The main objective of the project focuses on the study of the effectiveness of a functional component extracted from Psidium guava, psiguavin, as a potential inhibitor of pancreatic lipase and, therefore, as an adjuvant for the treatment of obesity.

That is, the aim is to verify from various experimental perspectives the effect of psiguavin on the activity of the enzyme pancreatic lipase (EC 3.1.1.3), which is the main enzyme responsible for the digestion of lipids from the diet. Our preliminary studies have shown that there is a strong interaction between psiguavin and the active center of pancreatic lipase; however, it is necessary to confirm these initial hypotheses through a clinical trial. Taking into account that the usefulness of this compound is based on the reduction of dietary calorie intake, in order to confirm its therapeutic usefulness, a clinical trial will be proposed.

To this end, the following specific objective is defined, which is intended to be achieved with the execution of the project:

• Evaluate the effect of psiguavin on weight loss of people with overweight/obese people.

The latest data published by the World Health Organization (WHO) report that overweight and obesity are the most prevalent diseases worldwide. In 2016, 39% of adults worldwide were overweight, and 13% were obese. Although there are many factors involved in the development of obesity, an excessive intake of calories, especially in the form of fat, and a sedentary lifestyle are still considered the key factors for the development of overweight.

Currently, the standard treatment or therapy for obesity is the modification of habits or lifestyles, reducing energy intake through low-calorie diets, and increasing energy expenditure with physical activity programs. The problem is that the effectiveness of these interventions is usually very modest, especially in the long term. On certain occasions (such as when weight losses are very small), in addition to this therapy that we can define as "conventional", certain drugs can be prescribed to reduce caloric intake and improve the effectiveness of the dietary intervention.

There are various drugs approved by the EMA and the AEMPS for the treatment of obesity: on the one hand, there are centrally acting agents such as the naltrexone-bupropion combination. On the other hand, peripherally acting agents, such as liraglutide or orlistat, have shown greater effectiveness for weight loss. Orlistat (Xenical®) is the best-selling obesity drug in the world, and is the only drug approved for adolescents; Its effectiveness is similar to other drugs, but it is safer because its adverse effects are related to gastrointestinal alterations, such as fecal urgency, fecal incontinence, flatus, steatorrhea, among others, which are frequently the cause of abandonment of this drug. treatment. For all these reasons, it seems evident that the most appropriate treatment for addressing obesity would be through a mechanism similar to that of orlistat, and if possible with greater effectiveness and fewer adverse effects.

Our previous in silico and in vitro studies have shown that the bioactive component of guava, psiguavin, has pharmacological characteristics very similar to orlistat, which is why we considered this clinical trial to confirm, in vivo, these previous data.

Psiguavin is a compound from the family of hydrolyzable tannins extracted from guava (Psidium guajava). This compound has been used in traditional botany for the treatment of disorders related to the accumulation of liver fat induced by excess sugars. Despite this, there are no clear bibliographic references on the compound's potential for use as a bioactive compound for application in the treatment of obesity.

To this end, a double-arm, double-blind, randomized, placebo-controlled study will be carried out to analyze weight loss in overweight/obese patients during a period of 3 months of treatment plus one year of follow-up.

Inclusion Criteria:

• Being between 18 and 65 years old
• Having a BMI between 25 and 40
• Voluntarily taking part in the study

Exclusion Criteria:

• Have been on a diet for at least 6 months before the start of the study.
• Taking chronic medication that can alter metabolism (thyroid drugs, corticosteroids, etc.)
• Having a contraindication for guava
• Having an intestinal chronic disease
• Being pregnant