ACYLATED TRITERPENOIDS,FLAVONOIDS,AND LIGNANS ISOLATED FROM THE STEMS OF Tetracera loureiri

摘要

The genus Tetracera(family Dilleniaceae)contains about 50 species with a pantropical distribution,of which 20 occur in the Neotropical area.In traditional folk medicine,some species have been used as febrifuge,diuretic agent,and antijaundice [1].Tetracera species has been reported to exhibit a broad range of pharmacological activities such as antidiabetic,analgesic,anti-inflammatory,antipyrexic,anti-HIV and anti-reverse transcriptase,antihyperglycemic,anti-mycobacterial,antioxidant,anti-ulcerogenic,hepatoprotective,DNA polymerase(3 inhibitory,glucose-uptake modulating,and xanthine oxidase inhibition activity [2-12].Previous phytochemical investigations of members of this genus have resulted in the isolation of several classes of compounds,including flavonoids and terpenoids [9-13].Among them,flavonoids from T.indica induced significant adipogenesis like insulin and enhanced adipogenesis like rosiglitazone [4].Tetraceranoate from stem bark of T.potatoria showed potent anti-mycobacterial activities[11].T loureiri(Finet & Gagnep.)Pierre ex Craib is a woody vine inhabiting evergreen forests in South east Asia,including many parts of Cambodia,Laos,Thailand,and Vietnam.A decoction of its stems with other herbal plants is the traditional Thai medicine used for the alleviation of fatigue and improvement of jaundice [8].There is only one previous report on the pharmacological activity of this plant [12].To our knowledge,there has been no report of a phytochemical investigation of T.loureiri so far.In continuation of our studies on chemical constituents from the stems of T.loureiri,12 compounds were isolated and elucidated as betulinic acid(1),erjthro-carolignan E(2),thгео-carolignan E(3),eucalyptolic acid(4),Зβ-o-trans-feruloyl-2α-hydroxyurs-12-en-28-oic acid(5),3β-O-(trans-p-coumaroyl)maslinic acid(6),jacoumaric acid(7),quercetin(8),europetin(9),kaempferol(10),rhamnetin(11),and rhamnocitrin(12).To the best our knowledge,compounds 2,3,5,7,and 9 were obtained from the genus Tetracera for the first time.Moreover,compounds 4 and 6 has not been reported in the species of T.loureiri.