[01] Ubaoji Kingsley, Department of Biochemistry and Molecular Biology, Nasarawa State University, Keffi, Nigeria; Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka, Nigeria. [02] Nwozor Kingsley, Department of Chemistry, Federal University Gusau, Gusau, Nigeria. [03] Anaetoh Chisom, Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka, Nigeria. [04] Ekuma Emmanuel, Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka, Nigeria. [05] Ineh Mary, Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka, Nigeria. [06] Adibe Chioma, Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka, Nigeria. [07] Nmoye Patience, Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka, Nigeria. [08] James Chinedu, Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka, Nigeria. [09] Nwaokike Godwin, Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka, Nigeria. [10] Udechukwu Obianuju, Department of Applied Biochemistry, Nnamdi Azikiwe University, Awka, Nigeria. [11] Alaekwe Ikenna, Department of Chemistry, Federal University Gusau, Gusau, Nigeria.

The anti-diabetic and antioxidant activities of the methanolic extract of Tetrapleura tetraptera fruits and seeds were investigated. The dried fruits and seeds of T. tetraptera were separately collected, grounded and extracted in methanol and water. Alpha–amylase inhibitors are used to achieve greater control over hyperglycemia in type-II diabetes mellitus. The present study tends to screen alpha amylase inhibitors from natural sources like plants (T. tetraptera) in order to minimize the toxicity and side effects of the inhibitors currently used to control hyperglycemia. Similarly, the retinol, ascorbic acid, tocopherol, terpinoids, phenols, flavonoids, beta-carotene and lycopene contents of T. tetraptera were also studied using standard methods. Inhibition of Fe²⁺-induced lipid peroxidation in brain homogenate was evaluated on the seed, as free radical scavenging activity was determined on the fruit using DPPH (2,2-diphenyl-1-picryhydrazyl) method. Results for alpha-amylase inhibition show that the %inhibition (IC₅₀) of T. tetraptera fruit as compared to the standard acarbose were 4.276ug/ml and 4.087ug/ml respectively. Whereas that of T. tetraptera seed as compared to standard acarbose were 15110.00ug/ml and 521.89ug/ml respectively. T. tetraptera fruit showed high free radical scavenging activity as against the standard Butylhydroxyanisol (BHA) with effective concentrations (EC₅₀) of 423.467ug/ml and 307.50ug/ml for extract and BHA respectively. Similarly, T. tetraptera seed had a good inhibition on lipid peroxidation as compared to standard BHA with %inhibition (IC₅₀) of 575.75ug/ml and 728.75ug/ml for sample and standard respectively. In addition, results also showed that T. tetraptera contained 7.92±65mg/100mg and 7 ascorbic acid, 6.34±0.65mg/100g retinol, 4.86±0.57mg/100g tocopherol, 11.19±4.72GAE/100g phenols, 0.48±0.22CE/100g flavonoids, 18.67mg/g β-carotene and 6.825mg/100g terpenoids. These results suggest that T. tetraptera fruits and seeds can be used in the management of diabetes as well as oxidative stress reduction.

Tetrapleura tetraptera, Antidiabetes, Antioxidant, Alpha-Amylase, Hyperglycermia

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