# Microencapsulation of an Extract of _Sechium edule_ (Jacq.) Sw., with Antineoplastic Activity
## 4 Discussion
Authors such as [47] explored the effects of the degree of deacetylation and the molecular mass of different oligosaccharidesadriades of chitosan obtained from the enzymatic hydrolysis of high-molecular-weight chitosan in in vitro conditions. Authors assessed the antitumor activity in the PC3 (human prostate cancer cells), A549 (human lung cancer cell) and HepG2 (hepatocellular carcinoma cell) cell lines, showing that the COS had mean cytotoxic concentrations (CC50) of 25, 5 and 12.5 ug mL\({}^{-1}\) of inhibition, respectively, and defining that the relatively smaller size (molecular weight), higher solubility and lower degree of deacetylation are promising factors for the development of potential pharmaceutical or nutraceutical products with this material. Studies carried out with chitosan nanospheres at 85% deacetylation, with mean molecular weight and 40 nm diameter, showed a growth inhibition effect on Sarcoma 180 (S180) and mouse Hepatoma (H22) cells in vivo, finding that 2.5 mg kg\({}^{-1}\) oral administration led to 53% and 59% cellular inhibition, respectively [48]. These same nanospheres have also been evaluated in human hepatocellular carcinoma (BEL/402) cells in vivo (mice) via oral administration with 1 mg kg\({}^{-1}\) per day, obtaining 61.69% tumor growth inhibition, while in in vitro conditions they showed an IC\({}_{50}\) of 0.94 ug mL\({}^{-1}\) in 72 h [45]. Chitosan has proven to have inhibitory activity in different cancerous cell lines in vitro and in vivo [44; 45; 47; 48; 49], and its effect depends on different factors such as molecular weight, degree of deacetylation, and even how it is administered, whether orally or via intraperitoneal injection. This can be observed in the assessment of the effect of nanospheres on BEL/402 reported by [49]. The microspheres evaluated on HeLa cells had a statistical IC\({}_{50}\) of 8 ug mL\({}^{-1}\), and in the nanospheres evaluated by [49] it was 0.94 ug mL\({}^{-1}\); that is, the latter showed the same effect with a dose 8.5 times lower than the microspheres. This is probably due to their size since the nanospheres are 500 times smaller, which can facilitate their absorption in the cell membrane [19] and influence the inhibitory effect. It is possible the microspheres obtained in this study have the same mode of action as the nanospheres on BEL/402 that were manufactured with chitosan with the same degree of deacetylation, which causes disruption of the cell membrane in cancer cells, decreases the superficial negative load, decreases the potential of the mitochondrial membrane, induces lipid oxidation and disrupts the fatty acids of the membrane and DNA fragmentation [49]. For this effect, it is suggested that the amino groups interact with negatively charged phospholipid components in the membranes, which leads to the release of proteins and other intracellular constituents, accelerating the exchange with the medium, in addition to forming chelates and inhibiting some enzymes [26; 50]. This effect is perhaps not as evident in the lymphocytes because of the very precise function that they have. Since these are cells with a very heterogeneous population and are highly specific, every type of lymphocyte presents in its membrane a single type of very specific receptor, which is why the recognition of antigens is quite broad, and they have the capacity of responding to any pathogen or strange substance that enters an organism. When there is an antigen, only the lymphocytes that recognize it are activated and proliferate, eliminating it quickly [51]; therefore, it is likely that this mechanism inhibits the effect of chitosan on these cells. The amino group that has the chitosan makes it possible for it to be soluble in water because of its load, which makes it bioadhesive; this improves the permeation through negatively loaded surfaces, for example the mucous and basal membranes, inducing chitosan to ease the bioavailability of polar drugs and their transport through the epithelial surfaces [52].