| Cinnamomum cassia Presl is a tree in Lauraceae.Cinnamomum cassia Presl var.macrophylum Chu is the only variety of cinnamon.C.cassia and C.cassia var.macrophylum are very similar in appearance.There are three entries for C.cassia in the Chinese Pharmacopoeia:(1)Rougui,Cortex Cinnamomi,is the dry stem bark of C.cassia peeled in the fall.It is used in traditional Chinese medicine as an antiinflammatory,stomachic agent,and analgesic.(2)Guizhi,Ramulus Cinnamomi,is the dry young branches of C.cassia collected in summer and spring and is used as an antipyretic and analgesic against rheumatic and influenza pain.(3)Rouguiyou,Oleum Cinnamomi,is the essential oil of C.cassia obtained by steam distillation of the dry stem barks,branches and leaves.Cinnamon mainly contains volatile oil,polysaccharides,polyphenols,coumarin and inorganic elements,and has anti ulcer,anti-inflammatory,antibacterial,anti-tumor,prevention of urinary disease,sedation,antispasmodic,antipyretic and other pharmacological effects.C.cassia and C.cassia var.macrophylum are similar in appearance,and the processed cinnamon is difficult to distinguish.Cinnamon oil is the main source of income,but the oil yield of cinnamon and large leaf is different,which is different in commercial value.At present,there is no unified understanding of the mechanism of the difference in the content of volatile oil between C.cassia and C.cassia var.macrophylum.It is of great theoretical and practical significance to systematically study the mechanism of the difference in volatile oil content.In this paper,C.cassia and C.cassia var.macrophylum were used as experimental materials to analyze the characteristics of two plants,including apparent,microscopic and physical and chemical characteristics.The metabolic group database and transcriptional group database of C.cassia and C.cassia var.macrophylum were constructed.1.Appearance and microstructure of C.cassia and C.cassia var.macrophylumThe bark,branch,leaf and new bud of cinnamon were observed by naked eye observation and photo.It was found that the bark and new buds of cinnamon were significantly different.The outer surface of cinnamon bark is gray brown,smooth,vertical wrinkles are irregular,the outer surface of the large leaves is reddish brown,the outer layer of cinnamon peel is mostly exfoliated and rough,and there is obvious residual embolus.The new buds of C.cassia are green,the young branches are slightly four sides,yellow brown,with longitudinal lines,densely covered with gray yellow villi;the new buds of C.cassia var.macrophylum are brown red,the young branches are slightly four sides,and the dark red brown ones are densely covered with yellow villi.The transverse section of cinnamon and cassia leaves was observed by microscope.It was found that there was no significant difference in the transverse section of branches and leaves,and the difference of skin was large.The main difference is the number of cork layer and the arrangement of stone cells.The remaining layer of cinnamon cork layer is less,and the large leaves clear several layers of cinnamon cork tissue,and the stone cells are connected into a complete waveform ring.2.ISSR analysis of C.cassia and C.cassia var.macrophylum56 samples of C.cassia and C.cassia var.macrophylum were amplified by ISSR-PCR,and the amplified bands were analyzed by gel electrophoresis.The results showed that the amplified product of cinnamon was specific to 200-300 bp with primer ubc825,but there was no such band in the broad C.cassia var.macrophylum.According to this band,the cinnamon and the large leaf purified GUI could be distinguished.The primers ubc855 had a specific band in 1000-2000 bp,which could distinguish the samples from huangshakou village,Lishao Town,Luoding City,Guangdong Province.The primers ubc876 were no bands in 750-1000 bp,and other regions had special bands.All samples of Siwang village,Ziliang Town,Rongxian County,Yulin City,Guangxi Province could be distinguished.The results of cluster analysis and principal component analysis are consistent with the results of specific bands3.Physiological and biochemical differences of different parts of C.cassia and C.cassia var.macrophylumThe indexes of volatile oil,cinnamaldehyde,procyanidin,total flavonoids,soluble sugar,soluble protein and water in leaves,branches and skins of C.cassia and C.cassia var.macrophylum were detected.The results showed that the content of essential oil in the cortex of C.cassia var.macrophylum was 95.2% higher than that of C.cassia,18.2% in the branch of the large leaf,58.9% in the leaves,and the content of Cinnamaldehyde and volatile oil in the leaves of the C.cassia was the same.The content of procyanidin and total flavonoids in different parts of the C.cassia var.macrophylum was higher and the difference was smaller,and the total flavonoids in the leaves of C.cassia var.macrophylum were much lower.The content of total flavonoids in branches was 28.2% and that of bark was higher than that of C.cassia.The results also showed that the soluble protein content of C.cassia fresh products was 0.87-5.09mg/g,that of the fresh C.cassia var.macrophylum was 1.06-5.12mg;The soluble sugar content of cinnamon was lower than that of the leaves.The contents of total flavonoids,procyanidin,soluble sugar(including fresh and dry),soluble protein in cinnamon leaves were almost twice as high as cinnamon.The contents of various components in the branches of cinnamon C.cassia var.macrophylum were similar to C.cassia,and the former was slightly higher than that of the latter;but the volatile oil,cinnamaldehyde,procyanidin and total flavonoids in the bark of the cinnamon were significantly higher than that of cinnamon.Dry and fresh products have a great influence on the determination of soluble protein content,and drying will destroy the soluble protein and reduce the content.4.Molecular mechanism of the difference of the content of phenylpropane compounds between C.cassia and C.cassia var.macrophylumThe database of C.cassia and C.cassia var.macrophylum metabolizing group and transcription group were constructed,and the differences were compared with those of cinnamon metabolizing group.5277 different ions were screened out in the metabolic group database,2843 of which were up regulated and 2434 down regulated.The main metabolites are sesquiterpene and triterpene biosynthesis,phenylpropane,flavonoids and diterpenoid.There were 209807 differentially expressed genes in the transcriptional group database,including 101911 up regulated genes,107895 down regulated genes,12260 differential genes in the branches and leaves of the skin.The main genes are phenylpropane biosynthesis,flavonoids biosynthesis and photosynthesis pathway.73 genes were involved in the reaction in photosynthesis pathway,and almost all the branches and leaves of the large leaf were up regulated.Except bg1 b,pal and CCR,the 30 genes of phenylpropane pathway were up regulated,and almost all of them were up regulated.Compared with cinnamon,most TFs genes were down regulated in branches,but up regulated in leaves.These TFs genes may contribute to the production of cinnamaldehyde,coumarin and flavonoids.The results showed that the difference genes and metabolites may regulate the biosynthesis of phenylpropane,photosynthesis may play a positive role in flavonoid biosynthesis,and TFs gene may contribute to the synthesis of phenylpropane compounds. |
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