# Hydrogen-rich water-alleviated ultraviolet-B-triggered oxidative damage is partially associated with the manipulation of the metabolism of (iso)flavonoids and antioxidant defence in Medicago sativa.
> 水素水処理がアルファルファのUVB誘発酸化傷害を軽減する：（イソ）フラボノイド代謝と抗酸化防御機構の関与


## Abstract

In alfalfa (Medicago sativa) seedlings exposed to ultraviolet-B (UVB) irradiation, endogenous H2 production was elevated, and pretreatment with hydrogen-rich water (HRW) reproduced this response. HRW pretreatment substantially reduced lipid peroxidation and reactive oxygen species (ROS) accumulation, and alleviated growth inhibition caused by UVB stress. Metabolic profiling via UPLC-MS identified 40 (iso)flavonoid compounds in UVB-exposed plants, of which 22 were upregulated by HRW, with isoflavone and flavanone subfamilies showing the most pronounced increases. Specific compounds elevated included daidzein, formononetin glucoside-malonate, naringenin, and garbanzol, among others. In vitro assays confirmed that the HRW-modulated (iso)flavonoid profile exhibited enhanced ROS-scavenging and antioxidant capacity. Transcriptional analysis revealed that HRW further amplified UVB-induced upregulation of (iso)flavonoid biosynthetic genes, while activities and transcript levels of key antioxidant enzymes were also increased. These findings collectively indicate that HRW-conferred UVB tolerance in alfalfa is partially mediated through coordinated regulation of (iso)flavonoid metabolism and antioxidant defense systems.

### Mechanism

HRW amplifies transcription of (iso)flavonoid biosynthetic genes, increasing accumulation of isoflavone and flavanone subclasses that scavenge ROS, while simultaneously inducing antioxidant enzyme activity, thereby reducing UVB-induced oxidative stress in alfalfa.

## Bibliographic

- **Authors**: Xie Y, Zhang W, Duan X, Dai C, Zhang YJ, Cui W, et al.
- **Journal**: Funct Plant Biol
- **Year**: 2015
- **PMID**: [32480752](https://pubmed.ncbi.nlm.nih.gov/32480752/)
- **DOI**: [10.1071/FP15204](https://doi.org/10.1071/FP15204)
- **Study type**: other
- **Delivery route**: hydrogen-rich water
- **Effect reported**: positive

## Delivery context

Hydrogen-rich water is a low-risk delivery route, but the achievable systemic hydrogen dose is bounded. For clinical applications, inhalation is the most efficient route; inhalation, however, carries explosion risk, and concentration matters (empirical LFL of 10% applies to inhalation environments; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

## Safety notes

Hydrogen-rich water is a low-risk delivery route, but the achievable systemic hydrogen dose is bounded. For clinical applications, inhalation is the most efficient route; inhalation, however, carries explosion risk, and concentration matters (empirical LFL of 10% applies to inhalation environments; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 32480752. https://h2-papers.org/en/papers/32480752
> **Source**: PubMed PMID [32480752](https://pubmed.ncbi.nlm.nih.gov/32480752/)