PENTACYCLIC TRITERPENOIDS FROMEUCLEA KELLAU

Abstract

Euclea kellau H o c h s t., also known as Euclea schimperi D a n d i , is a shrub of the Ebenaceae family commonly found in the highlands and other dry, stony areas of tropical and equatorial Africa.Local folk medicine attributes many therapeutic properties to this plant: the Masai drink a decoction of the bark for splenic pain and swelling, the Digo and Sekuma take a decoction of the root, which is purgative, for ancylostomiasis, and the Nyamwezi use the powdered leaf as a snake-bite remedy [I].Ethiopians treat .the pots in which milk is kept kith the smoke of an Etzclea kellau branch fire and the milk reportedly does not curdle.'The present paper, in which we describe the pentacyclic triterpenoids isolated in large quantities (in some cases, up to 10% of the total; dried drug) from the chloroform extract, is the first study ever published regarding the natural products contained in this plant.The following triterpenoids were isolated: lupeol, a-amyrin, betulin, uvaol, ursolic acid and its Iactone. Lupeol and betulin were found only in the branches, a-amyrin and uvaol only in the leaves and abundant ursolic acid with a small amount of ursolic acid lactone in both branches and leaves.The lupeol-betulin-ursolic acid-ursolic acid lactone sequence, found in the branches and the a-amyrin-uvaol-ursolic acid-ursolic acid lactone sequence found in the leaves are sharply differentiated according to the morphological structure of the plant. Where the bark ends and the leaf begins, the triterpenoid sequence changes its composition.The following considerations should be made about the two triterpenoid sequences: the first two members of the branch sequence (lupeol and betulin) 'belong to the lupane steric series, whereas the first two members of the leaf sequence (a-amyrin and uvaol) belong to the ursane steric series.Ursolic acid and its lactone, which are common to both sequences, are biogenetically justified in the leaves (they are products of the oxidation of a-amyrin through uvaol), but their presence in the branches is surprising, where there is no trace of their precursors. The absence of betulinic acid in the branches should also be noted since this substance is the normal biological derivative of betulin oxidation and has consistently been found in large quantities in the wood of other Ebenaceae (Diospyros celebica B a k h, D. ebenum Koen, D. kaki L.) [2-41.

Antimicrobial Triterpenoids from Vladimiria muliensis

“…Compounds 4-6 were identified as 11R,12R-epoxy-D-friedours-14-en-3β-ol, 15 11R-hydroxyurs-12-en-3-one, 11 and urs-12-ene-3β,28-diol, 16 respectively, by comparing their spectroscopic data with literature values.…”

Phytochemical, Antiplasmodial, and Cytotoxic Investigation of Euclea natalensis A.DC. subsp. natalensis Leaves

“…The aerial parts of E. divinorum Hiern afforded glycosides of quercetin, myricetin and dihydrokaempferol [43] . Also, lupene‐, oleanane‐ and ursane‐type triterpenoids have been isolated from other Euclea species [14,44] . This is the first report of the isolation of flavonoid glycosides and triterpenoids from the leaves of E. natalensis .…”

“…[43] Also, lupene-, oleanane-and ursane-type triterpenoids have been isolated from other Euclea species. [14,44] This is the first report of the isolation of flavonoid glycosides and triterpenoids from the leaves of E. natalensis. The isolation of flavonoid glycosides and triterpenoids, and the absence of naphthoquinones in the leaves of E. natalensis is in agreement with the phytochemistry of other Euclea species.…”

In vitro 12(S)-HETE inhibitory activities of naphthoquinones isolated from the root bark of Euclea racemosa ssp. schimperi

“…Phytochemical investigation of Euclea racemosa ssp. schimperi showed the presence of 1,4-naphthoquinones, 7-methyljuglone, and its dimers diospyrin, isodiospyrin, and mamegakinone in the roots ( Van der Vijver and Gerritsma, 1974); and pentacyclic triterpenoids in the leaves and twigs (Orzalesi et al, 1970). Although there is no pharmacological report on this species, the naphthoquinones are known for their wide range of biological activities.…”