foot ulcers in neuropathic patients diagnosed with diabetes type 2. Fifty patients were enrolled in a prospective, randomized, double-blind trial, to verify the efficacy and safety of a topical dressing containing 0.1% P1G10, versus a Hydrogel (positive control) protocol currently applied at the Health Center to treat this condition. Upon completion of the intervention, the outcome evaluated the number of patients attaining full epithelization (100%), or at least 80% healing in both arms (P1G10 versus Hydrogel). Statistical analysis compared the endpoint data on each group to assess the significance of differences.

Volunteers admitted for the study were randomly assigned into two distinct treatment groups. Randomization was performed by simple and stratified draw for each type of treatment. The treatment options were: a) Hydrogel™ and b) P1G10. The active principle had been previously dissolved in water and dispersed into Polawax dressing at 0.1% w/w final. Polawax™ is an emulsifying wax for cosmetic preparations. According to the manufacturers, it is able to hold together all types of ingredients without residue or separation. It is, therefore, ideal for "oil in water" creams and lotions. Number were used to identify both formulations.

The staff participating in this clinical trial, including researchers was unaware of the identity of the formulation applied on each proband. Each formulation used during the intervention was dispensed weekly at the Laboratory of Antitumor Substances of the Institute of Biological Sciences of the Federal University of Minas Gerais by members of the research group who had no contact with the staff responsible for the application of the protocol. The formulations were stored at 4°C until its application.

The treatment and the collection of data, took place between August 2012 and October 2016, and it was carried out by health professional and a technical assistant previously trained to evaluate and perform the procedure.

The application of the intervention was done three times per week (Monday, Wednesday and Friday), completing 48 applications or until full epithelialization of the ulcer was observed, whichever occurred first. The treatment was performed exclusively at the outpatient level. When the proband could not attend the scheduled treatment, he (she) was instructed to perform the dressing change only with 0.9% saline solution. Patients who missed two consecutive scheduled interventions were withdrawn from the study.

Ulcers were cleaned with 0.9% physiological solution using soft pressure, without scrubbing or addition of antiseptic substances. Subsequently, a thin layer of the ointment containing P1G10 or Hydrogel was applied over the ulcer bed, covering all its extension. Then double gauze was applied, fixed with adhesive tape and crepe bandage, if necessary. In cases of users with more than one wound, each wound received identical treatment, but only one ulcer was selected for the study.

During the first week of treatment, the subjects were observed for 30 minutes after the intervention, in order to verify possible undesirable effects. After this interval, if they did not present adverse events, they were released. Users were also instructed to contact the responsible investigators by telephone if they observed the emergence of any adverse effects. A prior trial of the formulation containing 0.1% P1G10 applied onto the arm of healthy individuals during one-month did not induce local or systemic affects.

Inclusion Criteria:

• Clinical diagnosis of diabetes 2 had
• Hemoglobin ≥ 9.0 g/dl
• total leukocytes ≥ 300/ mm3
• platelets ≥ 100.00/mm3
• total bilirubin ≤ 1.0 mg/dL
• aspartate aminotransferase between 14 and 17 U/L in males and 10 and 33 U/L in females
• pyruvate transaminase between 10 and 40 U/L in males and 7 and 35 U/L in females
• creatinine between 0.70 and 1.20 mg/dL in males and 0.6 and 1.0 mg/dL in females

Exclusion criteria

• pregnant females
• lactating mothers
• highly exuding ulcers
• patients receiving alternative treatments for ulcers
• reported allergy to the components included in the formulation,
• concomitant uncontrolled morbidity
• current active infections,
• HIV serum positives
• diagnosed with neoplasia or undergoing treatment with a cytostatic, or immunosuppressing agent
• individuals subjected to radiotherapy within the last 3 months before beginning the trial.