Inhibition of Pancreatic Lipase by Culinary Plant Extracts
- 1. Department of Chemistry, Marmara University, Turkey
Abstract
Obesity is a strong risk factor for various diseases, such as hypertension, arteriosclerosis and diabetes. Therefore, an effective way to prevent obesity is to inhibit fat absorption from intestines. Pancreatic lipase is a key enzyme for lipid absorption. One of the approaches to reduce obesity is treatment with natural products. Many plants have been reported to inhibit lipase activity which is attributable to the presence of secondary metabolites such polyphenols, benzopyrones whose members include flavonoids, saponins, coumarins etc. are active inhibitors of pancreatic lipase. In our study using porcine pancreatic lipase, a series of plants were screened for their pancreatic lipase inhibitory activities. According to the results; green apple, green tea and avocado extracts had the highest antilipase activities. These plants based diets may be involved in weight control programs.
Citation
Danis O, Ogan A, Anbar D, Dursun BY, Demir S, et al. (2015) Inhibition of Pancreatic Lipase by Culinary Plant Extracts. Int J Plant Biol Res 3(2): 1038.
Keywords
• Obesity
• Lipase
• Lipase inhibition
• Anti-obesity plants
ABBREVIATIONS
PL: Pancreatic Lipase
INTRODUCTION
Obesity results from complex interactions of genetic, behavioral and environmental factors correlating with economic, social status and life styles [1-2]. Primary causes of obesity are insufficient exercise and un healthy food choices [3-4]. Only a few substances such as or list at (tetrahydrolipstatin) interact directly with lipases [5-7] but, causes unpleasant side effects on gastrointestinal system and kidneys [8]. A considerable interest has recently aroused to the potential of natural products for their health promotion and disease prevention [9-10]. Their action on multiple molecular targets, thus offers advantages over treatments with single chemicals. These products contain dietary phytochemicals with high potential their anti-obesity effects are mediated by regulation of various pathways, including lipid absorption [11-13].
Thus, the objective of this study was to examine the crude methanol extracts of 23 different parts (seeds, fruits, leaves, roots, stem, bark and whole part) of some culinary, herbal and aquatic plants assumed to induce body weight reduction in Turkish folk medicine for their pancreatic lipase (PL) inhibitory activities.
MATERIALS AND METHODS
Sampling of plant materials
The plant materials of the present study were gathered from local markets in ?stanbul,
Extraction of plants
To 0.5 g of dried and ground herbs and 2.0 g of ground fresh fruits and vegetables, 8 mL of water : methanol (1:1) mixture was added, treated with ultrasound for 10 min and macerated at room temperature for 24 h. The macerate was then treated with ultrasound for 10 min and the supernatant was separated by centrifugation (10 min, 3000 rpm). After filtration of the supernatant under reduced pressure, the filtrate was stored at -20 °C [16]. For avoiding lipase denaturation, extracts exhibiting low and high pH values were neutralized.
Inhibitory activity assay
The ability of the compounds to inhibit porcine pancreatic lipase was evaluated using previously reported methods with a minor modification [17]. Briefly, an enzyme buffer was prepared by the addition of 30 µL (10 units) of a solution of porcine pancreatic lipase (Sigma, St. Louis, MO) in 10 mM MOPS (morpholine propane sulphonic acid), and 1 mM EDTA, pH 6.8 to 850 µL of Tris buffer (100 Mm Tris-HCl and 5 mM CaCl2 , pH 7.0) and or list at (Roche, Switzerland)as a positive control with a concentration of 0.01 μg/mL was mixed with 880 µL of enzyme buffer, and incubated for 15 min at 37 o C. Then, 20 µL of the substrate solution (10 m Mp-nitrophenylbutyrate in dimethyl formamide) was added and the enzymatic reaction was allowed to proceed for 15 min at 37o C. Pancreatic lipase activity was determined by measuring the hydrolysis of p-nitrophenylbutyrateto p-nitrophenol at 405 nm using the Helios Zeta UV-Vis spectrometer (Thermo Sci., Waltham, MA, USA). Inhibition of lipase activity was expressed as the percentage decrease in the optical density when porcine pancreatic lipase was incubated with the test compound. All samples were assayed in triplicate and an inhibitor blank was prepared for each sample.
RESULTS AND DISCUSSION
Retardation of nutrient absorption and digestion may be used as an approach to manage obesity and related diseases. The methanol extracts of 23 culinary plants assumed to have weight reducing effect were screened for their PL inhibitory activities. The results were tabulated to show the list of plants that display 40% and over 40% inhibitory activity (Tables 1 & 2). Evaluating the results, seven extracts can be regarded as poor PL inhibitors. Among the extracts exhibiting over 40% inhibition, namely avocado (Persea americano) displayed 87%, green tea (Camellia simensis); 85% and apple (green skin; Granny Smith variety (Malusdomestica x M.sylvestris) 99% inhibitory activities, respectively. As there is a likelihood that the inhibitory effect observed could be due to the acidic plant extracts having pH values below 4.0, such as lemon, pineapple, grapefruit although had high inhibitory effects were excluded from the group. When the pH of these extracts was adjusted to 6-7 inhibitory activities decreased drastically. Lipase inhibitory activity of green tea is thoroughly examined in many reports [18,19]. Green tea is a rich source of polyphenols, Gondoin et al. [20] reported EC50 value as 25 µg GAE/ml for green tea hot water infusions which is consistent with our findings where as black tea displayed lower inhibition than green tea. In a study of Bose et al. [21] it was shown that the major flavanol(-)-epigallocatechin-3- gallate which is the most abundant polyphenol in green tea had decreased mesenteric fat weight of high fat-induced obesity mices. Avocado was also shown as a potent inhibitor of lipase as shown in a study of Ado et al. [22] and Rodriquez-Carpenaet al.[23], phenolic substances are widely distributed in flesh and seed of avocado,pyrogallol and protocatechuic acid are the main polyphenol contents of avocado. Apple polyphenol extracts are also potent inhibitors of PL[23]. Pectin extracted from apple (Maluspumila) showed 94.30% lipase inhibition in a study of Kumar et al. [24]. Oligomericprocyanidins were found as main active components for lipase inhibition [25] and lipase inhibitory activity exhibited by apple peels from different cultivars may be due to their ursenoic acid content [26].
According to our evaluation, a diet supported with avocado, green tea and green apple cultivar “Granny Smith” may help to inhibit lipase and weight control.
CONCLUSION
A diet focusing on avocado, green tea and green apple may reduce body weight and compounds from these plants may be developed as anti-obesity clinical products.
