Broussonetia The Chemical Composition And Biological Activity

Broussonetia Vent, Moraceae, is adeciduous tree or shrub, There are four species in China: B. papyrifera; B. kazinoki; B. kaempferi; B. kurzii.Broussonetia papyrifera (Linn.) grows resourcefully in Asia and Pacific countries such as China, Thailand and USA. The roots, barks leaves and fruits of this plant are all used in traditional chinese medicines.This study focuses on researching the chemical constitutions and bioactives of B. papyrifera. The results and innovation can be summarized as follow:1 Phytochemistry investigationThe methanol extract from the leaves and fruits of B. papyrifera was defatted with petroleum ether. The defatted extract (BPE) was absorbed using columns of macroporous resin D101, then eluted with aqueous ethanol of different concentration to yield five parts respectively.By the phytochemical analysis, 27 compounds were isolated using silica gel column, Sephadex LH-20 column and high-speed counter-current chromatography (HSCCC). 12 compounds were identified, and 10 of them were phenolic compounds. Their structures were identified by a combination of spectroscopic methods as 7-hydroxy-6-methoxycoumarin (F01), apigenin (5,7,4′-trihydroxyflavone) (F02), luteolin (5,7,3′,4′-tetrahydroxyflavone) (F03), scopoletin (7-hydroxycoumain) (L01), rutin (L02), luteolin-7-O-β-D-glucopyranoside (L03), 5,4′-dihydroxy- 7-methoxyl- flavone (L04), quercetin (5,7,3′,4′-tetrahydroxyflavonol) (L05), kaempferol (5,7,4′- trihydroxyflavonol) (L06), apigenin-7-O-β-D-glucopyranoside (L12)2 Studies on biological activities2.1 Determination of radical scavenging and antioxidantThe antioxidant activities of each part and the compounds were assayed by using in vitro methods like 1,1-diphenyl-2-picrylhydrazyl (DPPH·) assay (DRA), superoxide anion scavenging(SRA), hydroxyl radical scavenging (SRA) and total antioxidant capacity assay (TAC) to illustrate the structure-activity relationship between flavone and radical scavenging activity.The results suggested that FE-2 (DRA, 2.678 mg/l; HRA, 89.267 U/mg; SRA, 12.125 U/mg; TAC, 26.387 U/mg), LE-2 (DRA, 2.050 mg/l; HRA, 98.349 U/mg; SRA, 9.687 U/mg; TAC, 30.307 U/mg) showed better activities comparing with Vc. Of all the compounds, F03 and L05 displayed better activities comparing with Vc. So FE-2 and LE-2 were the active parts, F03and L05 were the effective compounds.2.2 Determination of inhibiting tyrosinaseThe tyrosinase-inhibiting activities of each part and the compounds were assayed to find more effective tyrosinase inhibitors and illustrate the structure-activity relationship. Luteolin (F03) isolated was used as standard.The results suggested that FE-3 (IC50 = 0.351 mg/l), LE-2 (IC50=0.391 mg/l), F01 (IC50 = 0.223 mM/l), F03 (IC50 = 0.231 mM/l), L03 (IC50 = 0.252 mM/l) and L05 (IC50 = 0.251 mM/l) displayed better activities. So FE-3 and LE-2 were the active parts, and L08 was the most effective compound.