The Antitumor And Immunological Activities Of Heat-modified Pectin From The Heads Of Helianthus Annuus L.

Helianthus annuus L.(Sunflower)was widely planted in China.The seeds were used to produce oil.However,the heads,leaves,and stems were used as animal feed,fuel or waste.The unreasonable use of the byproduct of Helianthus annuus L.leads to the environmental pollution and waste of resource.Several studies showed that Helianthus annuus L.are rich in pectin.Pectin which is rich in galacturonan is mainly derived from plant cell wall.Pectin has the anti-tumor,anti-oxidant,immune modulation activity and et al.Heat modified pectin was obtained by treating with high temperature and high pressure.Heat modification is known to degrade pectin into pectin fragments,oligosaccharides,monosaccharides and some small molecules.The pectin fragments and the small molecules are easy to be absorbed by human body,which attracted the attention of more and more attentions.For this,we extracted the pectin from the heads of Helianthus annuus L.and made a heat modification.Further,we analyzed the anti-tumor and immune activity of the pectin and heat modified-pectin.According to the previous method by our group,we extracted the pectin from the heads of Helianthus annuus L.(HAP),and analyzed the monosaccharide composition.The result showed that HAP was mainly composed of galacturonic acid(GalA,79.9%).Then,we obtained the HT-HAP(Heat-treated HAP)by heat modifying.The cell viability assay and anti-tumor assay(in vivo)were applied to compare the anti-tumor activity of HAP and HT-HAP.The results showed that HT-HAP significantly decreased cell viability of some tumor cells,whereas HAP had no effect on them.The in vivo results showed HT-HAP could significantly inhibit the B16F10 and CT26 tumor growth,whereas HAP had no effect on both of them.HT-HAP was composed of pectin fragments and small molecules.To identify the active components and mechanism of the action of HT-HAP,the flow cytometry assay,western blot assay,endotheliocyte migration,capillary tube formation and anti-tumor assay(in vitro and in vivo)were applied.The results showed that the anti-tumor effect of HT-HAP were attribute to the small molecules but not the pectin fragments.The mechanism was related to the attenuation of the Akt activation and angiogenesis in the tumors.The immunocompetence were studied in the tumor-bearing mice treated with HAP and HT-HAP.The results showed that the heat modification could significantly enhance the immunocompetence of Helianthus annuus L.pectin in the tumor bearing mice.And both of the small molecules and pectin fragment could enhance the immunity,with the later more effective.To further evaluate the effect of HT-HAP on the immunocompetence.We analyzed some immune indexes treated by HT-HAP in the normal and CTX-induced immunosuppressed mice.The results showed that HT-HAP could significantly enhanced the immune activity on the immunosuppressed mice.However,HT-HAP had no effect on the normal mice.These results indicated HT-HAP had different effects on the different immune conditions.In conclusion,we found that HAP had no effect on the anti-tumor and immune modulation activity.After heat modifying,the pectin(HT-HAP)could significantly inhibit tumor growth and promote immunity.Besides,the heat modified pectin was virtually non-toxic.These results will provide the theory basis for the reuse of the discarded byproduct and the development of sunflower pectin as the functional foods.