Abstract
Anabasis articulata, traditionally used to treat diabetes, is rich in saponin content. This study was
performed to investigate the agonistic effect of its saponins on peroxisome proliferator-activated
receptor-α and peroxisome proliferator-activated receptor-γ in human hepatoma (HepG2) cells to explore the possibility of the involvement of
these nuclear receptors in the mechanism of the antidiabetic effect of the plant.
Chemical investigation of the n-butanol fraction resulted in the isolation of three new and one known 30-noroleanane
triterpenoid saponins. The structures of the new compounds were elucidated as 3β-hydroxy,23-aldehyde-30-norolean-12,20(29)-dien-28-oic acid-28-O-β-D-glucopyranosyl ester (1), 3β-O-D-galactopyranosyl-23-aldehyde-30-norolean-12,20(29)-dien-28-oic acid-28-O-β-D-glucopyranosyl ester (2), and 3β-O-D-xylopyranosyl-30-norolean-12,20(29)-dien-28-oic acid 28-O-β-D-glucopyranosyl ester (3), while the known 30-nortriterpenoidal saponin was identified as boussingoside E
(4). Although, the isolated saponins (1 – 4) did not show > 1.5-fold activation of peroxisome proliferator-activated receptor-γ, but two of them (1 and 3) activated peroxisome proliferator-activated receptor-α to the higher extents of 2.25- and 1.86-fold, respectively. These results suggest
that the reported antidiabetic action of the isolated saponins may not solely involve
the activation of peroxisome proliferator-activated receptor-γ. However, the agonistic activity of the n-butanol fraction of A. articulata (1.71-fold induction) and two of its saponins (1 and 3) towards peroxisome proliferator-activated receptor-α may be beneficial in the cardiovascular condition that is closely associated with
diabetes and other metabolic disorders.
Key words
PPAR
α
- PPARγ -
Anabasis articulata
- antidiabetic - Amaranthaceae - triterpene saponins