Evaluation of Bacillus subtilis SPB1 biosurfactant effects on hyperglycemia, angiotensin I-converting enzyme (ACE) activity and kidney function in rats fed on high-fat–high-fructose diet

Abstract

This study investigated the protective and the curative effects of Bacillus subtilis SPB1 crude lipopeptide biosurfactant in alleviating induced obesity complications in rats fed on high-fat–high-fructose diet (HFFD). Male Wistar rats were divided into five groups with the following treatment schedule: normal diet-fed rats (CD), HFFD-fed rats, HFFD-fed rats supplemented with SPB1 biosurfactant from the first day of the experiment (HFFD + Bios1), rats fed on HFFD receiving standard drug (HFFD + Torva), or SPB1 biosurfactant (HFFD + Bios2) during the last 4 weeks of the study. HFFD induced hyperglycemia, manifested by a significant (p < 0.001) increase (20%) in the levels of glucose and α-amylase activity in the plasma, when compared with CD. The administration of SPB1 biosurfactant to rats fed on HFFD reverted back normal blood glucose and α-amylase activity levels. Also, the findings clearly showed that acute oral administration of SPB1 biosurfactant reduced significantly (34%) the peak of blood glucose concentration 60 min after glucose administration, as compared with untreated rats fed on HFFD. Furthermore, renal dysfunction indices such as creatinine and urea as well as the level of angiotensin I-converting enzyme (ACE) exhibited remarkable increases in serum of rats fed on HFFD by 28.35%, 46%, and 92%,. Interestingly, SPB1 lipopeptides treatments decreased the creatinine and urea levels significantly (p < 0.001) near normal values, as compared with that of the HFFD group, and also showed an improvement of the kidney cortex architecture. Moreover, SPB1 biosurfactant displayed a potent inhibition of ACE activity in vitro (CI₅₀ value=1.37 mg/mL) as well as in vivo in obese rats by 42% and 27.25% with HFFD + Bios1 and HFFD + Bios2 treatments, respectively, and comparatively with the HFFD group. Besides, SPB1 lipopeptides treatments improved some of serum electrolytes such as Na⁺, K⁺, Ca²⁺, and Mg²⁺. The results showed that SPB1 lipopeptide biosurfactant presented useful hypoglycemic and antihypertensive properties, and was able to alleviate renal lipid deposition in rats fed on a hypercaloric diet.

• Biosurfactant
• OGTT
• Hypoglycemic
• ACE
• Kidney Function

Acknowledgements

The authors are indebted to Mr Chedli Tmar for his skillful technical assistance.

Declaration of interest

The authors declare that they have no conflict of interest. This work was supported by the Ministry of Higher Education and Scientific Research in Tunisia.