The Inhibitory Activity of Camellia oleifera Leaves Extract against 5α-Reductase and Chemical Components Analysis

Objective: To study the 5α-Reductase (5α-R) inhibitory activity of Camellia oleifera (COLE) leaves extract, and to analyze the material basis of its extract with high 5α-R inhibitory activity. Method: Firstly, a 5α-R enzymatic reaction system was established, and the 5α-R activity was measured by high performance phase chromatography(HPLC). The extracts of Camellia oleifera leaves with different solvents were prepared, and the 5α-R inhibitory activity was measured and compared, with Dutasteride as the positive drug; 5α-R inhibition rate was used to select the best solvent of Camellia oleifera leaves extract; Folin-Ciocalteu method and sodium nitrite-aluminum nitrate-sodium hydroxide color method was used to determine the total phenol and total flavonoid content of each extract, and correlation between the 5α-R inhibition rate of each extract and the content of polyphenol and flavonoids was analyzed; ultra-high performance liquid chromatography tandem triple quadrupole time-of-flight mass spectrometry (UPLC-TRIPLE TOF-MS/MS) was used to analyze the chemical components of extract with the highest 5α-R inhibitory activity. Results: The enzymatic reaction system was determined as follows: 300 μL of phosphate buffer, 500 μL of 0.76 mg/mL enzyme extract, 50 μL of 2.0 mmol/L testosterone, 50 μL of sample, 2.0 mmol/L of NADPH 100 μL, reacted at 37 ℃ for 30 min. Different Camellia oleifera extracts had different levels of 5α-R inhibitory activity. The 50% ethanol extract of Camellia oleifera had the highest inhibition rate, reaching 49.77% ± 4.43%. Taking 5α-R inhibitory effect as an indicator, 50% ethanolwas the best extraction solvent. Pearson correlation analysis showed that the 5α-R inhibition rate of each Camellia oleifera extract was highly correlated with the content of total phenols and total flavonoids (r>0.6, r>0.8); UPLC-TRIPLE TOF-MS/MS analysis 22 kinds substances, five of which were reported that had the 5α-R inhibitory activity. Conclusion: The extract of Camellia oleifera leaves had 5α-R inhibitory activity and was a potential 5α-R inhibitor. Its inhibitory activity was related to the content of polyphenols and flavonoids. Quercetin, rutin, catechin, 3-O-galloyl-4, 6, -(S)-hexahydroxybiphth-aloyl-α/β-D-glucopyranose (Gemin D), 3, 4, 6-tri-O-galloyl-α/β-D-glucopyranose (GAG), might be the material basis for COLE to exert 5α-R inhibitory activity.