Papaya polysaccharides regulate intestinal flora in vivo
Authors: Yu-Wen Hung  , Chia-Chi Chen  , Yun-Xuan Chang  , Tzu-Yun Chi  , Ya-Peng Wang  , Ya-Ling Cyue  , Pi-Hsin Chen  , Yen-Jung Lu  , Shih-Yi Guo  , Yu-Ying Fang  , Yan-Zhong Wu  , Chien-Chao Chiu  , Ching-Feng Chiu  , Hsuan-Wen Chiu  , Wei-Huang Tsai  , Yu-Hsing Lin  , Tsung-Han Wu  , Shao-Wen Hung  
Published: July 2023

Mainly, papaya is a fruit grown in tropical and subtropical regions. It is a nutritionally rich fruit that is widely recognized for its various benefits. There are some common benefits of papaya include improvement of digestion, abundant vitamin C, immune system boosts, promotion of cardiovascular health, support of eye health, enhance of gut health etc. Papaya polysaccharides (PP) are natural polysaccharide compounds extracted from papaya. They are complex compounds composed of polysaccharide molecules obtained from papaya pulp, peel, or juice. PP are believed to possess various pharmacological activities and health benefits include immunomodulation, antioxidant effects, anti-inflammatory effects, blood glucose-lowering effects, hepatoprotective effects etc. It is important to note that although papaya polysaccharides have potential health benefits, current research on them is still relatively limited. Further scientific studies are needed to validate and deepen our understanding of their mechanisms of action and their application in different disease conditions. Therefore, we focused on the effects of PP regulate intestinal flora in vivo in this study. The results were revealed that long-read sequencing platform, Oxford Nanopore Technologies (ONT), was used to classify the gut microbiota in rat fecal samples. A total of 945 bacterial strains were identified through comprehensive strain identification. The obtained sequencing reads were analyzed using the CLC Genomics Workbench software. Moreover, CLC Genomics Workbench software performed Weighted UniFrac and Bray-Curtis analyses to measure the dissimilarity of identified bacterial species between different groups. Subsequently, the PERMANOVA statistical method was employed to determine the significance of differences in the composition of bacterial species between groups. Comparing the relative abundance changes of identified bacterial species in the fecal samples after 28 days of low-dose PP consumption [100 mg/kg body weight (BW)] with the normal diet group, 46 intestinal bacterial strains showed statistically significant differences. After comparing the relative abundance changes of identified bacterial species in the fecal samples following 28 days of high-dose PP consumption (200 mg/kg BW) with the normal diet group, 45 intestinal bacterial strains showed statistically significant differences. Using CLC Genomics Workbench software, a heat map was generated by selecting bacterial strains in the high (28) group that exhibited a relative abundance increase or decrease of more than 4-fold. After database analysis, a total of 945 intestinal bacterial strains were identified in this study. It was observed that the proportions of intestinal bacterial communities changed after consuming PP. Among them, 42 bacterial strains showed an increase in abundance after PP consumption. According to the criteria for determining good and bad bacteria, out of the total 118 bacterial genera considered, 69 belong to the "good bacteria" category (probable probiotics), while 49 belong to the "bad bacteria" category (potential pathogens). After PP treatment, PP (100 mg/kg BW and 200 mg/kg BW) can decrease the percentage of potential pathogens in the stool of SD rats. Taken all results together, to consume PP for 28 days can alter the composition of SD rats’ gut microbiota. Further analysis is needed to explore the effects of changes in SD rats’ gut microbiota on relevant mechanisms in the body. The findings of this study can serve as a foundation for the application of PP in regulating gut microbiota as raw materials or products.