Purpose: To evaluate the antioxidant effect of 80 % ethanol extract and its n-hexane and
dichloromethane fractions of Ya-hom Intajak, and its 47 medicinal plants components.
Methods: The 80 % ethanol extract and its n-hexane and dichloromethane fractions were investigated
on human low-density lipoprotein (LDL) peroxidation by thiobarbituric acid reactive substances (TBARS)
assay. Antioxidant effect was also determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical
scavenging capacity and ferric reducing antioxidant power (FRAP) assays.
Results: The extract of Ya-hom Intajak exhibited moderate DPPH scavenging activity with an IC
50 value
of 99.08 μg/ml and a FRAP value of 1.12 mmol FeSO4/g. Among the individual plants,
Terminalia
chebula
Retz.,
Caesalpinia sappan
L.,
Cinnamomum bejolghota
(Buch.-Ham.) and
Ci. verum
J.
Presl,
showed strong antioxidant activities.
T. chebula was the most potent plant in the DPPH assay while
Ca.
sappan had the highest FRAP value. Among the extracts, the dichloromethane fraction showed the
highest inhibitory effect on LDL peroxidation with a half maximal inhibitory concentration (IC
50) value
comparable to that of probucol (0.82 μg/ml). Pearson correlation analysis revealed that total phenolic
content (TPC) showed high positive correlations with FRAP (r = 0.908, p < 0.01) and DPPH activities (r
= 0.648, p < 0.01).
Conclusion: Ya-hom Intajak is a valuable source of natural antioxidants and has a potential application
as a cardiovascular protective formulation.
