Abstract:

The process conditions of ultrasonic-assisted enzymatic hydrolysis of flavonoids from camellia seed cake were optimized by orthogonal tests, and the enzymatic reaction system of 5α-reductase type Ⅱ in vitro was established to investigate the activity of camellia seed cake extract on 5α-reductase type Ⅱ. Moreover, the molecular docking model was used to simulate and predict the inhibition of 5α-reductase type Ⅱ by flavonoids from camellia seed cake, which provided the basis for the development of camellia seed cake and other plants. The results show that the extraction process optimized by the orthogonal experiment is as follows: 50 ℃, 50% ethanol, adjusting pH to 6 for enzymatic hydrolysis, adding 2.5% of camellia seed cake for enzymatic hydrolysis for 1 h, and then ultrasonically extracting at 45 kHz, 50 ℃ for 30 min. The yield of total flavonoids is （10.13±0.32） mg/g under this optimized condition. It is preliminarily deduced that camellia seed cake mainly contains kaempferol 3-O-[2-O-β-D-galactose-6-O-α-L-rhamnose]-β-D-glucoside and kaempferol 3-O-[2-O-β-D-xylose-6-O-α-L-rhamnose]-β-D-glucoside by chromatography coupled with mass spectrometry （UPLC Q-TOF MS）. Camellia seed cake extract has a certain inhibitory activity of 5α-reductase type Ⅱ. Through molecular docking simulation, it is speculated that the binding energy of kaempferol 3-O-[2-O-β-D-xylose-6-O-α-L-rhamnose]-β-D-glucoside to 5α-reductase is close to that of finasteride, which is considered as the main active molecule of 5α-reductase inhibitor in the total flavonoid of camellia seed cake.

Key words: ultrasound-assisted enzymatic hydrolysis, 5α-reductase type Ⅱ, camellia seed cake, molecular docking