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Improved Peripheral Insulin Sensitivity and Pancreatic Islet Function in Obese Rats Treated with Polyphenol‐Rich Extract of Syzygium cumini Leaves
Author(s) -
França Lucas Martins,
Sanches Jonas Rodrigues,
Chagas Vinicyus Teles,
Gaspar Renato Simões,
Santos Kayque Almeida,
Maranhão Marina Cristine Silva,
Carneiro Everardo Magalhaes,
Cappelli Ana Paula Gameiro,
Andrade Paes Antonio Marcus
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.692.8
Subject(s) - syzygium , metabolic syndrome , medicine , adipose tissue , insulin resistance , obesity , triglyceride , endocrinology , polyphenol , chemistry , traditional medicine , biochemistry , antioxidant , cholesterol
Syzygium cumini (L.) Skeels (Myrtaceae) has been traditionally used to treat of metabolic disorders, especially diabetes mellitus. Although there are many studies used extracts from seed and fruit pulp, the works with the leaves are scarce. As there is considerable interest in bioactive compounds to treat metabolic syndrome and its clustered risk factors, we sought to characterize the metabolic effects of hydroethanolic extract of S. cumini leaves (HESc) on lean and monosodium L‐glutamate(MSG)‐induced obese rats. At 60 days of age, both groups were randomly assigned to receive HESc (500 mg/kg; v.o) or vehicle for 30 days. At the end of treatment, obese+HESc exhibited significantly lower body weight gain (199.4 ± 8.6 g), body mass index (328.0 ± 3.8 g 1/3 .cm −1 ), and white adipose tissue mass (2.58 ± 0.19 g/100 g bw), compared to obese rats receiving vehicle (245.1 ± 14.9 g; 3.47 ± 3.09 g 1/3 .cm −1 ; 3.65 ± 0.55 g/100 g bw, respectively). No difference was observed between lean groups. Obese rats treated with HESc showed a 2‐fold increase in lipolytic activity in the periepididymal fat pad compared to obese rats without treatment (4.81 ± 0.44 vs. 2.75 ± 0.36 mg/mg/h), as well as, reduced triglyceride levels in serum (129.3 ± 13.2 vs. 237.4 ± 36.3 mg/dL), liver (8.71 ± 1.04 vs. 18.38 ± 2.39 mg/g tissue) and skeletal muscle (8.03 ± 1.03 vs. 13.2 ± 1.44 mg/g tissue). Furthermore, HESc also improved hyperinsulinemia (1.125 ± 0.23 vs. 1.93 ± 0.24 ng/mL) and insulin resistance in obese+HESc rats (HOMA‐IR index: 6.02 ± 1.3 vs. 10.8 ± 1.9), as compared to obese rats. HESc had no effect in lean rats. Assessment of ex vivo glucose‐stimulated insulin secretion showed HESc potentiated pancreatic function in islets isolated from both lean (1.84 ± 0.24 vs. 0.96 ± 0.14 ng/mL/h) and obese rats (3.20 ± 0.39 vs. 2.32 ± 0.22 ng/mL/h) treated with HESc. In addition, HESc (100 μg/mL) increased glucose stimulated insulin secretion from both isolated rat islets (4.2 ± 1.09 vs. 1.83 ± 0.29 ng/mL/4 islets/h) and INS‐1E β cells (23.9 ± 2.5 vs. 12.3 ± 1.11 ng/mL/4h), as compared to basal insulin release. HPLC‐MS/MS characterization of the HESc polyphenolic profile, at 254 nm, identified 15 compounds pertaining to hydrolysable tannins and flavanol subclasses. These data demonstrate that S. cumini leaves improved peripheral insulin sensitivity via stimulating/modulating beta cell insulin release, which was associated with improvements in metabolic outcomes in MSG‐induced obese rats. Support or Funding Information FAPEMA, CAPES, CNPQ and UFMA