# Natural Extracts from White Common Bean
## 3 Results and Discussion
### Intracellular Lipid Accumulation  
A recent in vivo study revealed that the consumption of whole common bean foods reduces the fat mass of obese rats and regulates the expression level of genes implicated in lipid metabolism [15]. In this study, an in vitro experiment was performed to demonstrate the influence of different white common bean bioactive components on lipid accumu  
Figure 1: The cytotoxicity of CBP (**A**), \(\alpha\)-AIE (**B**), and NSP (**C**). Cultures in basal medium served as control. Three independent experiments were performed, and the data were shown as mean \(\pm\) SD. There is no significant difference between the experimental groups and the control group.  
lation. As shown (Figure 2A), compared with the adipocyte group, CBP significantly suppresses lipid accumulation in the mature adipocyte, suggesting inhibitory effects on 3T3-L1 adipocyte differentiation. The Optical Density (O.D.) absorbance is reduced to 79.29% and 35.13% by 150 ug/mL of CBP and 300 ug/mL of CBP, respectively (Figure 2B). Consistent with our results, [PERSON] et al. 2015 reported that the phenolic compound extracts from raspberry show inhibitory effects on the lipid accumulation within a dose from 1 to 50 uM in a dose-dependent manner [28]. From the results of phenolic compounds composition analysis, ferulic acid and \(p\)-coumaric acids are the major phenolic compounds in CBP. In a previous study, the similar inhibitory effects of these two compounds from corn silk extracts on the 3T3-L1 adipocyte differentiation were proven [36]. [PERSON] et al. also reported that phenolic acids, including ferulic acid and \(p\)-coumaric acids, significantly inhibit the differentiation of 3T3-L1 cells due to the binding affinity to PPAR\(\gamma\)[37]. These results indicate that CBP contributes to the anti-obesity effects of common bean foods through inhibiting 3T3-L1 adipocyte differentiation.  
Figure 2: Effects of CBP, \(\alpha\)-AIE, and NSP on lipid accumulation in 3T3-L1 cells. (**A**) Oil red O staining, and (**B**) Optical Density (O.D.) absorbance value. The data was expressed as mean \(\pm\) SD. Different letters mean significantly difference (\(p<0.05\)).  
Due to the starch blocker role, \(\alpha\)-AI is always thought to be the major bioactive component responsible for the anti-obesity effects of common bean foods [38,39]. Our results showed that the \(\alpha\)-AIE from white common bean inhibits the 3T3-L1 adipocyte differentiation (Figure 2A). The O.D. absorbances are reduced to 90.20% and 68.28% by 2 mg/mL of a-AIE and 4 mg/mL of a-AIE, respectively (Figure 2B). These results give us a new insight into the mechanism of the anti-obesity effects of a-AI from common bean, except for the inhibition of starch digestion.  
Although recent evidence suggested that plants NSP can restrain the adipocyte differentiation [13,40], in this study, the NSP from white common bean displays no inhibitory effects on 3T3-L1 adipocyte differentiation, and it even slightly promotes the lipid accumulation in 3T3-L1 cells (Figure 2A). Compared with the adipocyte group, the O.D. absorbances are increased to 112.12% and 119.07% by 2 mg/mL of NSP and 4 mg/mL of NSP, respectively (Figure 2B). A similar phenomenon was reported by [PERSON] et al., who found that the addition of astragalus polysaccharides (ASP) increases lipid accumulation in 3T3-L1 cells after 6 days of differentiation, which may own to the improvement effect of ASP on the insulin sensitivity of cells [41]. Different polysaccharides have different chemical structures, such as molecular weight, monosaccharide composition, and functional groups, which may lead to different bioactivities.