Corrigendum to "Toxicopathological, proinflammatory and stress response evaluation of Terminalia catappa extract in male Wistar rats" [Toxicol. Rep. 8 (2021) 1769-1776].

[This corrects the article DOI: 10.1016/j.toxrep.2021.10.005.].

Toxicopathological, proinflammatory and stress response evaluation of Terminalia catappa extract in male Wistar rats.

The present study was carried out to assess the oral safety, proinflammatory and stress response effect of Terminalia catappa aqueous leaf extract (TCA) in male Wistar rats. The acute and sub-acute oral toxicity of TCA was assessed using guidelines 423 and 407 of the Organisation for Economic Co-operation and Development (OECD), respectively. Signs of clinical toxicity, morbidity and mortality were observed. The biochemical, haematological, proinflammatory, stress response and histopathological indices were assessed. In the acute toxicity study, no sign of clinical toxicity, morbidity, and mortality was observed for TCA treatment, up to 5000 mg/kg bwt. However, in the sub-acute toxicity study, repeated daily TCA treatment significantly (p<0.05) altered the body weight gain, plasma alkaline phosphatase activity and albumin concentration. There were no obvious morphological and macroscopic alterations in the organs investigated. TCA appear not to elicit any proinflammatory, stress, systemic and organ toxic effect when utilised at the reported dose and time frame.

Protective Role of Picralima nitida Seed Extract in High-Fat High-Fructose-Fed Rats.

Picralima nitida is a therapeutic herb used in ethnomedicine for the management of several disease conditions including diabetes. This study examined the potential palliative effect of aqueous seed extract of Picralima nitida (APN) on dyslipidemia, hyperglycemia, oxidative stress, insulin resistance, and the expression of some metabolic genes in high-fat high-fructose-fed rats. Experimental rats (2 months old) were fed a control diet or a high-fat diet with 25% fructose (HFHF diet) in their drinking water for nine weeks. APN was administered orally during the last four weeks. Anthropometric and antioxidant parameters, lipid profile, plasma glucose, and insulin levels and the relative expression of some metabolic genes were assessed. APN caused a significant decrease (P < 0.05) in weight gained, body mass index, insulin resistance, plasma glucose, and insulin levels. High-density lipoprotein cholesterol level was significantly increased (P < 0.05), while triacylglycerol, cholesterol, low-density lipoprotein, cardiac index, atherogenic index, coronary artery index, and malondialdehyde levels in plasma and liver samples were also significantly decreased (P < 0.05) by APN at all experimental doses when compared to the group fed with an HFHF diet only. APN also significantly (P < 0.05) upregulated the relative expression of glucokinase, carnitine palmitoyltransferase-1 (CPT-1), and leptin at 400 mg/kg body weight when compared to the group fed with an HFHF diet only. This study showed that APN alleviated dyslipidemia, hyperglycemia, and oxidant effect associated with the intake of a high-fat high-fructose diet.

GC-MS Analysis and Inhibitory Evaluation of Terminalia catappa Leaf Extracts on Major Enzymes Linked to Diabetes.

Terminalia catappa leaves are used in managing both diabetes mellitus and its complications in Southwest Nigeria. However, its inhibitory activity on enzymes implicated in diabetes is not very clear. This study investigated the in vitro inhibitory properties and mode of inhibition of T. catappa leaf extracts on enzymes associated with diabetes. The study also identified some bioactive compounds as well as their molecular interaction in the binding pocket of these enzymes. Standard enzyme inhibition and kinetics assays were performed to determine the inhibitory effects of aqueous extract (TCA) and ethanol extract (TCE) of T. catappa leaves on α-glucosidase and α-amylase activities. The phytoconstituents of TCA and TCE were determined using GC-MS. Molecular docking of the phytocompounds was performed using Autodock Vina. TCA and TCE were the most potent inhibitors of α-glucosidase (IC50 = 3.28 ± 0.47 mg/mL) and α-amylase (IC50 = 0.24 ± 0.08 mg/mL), respectively. Both extracts displayed a mixed mode of inhibition on α-amylase activity, while mixed and noncompetitive modes of inhibition were demonstrated by TCA and TCE, respectively, on α-glucosidase activity. The GC-MS analytic chromatogram revealed the presence of 24 and 22 compounds in TCE and TCA, respectively, which were identified mainly as phenolic compounds, terpenes/terpenoids, fatty acids, and other phytochemicals. The selected compounds exhibited favourable interactions with the enzymes compared with acarbose. Overall, the inhibitory effect of T. catappa on α-amylase and α-glucosidase may be ascribed to the synergistic action of its rich phenolic and terpene composition giving credence to the hypoglycaemic nature of T. catappa leaves.