The objective of this study was to investigate the effects of separate and concurrent supplementation of natural nano-sized clinoptilolite (NCLN) and Nigella sativa (NS) on oxidative stress (OS), anti-oxidative parameters and body weight (BW) in high-fat-diet (HFD)/streptozotocin (STZ)-induced diabetic rats.

In this experimental study, 42 male Wistar rats were divided into diabetic (n=36) and non-diabetic (n=6) groups. The diabetic group (DG) was fed with a HFD for one month, then injected with intra-peritoneal single dose STZ (35 mg/kg BW). The DG was divided into 4 subgroups: [1] control (DC), [2] NS 1%/food, [3] NCLN 2%/food, [4] NS 1%/food + NCLN 2%/food. At the end of the 7th week, malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPX) levels and total antioxidant capacity (TAC) were measured.

The MDA level was decreased in the NCLN (p = 0.011) and NCLN+NS (p = 0.007) groups compared to the DC group. The GPX level increased in the NS and NCLN groups compared to the DC group (p = 0.014 and p = 0.034). In addition, the level of TAC demonstrated increase in the untreated DG and NS groups, as compared to the normal control (NC) group (p_DC = 0.031 and p_NS = 0.024). Moreover, in the NS+NCLN group, the level of SOD decreased in comparison to the NS and NCLN groups (p < 0.01). At the end of the 7th week, BW decreased in the diabetic subgroups in comparison to the NC group. Treatment with NS and/or NS+NCLN insignificantly prevented severe weight loss in the fifth week of the treatment.

According to results, separate supplementation of NS and NCLN was more beneficent on anti-oxidative parameters than concurrent supplementation of NS and NCLN.