Cancer is one of the leading causes of death worldwide, making the search for alternatives for its control a critical issue. In this context, exploring alternatives from natural sources, such as certain vegetables containing a variety of secondary metabolites with beneficial effects on the body and that play a crucial role in the fight against cancer, is essential. Among the compounds with the greatest efficacy in controlling this disease, those with antioxidant activity, particularly phenolic com-pounds, stand out. A remarkable example of this group is protocatechuic acid (PCA), which has been the subject of various revealing research on its activities in different areas. These studies sustain that protocatechuic acid has anti-inflammatory, antimutagenic, antidiabetic, antiulcer, antiviral, antifibrogenic, antiallergic, neuroprotective, antibacterial, anticancer, antiosteoporotic, anti-aging, and analgesic properties, in addition to offering protection against metabolic syndrome and con-tributing to the preservation of hepatic, renal, and reproductive functionality. Therefore, this paper aims to review the biological activities of PCA, focusing on its anticancer potential and its in-volvement in the control of various molecular pathways involved in tumor development, sup-porting its option as a promising alternative for cancer treatment.

The Sechium edule Perla Negra cultivar is a recently-obtained biological material whose progenitors are S. edule var. nigrum minor and S. edule var. amarus silvestrys, the latter of which has been reported to have antiproliferative activity against the HeLa P-388 and L-929 cancer cell lines. The present study aimed to determine if the methanolic extract of the fruit of the Perla Negra cultivar had the same biological activity. The methanolic extract was phytochemically characterized by thin layer chromatography (TLC) and column chromatography (CC), identifying the terpenes and flavonoids. The compounds identified via high performance liquid chromatography (HPLC) were Cucurbitacins B, D, E, and I for the terpene fractions, and Rutin, Phlorizidin, Myricetin, Quercetin, Naringenin, Phloretin, Apigenin, and Galangin for the flavonoid fractions). Biological activity was evaluated with different concentrations of the methanolic extract in the HeLa cell line and normal lymphocytes. The methanolic extract inhibited the proliferation of HeLa cells (IC₅₀ 1.85 µg·mL⁻¹), but the lymphocytes were affected by the extract (IC₅₀ 30.04 µg·mL⁻¹). Some fractions, and the pool of all of them, showed inhibition higher than 80% at a concentration of 2.11 µg·mL⁻¹. Therefore, the biological effect shown by the methanolic extract of the Perla Negra has some specificity in inhibiting tumor cells and not normal cells; an unusual feature among molecules investigated as potential biomedical agents.

Microencapsulation is a technique used in pharmaceuticals as an administration vehicle. Encapsulating secondary metabolites for therapeutic purposes has been promoted recently. Microencapsulation based on chitosan was developed for the methanol extract of cv. Perla negra (S. edule (Jacq.) Sw.) (Cucurbitaceae) fruits to evaluate its viability as an administration vehicle and to assess the possible negative interaction between the extract and chitosan. Microencapsulation was performed by coacervation, implementing a method with constant sonication. The microparticles obtained were registered by means of Scanning Electron Microscopy. The presence of the bioactive in aqueous medium was recorded for release tests, measuring with spectrophotometry its concentration as a function of time. The assessment of the biological effect of the microencapsulated extract was done on the HeLa cell line and control cells (lymphocytes). Microspheres with an average size of 20 µm and a loading capacity of 98% were obtained. The highest concentration of released extract was 24 µg mL⁻¹ at 23 h. The mainly chitosan-based microspheres did not affect the antiproliferative activity of the extract of cv. Perla negra and proved to be a potential vehicle for its therapeutic administration. The empty microspheres made with chitosan also showed to have an antiproliferative effect, and those loaded with extract showed cellular inhibition (statistical IC₅₀) of 8 µg mL⁻¹ without affecting the lymphocytes. Chitosan does not interfere with the biological activity of the metabolites incorporated into the microspheres since they retain their inhibitory activity on proliferation in tumor cells, thus constituting a potential vehicle for the therapeutic administration of fruit extract.