1. INTRODUCTION:

Gentiana, a cosmopolitan and important genus of the Gentianaceae family, comprises 400 species distributed among the world. The name Gentian is derived from the name of a king who was first identified the plant or healed by it, his name was Gentius. Dioscorides (the Greek physician) believed that the king Gentius was identified the properties of this plant and used the plant root in 167 BC by the incidence of Plague [1]. The liver performs a vital role in metabolism, secretion, storage, and detoxification of endogenous and exogenous substances.

Oxidative stress and free radicals enhance the severity of hepatic damage, which can be overcome by the antioxidant mechanism[2]. Plant extracts can be the best source of such antioxidants and mediate hepatoprotective activity. Further Earlier research ongentianaceae familyof flavonoids shows diverse activity such as antioxidant, anticancer, hepatoprotective etc. Gentiana luteais avalidated plant for its hepatoprotective activity. By considering above findings we perform molecular docking to confirm the hepatoprotective activity of flavonesGenkwanin, isovitexin, saponarin and apigenin present in the gentianaceae family.

2. MATERIALS AND METHODS:

CHEMDRAW ULTRA:

ChemDraw ultra is the industry standard structure, drawing suite for the serious chemist to draw accurate, chemically-aware structures for use in database queries, preparation of publication-quality graphics, and entry for modeling and other programs that require an electronic description of molecules and reactions as well as advanced prediction tools and full Web integration usingChemDrawAxtiveX/plugin. ChemDraw Ultra is the gold standard for chemical drawing, publicationand query preparation[3].

The structures are drawn and saved as mol file and further used for docking with FRED software.

Fig 1: Chemdraw protocol

PROTEIN DATA BANK(PDB):

The protein Data Bank (PDB) is a repository for the 3-D structural data of largebiological molecules, such as proteins and nucleic acids. The PDB is overseen by an organization called the Worldwide Protein Data Bank, wwPDB. The PDB is a key resource in areas of structural biology, such as structural genomics. Most major scientific journals such as the NIH in the USA, now require scientists to submit their structure data to the PDB. If the contents of the PDB are thought of as primary data, then there are hundreds of derived (i.e., secondary) database that categorize the data differently. For example, both SCOPand CATH categorize structures according to type of structure and assumed evolutionary relations ,GO categorize structures based on genes.

Fig 2: Protein targets from PDB

DOCKING PROGRAMS:

FRED:

Based on original scientific perspective and efficient computational algorithms, FRED is an accurate and fast docking program, typically processing 3 ligands in a second. For each, FRED exhaust exhaustively examines all possible poses with in the protein active site, filtering for shape complementarity and pharmacophoric features before selecting a single pose based upon a consensus of scoring functions. Ligands are then scored and ranked with a choice of structure-based or ligand-based scoring functions. When using a well-chosen set of conformers FRED predicts binding modes quite well. FRED is considered as a good docking engine for, structure based Virtual screening.

This OEDocking distribution contains three primary command line programs for docking molecules.

·         FredDocks multiconformer molecules using an exhaustive search algorithm.

·         Uses the structure of a target protein to dock and score molecules.

·         Uses one structure of the target protein.

·         Can utilize multiple processors via MPI on supported platforms

DOCKING PROCEDURE:

Step1: Load the receptor molecule using "MOLECULE" option.

Step2:

Select a specific place in the receptor molecule using "BOX” option.

Step3:.

To find the flexible way for drug in the receptor molecule using "TWEAK "option.

Step4:

To find the mutable residues in the receptor molecule using "SHAPE" option.

Step5:

The Docking value obtains by using the "TRIAL DOCKING" option

Step6:

Using "FINISH" option quit the FRED program.

Fig 3: Flow chart of docking procedure used in FRED software.

3. RESULTS AND DISCUSSION:

Table1 shows binding affinity of Genkwanin, Isovitexin, Saponarin and Apigenin with seven liver corrective targets 1JEN-Human-S-Adenosyl methionine decarboxylase, 2OOL-Human sperimidine synthase, 2PO2-Crystal structure of the alpha subunit of human-S-Adenosyl methionine Synthetase II, 1JBQ-Structure of human cystathionoine beta synthase a unique pyridoxal 5’ phosphate dependent heme protein, 2AZT-Crystal structure of H 176 N mutant of human glycine N-Methyl transferase, 2OBV-Crystal structure of the human-S-Adenosyl methionine synthase-I in complex with the product, 1093-Methionine adenosyl transferase complexed with ATP and a L-Methionine analogus.Genkwanin binds with five liver corrective targets and shown -167.53 with 1JEN as maximum binding energy.Isovitexinbinds with 4 targets with maximum binding energy of -21.09.Saponarin binds with four targets with maximum binding energy of -38.04. Apigenin, a common flavone has good hepatoprotective and binds with all the mentioned targets whose binding energy ranging from -03.25 to -37.98. Genkwanin, a flavonoid from Gentianaceae shows maximum affinity with 1JEN.Al-Qarawi A.A et al., reported the hepatoprotective activity of flavonoids [4] from Gentianaceae family. Fatemeh Mirzaeeet al., stated that flavonoids from Gentianakurrooextract exhibit liverprotectiveactivity.[5] Yadav. J. Pet al., testified the flavonoid apigenin is responsible for hepatoprotective activity [6]. By corroborate with the above references, we confirm the liver corrective property of flavonoid using in-silico methods.

Table 1: Binding Affinity of flavones with sevenliver corrective targets

Target Enzymes	Binding Affinity
Target Enzymes	Genkwanin	Isovitexin	Saponarin	Apigenin
1JEN	-167.53	16.54	42.47	-03.25
2OOL	36.66	36.66	-24.18	-34.05
2PO2	-21.09	-21.09	42.47	-37.98
IJBQ	16.54	16.54	-16.56	-03.25
2AZT	-9.83	-9.83	-16.37	-28.58
2OBV	-20.01	-20.1	2.5	-38.04
1O93	-6.06	-6.06	-22.1	-25.58

Fig 6: Genkwanin (4',5-Dihydroxy-7-methoxyflavone)

Fig 7: Genkwanin Binding affinity with seven liver corrective targets

Fig 8: Isovitexin(1S)-1,5-Anhydro-1-[5,7-dihydroxy-2-(4-hydroxyphenyl)-4-oxo-4H-chromen-6-yl]-D-glucitol

Fig 9: Isovitexin Binding affinity with seven liver corrective targets

Fig 10: Saponarin (Saponaretin-7-O-glucoside)

Fig 11: Saponarin Binding affinity with seven liver corrective targets

Fig 12: Apigenin (4′,5,7-trihydroxyflavone)

Fig 13: Apigenin Binding affinity with seven liver corrective targets

4. CONCLUSION:

It can be concluded that flavonoids, Genkwanin, Isovitexin, Saponarin andApigenin present in Gentianaceae family provided the scientific validation for liver corrective activityusing in-silico methods.

5. ACKNOWLEDGEMENT:

The author Dr.R.Arivukkarasu whole heartedly thank Dr.A.Thamaraiselvan, Head, Department of Chemistry, Thiyagarajar college, Madurai, Tamilnadu, 625009. The authors are thankful to Chairman and Secretary of Kovai Medical Centre Research and Educational Trust, Tamilnadu for providing facilities necessary for carrying out the work.

5. REFERENCES:

1. Mirzaee, F., Hosseini, A., Jouybari, H. B., Davoodi, A., &Azadbakht, M.Medicinal, biological and phytochemical properties of Gentiana species. Journal of Traditional and Complementary Medicine.2017,7(4), 400–408.

2. Lü, J.-M., Lin, P. H., Yao, Q., & Chen, C. Chemical and molecular mechanisms of antioxidants: experimental approaches and model systems. Journal of Cellular and Molecular Medicine.2009,14(4), 840–860.

3. ChemDraw Ultra 9.0. CambridgeSoft, 100 CambridgePark Drive, Cambridge, MA 02140. www. cambridgesoft.com. See Web site for pricing options. Kimberley R. Cousins Journal of the American Chemical Society.2005,127 (11), 4115-4116.

4. Al-Qarawi AA, Mousa HM, Ali BH, Abdel-Rahman H, El-Mougy SA. Protective effect of extracts from dates (Phoenix dactylifera L.) n carbon tetrachloride- induced hepatotoxicity in rats. Intern. J. Appl. Res. Vet. Med., 2004; 2: 176-180.

5. Fatemeh Mirzaee, Amirsaeed Hosseini, Hossein BakhshiJouybari, Ali Davoodi, and Mohammad Azadbakht.Medicinal, biological and phytochemical properties of GentianaspeciesJTradit Complement Med. 2017 Oct; 7(4): 400–408.

6. Yadav. J.P, Vedpriya Arya, Sanjay Yadav, Manju Panghal, Sandeep Kumar, Seema Dhankhar, Cassia occidentalis L.: A review on its ethnobotany, phytochemical and pharmacological profile Fitoterapia.2010,81;223–230.

Received on 15.01.2019 Modified on 09.02.2019

Res. J. Pharmacognosy and Phytochem. 2019; 11(2):49-53.

DOI: 10.5958/0975-4385.2019.00010.4