Cannabisin A and B from hemp seed hulls improve glucose homeostasis by re-engaging insulin, leptin, and AMPK pathways via selective PTP1B inhibition.

BACKGROUND

Protein-tyrosine phosphatase 1B (PTP1B) is a master negative regulator of insulin and leptin receptor tyrosine kinase (RTK) signaling, and its chronic overactivation is strongly implicated in metabolic dysfunction. However, natural compounds capable of simultaneously inhibiting PTP1B and stimulating AMPK-the two major metabolic control nodes-remain scarce.

METHODS

Two phenylpropionamide lignanamides, Cannabisin A (CA) and Cannabisin B (CB), were isolated from hemp seed hulls and their functions were evaluated using a multimodal workflow integrating molecular docking (AutoDock 4.2), mixed-type Lineweaver-Burk kinetic modeling, and 100 ns molecular dynamics simulations (CHARMM36/TIP3P). Functional assays included in vitro models such as enzyme inhibition, insulin- and leptin-stimulated glucose uptake assays in C2C12 myotubes and hepatocytes (Hepa1C1C7 and primary hepatocytes from high-fat diet mice), and in vivo models such as a multiple low-dose streptozotocin (MLD-STZ)-induced diabetic mouse model (C57BL/6J). In silico analyses of human transcriptomic and GWAS data (GEO, HuGeAMP) were conducted to assess translational relevance. BioTransformer-based metabolic predictions were used to explore absorption feasibility.

RESULTS

CA and CB inhibited PTP1B with IC₅₀ values of 0.37 and 0.84 μM, respectively. Kinetic analysis demonstrated competitive-dominant (CA) and mixed-type (CB) inhibition, while MD simulations confirmed stable binding via catalytic-site residues (Asp48, Asp181, Arg221, Phe182). In PA-challenged C2C12 cells, both compounds restored glucose uptake and reactivated p-IRS-1, p-AKT, p-AMPK, and p-JAK2/STAT3. Similar recovery was observed in hepatocyte models, including suppression of SREBP-1c and enhancement of GLUT2 in primary HFD hepatocytes. In vivo, oral administration of CA/CB (1.5 and 3 mg/kg) in MLD-STZ diabetic mice improved fasting glucose in a dose-dependent manner, restored OGTT and ITT responses, and reactivated IRS-1/AKT/JAK2 signaling in skeletal muscle and AMPK/AKT/GLUT2 signaling in liver. Human transcriptome data and BioTransformer PK modeling showed that orally administered CA and CB can acquire sufficient polarity through O-demethylation and hydroxylation to exert PTP1B inhibitory effects in obesity and type 2 diabetes.

CONCLUSION

CA and CB are natural dual-target antidiabetic agents that inhibit PTP1B while activating AMPK, enabling coordinated re-engagement of insulin, leptin, and metabolic signaling. Their multi-tissue efficacy in vitro, ex vivo, and in vivo, combined with human-dataset alignment, highlights their translational potential as first-in-class insulin/leptin sensitizers derived from hemp seed hulls.