Piperine is known for its versatile therapeutic activity. It has been used for various disease conditions (e.g., cold, cough, etc.). Piperine is an alkaloid found in black pepper. It possesses various pharmacological actions like anti-inflammatory, anti-oxidant, anti-cholinergic, and anti-cancerous. The above-mentioned properties will be studied by selecting target proteins COX-2 protein, angiotensin converting enzyme, acetylcholineesterases, and survivin using computational docking study. This chapter explains the inhibition property of piperine against selected target protein from the results of docking studies. Based on the docking scores and protein-ligand interactions, piperine was found to bind well in the active site of the selected target proteins. It ensures the binding efficacy of piperine against selected target proteins. Docking scores and protein-ligand interactions plays an important role in its therapeutic activity.
TopIntroduction To Piperine
Piperine is an alkaloid widely present in the fruit of black pepper. Pepper is obtained from the medicinal plant, Piper nigerum and belongs to piperacea family (Figure 1) (Zoheir and Aftab, 2014). Piperine (Figure2) has wide therapeutic activity like anti-inflammatory, anti-oxidant property, antimicrobial activity, etc. (Vijaya kumar et al., 2014, Nisar ahmad et al., 2012). Many experimental studies revealed that it enhances oral bioavailability of certain drugs, nutrients and vaccines by inhibiting certain enzymes (Majeed and Prakash, 2000, Keith singletssry, 2010).
Figure 2. Piperine extracted from black pepper
TopStructure Of Piperine
The structure of piperine (Figure 3) consists of methylenedioxyphenyl ring, basic piperidine moiety attached through a carbonyl amide linkage and side chain with conjugated double bond.
TopTarget Proteins
Anti-Inflammatory
Experimental studies shows that the piperine controls the prostaglandin synthesis thereby control the cause of fever and severe pain. COX-2enzyme stimulates the release of prostaglandin. COX enzyme was selected to study the anti-inflammatory action of piperine. COX enzymes convert archidonic acid into prostaglandins. By blocking or inhibiting this enzyme, the synthesis of prostaglandins is blocked, which in turn relieves some of the effects of pain and fever (Subbaramaiah et al., 2000, Dubois etal.,1998).
Cyclooxygenase Enzyme-2 (COX-2)
COX-2 is absent from most normal tissues and in some specific regions in the uterus, kidney and brain. Inflammatory cytokines such as Tumor Necrosis Factor (TNF) and interleukins (IL) induced the COX-2 expression. Mutation in c-src, Ras, APC, p53 and STK11/Lkb1, also encourage COX-2 transcription (Christopher et al., 1999, Tsuji et al., 2001). Furthermore, COX-2 has been shown to be induced in response to chemotherapy and radiotherapy (Steinauer et al., 2000, Subbaramaiah, et al., 2000). Increased synthesis of prostaglandins in found in neoplasic and inflamed tissues due to COX-2 expression (Dubois et al., 1998, Subbaramaiah & Dannenberg, 2003). In most human cancers, COX-2 expression has been documented (Koki et al., 2002). Tumor cells, activated stromal fibroblasts, tumor infiltrating inflammatory cells and angiogenic endothelial cells can also express COX-2 (Masferrer et al., 2000)(Figure 4).
Figure 4. X-ray crystallographic structure of COX-2 with 1.9 Å resolution (PDB ID: 5f19)
The α-helix represents in red color, yellow color represents β-sheets, and green color represents loops.