Molecular Evaluation Of Different Huazhoujuhong (Citrus Grandis Osbeck Var. Tomentosa Hort.) Germplasm And Determination On Its Main Flavonoids Content

Huazhoujuhong is classified in Rutaceae as Citrus grandis Osbeck var. tomentosa Hort. Dried pericarp of immature or nearly mature fruit have long been used as medicine. It is mainly produced in Huazhou, Guangdong province, noted as small, sour and bitter taste. Huazhoujuhong has different germplasms, which were under local named of Zhengmao, Fumao, Jiaxiyang and Guangqing. Zhengmao is so far the best medicine resources of all. Flavonoids in Huazhoujuhong are mainly naringin and rhoifolin. Huazhoujuhong have wide effects on relieving cough, anti-inflammatory, and so on.Based on previous researches of others, different germplasms of Huazhoujuhong were subjected to genetic relationship study via SSR molecular marker, and contents of it active compounds were determined also. Results shown that:1. Simple sequence repeat (SSR) markers were employed to evaluate the genetic diversity of the collected accessions.12 pairs of SSR primers that had polymorphisms bands were selected out of the used 120 pairs of SSR primers, there were total of 176 alleles identified, including 175 polymorphic amplicons. The fraction of polymorphic loci was 99.43%. Result indicated a close relationship between Huazhoujuhong and pummelo, proving Huazhoujuhong belongs to pummelo. However, significant genetic difference was found between germplasms under the same local name, such as Zhengmao, possibly owing to their sexual propagation with seeds.2. The method of flavonoids extraction from Huazhoujuhong was optimization, and naringin and rhoifolin detection by HPLC was established. The 0.3% formic acid solution was used as mobile phase A, methanol was used as mobile phase B. The column was Waters Symmetry C18, with the column temperature was set at 30℃, and flow at 1mL/min. During the gradient elution,2 flavonoids of naringin and rhoifolin were eluted and totally separated. The relative standard deviations of the precision, stability and repeatability meet the requirements of separation.3. The content of flavonoids of fruitlets (in years of 2011 and 2012) were determined aftwards, as a result, the content of naringin and rhoifolin in Huazhoujuhong was found significantly higher than that in other pmeloes. What’s more, the content of flavonoids of same germplasm in different orchard was significantly varied, and the content of naringin in Fumao (Li’s orchard) was particularly high, which might be owing to the different growing circumstances such as the mineral elements in soil and managements’operations.4. The content of flavonoids in Zhengmao and Jiaxiyang(Wu’s orchard) duing fruit development were measured by HPLC. Result shows that the content of naringin and rhoifolin underwent a general decline in both peel and pulp; the content of naringin in pulp (including segment membrane) was significantly higher than that in peel, while that of rhoifolin was significantly lower than that in the peel.