Isolation of a New Trypsin Inhibitor from the Faba Bean (Vicia faba cv. Giza 843) with Potential Medicinal Applications

Evandro      Fei Fang; Abdallah      Abd Elazeem Hassanien; Jack      Ho Wong; Clara      Shui Fern Bah; Saeed      Saad Soliman; Tzi      Bun Ng

Abstract

A new 15-kDa Bowman-Birk type trypsin inhibitor (termed VFTI-G1) was isolated from the seeds of Faba bean (Vicia faba cv. Giza 843) using cation exchange chromatography on an SP-Sepharose column, anion exchange chromatography on Q-Sepharose and Mono Q columns, and finally size exclusion chromatography on a Superdex 75 column. VFTI-G1 manifested significant antiproteolytic activity against trypsin (5761 BAEE units/mg, Ki 20.4×10-9 M), but only a slight chymotrypsin inhibitory activity ( < < 10 BTEE units/mg). The suitable environment to sustain its trypsin inhibitory activity was at temperatures below 60 °C and at pH 7. Its trypsin inhibitory activity was inhibited by the reducing agent dithiothreitol in a dose-dependent manner, indicating the significance of intact disulfide bonds to the trypsin inhibitory activity. It inhibited HIV-1 reverse transcriptase (RT) activity with an IC50 of about 0.76 μM. Furthermore, VFTI-G1 showed specific antiproliferative activity toward HepG2 hepatoma cells by inducing chromatin condensation and cell apoptosis. The HIV-1 RT inhibitory activity of VFTI-G1 and its specific antiproliferative activity toward Hep G2 cells may find medical applications.

Keywords: Apoptosis, hepatoma, purification, trypsin inhibitor, Vicia faba, 15-kDa Bowman-Birk type trypsin inhibitor, VFTI-G1, HepG2 hepatoma cells, HIV-1 RT inhibitory activity, trypsin inhibitors, hemagglutinin, alphagalactosidase, procyanidins, Giza843 Trypsin Inhibitor, trypsin inhibitor (VFTI-G1), Tris-HCl buffer, Soybean trypsin inhibitor, Assays of HIV-1 Reverse Transcriptase (RT), Antiproliferative Activity, Nuclear Morphological Changes, Annexin-V, Propidium Iodide (PI) Staining, Antifungal Activity, chymotrypsin inhibitory activity, Anti-HIV-1 RT, Antitumor Activities of VFTI-G1, Hep G2 cells, escalating concentrations, HIV-1 reverse transcriptase, Antiproliferative activity of VFTI-G1, trypsin inhibitory activities, type proteinase inhibitor, homologous retroviral protease, Apoptosis-inducing activity of VFTI-G1, Annexin V-FITC/ PI, cytometry analysis, chymotrypsin-like activity, gastric carcinoma MKN-1, alpha-1-antitrypsin (AAT), Rhizobium-legume interactionApoptosis, hepatoma, purification, trypsin inhibitor, Vicia faba, 15-kDa Bowman-Birk type trypsin inhibitor, VFTI-G1, HepG2 hepatoma cells, HIV-1 RT inhibitory activity, trypsin inhibitors, hemagglutinin, alphagalactosidase, procyanidins, Giza843 Trypsin Inhibitor, trypsin inhibitor (VFTI-G1), Tris-HCl buffer, Soybean trypsin inhibitor, Assays of HIV-1 Reverse Transcriptase (RT), Antiproliferative Activity, Nuclear Morphological Changes, Annexin-V, Propidium Iodide (PI) Staining, Antifungal Activity, chymotrypsin inhibitory activity, Anti-HIV-1 RT, Antitumor Activities of VFTI-G1, Hep G2 cells, escalating concentrations, HIV-1 reverse transcriptase, Antiproliferative activity of VFTI-G1, trypsin inhibitory activities, type proteinase inhibitor, homologous retroviral protease, Apoptosis-inducing activity of VFTI-G1, Annexin V-FITC/ PI, cytometry analysis, chymotrypsin-like activity, gastric carcinoma MKN-1, alpha-1-antitrypsin (AAT), Rhizobium-legume interaction