A. S. Gromova

Natural products from medicinal plants: non-alkaloidal natural constituents of the Thalictrum species

Thalictrum is an important plant genus that is widely used in traditional medicine. In this review considerable attention has been given to triterpenoid saponins in connection with their specific distribution in the Thalictrum genus and with their biological activity. All other non-alkaloid compounds isolated from the Thalictrum genus are also reviewed; these metabolites are discussed in relation to their structural features and to their role in the plants.

Structural Studies and Biological Activity of Plant Triterpenoids from the Thalictrum Genus

Structures and chemical and spectral properties of triterpenoids isolated from plants of the Thalictrum genus were systematized for the first time. Features of 13C NMR spectra of cycloartane triterpenoids were discussed. Data for the biological activities of certain cycloartane and oleanane triterpenoids were given.

Application of13C NMR spectroscopy and of fab mass spectrometry in the investigation of the minor triterpenoids ofThalictrum minus

Five minor triterpenoids have been isolated from the chloroform-soluble fraction of a methanolic extract ofThalictrum minus by chromatography on silica gel: (I) — oleanolic acid; (II) — oleanolic acid 3-0-α-L-arabinopyranoside; (III) — oleanolic acid 3-0-[0-β-D-glucopyranosyl-(1 → 3)-α-L-arabinopyranoside]; (IV) — oleanolic acid 3-0-[0-α-L-rhamnopyranosyl(1 → 2)-0-β-D-glucopyranosyl-(1 → 3)-α-L-arabinopyranoside]; and (V) — oleanolic acid 28-0-β-D-glucopyranoside 3-0-[0-β-D-glucopyranosyl-(1 → 3)-α-L-arabinopyranoside]. This is the first time that any of the compounds isolated have been detected in plants of the genusThalictrum. The possibility has been shown of determining the structures of triterpene glycosides on the basis of13C NMR spectroscopy and FAB mass spectrometry without chemical transformations of the glycosides.

Triterpene glycosides of Thalictrum squarrosum. IV. Structures of squarrosides A1, A2, B1, and B2

Four new cycloartane glycosides have been isolated from a methanolic extract ofThalictrum squarrosum Stephan ex Willd.: squarroside A1 (I) — (21R, 22S, 23R)-3β-(β-D-glucopyranosyloxy)-21α-methoxy-21,23-epoxycycloart-24-ene-22β,30-diol, C30H60O10; squarroside A2 (II) — the (21S)-epimer of compound (I); squarroside B1 (III) (21R, 22S, 23R)-3gb-[O-α-L-rhamnopyranosyl-(1 → 6)-β-D-glucopyranosyloxy]-21α-methoxy-21,23-epoxycycloart-24-ene-22β,30-diol, C43H70O14; and squarroside B2 (IV) — the (21S)-epimer of compound (III). The proposed structures were determined on the basis of1H and13C NMR spectroscopy, FAB mass spectrometry, and chemical transformations.

Triterpene glycosides of Thalictrum squarrosum. III. Structures of squarrogenins 1 and 2

Two genins — squarrogenin 1 and squarrogenin 2 — have been isolated from nodding meadow rue by the hydrolysis of squarrosides A1 and A2. The compounds are epimeric at C-21 and have the following structures: 1 — (21R, 22S, 23R)-21-methoxy-21,23-epoxycycloart-24-ene-3β,22β-30-triol, C31H50O5, mp 169–171°C (hexane-acetone), [α]54620 −11.06° (c 4.52; pyridine); and 2 — (21S, 22S, 23R)-21-methoxy-21,23-epoxycycloart-24-ene-3β,22β,30-triol, C31H50O5, mp 190–193°C (hexane-acetone), [α]54620 +106.6° (c 0.3; pyridine). The results of1H and13C NMR spectroscopy and of mass spectrometry for the new compounds are given.

A flavonoid glycoside and hydrocarbons and sterols from Thalictrum simplex

Continuing a chemical study of plants of the genus Thalictrum, we have investigated the epigeal part of Thalictrum simplex (slimtop meadow rue), fam. Ranunculaceae. The material was gathered in Irkutsk province during the vegetation period. The air dry raw material was extracted with 80% methanol, and the extract was evaporated and treated with chloroform. From the chloroform extract, by repeated column chromatography on silica gel L 40/100 in the chloroform-methanol-water (70:12:1) system, we obtained fractions 1 and 2, and in the ethyl acetate-methanol-water (10:2:3) system fraction 3.

Triterpene glycosides ofThalictrum squarrosum I. Structure of squarrofuric acid

Squarrofuric acid has been isolated fromThalictrum squarrosum by the acid hydryolysis of a methanolic extract. It is suggested that is is an artefact formed on hydrolysis and has the structure of 3β, 30-dihydroxy-22,25-epoxylanost-9(11)-en-21-oic acid.1H and13C NMR spectra are given for squarrofuric acid and nine of its derivatives. The mass-spectral characteristics and physicochemical constants of the compounds studied are presented.

Triterpene saponins fromThalictrum minus. IV. The structure of thalicoside A

The predominating saponin, which has been called thalicoside A, has been isolated from low meadow rue (Thalictrum minus). It has been established by chemical and spectral methods that thalicoside A is 3β,16β,22(S),29-tetrahydroxy-9,19-cyclo-20(S)-lanost-24-ene 3-O-β-D-galactopyranoside 29-O-β-D-glucopyranoside.

Triterpene saponins fromThalictrum minus. III. The structure of thalicogenin

The periodate oxidation with subsequent alkaline degradation of the products of the oxidation of the predominant saponin isolated fromThalictrum minus has yielded the native genin, which has been called thalicogenin. The structure of thalicogenin as 3β,16β,22(S),29-tetrahydroxy-9,19-cyclo-20(S)-lanost-24-ene has been established on the basis of chemical transformations and by spectral methods.

Triterpene glycosides and their genins fromThalictrum foetidum. I. The structure of foetoside C

A new glycoside — foetoside C — has been isolated from the epigeal part ofThalictrum foetidum L. and, on the basis of chemical transformations and spectral characteristics its structure has been established as oleanolic acid 28-[O-α-D-glycopyranosyl-(1 → 6)-O-β-D-glucopyranoside] 3-O-[O-β-D-xylopyranosyl-(1 → 3)-O-α-L-rhamnopyranosyl-(1 → 2)-α-L-arabinopyranoside].