Tetracarpidium conophorum nuts (African walnuts) up-regulated adiponectin and PPAR-γ expressions with reciprocal suppression of TNF-α gene in obesity

J Cell Mol Med. 2024 Dec;28(24):e70086. doi: 10.1111/jcmm.70086.

Abstract

Tetracarpidium conophorum nuts are nutrient-dense Nigerian snacks associated with weight regulation. This study explores the nuts' impact on adipose tissue gene expression associated with low-grade inflammation. Ethanol whole extract (EWE), ethyl-acetate fraction (EAF) and the resulting residue (RES) were orally administered once daily to MSG-induced obese rats for 6 weeks (n = 6). Afterward, the RNA synthesis of inflammation-associated genes was measured, and GC-MS ligands in the extract and fractions were docked against their protein products in silico. The study found that in obese animals, PPAR-γ and Adiponectin expressions were down-regulated, while TNF-α was up-regulated, indicating an increased low-grade inflammatory process in adipose tissue. After 6-week oral treatments with EWE, EAF and RES, PPAR-γ and Adiponectin expressions increased significantly, while TNF-α expression decreased, suggesting the modulation of obesity-induced inflammation in adipose tissue. The in silico molecular docking analysis identified four lead compounds likely responsible for the observed effect, namely 6-Isopropenyl-4,8a-dimethyl-4a,5,67,8,8a-hexahydro-1H-naphthalen-2-one, 9,12,15-Octadecatrienoic methyl ester (Z,Z,Z), 9,12,15-Octadecatrienoic acid and Hexanedioic acid, bis(2-ethylhexyl). Of these compounds, 6-Isopropenyl-4,8a-dimethyl-4a,5,67,8,8a-hexahydro-1H-naphthalen-2-one demonstrated the strongest affinity to the binding cavities of PPARγ (-7.3 kcal/mol), Leptin (-5.2 kcal/mol), Adiponectin (-7.1 kcal/mol) and TNF-α (-6.3 kcal/mol) and was better than the standard drug, Orlistat (-6.7, -4.4, -6.8 and - 4.5 kcal/mol, respectively). The study reveals that T. conophorum nuts possess bioactive compounds/drug candidates that can exert positive modulation, at the molecular level, the low-grade inflammatory process associated with obesity, which normally facilitates the outset of complications.

Keywords: PPARγ; TNF‐α; Tetracarpidium conophorum nuts; adiponectin; obesity.

MeSH terms

  • Adiponectin* / genetics
  • Adiponectin* / metabolism
  • Adipose Tissue / drug effects
  • Adipose Tissue / metabolism
  • Animals
  • Gene Expression Regulation / drug effects
  • Juglans* / chemistry
  • Male
  • Molecular Docking Simulation*
  • Nuts* / chemistry
  • Obesity* / genetics
  • Obesity* / metabolism
  • PPAR gamma* / genetics
  • PPAR gamma* / metabolism
  • Plant Extracts* / chemistry
  • Plant Extracts* / pharmacology
  • Rats
  • Rats, Wistar
  • Tumor Necrosis Factor-alpha* / genetics
  • Tumor Necrosis Factor-alpha* / metabolism
  • Up-Regulation / drug effects

Substances

  • PPAR gamma
  • Tumor Necrosis Factor-alpha
  • Adiponectin
  • Plant Extracts