Research On Phenolic Acids And Their Biological Activity In Kandelia Obovata And Aegiceras Corniculatum

Kandelia obovata Sheue,Liu&Yong and Aegiceras corniculatum(Linn.)Blanco,two most widely distributed species of mangrove plants in Fujian Province,contain phenolics,terpenes,polysaccharides,alkaloids,fatty acids,stetols et al for which used as folk medicine.The phenolic acids is one kind of phenolics,mainly derived from shikimic acid metabolism.Cereal grains,vegetables,fruits and tea usually have most of their phenolic acids in the free form or form ester and glycoside linkages with other components.Phenolic acids display strong bioactivities such as antioxidant,anticancer,antivirus and anti-inflammation et al.Recently,research on the form of phenolic acids are becoming hotspots.Many studies showed that the forms of compounds in mangrove plants are related to fighting for extreme stresses.Thereby,study on different forms of phenolic acids and their biological activities in Ko and Ac has important significance for better understanding and development of mangrove plants.In this research,four different forms of phenolic acids were extracted from stem,leaves and fruits,namely free,solubly esterified,solubly glycosided and insoluble-bound phenolic acids.The total phenolic contents,the composition and distribution of four forms of phenolic acids were all determined.The results showed that the TPC of free,esterified,glycosided and insoluble-bound parts were in the ranges of 2.51?-7.21,2.72?10.54,2.10?12.05 and 1.43?11.10 mg GAE/g DW;The composition and content distribution of four forms of phenolic acids and their antioxidant activity are various in different parts of Ko and Ac.It is rather remarkable that chlorogenic acid was the principal phenolic acid in free form in all parts of Ko while gallic acid was principal phenolic acid in esterified form in stem and leaves of Ac.From the perspective of tumor prevention,the antioxidant activity of phenolic acids in different forms was evaluated by different methods(DPPH analysis,ABTS analysis,FRAP analysis,Protection effects on DNA breakage)and the correlation analysis between TPC and antioxidant activity was also assessed.Meanwhile,different forms of phenolic acids were studied for their effects on nitrite,proliferation of human hepatocarcinoma SMMC-7721 cells and murine B16 melanoma cells.The results showed that antioxidant activity of four forms of phenolic acids in leaves of Ko was all in the decreasing order of glycosided>esterified>free>insoluble-bound and completely opposite trend was found in the stem,namely insoluble-bound>free>esterified>glycosided.The strongest antioxidant activity in the fruits of Ko was glycosided phenolic acids while in the stem and leaves were esterified phenolic acids which were all in agreement with their total phenolic contents;Whether Ko or Ac,it's easy to observe that TPC was highly positively correlated to antioxidant activity;The protective rates of phenolic acids in different forms of leaves,stems and fruits of Ko on supercoiled plasmid DNA breakage were in the range of 36.36±3.85%?56.44±1.54%,while 45.05±4.26%?71.06±3.40%in leaves and stems of Ac;Comparing with VE,four forms of phenolic acids had strong capabilities of eliminating nitrite in simulated human gastric juice A and B and the capability in gastric juice A is generally better than gastric juice B;Free,esterified,glycosided phenolic acids in stem and esterified,glycosided phenolic acids in leaves of Ko have strong inhibitory effect on SMMC-7721 cells,the IC50 values were 234.88± 18.17?176.69± 12.75?215.121±23.16?145.12±13.45 and 125.25±20.27 ?g/mL,respectively.Meanwhile,esterified and glycosided phenolic acids in stem and leaves of Ac have strong inhibitory effect on B16 melanoma cells,the IC50 values were 208.32±23.26?105.26±5.33,52.33±7.26 and 299.13±10.96 ?g/mL,respectively.The effects of different forms of phenolic acids on mushroom tyrosinase were further studied.Firstly,the monophenolase acticity of mushroom tyrosinase was determined and it was found that glycosided phenolic acids in leaves and esterified phenolic acids in fruits of Ko could inhibite it while other forms of phenolic acids in stem and leaves and free phenolic acids in fruits of Ko could activate it.Four forms of phenolic acids in stem and leaves of Ac all resulted in a decrease in diphenolase activity.The IC50 values of free phenolic acids in leaves was 39.24 ?g/mL and of insoluble-bound,free,esterified,glycosided were 72.25?93.31?99.72 and 117.05?g/mL,respectivelv.Secondlv,the determination of diphenolase activity showed that those could inhibite it and reach the IC50 values were free phenolic acids in leaves and stem of Ko and stem of Ac.The IC50 values of them were 95.34 ± 4.21?96.26± 5.07?g/mL and 71.68 ± 1.09?g/mL,respectively.In summary,the forms and contents of phenolic acids of mangrove plant(Ko and Ac)under extreme condition and their cancer chemoprevention and effect on mushroom tyrosinase were deeper understood in this study which provide theoretical basis for their further exploitation.