Gramine (Donaxine), a natural indole alkaloid, present in several plant species, acts as an active adiponectin receptor (AdipoR) agonist, with IC50s of 3.2 and 4.2 μM for AdipoR2 and AdipoR1, respectively. Gramine is also a human and mouse β2-Adrenergic receptor (β2-AR) agonist. Gramine has anti-tumor, anti-viral and anti-inflammatory properties.

Assay of protein kinase C: Protein kinase C is arrayed by measuring 32PI transferred from [gamma-32PI] ATP to lysine-rich histone type Ill-s. The reaction mixture (80 μL) contained 50 mM Tris-HCI. pH 7.4, 100 μM CaCl2, 10 mM MgCI2, 37.5 μL/mL histone type Ill-s, 10 μM [gamma-32PI] ATP (1250 cpm/pmol), 31 μM bovine brain phosphatidylserine and 0.5 μM 1,2 sn-dioleylglycerol. Fifteen μL of purified PKC (final concentration in assay 0.38 μg/mL) is added to the incubation mixture. After 10 min at 30°C, the reaction is stopped by addition of 30 μL of casein 30 mg/mL and 0.9 ml of 12% trichloroacetic acid. The acid precipitable material is collected by centrifugation, dissolved in 1N NaOH (100μL) and precipitated again with 1 ml of 12% trichloroacetic acid. The pellet is dissolved in 1N NaOH (100μL) and 32P incorporation is measured by scintillation counting in Aquasol.