Study Chemical Constituents And Phenol Oxidase Inhibiting Activities Of Juglans Mandshurica Bark

The bark of Juglans mandshurica Maxim. belongs to Juglandaceae family, Juglans genus. In addition to walnut nuts, bark, fruit, leaves the root bark can also be used as folk medicine with antioxidant, anti-tumor and significant insecticidal activity.In this work, the research were mainly focused on the chemical constituents of Juglans mandshurica Maxim, bark and also its inhibition on phenol oxidase activity. Preliminary experiments which is study PO inhibiting activities of extracted components from petroleum ether, chloroform, n-butanol and water. It found that the greatest inhibition is n-butyl alcohol extracted components, so this experiment studies the n-butyl alcohol extraction composition and their activities. This experiment alcohol extract of Juglans mandshurica Maxim. bark was isolated using silica gel, ODS, MCI, Sephadex LH-20 and preHPLC chromatography. Combined with physicochemical properties and modern spectroscopy,21 compounds were identified as following:seven flavonoids compounds, quercetin-3-O-a-L-rhamnoside (8), kaempferol-3-O-a-L-rhamnoside (9), dihydroquercetin (11), kaempferol (15), soybean isoflavone (18), dihydrokaempferol (20), naringenin (21); eight phenolic acids compounds,3,3’-dimethoxyellagic acid (1), ellagic acid (4),4’-dihydro phaseic acid (12), gallic acid (13),3,3’-dimethoxyellagic acid-4’-O-β-D-xylose (14), methyl gallate (16), ethyl gallate (17),4,4’-dimethoxyellagic acid (19); three diarylheptanoids compounds, rhoiptelol (6), (3R)-3’,4"-epoxy-1-(4-hydroxyphenyl)-7-(3-methoxyphenyl) heptan-3-ol (7), rhoiptelol C (10); juglanthrthracenoside A (2), regiolone (3) and P-sitosterol (5), in which, compounds 12,14,16,17,18,19 were isolated from Julans genus for the first time.On the other hand, the inhibitory effect of phenol oxidase of isolated flavonoid, ellagic acid and diarylheptane was researched. The results showed that all of these three kinds of compounds have inhibitory effect on PO. In which, the inhibitory effect of rhoiptelol C, dihydrokaempferol and naringenin are 5 to 10 times more than positive control-arbutin. The inhibitors of PO have been widely used in medical pesticide, food, cosmetic and other fields, current work have great significance from theory and practice opinion.