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Journal of Thai Traditional & Alternative Medicine Vol. 8 Nos. 2-3 May-December 2010 Òˆ˘
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Abstract
Effects of Medicinal Plant Extracts on Pancreatic Lipase and HMG-CoA reductase
Somchit Niumsakul*, Duangpen Pattamadilok*, Nanteetip Limpeanchob**, Kornkanok Ingkaninan**,
Prapai Wongsinkongman*
*Medicinal Plant Research Institute, Department of Medical Sciences, Nonthaburi 11000
**Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000

The present study was conducted to screen the potential lipid-lowering effect of medicinal plants. The
aim of this research was to perform in vitro assay to determine the inhibitory activity of plant extracts on two
enzymes of pancreatic lipase and HMG-CoA reductase that are important for lipid digestion and cholesterol
synthesis, respectively. The pancreatic lipase inhibitory activities were tested with nine Thai medicinal plants,
namely Nelumbo nucifera Gaertn. leaves, Psidium guajava L. leaves, Tiliacora triandra (Colebr.) Diels leaves,
Moringa oleifera Lamk. leaves, Averrhoa bilimbi L. leaves, Garcinia cowa Roxb. ex DC. leaves, Morinda citrifolia
L. leaves, and Gynostemma pentaphyllum (Thunb.) Makino. roots, and Alpinia galanga (L) Willd rhizomes.
The results showed that each crude extract demonstrated different potency inhibitory activities against pan-
creatic lipase represented by 50 percent inhibitory concentration (IC 50 ). Then, these crude extracts were fur-
ther purified using partition and column chromatography techniques. It was found that the partial purified
portion of the ethanolic extract of lotus leaves, N. nucifera Gaertn. (Nn-E3), showed the best activity against
the pancreatic lipase enzyme with IC 50 at 36.80 μg/ml. Orlistat was used as a positive control as a pancreatic
lipase inhibitor. Crude and partial purified extracts from five Thai medicinal plants, namely N. nucifera leaves,
G. cowa leaves, M. citrifolia leaves, P. guajava leaves, and A. bilimbi leaves, showed inhibitory activity against
HMG-CoA reductase where pravastatin was used as a positive control. Among these extracts, the most potent
ones were the partial purified portion of the ethanolic extract of G. cowa leaves (GC2) and the partial purified
portion of the ethanolic extract of N. nucifera leaves (Nn-E4), which completely inhibited HMG-CoA reduc-
tase enzyme (100% inhibition) at 10 μg/ml concentration. The results of this study will be useful to further
investigate and identify the active compounds from the potential herbs. Development of herbal products for
treatment of patients with hyperlipidemia may be possible in the future.
Key words: Lipid lowering, pancreatic lipase, HMG-CoA reductase