Nutr Res Pract.  2024 Jun;18(3):345-356. 10.4162/nrp.2024.18.3.345.

Hypoglycemic and hypolipidemic effects of unsaponifiable matter from okra seed in diabetic rats

• Seo D
• Kim N
• Jeon A
• Kwon J
• Baek Ih
• Shin EC
• Lee J
• Kim Y

• KMID: 2558508
• DOI: http://doi.org/10.4162/nrp.2024.18.3.345

Abstract

BACKGROUND/OBJECTIVES
Okra seed is a rich source of various nutritional and bioactive constituents, but its mechanism of action is still unclear. The aim of this study was to evaluated the effects on glucose uptake and serum lipid profiles of unsaponifiable matter (USM) from okra seed in adipocytes and diabetic animal models.
MATERIALS/METHODS
USM was prepared from okra seed powder by saponification. The contents of phytosterols and vitamin E in USM were measured. 3T3-L1 preadipocytes were cultured for 6 days with different concentrations of USM (0–200 μg/mL). The diabetic rats were administered with or without USM for 5 wk.
RESULTS
In the USM, the contents of phytosterols and vitamin E were 394.13 mg/g USM and 31.16 mg/g USM, respectively. USM showed no cytotoxicity and led to an approximately 1.4-fold increase in glucose uptake in 3T3-L1 adipocytes. The treatment of USM also increased the expressions of peroxisome proliferator-activated receptor-γ and glucose transporter-4 in a dose-dependent manner in adipocytes. The body weight change was not significantly different in all diabetic rats. However, blood glucose and the weights of liver and adipose tissues were significantly reduced compared to those in the control diabetic rats. Treatment with USM decreased the levels of triglycerides, total cholesterol, and low-density lipoprotein cholesterol compared to the control group. The USM group also showed significantly decreased atherogenic indices and cardiac risk factors.
CONCLUSION
These results suggest that USM from okra seed improves the hypoglycemic and hypolipidemic effects in diabetic rats, and provides valuable information for improving the functional properties of okra seed.

Keyword

Okra; seeds; phytosterols; tocopherols; hypoglycemia

Figure

• 

  Fig. 1 Effects of USM from okra seed on cytotoxicity (A) and 2-deoxyglucose uptake (B) in 3T3-L1 adipocytes. The results are expressed as means ± SD. Different letters above bars indicate significant difference (P < 0.05).USM, unsaponifiable matter; ns, not significant.

• 

  Fig. 2 Effects of USM from okra seed on PPARγ (A) and GLUT4 (B) protein expressions, and PPARγ (C) and GLUT4 (D) mRNA expression in 3T3-L1 adipocytes. The results are expressed as means ± SD. Mean values with different superscripts are significantly different (P < 0.05).USM, unsaponifiable matter; PPARγ, peroxisome proliferator-activated receptor-γ; GLUT4, glucose transporter-4.

• 

  Fig. 3 Effect of unsaponifiable matter (10 mg/kg) from okra seed on body weight (A) and blood glucose levels (B). The results are expressed as means ± SD. Mean values with different superscripts are significantly different (P < 0.05). Quercetin was used as positive control sample (30 mg quercetin/kg).CON, control; QUE, quercetin; USM, unsaponifiable matter; ns, not significant.

• 

  Fig. 4 Effect of unsaponifiable matter (10 mg/kg) from okra seed on liver (A), epididymal fat (B) and abdominal fat weight. The results are expressed as means ± SD. Quercetin was used as positive control sample (30 mg/kg).CON, control; USM, unsaponifiable matter; QUE, quercetin; ns, not significant; ns, not significant.Asterisk (*) indicates a significant difference versus the control group (*P < 0.05, **P < 0.01).

• 

  Fig. 5 Effect of unsaponifiable matter (10 mg/kg) from okra seed on glucose level (A), BUN (B), creatin (C), ALT (D), TG (E), TC (F), LDL-C (G) and HDL-C (H). The results are expressed as means ± SD. Quercetin was used as positive control sample (30 mg quercetin/kg).BUN, blood urea nitrogen; ALT, alanine transaminase; TG, triglyceride; TC, total cholesterol; LDL-C, low-density lipoprotein cholesterol; HDL-C, high-density lipoprotein cholesterol; CON, control; USM, unsaponifiable matter; QUE, quercetin; ns, not significant; ns, not significant.Asterisk (*) indicates a significant difference versus the control group (*P < 0.05, **P < 0.01, ***P < 0.001). Pound (#) indicates a significant difference between USM and QUE groups (##P < 0.01).

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  Fig. 6 Effect of unsaponifiable matter (10 mg/kg) from okra seed on AI (A) and the CRF (B) of plasma in GK rat for 5 wk. AI = (TC − HDL-C)/HDL-C; CRF = TC/HDL-C. The results are expressed as means ± SD. Quercetin was used as positive control sample (30 mg quercetin/kg).AI, atherogenic index; CRF, cardiac risk factor; GK, Goto-Kakizaki; TC, total cholesterol; HDL-C, high-density lipoprotein cholesterol; CON, control; USM, unsaponifiable matter; QUE, quercetin.Asterisk (*) indicates a significant difference versus the control group (***P < 0.001). Pound (#) indicates a significant difference between USM and QUE groups (##P < 0.01).

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