Table 3.

Inhibitory effects of compounds 1–5 on protein tyrosine phosphatase 1B (PTP1B).

Compounds	Inhibitory Effects on PTP1B a
1	45.7% b
2	37.8% b
3	13.7% b
4	19.2 ± 1.0
5	24.3 ± 1.2
Ursolic acid b	3.1 ± 0.2

^a Values (IC₅₀ = μM) represent mean ± SD of triplicate experiments; ^b inhibition percentage at 50 μM.