Enzyme-resistant fractions of beans lowered serum cholesterol and increased sterol excretions and hepatic mRNA levels in rats.
Feeding rats beans with resistant starch reduces their serum cholesterol concentration; however, the mechanism by which this occurs is not fully understood. We examined the effects of enzyme-resistant fractions of adzuki (Vigna angularis) and tebou (Phaseolus vulgaris, var.) beans on serum cholesterol and hepatic mRNA in rats. Rats were fed a cholesterol-free diet with 50 g of cellulose powder (CP)/kg, 50 g of an enzyme-resistant fraction of adzuki starch (AS)/kg, or 50 g of an enzyme-resistant fraction of tebou starch (TS)/kg diet for 4 wk. There were no significant differences in body weight, liver weight, and cecum contents among the groups, nor was there a significant difference in food intake among the groups. The levels of serum total cholesterol, VLDL + intermediate density lipoprotein + LDL-cholesterol, and HDL cholesterol in the AS and TS groups were significantly (P < 0.05) lower than in the CP group throughout the feeding period. Total hepatic cholesterol in the CP group was significantly (P < 0.05) lower than in the AS and TS groups, fecal cholesterol excretion in the TS group was significantly (P < 0.05) greater than in the CP and AS groups, and the fecal total bile acid concentrations in the AS and TS groups were significantly (P < 0.05) higher than in the CP group. Cecal acetate, propionate, and n-butyrate concentrations in the AS and TS groups were significantly (P < 0.05) higher than in the CP group. The level of hepatic scavenger receptor class B1 (SR-B1) mRNA in the TS group was significantly (P < 0.05) higher than in the CP group, and the levels of hepatic cholesterol 7alpha-hydroxylase mRNA in the AS and TS groups were significantly (P < 0.05) higher than in the CP group. These results suggest that AS and TS have a serum cholesterol-lowering function due to the enhanced levels of hepatic SR-B1 and cholesterol 7alpha-hydroxylase mRNA.
Department of Animal Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
Kyu-Ho
KH
Han
Michihiro
M
Fukushima
Teruhiko
T
Kato
Michiyuki
M
Kojima
Kiyoshi
K
Ohba
Ken-ichiro
K
Shimada
Mitsuo
M
Sekikawa
Masuo
M
Nakano
D000818:Animals; D001647:Bile Acids and Salts / Q000032:analysis; D001835:Body Weight / Q000187:drug effects; D002784:Cholesterol / Q000032:analysis / Q000097:blood*; D002790:Cholesterol 7-alpha-Hydroxylase / Q000235:genetics; D004032:Diet; D007887:Fabaceae / Q000737:chemistry*; D005227:Fatty Acids / Q000032:analysis / Q000737:chemistry; D005243:Feces / Q000737:chemistry; D005247:Feeding Behavior / Q000187:drug effects; D005766:Gastrointestinal Contents; D006863:Hydrogen-Ion Concentration; D008099:Liver / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D008297:Male; D009929:Organ Size / Q000187:drug effects; D010434:Pepsin A / Q000378:metabolism*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D013261:Sterols / Q000097:blood / Q000378:metabolism*; D013997:Time Factors
D001647:Bile Acids and Salts; D005227:Fatty Acids; D010936:Plant Extracts; D012333:RNA, Messenger; D013261:Sterols; D002784:Cholesterol; D002790:Cholesterol 7-alpha-Hydroxylase; D010434:Pepsin A