In Silico Identification of Peptides with PPARγ Antagonism in Protein Hydrolysate from Rice (Oryza sativa).

At least half the population in industrialized countries suffers from obesity due to excessive accumulation of adipose tissue. Recently, rice (Oryza sativa) proteins have been considered valuable sources of bioactive peptides with antiadipogenic potential. In this study, the digestibility and bioaccessibility in vitro of a novel protein concentrate (NPC) from rice were determined through INFOGEST protocols. Furthermore, the presence of prolamin and glutelin was evaluated via SDS-PAGE, and their potential digestibility and the bioactivity of ligands against peroxisome proliferator-activated receptor gamma (PPARγ) were explored by BIOPEP UWM and HPEPDOCK. For the top candidates, molecular simulations were conducted using Autodock Vina to evaluate their binding affinity against the antiadipogenic region of PPARγ and their pharmacokinetics and drug-likeness using SwissADME. Simulating gastrointestinal digestion showed a recovery of 43.07% and 35.92% bioaccessibility. The protein banding patterns showed the presence of prolamin (57 kDa) and glutelin (12 kDa) as the predominant proteins in the NPC. The in silico hydrolysis predicts the presence of three and two peptide ligands in glutelin and prolamin fraction, respectively, with high affinity for PPARγ (≤160). Finally, the docking studies suggest that the prolamin-derived peptides QSPVF and QPY (-6.38 & -5.61 kcal/mol, respectively) have expected affinity and pharmacokinetic properties to act as potential PPARγ antagonists. Hence, according to our results, bioactive peptides resulting from NPC rice consumption might have an antiadipogenic effect via PPARγ interactions, but further experimentation and validation in suitable biological model systems are necessary to gain more insight and to provide evidence to support our in silico findings.

HPLC Method Validation for Jatropha dioica Extracts Analysis.

Jatropha dioica is a popular plant used in Mexican herbal medicine to treat several diseases. Cytotoxicity, antimicrobial and antiviral activities have been reported for root extracts, while riolozatrione, 6-epi-riolozatrione, citlalitrione and jatrophatrione, among others, have been identified as the principal components. In this work, an HPLC/DAD method for the analysis of riolozatrione and other major compounds in extracts of different polarities was validated. The analysis was carried out on an AccQ-Tag column with a water-acetonitrile mixture as mobile phase. Flow rate was 0.2 mL/min, and the separation was carried out in gradient mode with UV detection set at 254 nm. The resulting method showed good reproducibility in both retention times and peak areas of riolozatrione, 6-epi-riolozatrione, citlalitrione and jatrophatrione, with relative standard variations lower than 4.5 and 10.5% respectively. In addition, this method provides a good performance for riolozatrione quantitation, with recoveries between 102 and 108% and RSDs lower than 2.5%. The polarity of the extracting solvent did not affect the performance of the chromatographic method. The developed method was applied for the analysis and quantification of riolozatrione in extracts of Jatropha dioica collected in several seasonal stages and years (2014-2017).