Antihyperglycaemic Activity of Standardised Ethanolic Extract of Swietenia macrophylla King Seeds on Goto-Kakizaki Type 2 Diabetic Rats

TL;DR

This study shows that an ethanolic extract from Swietenia macrophylla seeds helps reduce blood sugar in diabetic rats, supporting its traditional use as an anti-diabetic remedy.

Contribution

The study validates a method to quantify key bioactive compounds in the extract and demonstrates its antihyperglycemic effects in a rat model of Type 2 diabetes.

Findings

A 500 mg/kg dose of SMEE significantly reduced fasting blood glucose levels in diabetic rats.

The extract improved glucose regulation during oral glucose tolerance tests over eight days.

The RP-HPLC method accurately quantified swietenine and 3,6-O,O diacetyl swietenolide in the extract.

Abstract

Swietenia macrophylla (S. macrophylla), commonly known as “sky fruit”, belongs to the Meliaceae family and is predominantly distributed in the neotropical areas of Central America, Southern Asia and the Pacific region. The plant has a rich tradition of being utilised for its anti-diabetic properties and other health benefits. This study focused on the S. macrophylla seeds ethanolic extract (SMEE) to explore its antihyperglycemic effects in Goto-Kakizaki (GK) Type 2 diabetic rats. Bioactive compounds were extracted using maceration, and a reversed-phase high-performance liquid chromatography (RPHPLC) method was validated to separate two limonoids, swietenine and 3,6-O,O diacetyl swietenolide, from the extracts. The 500 mg/kg SMEE dosage significantly reduced fasting blood glucose levels, making it the selected treatment dose. The SMEE group consistently improved glucose regulation during oral glucose tolerance test (OGTT) on the first (9.88 ± 0.69 mmol/L) and eighth (6.12 ± 0.30 mmol/L) days, showing lower initial fasting blood glucose levels. The RP-HPLC method validation confirmed high linearity, ensuring precise quantification within the 1.56 μg/mL to 200 μg/mL range for swietenine and 3,6-O,O diacetyl swietenolide. The content of these compounds in 1 mg of SMEE was determined as 27.5 μg (2.75%) and 14.53 μg (1.45%), respectively. This study provides robust evidence supporting the antihyperglycaemic properties of S. macrophylla seeds. Future studies could evaluate the long-term metabolic effects of S. macrophylla extract on glucose metabolism, oxidative stress and liver function.

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