Studies On The Chemical Constituents Of Whitfordiodendron Filipes Var.tomentosum

The plant Whitfordiodendron filipes var.tomentosum belongs to the Whitfordiodendron genus,which is widely distributed in Yunnan Province and Guangxi Autonomous Region,China.The plants of Whitfordiodendron genus are not only a tasty food but also an effective material medica which could produce plenty of secondary metabolites including flavonoids,alkaloids,terpenoids and steroids,and these compounds exhibit significant bioactivities such as antitumor,anti-inflammatory,hypoglycemic.However,no study have been conducted on the chemical constituents of W.filipes var.tomentosum.Therefore,the chemical and biological research of W.filipes var.tomentosum was performed herein.The dried vine part of W.filipes var.tomentosum was cut and then extracted with ethanol at room temperature.The extract was concentrated under reduced pressure to give crude extract which was partitioned between petroleum ether and ethyl acetate to sequentially give two sub-extracts(petroleum ether extract and ethyl acetate extract).The bioassays of these sub-extracts showed that they exhibited antioxidant activity against DPPH and ABTS.The antioxidant activity of ethyl acetate extract is stronger than petroleum ether extract.With the guide of the antioxidant properties,both sub-extracts were fractionated and purified by silica gel and sephadex column chromatography.The structures of compounds isolated from W.filipes var.tomentosum was elucidated by spectroscopic technology such as NMR and MS.Eleven compounds were isolated from W.filipes var.tomentosum,which were elucidated as 3-acetyloleanolic acid(1),oleanolic acid(2),monogynol A(3),2,4-di-tertbutylphenol(4),(20R)-22E-24-ethylcholesta-4,22-dien-3-one(5),lupeol(6),20-hydroxylupan-3-one(7),20-taraxastene-3R,28-diol(8),betulonic acid(9),dammar-24-ene-3βacetoxy-20S-ol(10)and β-stigmasterol(11)respectively.Among them,compounds 1-3,610 are pentacyclic triterpenoids,4 is phenolic and 5,11 are steroids.In addition,compounds 1-5,7-10 were isolated from the Whitfordiodendron genus for the first time.The result of antioxidant experiments in vitro showed that 1-3,6-9 possess significant antioxidant bioactivity against DPPH and ABTS and 8 had moderate activities,which supported the antioxidant properties of the corresponding sub-extracts.In addition,the antidiabetic activity was evaluated using α-glucosidase as a target.In vitro hypoglycemic bioassays showed that compounds 1,2,6 and 9 exhibited significant inhibition against αglucosidase.The molecular docking analysis of compounds 1,2,6 and 9 showed that these compounds could combine with the enzyme via hydrogen bonds.