The anti-obesity potential of sigmoidin A

During the last few decades, the prevalence of obesity in the western world has dramatically increased with epidemic proportions. Hand in hand with this statistic, the incidences of obesity-linked diseases such as diabetes are increasing with pandemic rate. The search for novel drugs and nutritional intervention approaches for obesity is now of significant importance.

The anti-obesity potential of eriodictyol (ERD) and its close structural analogue, sigmoidin A (SGN), were evaluated. SGN was isolated from Erythrina abyssinica Lam. ex DC. (Fabaceae).

Concentrations between 300 and 0.1 µM of test samples and reference drugs made in three-fold dilutions were tested for enzyme inhibitory effects. The major obesity target, pancreatic lipase, was used to test the anti-obesity potential while the selective effects of the compounds were determined through assessments of effects on α-glucosidase.

The inhibitory effect of SGN on pancreatic lipase (IC₅₀, 4.5 ± 0.87 µM) was 30-times greater than that of ERD (IC₅₀, 134 ± 19.39 µM) while their effect on α-glucosidase enzyme was comparable (IC₅₀ value of 62.5 ± 9.47 and 57.5 ± 13.15 µM). The anti-obesity drug, orlistat, inhibited pancreatic lipase with an IC₅₀ value of 0.3 ± 0.04 µM, while the anti-diabetic drug, acarbose, inhibited α-glucosidase with an IC₅₀ value of 190.6 ± 16.05 µM.

Although less active than the standard anti-obesity drug, orlistat, the observed activity indicated that prenylation of the flavonoid skeleton potently enhances anti-lipase activity.

Such groups of flavonoids need to be further investigated for their therapeutic and nutritional benefit in combating obesity problems.