A new ester of fatty acid from a methanol extract of the whole plant of Amaranthus spinosus and its α-glucosidase inhibitory activity.

BACKGROUND

Amaranthus spinosus Linn. (Amaranthaceae), commonly known as "spiny pigweed", is used both in the Indian traditional system and in folk medicine to treat diabetes.

OBJECTIVE

The present study evaluates the scientific basis of antidiabetic activity of chloroform fraction of methanol extract of A. spinosus and of an isolated constituent of A. spinosus.

METHODS

HPLC analysis was performed to determine the purity and the amount of the constituent present in the plant extract. The yeast α-glucosidase inhibition technique was used to determine the antidiabetic activity of A. spinosus. Acarbose was used as a standard. An appropriate therapeutic approach for preventing diabetes mellitus and obesity is to retard the absorption of glucose by inhibition of α-glucosidase.

RESULTS

One novel fatty acid with strong α-glucosidase inhibitory activity - (14E, 18E, 22E, 26E) - methyl nonacosa-14, 18, 22, 26 tetraenoate [1] (IC50 value 6.52 µM/mL) and β-sitosterol [2] were purified. Compound 1 was found to be more potent than the methanol extract. HPLC quantitative analysis revealed that 0.15% of compound 1 and 0.06% of compound 2 were present in the plant extract.

CONCLUSIONS

This novel fatty acid can potentially be developed as a novel natural nutraceutical for the management of diabetes.