Hormon sensitive lipase inhibitor
Introduction: Obesity is one of the most dangerous risk factors related to widespread cardiovascular diseases as well as diabetis prevalence by increasing insulin resistance amonge all population world wide. Huge efforts done by pharmaceutical industries to manage obesity related complications through search about different molecular targets in humans that play a role in reducing endogenous cholesterole production or reducing exogenous cholesterole absorption, however antidiabetic agents prove their efficacy ,but their side effects guide to natural products Hormone sensitive lipase is an intracellular lipase that responsible a bout converting cholesterol esters and triglyceride to free cholesterol and fatty acid, respictively, which make its inhibition an interesting mechanism to reduce levels of circulated and stored triglecyride and cholesterol in human body. As its name indicate ;its activation depend on hormons : epinephrin,glucagone and ACTH mainly ,and to lesser extent being activated via cyclic AMP-dependent protein kinase
Natural Resources of HSL inhibitors:
• Aerial parts of Rosemary,( Rosmarinus officinalis);which previously investigated for theraputic benefit in ( common cold , as antispasmodic,hypoglycemic, diuretic ,anticarcinogenic,and antioxidant) These biological activities have been attributed to different constituents of rosemary such caffeic acid ,rosmarinic acid (RA) and chlorogenic acid (CA) • Methanolic extractions of different ground plant material result with different percentages of inhibitory activity as shown below:
Plant name Family % of inhibition at 200 µg/ml IC50 (µg/ml) Anagallis arvensis L Primulaceae 42.3 751.9 Anchusa italica Retz. Boraginaceae 57.41 132.8 Chrysanthemum coronarium L. Asteraceae 49.7 463.7 Cinnamomum verum J. Presl Lauraceae 25.8 –
Cleome africana Botsch. Capparaceae 53.8 168.9 Convolvulus althaeoides L. Convolvulaceae 22.55 –
Eryngium creticum Lam. Apiaceae 18.68 - Glaucium aleppicum Boiss. & Hausskn. ex Boiss . Papaveraceae 41 289.7 Haplophyllum buxbaumii (Poir.) G. Don. Rutaceae 60.1 101.3 Helianthemum ledifolium Mill. Cistaceae 1.2 –
Hypecoum dimidiatum Delile Papaveraceae 25.0 – Hypericum triquetrifolium Turra Clusiaceae 31.92 828.6
Linum pubescens Banks & Sol. Linaceae 25.5 – Majorana syriaca (L.) Kostel. Lamiaceae 17.42 –
Malva nicaeensis All. Malvaceae 55.8 51.07
Mentha spicata L. Lamiaceae 37.33 421.3
Methodology:
Materials: Plant material as mentioned above ,and other materials for comparison : pancreatic lipase type II; orlistat; collagenase, protease inhibitor tablet; rosmarinic acid; chlorogenic ; caffeic acid; and gallic acid
Plant extraction : Using methanolic extraction by putting plant material in specific concentration of methanol to be cooled later then centifuged and collect solid residue for analysis testing
Extraction of HSL enzyme : Using adipose tissue of rat to obtain isolated fat cells (major storage site of HSL enzyme) ,these cells added to media that enhance fat cells floatening to be decanted and washed then subjected for further dilutions and proccessing.
Quantification of HSL activity: Using spectrophotometric assay HSL inhibition by test extract: HSL inhibition done by adding once prepared plant extract ,another by adding pure inhibitory compound and the inhibitory activity of HSL measured with(test inclination) and without (blank inclination) extract. HSL should be incubated previously with each particular inhibitor for at least 3 min at 37°C before adding the substrate The following formula used to measure % of inhibition: % of inhbition = (1 –( Test Inclination/ Blank Inclination))
- The same test applied on pancreatic lipase to compare it with HSL
Results and conclusion: Natutral products actually prove their efficacy in inhibiting HSL, which made them highly candidate to be develop to clinical products for managing obesity, and reducing insulin resistance Lipase inhibitory activity of extracts were tested on both HSL and pancreatic lipase, the rosemary extract was more effective against PL than that of HSL,extra information is summarized in the following tableL:
The inhibitory effect of these extracts is dose dependent in which its ranges within (25-400 µg/ml). The dose effect relationship result as follow: