title: Enrichment of humic material with hydroxybenzene moieties intensifies its physiological effects on the nematode Caenorhabditis elegans.
abstract: Dissolved humic substances are taken up by organisms and interact on various molecular and biochemical levels. In the nematode Caenorhabditis elegans, such material can promote longevity and increase its reproductive capacity; moreover, the worms tend to stay for longer in humic-enriched environments. Here, we tested the hypothesis that the chemical enrichment of humic substances with hydroxybenzene moieties intensifies these physiological effects. Based on the leonardite humic acid HuminFeed (HF), we followed a polycondensation reaction in which this natural humic substance and a dihydroxybenzene (hydroquinone or benzoquinone) served as reaction partners. Several analytical methods showed the formation of the corresponding copolymers. The chemical modification boosted the antioxidant properties of HF both in vitro and in vivo. Humic substances enriched with hydroxybenzene moieties caused a significantly increased tolerance to thermal stress in C. elegans and extended its lifespan. Exposed nematodes showed delayed linear growth and onset of reproduction and a stronger pumping activity of the pharynx. Thus, treated nematodes act younger than they really are. In this feature the modified HF replicated the biological impact of hydroquinone-homopolymers and various plant polyphenol monomers, thereby supporting the hydroxybenzene moieties of humic substances as major effective structures for the physiological effects observed in C. elegans.
authors: Department of Biology, Freshwater and Stress Ecology, Humboldt-Universität zu Berlin, Berlin, Germany. ralph.menzel@biologie.hu-berlin.de
authors: Ralph
authors: R
authors: Menzel
authors: Stefanie
authors: S
authors: Menzel
authors: Sophie
authors: S
authors: Tiedt
authors: Georg
authors: G
authors: Kubsch
authors: Reinhardt
authors: R
authors: Stösser
authors: Hanno
authors: H
authors: Bährs
authors: Anke
authors: A
authors: Putschew
authors: Nadine
authors: N
authors: Saul
authors: Christian E W
authors: CE
authors: Steinberg
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000187:drug effects* / Q000254:growth & development; D002850:Chromatography, Gel; D004578:Electron Spin Resonance Spectroscopy; D006812:Humic Substances; D009682:Magnetic Resonance Spectroscopy; D008903:Minerals; D019800:Phenol
chemical_list: D006812:Humic Substances; D008903:Minerals; C568542:leonardite; D019800:Phenol