Molecular Docking and Simulation Studies of Antidiabetic Agents Devised from Hypoglycemic Polypeptide-P of Momordica charantia

Diabetes mellitus termed as metabolic disorder is a collection of interlinked diseases and mainly body's inability to manage glucose level which leads to cardiovascular diseases, renal failure, neurological disorders, and many others. The drugs contemporarily used for diabetes have many inevitable side effects, and many of them have become less responsive to this multifactorial disorder. Momordica charantia commonly known as bitter gourd has many bioactive compounds with antidiabetic properties. The current study was designed to use computational methods to discover the best antidiabetic peptides devised from hypoglycemic polypeptide-P of M. charantia. The binding affinity and interaction patterns of peptides were evaluated against four receptor proteins (i.e., as agonists of insulin receptor and inhibitors of sodium-glucose cotransporter 1, dipeptidyl peptidase-IV, and glucose transporter 2) using molecular docking approach. A total of thirty-seven peptides were docked against these receptors. Out of which, top five peptides against each receptor were shortlisted based on their S-scores and binding affinities. Finally, the eight best ligands (i.e., LIVA, TSEP, EKAI, LKHA, EALF, VAEK, DFGAS, and EPGGGG) were selected as these ligands strictly followed Lipinski's rule of five and exhibited good ADMET profiling. One peptide EPGGGG showed activity towards insulin and SGLT1 receptor proteins. The top complex for both these targets was subjected to 50 ns of molecular dynamics simulations and MM-GBSA binding energy test that concluded both complexes as highly stable, and the intermolecular interactions were dominated by van der Waals and electrostatic energies. Overall, the selected ligands strongly fulfilled the drug-like evaluation criterion and proved to have good antidiabetic properties.

Triterpenoids

This review covers newly isolated triterpenoids that have been reported during 2015.

Cucurbitane triterpenoids from the fruit of Momordica charantia L. and their anti-hepatic fibrosis and anti-hepatoma activities

Momordica charantia L. (Cucurbitaceae) is a popular vegetable and traditional folk medicine, that has been used for hundreds of years. In this study, three undescribed cucurbitane-type triterpene glycosides furpyronecucurbitane A, goyaglycoside I and charantagenin F along with nine known compounds were isolated from the immature fruit of Momordica charantia L. Their structures were identified on the basis of extensive 1D, 2D NMR and HRESIMS spectroscopy analysis. All isolated compounds were examined for their anti-hepatic fibrosis activity against murine hepatic stellate cells (t-HSC/Cl-6) and anti-hepatoma activity against two kinds of liver cancer cell lines (HepG2 and Hep3B). Among them, karaviloside III exhibited excellent inhibitory activity against activated t-HSC/Cl-6 cells and cytotoxic activity against Hep3B and HepG2 cell lines with IC₅₀ values of 3.74 ± 0.13, 16.68 ± 2.07 and 4.12 ± 0.36 μM, respectively, which may potential to be developed as a chemotherapy agent for treatment hepatic fibrosis or carcinoma and protection against both diseases.

Antiaging of Cucurbitane Glycosides from Fruits of Momordica charantia L

Methanol extracts of Momordica charantia L. fruits are extensively studied for their antiaging activities. A new cucurbitane-type triterpenoid (1) and nine other known compounds (2–10) were isolated, and their structures were determined according to their spectroscopic characteristics and chemical derivatization. Biological evaluation was performed on a K6001 yeast bioassay system. The results indicated that all the compounds extended the replicative lifespan of K6001 yeast significantly. Compound 9 was used to investigate the mechanism involved in the increasing of the lifespan. The results indicated that this compound significantly increases the survival rate of yeast under oxidative stress and decreases ROS level. Further study on gene expression analysis showed that compound 9 could reduce the levels of UTH1 and SKN7 and increase SOD1 and SOD2 gene expression. In addition, it could not extend the lifespan of the yeast mutants of Uth1, Skn7, Sod1, and Sod2. These results demonstrate that compound 9 exerts antiaging effects via antioxidative stress and regulation of UTH1, SKN7, SOD1, and SOD2 yeast gene expression.