Determination of flavonoids from Perilla frutescens var. japonica seeds and their inhibitory effect on aldose reductase

Perilla frutescens var. japonica (PF) is an annual aromatic herb has been consumed as a food ingredient and medicinal crop in Asian countries. To evaluate the therapeutic efficacy of aldose reductase (AR) inhibition, we tested the PF seeds. The stepwise polarities of PF were tested for AR inhibition, and we determined the CH 2 Cl 2 and EtOAc fractions to be good inhibitors (5.81 and 3.99 μg/mL, respectively). Compounds 1 – 3 were isolated from the CH 2 Cl 2 and EtOAc fractions and identified as luteolin ( 1 ), apigenin ( 2 ), and diosmetin ( 3 ) by physicochemical and spectroscopic data. Among them, luteolin ( 1 ) and apigenin ( 2 ) had high AR inhibitory activity (1.89 and 4.18 μM). Deulsaem, a variety of PF, was determined to have the highest flavonoid content among ten PF seeds tested (2.10 mg/g). This study suggests that PF could be utilized as a natural source to treat diabetic complications.