Antioxidant and anti-inflammatory effects of Boswellia dalzielii and Hibiscus sabdariffa extracts in alloxan-induced diabetic rats

Abstract

Diabetes mellitus (DM) is one of the leading worldwide public health problems. It is characterized by hyperglycemia which induces oxidative stress and inflammation, both involved in the pathogenesis of diabetes. We previously showed that Boswellia dalzielii (BD) and Hibiscus sabdariffa (HS) extracts reduced hyperglycemia and hyperlipidemia in alloxan-induced diabetic rats. In the present study, we evaluated the antioxidant and anti-inflammatory activities of both plants in alloxan-induced diabetic rats. Two sets of experiments were conducted in male Wistar rats subjected to a single intraperitoneal injection of alloxan monohydrate (150 mg/kg, b. w.). Then, diabetic rats were daily administered with either BD (1st set of experiments) or HS (2nd set of experiments) at 100, 200, and 400 mg/kg orally for 21 consecutive days. Glibenclamide (10 mg/kg) was also administered as a reference drug. At the end of the study, the animals were anesthetized, and blood samples were collected from each animal. Then, oxidative stress and inflammatory biomarkers in the serum were determined. We found that treatment with BD and HS significantly reduced malondialdehyde (MDA) and enhanced the levels of reduced glutathione (GSH), superoxide dismutase (SOD), and catalase (CAT). These extracts also significantly decreased the inflammatory markers tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β). From the results obtained, it can therefore be concluded that BD and HS have the potential to being developed as natural sources of antioxidant and anti-inflammatory agents that can be used for the prevention or treatment of DM.

Keywords: Alloxan; Anti-inflammatory; Antioxidant; Boswellia dalzielii; Diabetes mellitus; Hibiscus sabdariffa.

Fig. 1

Effects of B. dalzielii extract on antioxidant biomarkers in alloxan-induced diabetic rats. A: MDA, B: GSH, C: SOD and D: CAT. Data are expressed as mean ± SEM (n = 6); $$$: p < 0.001 as compared to normal; **: p < 0.01, ***: p < 0.001 as compared to diabetics. NOR = normal control, DIA = diabetic control, BD100 = extract of B. dalzielii at 100 mg/kg, BD200 = extract of B. dalzielii at 200 mg/kg, BD400 = extract of B. dalzielii at 400 mg/kg, GLI = glibenclamide.

Fig. 2

Effects of B. dalzielii on serum inflammatory markers in alloxan-induced diabetic rats. A: TNFα, B: IL-6 and C: IL-1β. Data are expressed as mean ± SEM (n = 6); $$$: p < 0.001 as compared to normal; ***p < 0.001 as compared to diabetics. NOR = normal control, DIA = diabetic control, BD100 = extract of B. dalzielii at 100 mg/kg, BD200 = extract of B. dalzielii at 200 mg/kg, BD400 = extract of B. dalzielii at 400 mg/kg, GLI = glibenclamide.

Fig. 3

Effects of H. sabdariffa extract on antioxidant biomarkers in alloxan-induced diabetic rats. A: MDA, B: GSH, C: SOD and D: CAT. Data are expressed as mean ± SEM (n = 6); $$$: p < 0.001 as compared to normal; *: p < 0.05, **: p < 0.01, ***: p < 0.001 as compared to diabetics. NOR = normal control, DIA = diabetic control, HS100 = extract of H. sabdariffa at 100 mg/kg, HS200 = extract of H. sabdariffa at 200 mg/kg, HS400 = extract of H. sabdariffa at 400 mg/kg, GLI = glibenclamide.

Fig. 4

Effects of H. sabdariffa on serum inflammatory markers in alloxan-induced diabetic rats. A: TNFα, B: IL-6 and C: IL-1β. Data are expressed as mean ± SEM (n = 6); $$$: p < 0.001 as compared to normal; **p < 0.01 as compared to diabetics, ***p < 0.001 as compared to diabetics. NOR = normal control, DIA = diabetic control, HS100 = extract of H. sabdariffa at 100 mg/kg, HS200 = extract of H. sabdariffa at 200 mg/kg, HS400 = extract of H. sabdariffa at 400 mg/kg, GLI = glibenclamide.