ABSTRACT:
The antioxidant and enzyme inhibition properties of the isoflavone genistein (
1
) and the alkaloid 11‐α‐hydroxyerysotrine (
2
) isolated from the leaves of
Erythrina speciosa
were assessed. Both compounds exhibited notable in vitro antioxidant activities; 11‐α‐hydroxyerysotrine (
2
) demonstrated stronger effects than genistein in DPPH, ABTS, CUPRAC, and FRAP assays. On the other hand, genistein (
1
) demonstrated a higher metal chelating activity than 11‐α‐hydroxyerysotrine (
2
). Regarding enzyme inhibition, 11‐α‐hydroxyerysotrine (
2
) inhibited both acetyl‐ (AchE) and butyryl‐ (BchE) cholinesterases, though to a lesser extent than the standard drug galanthamine. Both compounds inhibited tyrosinase, yet a good inhibition was observed for 11‐α‐hydroxyerysotrine (
2
) as compared to genistein (
1
). Genistein (
1
) showed a lower α‐amylase inhibition effect (IC
50
: 3.43 mg/mL,
p
< 0.05) compared to the standard acarbose (IC
50
: 0.80 mg/mL). Regarding α‐glucosidase inhibition, genistein (
1
) (IC
50
: 1.02 mg/mL,
p <
0.05) was more active than acarbose (IC
50
: 1.78 mg/mL). 11‐α‐Hydroxyerysotrine (
2
) exhibited lower α‐amylase (IC
50
: 4.09 mg/mL) and α‐glucosidase (IC
50
: 4.48 mg/mL) inhibition effects. The in vitro biological results were further supported by network pharmacology approaches on Alzheimer's disease and in silico studies performed on AChE, BChE, tyrosinase, α‐amylase, and
β
‐glucosidase enzymes. The results of our study suggest 11‐α‐hydroxyerysotrine as a potential drug candidate for further investigation in managing oxidative stress‐related conditions, Alzheimer's disease, and hyperpigmentation disorders.
