# Probiotics and Curcumin Did Not Alter Low‐Dose Streptozotocin‐Induced Hyperglycemia and Oxidative Stress in a Rat Model

## TL;DR

This study found that probiotics and curcumin individually improved diabetes and oxidative stress in rats, but combining them did not provide extra benefits due to curcumin's low bioavailability.

## Contribution

The study reveals that curcumin's low bioavailability limits synergistic effects when combined with probiotics in a type 2 diabetes rat model.

## Key findings

- VSL#3 and curcumin individually improved body weight, fasting blood glucose, and antioxidant enzyme activities.
- The PRO+CUR group showed lower fasting blood glucose but no synergistic effects compared to individual treatments.
- Curcumin's low bioavailability and prooxidant effects likely hindered the combination's effectiveness.

## Abstract

This study aimed to investigate the individual and combined effects of the multi‐strain probiotic VSL#3 and curcumin on glycemic control, insulin resistance, and oxidative stress (OS) in a rat model of T2DM induced by a high‐fat diet (HFD) and streptozotocin (STZ). Forty male Sprague–Dawley rats were divided into five groups: negative control, positive control (PC) induced with HFD and STZ, VSL#3 probiotic (PRO) (2.5 × 1010 CFU/day VSL#3), curcumin (CUR) (200 mg/kg/day curcumin), and combination of VSL#3 and curcumin (PRO+CUR) (2.5 × 1010 CFU/day VSL#3 + 200 mg/kg/day curcumin). At the end of 8 weeks, the study assessed the effects of these interventions on body weight, food intake, fasting blood glucose, and insulin resistance (HOMA‐IR). Additionally, serum and pancreatic tissue antioxidant parameters, were measured, including TAC, SOD, CAT, GPx, and MDA. VSL#3 and curcumin individually improved body weight, fasting blood glucose, and antioxidant enzyme activities. The PRO+CUR group showed the highest body weight gain and lower fasting blood glucose (353.83 ± 39.48 mg/dL) compared to the PC group (p < 0.05). However, the PRO+CUR combination did not yield the expected synergistic effects, likely due to curcumin's low bioavailability and prooxidant effects. Serum TAC was highest in the CUR group (0.78 ± 0.05 U/ng), whereas the PRO+CUR group showed reduced TAC (0.16 ± 0.02 U/ng). HOMA‐IR values increased in the PRO and CUR groups, but no significant change was observed in the PRO+CUR group. This study demonstrates the therapeutic potential of probiotics and curcumin in T2DM. Probiotics enhanced antioxidant defenses and reduced OS, but the combination with curcumin showed no synergistic effects, likely due to curcumin's bioavailability.

In this study, a high‐fat diet/streptozotocin‐induced type 2 diabetes rat model was used to evaluate the individual and combined effects of the multi‐strain probiotic VSL#3 and curcumin on glycemic control, insulin resistance, and oxidative stress–related outcomes. Results indicated that VSL#3 and curcumin each modulated metabolic and antioxidant markers, whereas their combined administration did not provide a clear synergistic benefit, suggesting that curcumin‐related limitations (e.g., low bioavailability) may influence the overall response.