Neuroprotective and memory-enhancing effects of methanolic leaf extract of Peristrophe bicalyculata in rat model of type 2 diabetes mellitus

Anoka A Njan; Francisca O Adenuga; Abayomi M Ajayi; Olasubomi Sotunde; Mary O Ologe; Solomon O Olaoye; Ozlem Nazan Erdogan; Olugbenga E Iwalewa

doi:10.1016/j.heliyon.2020.e04011

Neuroprotective and memory-enhancing effects of methanolic leaf extract of Peristrophe bicalyculata in rat model of type 2 diabetes mellitus

Heliyon. 2020 May 22;6(5):e04011. doi: 10.1016/j.heliyon.2020.e04011. eCollection 2020 May.

Authors

Anoka A Njan¹, Francisca O Adenuga², Abayomi M Ajayi², Olasubomi Sotunde², Mary O Ologe¹, Solomon O Olaoye³, Ozlem Nazan Erdogan⁴, Olugbenga E Iwalewa²

Affiliations

¹ Department of Pharmacology and Therapeutics, Faculty of Basic Medical Sciences, University of Ilorin, Ilorin, Nigeria.
² Neuropharmacology and Ethnopharmacology Unit, Department of Pharmacology and Therapeutics, Faculty of Basic Medical Sciences, College of Medicine, University of Ibadan, Ibadan, Nigeria.
³ General Hospital, Kishi, Oyo State, Nigeria.
⁴ Department of Pharmacy Management, School of Pharmacy, Istanbul University, Beyazit, Istanbul 34116, Turkey.

Abstract

This study investigated the effect of methanolic leaf extract of Peristrophe Bicalyculata (MEPb) on type 2 diabetes mellitus (T2DM) associated cognitive decline in Wistar rats. 36 male rats weighing 130-200 g were assigned into 6 groups (n = 6) as follows: normal control, diabetic control, pioglitazone-treated diabetic and three MEPb-treated diabetic groups, type 2 diabetes mellitus was induced with low dose streptozocin (STZ) injection following 3 weeks of high fat diet (HFD) intake. Thirty days after diabetes induction, rats exhibited marked and persistent hyperglycemia, animals were treated with MEPb (50, 100 and 200 mg/kg) and pioglitazone (10 mg/kg) as standard. Morris water maze (MWM) test and Novel object recognition test (NORT) were used to assess learning and memory. Blood glucose level, oxidative stress makers, pro-inflammatory marker and acetylcholinestarase activities were analysed. Both MEPb and pioglitazone significantly (P < 0.05) reduced escape latency in treated animals compared to the diabetic control group in the MWM test. Methanolic leaf extract of Peristrophe bicalyculata and pioglitazone also significantly (P < 0.05) increased discrimination index in treated animals compared to the diabetic control group in the novel object recognition test. Serum, brain and liver MDA levels were significantly (P < 0.05) decreased in MEPb and pioglitazone treated rats compared to diabetic control. Serum and liver GSH as well as CAT levels were significantly (P < 0.05) increased while brain GSH and CAT levels shows apparent increase in MEPb and pioglitazone treated rats compared with diabetic control. Treatment with MEPb caused a significant (P < 0.05) decrease in brain nitrite level, interleukin 6 and acetylcholinesterase activity compared to diabetic control group. We conclude that Methanolic leaf extract of Peristrophe bicalyculata enhanced antioxidant capacity and prevented neuroinflammation, consequently improving brain neuronal cholinergic function in experimental animals.

Keywords: Alternative medicine; Diabetes; Diabetes mellitus; Endocrinology; Health sciences; Natural product chemistry; Neuroprotection; Oxidative stress; Peristrophe bicalyculata; Pharmaceutical science; Physiology; Pioglitazone.