# Properties of Different Varieties of Durian
## 3 Results and Discussion
### Binding Properties of Phenolic Properties of Durian Cultivars with Human Serum Proteins
As it was mentioned previously, the decrease in the fluorescence intensity of native proteins was used for the calculation of the binding properties [22,23]. The comparison of total binding properties of durian polyphenols with main serum proteins showed the following data (%) of durian vs quercetin: HSA1b: 54.4/17.7; HSGlo: 47.6/45.4; HS-Fib:38.2/9.4. As can be seen from the presented evaluation that quercetin shows lower numbers than durian polyphenols and this can be explained by the synergism of the substances [1,10,18,52]. As it was mentioned, polyphenols might act synergistically with other phytochemicals in different fruits [54, 55, 56, 57]. Our recent studies on the quenching of polyphenols with human serum proteins [22,23] and few reports were focused on the synergism of polyphenols as well as on their affinities for the proteins [58, 59, 60]. It was also shown that antioxidants may induce conformational and microenvironmental changes in interaction with human serum proteins, acting differently depending on the structure and bioactivity of the substances [61]. It was mentioned previously that the interaction of polyphenols with human serum proteins occurs through hydrophobic interaction. There are many studies explaining the essential role of polyphenics derived from fruits in the regulation of epigenetic modifications, resulting in antiproliferative protection [42,62]. The doses of polyphenol durian extracts during interaction with human serum proteins showed relatively high bioactivity and binding properties at 0.65 \(\mu\)g/mL. The antiproliferative activity of durian using a breast cancer cell line MCF-7 showed that durian fruit can be considered as a potential source of polyphenols with protective effects against the nitric oxide-induced proliferation of MCF-7 cells. At the concentration of 600 \(\mu\)g/mL, durian fruit extracts inhibited MCF-7 cell growth by 40% [42,63]. Pre-treatment of non-differentiated U937 cells with 40 mg/mL and 20 mg/ mL extract from the pulp of the Monthong cultivar of durian reduced H\({}_{2}\)O\({}_{2}\)-induced ROS formation by 30% and 18%, respectively, and with 40 mg/mL of extract of the pulp from Chanee decreased H\({}_{2}\)O\({}_{2}\)-induced production of reactive oxygen species (ROS) by 21% while the lower concentrations of this extract failed to significantly alter the generation of ROS. These results suggested that pulp from the Monthong cultivar of durian contained a greater concentration of antioxidant compounds than that of the Chanee cultivar what is exactly in accordance with the present results [18]. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-1 tetrazolium bromide) assay was used for the cytotoxicity of durian extract against Chang Liver cell lines [33]. The percentage of cytotoxicity increases with the higher concentrations of durian extract. The maximum cytotoxicity (74%) of fruit extract was recorded at 100 \(\mu\)g/mL. All durian fruit extracts at their higher concentrations (1-5 mg/mL) caused a significant decrease in HepG2 cancer cells viability. The cytotoxic effect (1 mg/mL) of immature and young durian fruits was significantly stronger (29.7 \(\pm\) 2.5; 27.3 \(\pm\) 2.1% of alive cells respectively) in comparison to the mature, ripe and overripe durians (51.3 \(\pm\) 3.1%; 51.3 \(\pm\) 3.2%; 53.3 \(\pm\) 4.0% of alive cells, respectively) [33]. The cytotoxic activity of methanol extracts of Monthong durian at different stages of ripening on human pulmonary carcinoma cells Calu-6 and human gastric carcinoma cells SNU-601 of immature, mature, ripe, and overripe durian samples were low, >85% of the cells were alive, even at the highest concentration (2 mg/mL) used in this experiment.