Abstract:
Bioassay-guided fractionation of an ethanolic extract of
Ochrosia borbonica led to the isolation of two known pyridocarbazole alkaloids, ellipticine (
1 ) and 9-methoxyellipticine (
2 ), and six known monoterpenoid indole alkaloids (
3-8 ). Lipid-lowering assay in 3T3-L1 cell model revealed that
1 and
2 could significantly inhibit the lipid droplet formation (EC
50=0.41 and 0.92 μmol·L
-1, respectively) and lower triglyceride levels by 50%-60% at the concentration of 1 μmol·L
-1, being more potent than the positive drug luteolin (EC
50=2.63 μmol·L
-1). A mechanistic study indicated that
1 and
2 could intercalate into supercoiled DNA, which consequently inhibited the mitotic clonal expansion of 3T3-L1 cells at the early differentiation phase, leading to the retardance of following adipogenesis and lipogenesis. These findings suggest that
1 and
2 may serve as promising leads for further development of anti-obesity drugs.