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Abstract. In this study, we investigated hypolipidemic mechanisms of the ethanolic extract of Ananas comosus L. leaves (AC) in mice and then determined its activities in related enzymes. The results showed that AC (0.40 g / kg) significantly inhibited the increase in serum triglycerides by 40% in fructose-fed mice. In mice induced by alloxan and high-fat diets, serum total cholesterol remained at a high level (180 -220 mg / dl) within 7 days of removing high-fat diets but reached normal level (120 -140 mg / dl) after AC (0.40 g / kg per day) treatment. Also, AC (0.40 and 0.80 g / kg) significantly inhibited serum lipids from the increase in Triton WR-1339-induced hyperlipidemic mice. AC (0.01 -100 µg / ml) selectively activated lipoprotein lipase (LPL) activity by 200% -400% and significantly inhibited 3-hydroxyl-methyl glutaryl coenzyme A (HMGCoA) reductase activity by 20% -49% in vitro. Furthermore, 2 months of fenofibrate (0.20 g / kg) administration particularly increased mice liver weights (0.0760 ± 0.0110 g / g) while AC (0.40 g / kg) had no effect (0.0403 ± 0.0047). Taken together, these results suggest that AC will be a new potential natural product for the treatment of hyperlipidemia that exerts its actions through mechanisms of inhibiting HMGCoA reductase and activating LPL activities. Its action mechanisms differentiate from those with fibrates but may be partly similar to those with statins. It is hopeful that AC may serve as the adjuvant for fibrates.

Two new compounds, coniferyl 9-O-[beta-D-apiofuranosyl(1-->6)]-O-beta-D-glucopyranoside (1) and sinapyl 9-O-[beta-d-apiofuranosyl(1-->6)]-O-beta-D-glucopyranoside (2), were isolated from the seeds of Punica granatum (pomegranate), together with five known compounds, 3,3'-di-O-methylellagic acid (3), 3,3',4'-tri-O-methylellagic acid (4), phenethyl rutinoside, icariside D1, and daucosterol. The structures of 1 and 2 were elucidated by spectroscopic data analysis. Compounds 1-4 exhibited antioxidant activity, which was evaluated by measurement of low-density lipoprotein (LDL) susceptibility to oxidation and by determination in vitro of malondialdehyde (MDA) levels in the rat brain.

The aim of this study is to demonstrate the effects of Ananas comosus L. leaves on diabetic-dyslipidemic rats. Hypoglycemic and hypolipidemic activities of the ethanolic extract of Ananas comosus L. leaves (EEACL) were evaluated in normal and alloxan-induced diabetic rats by oral glucose tolerance test and an olive oil load test. Anti-diabetic, anti-hyperlipidemic and anti-oxidative activities of EEACL were also investigated in diabetic-dyslipidemic rats induced by alloxan and a high-fat/high-cholesterol diet. EEACL at the dose of 0.40 g/kg significantly inhibited the increase in blood glucose in diabetic rats in oral glucose tolerance test, but did not cause any hypoglycerimic activity in normal rats. It also significantly inhibited the increase in postprandial triglycerides (TG) levels in both normal and diabetic rats in olive oil load test. After 15 days of treatment of diabetic dyslipidemic rats, EEACL significantly decreased blood glucose (-51.0%, P < 0.01), TG (-50.1%, P < 0.01), TC (-23.3%, P < 0.01), LDL-c (-47.9%, P < 0.01) and glycated albumin (-25.4%, P < 0.01) levels, significantly increased serum high-density lipoprotein cholesterol levels (66.2%, P < 0.01) and prevented lower body weight of diabetes (11.8%, P < 0.05), significantly lowered lipid peroxidation productions of blood (-27.8%, P < 0.01), brain (-31.6%, P < 0.05), liver (-44.5%, P < 0.01) and kidneys (-72.2%, P < 0.05) compared with those in untreated diabetic dyslipidemic rats. These data suggest that EEACL has anti-diabetic, anti-dyslipidemic and anti-oxidative activities, which may be developed into a new plant medicine for treatment of diabetes and its complications.