Researchers from the Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences and their collaborators have identified a group of natural compounds from Stahlianthus involucratus, a medicinal herb native to southwestern China, that have anti-obesity potential.

The study, published in Bioorganic Chemistry, identified oxygenated, aromatic cadinane-type sesquiterpenoid dimers (CSDs) as bioactive constituents of the herb.

Using bioactivity-guided fractionation, the researchers isolated thirteen CSDs (1–13) from the JST-80% fraction of the ethanol extract of S. involucratus. Eight of these compounds (1–8) were new. Notably, compounds 1–3 have unique carbon-deficient skeletons and rare pyran-4-one C-ring structures.

Anti-adipogenic screening in 3T3-L1 preadipocytes revealed that compound 13 (parviflorene A) exhibited the strongest anti-adipogenic activity. Due to its high abundance in the plant, compound 13 was selected for further study.

In vivo experiments showed that orally administering compound 13 significantly improved obesity-related phenotypes in mice fed a high-fat diet by inhibiting weight gain and lowering serum triglyceride and cholesterol levels while alleviating hepatic steatosis and white adipose tissue hypertrophy. No significant hepatorenal toxicity was observed.

Mechanistically, compound 13 simultaneously inhibited fat synthesis and enhanced energy-burning thermogenesis.

The researchers proposed plausible biosynthetic pathways for these novel compounds, suggesting that they originate from cadinane-type sesquiterpenoid monomers via hetero-Diels–Alder reactions followed by various oxidation and decarboxylation.

This study is the first to reveal that aromatic cadinane-type sesquiterpenoid dimers are the primary active components in Stahlianthus involucratus, validating their potential as functional foods or drugs for obesity intervention.

"Our study expands the application of traditional Chinese medicine in metabolic diseases and provides a scientific basis for developing natural product-based anti-obesity strategies," said JI Kailong of XTBG.

Stahlianthus involucratus (Image by LU Jianmei)

Stahlianthus involucratus (Image by LU Jianmei)