# Identification of Ginsentide-like Peptides from Cacao Beans with Oxidative Stress Protection

## TL;DR

Researchers discovered antioxidant peptides in cacao beans similar to ginseng's ginsentides, which may protect skin cells from oxidative damage.

## Contribution

Identification of ginsentide-like peptides (cocotides) in cacao with antioxidant and metal-binding properties.

## Key findings

- Cocotides tC1–tC12 are 33-residue methionine-rich peptides from cacao with structural similarity to ginsentides.
- Cocotide tC1 binds Fe3+ and acts as a strong antioxidant, protecting cells from oxidative stress.
- Cocotide tC1 affects mitochondrial and DNA repair pathways in skin keratinocytes.

## Abstract

Chocolate, derived from Theobroma cacao beans, is valued for its antioxidative benefits. However, little
is known about cacao-derived peptides that counter oxidative stress.
Ginsentides found in Panax ginseng are
cysteine-rich peptides that exhibit the “cure-all” health
benefits of ginseng by coordinating multiple physiological systems
to reduce cellular stress and damage. Here, we report the discovery
and characterization of ginsentide-like peptides from T. cacao beans and chocolate. By combining database
searches, isolation, and mass spectrometry analysis, we identified
a panel of 33-residue ginsentide-like peptides, termed cocotides tC1–tC12,
which are also rich in methionine. We isolated, purified, sequenced,
and chemically replicated cocotide tC1 for detailed characterization.
We showed that the highly compact tC1 is resistant to proteolytic
degradation, and its fluoresence-labeled form shows cell-penetrating
property. Modeling by AlphaFold3 revealed that cocotide tC1 and ginsentide
share a similar structural fold, but tC1 contains a metal-ion-binding
site composed of Met and Asn. We used N-terminal biotinylated tC1
and affinity-enrichment mass spectrometry to identify ferrochelatase
as one of its intracellular targets. Functional studies demonstrated
that cocotide tC1 is a Fe3+-binding peptide and a strong
antioxidant. Tandem-mass-tag-based quantitative proteomics analysis
showed that cocotide tC1 affects proteins associated with mitochondrial
functions, oxidative stress, cell proliferation and repair, protein
ubiquitination, and DNA damage in HaCaT keratinocytes. Altogether,
our findings indicate that cocotides are ginsentide-like peptides
with the potential to maintain cellular homeostasis and protect against
oxidative damage in skin keratinocytes.