Protective Effects of a Polyphenol‐Rich Extract from Syzygium cumini (L.) Skeels Leaf on Oxidative Stress‐Induced Diabetic Rats

Abstract

Syzygium cumini (L.) Skeels has been reported to exert anti-inflammatory and cardiometabolic activities due to its high content of polyphenols. We characterized the chemical composition and assessed the antidiabetic effects of a novel polyphenol-rich extract (PESc) obtained from S. cumini leaf. Rats were injected with alloxan (150 mg/kg, ip, ALX group) and followed up for 7 days. Some were orally treated with PESc (50 mg/kg/day) for 7 days before and after diabetes induction (ALX-PP) or only for 7 days after alloxan injection (ALX-P). ALX-P and ALX-PP decreased fasting glycemia in 37 and 43%, respectively, as compared to ALX. Triglycerides and total cholesterol serum levels were also significantly reduced in comparison to ALX. PESc presented high polyphenol concentration (71.78 ± 8.57 GAE/100 g), with flavonoid content of 8.21 ± 0.42 QE/100 g. Upon HPLC-MS/MS and MS/MS studies, five main polyphenols—gallic acid, quercetin, myricetin, and its derivatives—were identified. Myricetin was predominant (192.70 ± 16.50 μg/mg PESc), followed by measurable amounts of gallic acid (11.15 ± 0.90 μg/mg PESc) and quercetin (4.72 ± 0.06 μg/mg PESc). Kinetic assessment of total antioxidant capacity revealed PESc high potency, since maximum response was reached within 5 min reaction time in a concentration-dependent manner. Specific antioxidant activity of PESc was assessed against both DPPH• and ABTS•+, showing strong activity (IC50: 3.88 ± 1.09 and 5.98 ± 1.19 μg/mL, resp.). PESc also inhibited lipoxygenase activity (IC50: 27.63 ± 8.47), confirming its antioxidant activity also on biologically relevant radicals. Finally, PESc induced insulin secretion by directly stimulating INS-1E β cells in the absence of any cytotoxic effect. Overall, our results support that PESc is a potent antioxidant phytocomplex with potential pharmacological use as a preventive antidiabetic natural product.

Syzygium cumini Leaf Extract Reverts Hypertriglyceridemia via Downregulation of the Hepatic XBP-1s/PDI/MTP Axis in Monosodium L-Glutamate-Induced Obese Rats

“…In addition to its antihypertriglyceridemic effect, HESc also restored the hepatic fat accumulation of obese rats. This secondary, but not less important, property supports the possibility of synergism among the mechanism shown herein and other properties previously described for HESc, such as huge antioxidant capacity and improvement of peripheral insulin sensitivity [23, 24]. Finally, this dual action further corroborates the multitarget potentialities of the polyphenols contained into HESc as a potential phytocomplex against MetS-derived metabolic disturbances.…”

“…These effects were associated with the improvement of peripheral insulin sensitivity and β -cell function and attributed to the polyphenolic profile—mainly composed by myricetin derivatives, as well as other flavonoids and tannins—identified in HESc [23]. More recently, we reported the HPLC-MS/MS phytochemical characterization of a polyphenol-rich extract (PESc) prepared from the aforementioned HESc, which allowed the identification of five main compounds as follows: gallic acid, myricetin, myricetin-3- α -arabinopyranoside, myricetin deoxyhexoside, and quercetin, with myricetin accounting for nearly 20% of PESc total polyphenol content [24]. Notwithstanding, PESc exhibited a strong antioxidant capacity against both biological and nonbiological oxidants, which enabled it to protect mice from an oxidative stress-induced diabetic state [24].…”

“…More recently, we reported the HPLC-MS/MS phytochemical characterization of a polyphenol-rich extract (PESc) prepared from the aforementioned HESc, which allowed the identification of five main compounds as follows: gallic acid, myricetin, myricetin-3- α -arabinopyranoside, myricetin deoxyhexoside, and quercetin, with myricetin accounting for nearly 20% of PESc total polyphenol content [24]. Notwithstanding, PESc exhibited a strong antioxidant capacity against both biological and nonbiological oxidants, which enabled it to protect mice from an oxidative stress-induced diabetic state [24]. However, the molecular mechanisms responsible for the improvement of lipid metabolism promoted by S. cumini leaf remain poorly investigated.…”

The Protective Effects of Jamun Seeds and Orange Peels Extracts on Calcitonin Cells and Parathyroid Glands against Cypermethrin Toxicity

“…The adverse effects include neurological, genetic and hematological toxicities, generation of reactive oxygen species, and toxic alterations in the liver, kidneys and reproductive organs [5][6][7][8][9]. Jamun (Syzygium cumini) has antidiabetic, antimalarial, antibacterial, free radical scavenging, anti-ulcer and antifertility properties [4,10,11]. Citrus sinensis in orange peels contains hespiridin and possesses antioxidant, antiinflammatory, anti-cancer and antilipedemic activities [12].…”

Corrigendum to “Protective Effects of a Polyphenol-Rich Extract from Syzygium cumini (L.) Skeels Leaf on Oxidative Stress-Induced Diabetic Rats”

“…In the article titled “Protective Effects of a Polyphenol-Rich Extract from Syzygium cumini (L.) Skeels Leaf on Oxidative Stress-Induced Diabetic Rats” [1], the second affiliation should have been written as “Facultad de Medicina, Universidad de la Republica (UdelaR), Montevideo, Uruguay.” Also, the name of the seventh author was given incorrectly as Maria Nilce de Souza Ribeiro. The author's name should have been written as Maria Nilce de Sousa Ribeiro.…”