Phytochemical Studies On Two Traditional Medicinal Plants Of Zhuang Nationality

Jingxi,located in the southwest of Guangxi Zhuang Autonomous Region,is a county of compact nationalities with Zhuang predominating,and possesses strong ethnic characteristics.The traditional medicinal market of the Dragon-boat Festival is a cultural custom which has been handed down for generations.This market is a microcosm of how the local people have used the traditional medical plants for thousands of years.To reveal the diversity of medicinal plants and the scientific connotation,the traditional medicinal market and the surrounding villages were investigated and reported through the approaches of ethnobotany.Nearly 600 medicinal plant species were documented.They were valuable for medicinal uses including heat-clearing,treatment of rheumatism,bone fracture and injury,anti-inflammatory pain and so on.In order to provide reliable scientific data for utilization of folk medicinal plants,we selected two plant species(Striga asiatica(L.)O.Kuntze,Phlegmariurus squarrosus(Forst.)L.Love et D.Love)for studying their chemical constituents.Twenty-one compounds,including 8 new ones,were isolated from these two medicinal plants.Their structures were identified by using 1D&2D NMR combined with HR-LC-TOF-MS technology.The types of these compounds are flavanoids and alkaloids.Six flavonoids,diosmetin(1),apigenin(2),luteolin(3),chrysoeriol(4),apigenin-7-O-glucuronide(5)and acacetin(6),two phenolic glycosides,verbascoside(7)and isoverbascoside(8),as well as one norsesquiterpene,blumenol A(9)were isolated or detected from the EtOAc and n-BuOH extracts of the whole plants of S.asiatica.Their structures were identified by 1H&13C NMR,HR-LC-TOF-MS and co-injection with the reference standards.Among them,blumenol A(9)was firstly found from the Scrophulariaceae.Diosmetin(1)and isoverbascoside(8)were firstly reported from the genus Striga,while verbascoside(7)was reported from this plant for the first time.Based on our chemotaxonomic studies and the summary of phytochemical studies of Scrophulariaceae,Striga could be treated as a member in the family Scrophulariaceae,not in Orobanchaceae.Also,the antioxidant activities of some factions were evaluated by DPPH and ABTS assay.This supported the traditional medical usage of S.asiatica.Twelve compounds,including 8 new alkaloids,named squarrosusine A(1),squarrosusine B(2),squarrosusine E(4),8-epilycoposerramine U(5),squarrosusine D(6),squarrosusine F(9),squarrosusine C(11),squarrosusine C N-oxide(12),were isolated and identified from the whole plant of P.squarrosus.Their structures were determind by 1D&2D NMR spetra and structure modification.Acetylcholinesterase(AChE)inhibitory activity of the isolated compounds was assayed by the spectrophotometric method developed by Ellman et al.with slight modification.Biological tests showed that 12 compounds were inactive against AChE,and their anti-inflammatory activity is still in testing.