Abstract:
【Objective】 The aim of the study was to optimize the extraction process of free phenols and bound phenols from
Ficus hirta Vahl. root cortex with different leaf types, and analyze the composition and content differences of phenolic compounds in
Ficus hirta Vahl. root cortex with different leaf types, which could provide reference for the breeding, deep processing and utilization of
Ficus hirta Vahl. varieties.【Method】
Ficus hirta Vahl. root cortex with different leaf types (no-lobed, three-lobed, five-lobed) were used as experiment materials. The extraction methods of free phenols and bound phenols were determined by single factor experiment. The compositions and contents of phenolic compounds in
Ficus hirta Vahl. root cortex with different leaf types were determined by ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS). Finally,principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA) were used to screen the differential phenol compounds in
Ficus hirta Vahl. root cortex with different leaf types.【Result】 The extraction methods of free phenols and bound phenols from
Ficus hirta Vahl. root cortex: the solvent was 60% acetone, ratio of solid to liquid was 1∶20,free phenol was obtained by ultrasonic extraction at 25 ℃ for 10 min; 15 mL of 2 mol/L sodium hydroxide was added to the residue, and hydrolysis was conducted at 75 ℃ in a water bath for 4 h, then, residue was extracted by ethyl acetate, and dried by vacuum rotary evaporation, and bound phenol was obtained. The contents of free total polyphenols in no-lobed,three-lobed and five-lobed
Ficus hirta Vahl. root cortex were 7.41,9.50, and 8.59 mg/g,and the contents of bound total polyphenols were 11.46,9.96, and 8.80 mg/g. The contents of free total polyphenols and bound total polyphenols showed significant difference among the three leaf types (
P<0.05). The results of UPLC-MS analysis showed that, a total of 50 phenolic compounds were detected in free phenols and 49 phenolic compounds were detected in bound phenols. 3-
O-p-coumaroylquinic acid, sesamin, catechin, rutin, and isoorientin existed only in free type, while epicatechin gallate, catechin gallate, caffeic acid, and kaempferol existed only in bound type. The content of psoralen in free phenol part was the highest,which were 11868.37,14909.63, and 14050.10 μg/g in
Ficus hirta Vahl. root cortex with no-lobed,three-lobed and five-lobed respectively. Among the bounding polyphenols,coniferin,afcatechin,ferulic acid,naringin and umbelliferolactone were the most abundant. The results of PCA and PLS-DA analysis showed that, free sericol,free coniferin,free cryptochlorogenic acid,free afcatechin,free chlorogenic acid,free naringin,free psoralen,free bergamolide,bound coniferin,bound ferulic acid, and bound coumaric acid were the main differential phenolic compounds in
Ficus hirta Vahl. root cortex. Among them, free psoralen was the most important phenolic compound.【Conclusion】 The compositions and contents of phenolic compounds in root cortex of
Ficus hirta Vahl. with different leaf types vary greatly. Leaf type can be used as one of the criteria for distinguishing quality; moreover, there is a large amount of bound phenols in root cortex of
Ficus hirta Vahl., and it is important to focus on the utilization of the bound phenols to increase the added value of
Ficus hirta Vahl.