Abstract:
The stem and root bark of Anthostema aubryanum (Baill, family, Euphorbiaceae) are extensively used in African
ethnomedicine for treating and managing a number of disease conditions which include inflammation, pain,
wounds, boil, dyspepsia and a variety of other disease conditions. Although the chemistry and pharmacology of
many phytoconstituents isolated from the family are fairly established, the plant has not yet been investigated. In the
present study, an alkaloidal extract of the root bark was demonstrated to display a time- and dose (30-300 mg/Kg
p.o.)-dependent anti-inflammatory effect in rats (ED50=13.84±0.011) compared to diclofenac (ED50=1.994±0.002).
Comprehensive chromatographic and spectroscopic analyses have led to the isolation and characterization of two
major anti-inflammatory and antioxidant alkaloids as 5-methoxycanthin-6-one and canthin-6-one. The dose (10-100
mg/Kg p.o.)-dependent anti-inflammatory effects of the 5-methoxycanthin-6-one (ED50=60.84±0.010) and canthin-
6-one (ED50=96.64±0.012) were either comparable or significant as the positive control, diclofenac. The radical
scavenging activity of the alkaloidal extract (IC50=23.12±0.010), 5-methoxycanthin-6-one (IC50=27.62±0.090) and
canthin-6-one (IC50=33.60±0.011) was also significantly comparable to Vitamin E (IC50=8.605±0.002) used as
positive control. Canthinone alkaloids are well-known constituents of the Simaroubaceae and Rutaceae and display
a wide range of biological activities. However, they are being reported as constituents of the Euphorbiaceae here
for the first time.
