# Microencapsulation of an Extract of _Sechium edule_ (Jacq.) Sw., with Antineoplastic Activity
## 4 Discussion  
The study evaluated chitosan due to its harmless properties as a material for the microencapsulation of cv. Perla negra, whose antiproliferative effect has been registered [27]. The coacervation method with sonication was used, obtaining microspheres with an average size of 20 \(\upmu\)m with an extract release concentration of 24 \(\upmu\)g mL\({}^{-1}\) at 23 h. They showed antiproliferative activity in HeLa without damage to lymphocytes. The same activity was observed with the empty microspheres (chitosan only), showing that there is no interference between the encapsulating material and the extract and suggesting its use as an administration vehicle. Authors such as [3; 34; 38] obtained microspheres with a range of size of 1-30 \(\upmu\)m, following the same method of microencapsulation. It is likely that the difference in size is due to the agitation speed (Figure 1). [PERSON] et al. [34] mention that the release concentration they obtained was 0.0056 \(\upmu\)g mL\({}^{-1}\) at 140 min, releasing DNA from cow thymus (_Bos taurus_ L) with 85% of load efficiency, while [PERSON] et al. [38] mentioned a release of 1.30 mg mL\({}^{-1}\) at 120 min of bovine serum albumin (BSA) without recording the load efficiency. It is possible that the difference observed in the release time of the cv. Perla negra extract, compared to the release time of protein and DNA recorded by [PERSON] et al. [34; 38] as the load efficiency, is due to the nature of the encapsulated product, and mainly the morphology of the microparticles obtained. These authors obtained particles with a more compact internal structure than the internal structure obtained in this study, with greater definition of the matrix of the encapsulating material (Figure 1). Studies that have been carried out to evaluate the effects of terpenoids have reported antiviral, antibacterial, anti-hypertensive, anti-hyperglycemic, and anticancer activities against parasites as well as control of central nervous system disorders [39]. The effects of the flavonoids are diverse and include antiallergy, anti-depressive, antibacterial, anti-inflammatory, antioxidant, antiviral, and anticancer activities; flavonoids also can treat thrombosis, diabetes mellitus, rheumatoid diseases, cardiovascular diseases and gastric ulcers, and they offer hepatoprotection [40; 41; 42]. Table 1 shows that the secondary metabolites (terpenoids) were microencapsulated, which suggests that the antiproliferative activity is not at risk. Figure 3: Inhibition of the proliferation of HeLa cells and lymphocytes, as an effect of the application of empty microspheres and loaded microspheres with cv. Perla negra (_Schium edule_ (Jacq.) Sw.) methanol extract. The asterisk indicates the level of statistical significance (\(p\leq 0.05\)). The bars indicate \(\pm\) standard error of \(n=9\). Regarding the inhibitory effect of proliferation of empty microspheres on HeLa cells, [PERSON] et al. [43] mention that chitosan has antitumor, antiulcer, immune-stimulating, and antibacterial activities. It has also been reported that water-soluble chitosan has a low molecular weight in the growth of Sarcoma 180 (S180) tumor cells in mice. It had the highest value of inhibition at 64.2%, with a dose of 200 mg kg\({}^{-1}\) applied via intraperitoneal injection; 33.7% with a dose of 200 mg kg\({}^{-1}\) applied through oral administration [44]; 50% with a dose of 50 mg kg\({}^{-1}\) applied via intraperitoneal injection; and 31% with a dose of 400 mg kg\({}^{-1}\) via oral administration [45]. Another study evaluated the antimetastatic property of chitosan oligosaccharides (COS) on human breast carcinoma cells (MDA-MB-231), obtaining a response-dose relation and showing that cell migration through a membrane covered with Matrigel is inhibited, and the activity and amount of MMP9 protein decreased [46].