# In Vivo Atlas of Neuroprotective Cyclic Dipeptides Derived from Food Gelatin Using Peptidomics and Feature-Based Molecular Networking

## TL;DR

This study identifies neuroprotective cyclic dipeptides from gelatin in the body using advanced analytical methods.

## Contribution

A novel strategy combining peptidomics and molecular networking to identify bioactive cyclic dipeptides from gelatin in vivo.

## Key findings

- Cyclodipeptides (CDPs) from gelatin were first identified in serum using feature-based molecular networking.
- Twelve proline/hydroxyproline-CDPs showed neuroprotective effects in HT-22 cells, with cyclo-(Hyp-Ala) being the most effective.
- CDPs showed prolonged retention in the body and varied distributions in gastrointestinal and serum compartments.

## Abstract

Food gelatin is widely used in the food industry, yet
its in vivo active substances remain unclear. This
study proposes
a strategy for in vivo research on donkey-hide gelatin
that integrates peptidomics, feature-based molecular networks (FBMN),
and targeted spatiotemporal metabolomics to address the above issues.
Peptidomics based on database searching revealed a time-dependent
decrease in peptide numbers and an increase in oligopeptide ratios
in the small intestine over 24 h, with oligopeptides increasing from
50 to 100%. FBMN visualization in serum allowed the first identification
of cyclodipeptides (CDPs) originating from gelatin. Targeted metabolomics
detected 35 CDPs in serum, with 12 proline/hydroxyproline-CDPs being
particularly abundant. Spatiotemporal analysis revealed different
distributions of CDPs in the gastrointestinal and serum, and they
showed prolonged retention in vivo. Twelve proline/hydroxyproline-CDPs
displayed neuroprotective effects in HT-22 cells, with cyclo­(Hyp-Ala)
showing the highest efficacy. This study presents a strategy for identifying
exogenous bioactives in complex matrices, applicable to other food
proteins.