1. In vitro evaluation of inhibitory effects
of plant extracts on lipase activity
Joke Swaegers & Mitch Vrolijkx
Introduction
Obesity is the epidemic of the 21st century. It is a common
disorder of carbohydrate and fat metabolism characterized by
excess fat deposition. A strategy in the treatment of obesity is
to decrease the intake of fat. In humans, pancreatic lipase plays
a key role in splitting triglycerides into bioavailable glycerol and
fatty acids in the gastro-intestinal tract.
Materials and methods
Results and discussion
Conclusion
The list of different plant, herb and fruit extracts used in this
study is shown in the tabel below.
The results of the present study demonstrated that different
plant extracts exhibit an inhibitory effect on the lipase activity.
More research on the influence of extract concentration,
incubation time, and other natural products is necessary. In
addition, it will be important to identify the responsible
inhibiting compounds in the extracts.
Promotor research: Dr. ir. De Preter V
Management & Technologie, campus Gasthuisberg, Herestraat 49, 3000 Leuven
Family Scientific name Trivial name Used part of the plant
Rosaceae Malus domestica Apple Completely
Rutaceae Citrus limon Lemon Pulp
Solanaceae Capsicum annuum Chili pepper Completely
Vitaceae Vitis vinifera White grape Completely
Solanaceae Solanum lycopersicum Tomatoes Completely
Alliaceae Allium cepa Onion Completely
Ericaceae Vaccinium corymbosum Blueberry Completely
Grossulariaceae Ribes rubrum Red currant Completely
Rosaceae Rubus ideaus Raspberry Completely
Rosaceae Rubus fruticosus Blackberry Completely
Theaceae Camellia sinensis Black tea Leaves
Theaceae Camellia sinensis Green tea Leaves
Theaceae en
ericaceae
Camellia sinensis en
Vaccinium corymbosum
Blue fruit tea
Leaves and the fruit of the
blue berry
Rubiaceae Coffea arabica Coffee Beans
Forest
fruits
4-methylumbelliferyl oleate 4-methylumbelifferone
lipase
The inhibition of lipase activity was determined by measuring
the conversion reaction from 4-methylum-belliferyl oleate (4-
MUO) to 4-methylumbelliferone (4-Mubel) using a fluorimetric
method (λexcitation=375nm, λemission=449,6 nm).
0
20
40
60
80
100
Percentageofinhibition(%)
Finally, the anti-lipase activity of different plant extract was
evaluated and compared with the known inhibitor Orlistat. As
expected, an inhibitory effect of 59% of Orilstat was found on
lipase activity. Remarkably, some plant extracts had an even
higher inhibition than Orlistat. Overall, tea and coffee extracts
exhibited a stronger inhibition up to 100%. A surprising result in
this study was the effect of onion extract, a common eaten
vegetable in Belgium, which had a very high lipase inhibition.
No other study has demonstrated this before.
y = 6,6069x + 10,396
R² = 0,9558
y = 12,894x + 13,308
R² = 0,9169
0
10
20
30
40
50
60
70
80
90
100
0,00 2,00 4,00 6,00
intensity
Concentration 4-MUO [µmol/l]
21°C
37°C
First, the effect of temperature on the conversion of 4-MUO to
4-MUbel was investigated. More 4-MUBel was released from 4-
MUO at 37°C as compared to 21°C. In addition, the optimal
concentration lipase was determined and set at 100 µg/ml.
The inhibition of lipase may be an effective method for
managing obesity. Orlistat is a registered drug that functions as
a lipase inhibitor by inhibiting the absorption of dietary fats.
However, several studies have found that some natural
products may also inhibit pancreatic lipase activity. The aim of
the present study is to evaluate whether plant extracts have
inhibitory effects on pancreatic lipase.