RESUMEN
Cholesterol is a component of cell membranes and a precursor of hormones, and excess levels are associated with disease development; therefore, it must be maintained within the normal range. Silkworm cocoons are known to contain bioactive substances. Therefore, we compared the bioactivities of pigmented and white silkworm cocoons. Sericin extract of the Yeonnokjam (YN) variety, which contained a high flavonoid content, showed the highest antioxidant activity and inhibited cholesterol biosynthetic enzyme activity. YN-fed mice showed a 26% reduction in serum low-density lipoprotein cholesterol level. In addition, a 27% decrease in cholesterol accumulation in the liver was observed. Mechanistically, YN reduced the expression of 3-hydroxy-3-methylglutaryl-CoA reductase and acetyl-CoA acetyltransferase 2 proteins by 34 and 13%, respectively. In conclusion, YN suppresses cholesterol synthesis in the liver and stimulates bile acid secretion, which contributes to reduction in cholesterol levels, suggesting its potential as a cholesterol-lowering agent.
RESUMEN
In this study, we investigated the anti-hypertensive properties of mulberry products by modulating the renin-angiotensin system (RAS). Comparative analysis showed that the ethyl acetate fractions, particularly from the Cheongil and Daeshim cultivars, contained the highest levels of polyphenols and flavonoids, with concentrations reaching 110 mg gallic acid equivalent (GE)/g and 471 mg catechin equivalent (CE)/g of extract, respectively. The ethyl acetate fraction showed superior angiotensin-converting enzyme (ACE) inhibitory activity, mainly because of the presence of the prenylated flavonoids kuwanon G and H. UPLC/Q-TOF-MS analysis identified kuwanon G and H as the primary active components, which significantly contributed to the pharmacological efficacy of the extract. In vivo testing of mice fed a high-salt diet showed that the ethyl acetate fraction substantially reduced the heart weight and lowered the serum renin and angiotensinogen levels by 34% and 25%, respectively, highlighting its potential to modulate the RAS. These results suggested that the ethyl acetate fraction of mulberry root bark is a promising candidate for the development of natural ACE inhibitors. This finding has significant implications for the management of hypertension through RAS regulation and the promotion of cardiovascular health in the functional food industry.
RESUMEN
Diseases that occur in silkworms include soft rot, hardening disease, digestive diseases, and sepsis. However, research on the causes of bacterial diseases occurring in silkworms and the resulting changes in the microbial community is lacking. Therefore, we examined the morphological characteristics of sepsis and changes in the microbial community between silkworms that exhibit a unique odor and healthy silkworms; thus, we established a relationship between disease-causing microorganisms and sepsis. After producing a 16S rRNA amplicon library for samples showing sepsis, we obtained information on the microbial community present in silkworms using next-generation sequencing. Compared to that in healthy silkworms, in silkworms with sepsis, the abundance of the Firmicutes phylum was significantly reduced, while that of Proteobacteria was increased. Serratia sp. was dominant in silkworms with sepsis. After bacterial isolation, identification, and reinfection through the oral cavity, we confirmed this organism as the disease-causing agent; its mortality rate was 1.8 times higher than that caused by Serratia marcescens. In summary, we identified a new causative bacterium of silkworm sepsis through microbial community analysis and confirmed that the microbial community balance was disrupted by the aberrant proliferation of certain bacteria.