Preliminary Study On The Function Of Pigment Components Isolated From Hongqu

Monascus spp.,a kind of food and medicinal microbe,can produce various metabolites,such as Hongqu pigment,monacolins,γ-aminobutyric acid(GABA),which have been widely used as food fermentation starter,food colorant,function food.As an important metabolite of Monascus spp.,Hongqu pigment has been mainly used as a natural colorant in meat products and ferment soybean for centuries in China.Modern Research showed that,Hongqu pigment was a compound pigment including red,yellow and orange pigment,in which a variety of components were included.In recent years, many achievements such as extraction and separation,structure identification,stability of Hongqu pigment have been acquired,but system research on the functions of every component from Hongqu pigment have not been reported by now.In this paper,seven kinds of red pigment,four kinds of yellow pigment and two kinds of orange pigment were obtained by TLC(thin layer chromatography).Then antioxidant,antibacterial and anti-tumor functions of RP1,RP2,YP1,YP2,YP3,YP4,OP1,OP2 were studied.The main research contents were as follows:1.TLC was established to separate the components of Hongqu pigment.With 80%ethanol as extracting solvents,toluene,ethyl acetate and formic acid(7:3:1 v/v) was used as developing solvent of red pigment;with 80%ethanol as extracting solvents, yellow pigment was separated by using n-hexane,ethyl acetate and petroleum ether(30:17:5 v/v) as developing solvent;with ethyl acetate as extracting solvents,orange pigment were separated by using n-hexane,ethyl acetate and petroleum ether(30:17:5 v/v) as developing solvent,then scraped the silica gel alone with orange pigments, re-extracted with ethyl acetate,centrifuged,concentrated from supematant,orange pigment was separated again using toluene,ethyl acetate and formic acid(7:3:2 v/v).In these conditions,components of red,yellow and orange pigment can be separated effectively.Seven kinds of red pigment,four kinds of yellow pigment and two kinds of orange pigment were obtained.PT,RP,YP,OP,RP1,RP2,OP1 and OP2 were choosen as research materials for further experiment.The purification of RP1,RP2,YP1,YP2,YP3,YP4,OP1 and OP2 was checked by HPLC.The Chromatographic conditions were as follows:column(chromasil C18,5μm, 250mm×4.6mm);Mobile phase:acetonitrile and water(75:25 v/v);UV detectionλ=254 nm;flow rate(1.0 mL/min);column temperature(30℃);injection volume(30μL).In this condition,only one peak was on the HPLC chromatogram of every pigment component.It showed that the separated components obtained by TLC were puritied.2.Antioxidant function of pigment mixtures and pigment components was researched.Antioxidant function of PT,RP,YP,OP,RP1,RP2,OP1,OP2 was researched by three antioxidative models,·OH antioxidative test system,O₂^·- antioxidative test system and DPPH antioxidatve test system.The results revealed that red and orange pigment components had high antioxidative activities in the test models, among which Red Pigment No.2(RP2) had the highest antioxidative acitvity.RP2 at 40μg/mL scavenging rates on·OH and DPPH were 32%and 64%,respectively,20%and 41 %higher than those of Vc at the same concentration,respectively.Yellow pigment showed weak antioxidant function.3.Antibacterial function of pigment mixtures and pigment components was studied. The results indicted that orange components had fine inhibitory effect on gram-positive bacteria such as Staphylococcus aureus and Listeria monocytogenes;the inhibitory effect was stronger with the increasing concentration from 20μg/mL to 100μg/mL.Orange components had certain inhibition effect on gram-negative bacteria such as Escherichia coli,Shigella spp.and Salmonella spp.At 60μg/mL,inhibition rate of OP2 on Listeria monocytogenes was 38.49%,on Shigella spp.was 15.66%.Red pigment components also had certain inhibitory effect on gram-positive bacteria,but no inhibitory effect on gram-negative bacteria.At 60μg/mL,inhibition rate of RP2 on Listeria monocytogenes was 4.37%,on Shigella spp.was 9.2%.Yellow pigment showed no inhibitory effect.4.Anti-tumor function of pigment mixtures and pigment components was researched.The results revealed that the orange components especially OP2 had fine inhibitory effect on SP2/0,HepG2 and Hela cell,the effect was enhanced with the increasing concentration and time in 72 h,and in a concentration range of 0.05μg/mL～100μg/mL.At 48 h,100μg/mL,inhibition rate of OP2 on Hela cell was 36.84%,at 72 h was 44.96%.Red pigment components also had certain inhibitory effect on tumor cells, but inhibition rate was lower than orange components.At 100μg/mL,72 h,inhibition rate of RP2 on Hela cell was 32.83%,inhibition rate of OP2 was 44.96%.Yellow pigment showed weak inhibitory effect.