Hypoglycemic activity of root water decoction, sesquiterpenoids, and one polysaccharide fraction from Psacalium decompositum in mice.

The hypoglycemic activity of Psacalium decompositum (Asteraceae) was investigated in fasting healthy mice and alloxan-diabetic mice. The freeze-dried water decoction significantly reduced the blood glucose in normal mice (from 50.9 +/- 4.7 to 32.5 +/- 3.1 mg/dl) and in mild diabetic mice (from 208.5 +/- 13.0 to 52.3 +/- 7.0 mg/dl), 240 min after intraperitoneal administration (P < 0.005). This preparation also diminished fasting glycemia in severe diabetic mice, but the effects were minor (from 394.4 +/- 9.4 to 289.3 +/- 39.5 mg/dl). The main sesquiterpenoid constituents from P. decompositum roots, cacalol, cacalone and maturin, as well as the transformation product cacalol acetate, did not show a hypoglycemic effect on healthy mice. Nevertheless, two polysaccharide fractions (F1 and F3) obtained from the freeze-dried water extract significantly reduced the fasting glycemia in healthy mice. The best results were obtained with the F1 fraction.