The Determination of Quercetin in Plectranthus Scutellarioides (L) R.BR. Leves Extract and its In Silico Study on Histamine H4 Receptor

Abstract

Plectanthus Scutellaroides (L) R.Br., or jawer kotok, Family Lamiaceae, growts widely in Indonesia, and has a long history of therapeutic usage in Indonesia traditional jamu to cure various diseases. The brownish purple leaves of Plecranthus contain alkaloids, saponin, flavonoids, tannin, volatile oils, and quercetin which has been proven to exert antiinflammatory activity. In this research which has been proven to exert antiinflammatory activity. I this research, a determination of quercetin in plecranthus leaves extract was performed and followed by a study of this interaction with histamine H4 receptor to understand its-inflamatory. The dry leaves were macerated by using a mixture of methanol and water (1:1) for 48 hours and the solvent was evaporated at low temperature (40-50⁰C). Analysis of quercetin in the extract was performed by using reversed-phase HPLC method LC-10AT VP (shimadzu), Alantis Hilicsilica C18 (Waters) 150 mm x 4.6 mm, 5 µm as stationary phase and a mixture of acetanitrile, phosphoric acid, and methanol (40:50:10), flow rate 0.8 mL/ minute. In sillco study of quercetin with histamine H4 receptor was performed by using AutoDock Tools 3.0.5. Histamine H4receptor (H4R) belongs to G protein-coupled receptor which is involved in arthritis, astma, and inflammations. The 3D structure model of H4R was bulit by using MODELLER 9v7. Quercetin contained in Plecranthus extract was 0.05%. This compound interated H4R via hydrogen bond formation with (2.006A) and Glu 182 (2.048 A), and van der waals interaction with Trp90, Leu91, Asp94, Tyr95, Phe 168, Thr 178, Ser179, Tyr319, Phe344, and Tyr340, therefore Plecrathus leaves extract might a chance to be used as histamine H4 receptor inhibitor.