Preliminary Studies On Leaf Phytochemical Diversity Of Podophylloideae(Berberdaceae) And Its Association With Genetic And Environmental Variation

Podohylloideae(Berberidaceae)which consists of four genera,i.e.: Dysosma,Sinopodophyllum,Podophyllum and Diphylleia,is an important group of anti-cancer medicinal plants containing a variety of medicinal chemical components,such as podophyllotoxin.However,the type and contents of leaf compounds and factors affecting the differential expression of the leaf compounds of this subfamily remain unknown.In this study,we comprehensively analyzed the leaf compounds of the Podohylloideae,and then explored the effects of genetic and environmental factors on the contents of chemical composition in leaf of Dysosma.The main findings are as follows:1.Identification of bioactive compounds from Podohylloideae leaves.Twenty-four compounds were identified in the leaves of the subfamily,including 13 flavonoids and their derivatives,5 lignan compounds and their derivatives,and 6 organic acids.2.Analyses of antioxidant abilities of chemical composition in leaf.Biological activity analysis showed that the total phenolic content in the leaves was 0.001 – 0.014 GAE mg/g.The total flavonoid content was 0.019 – 0.036 RE mg/g.The ABTS free radical scavenging range was 6.882 – 16.285 mmol/g Trolox.The DPPH free radical scavenging range was 5.441 – 11.494 mmol/g Trolox.3.Phylogenetic signals of the content of bioactive compounds in Dysosma leaves.Phylogenetic signal detection was carried out to calculate the genetic distance between species,and phylogenetic trees were constructed using EST-SSR data.We found that the content of bioactive compounds in Dysosma showed significant phylogenetic signals(Blomber's K value is between 0.637 – 0.983,P < 0.05),suggesting that content of bioactive compounds in Dysosma leaves is affected by phylogenetic history in Dysosma.4 Comparison of factors affecting chemical composition in Dysosma leaves.Mantel tests showed that the genetic distance matrix calculated using the EST-SSR data was highly correlated with the matrix derived from compounds content(r = 0.250,P < 0.05).Structural Equation Model estimated that the genetic distance path coefficient was 0.71,while the environmental factor path coefficient was 0.29.The results suggest that the genetic distance contributed more than environmental factor for the compound content in Dysosma leaves.In summary,we analyzed chemical composition in leaf and basic antioxidant properties including total phenolic and total flavonoids,and explored the effects of genetic and environmental factors on the content of chemical composition in leaf of Dysosma.The results indicated that specific Podohylloideae species can be selected as a source of bioactive phytochemicals for medical use.