Triterpenes from the combined leaf and stem of Lithospermum caroliniense.

An investigation of the combined leaf and stem of Lithospermum caroliniense afforded two new pentacyclic triterpenoids based on the olean-12-ene and taraxast-12-ene skeletal types. The structures of these compounds were elucidated on the basis of spectral analysis as 1 alpha,3 beta,23-trihydroxyolean-12-ene-28-oic acid and 3 alpha,19 beta,21 alpha,23-tetrahydroxytaraxast-12-ene-28-oic acid.

Two isoflavones from the bark of Petalostemon purpureus.

Two new isoflavones, 6,7,8,3',4',5'-hexamethoxyisoflavone and 7,8,3',4',5'-pentamethoxyisoflavone, have been isolated and characterized from the combined root bark and stem bark of Petalostemon purpureus.

A new prenylated flavonol from the root of Petalostemon purpureus.

A new prenylated flavonol, petalopurpurenol (1), and a known dihydroflavonol, petalostemumol (2), have been isolated by DNA scission-guided fractionation of the organic portion of a 20% MeOH/CHCl3/H2O partition of a 50% MeOH/CHCl3 extract of the roots of Petalostemon purpureus. Compound 2 displayed moderate activity in DNA-scission assay. Both compounds 1 and 2 were evaluated for cytotoxicity in a panel of human cancer cell lines. The structures of petalopurpurenol (1) and petalostemumol (2) were determined by spectroscopic analysis.

Two isoflavones from the bark of Petalostemon purpureus.

Two new isoflavones, 6,7,8,3',4',5'-hexamethoxyisoflavone and 7,8,3',4',5'-pentamethoxyisoflavone, have been isolated and characterized from the combined root bark and stem bark of Petalostemon purpureus.

Two new aromatic constitutents from the rootwood of Aeschynomene mimosifolia.

The rootwood of Aeschynomene mimosifolia Vatke (Leguminosae) has yielded a new neoflavonoid, mimosifoliol (1), and an unusual C16-styrylcycloheptenone derivative, mimosifolenone (2). The structures of these compounds were determined on the basis of spectral analysis. Compound 1 demonstrated weak activity in DNA-strand scission assay, while compound 2 was found to be inactive. Mimosifoliol (1) was inactive toward several human cell lines, while 2 was moderately active against the KB cell line.

Effect of tannins on screening of plant extracts for enzyme inhibitory activity and techniques for their removal.

Ethyl acetate and aqueous extracts of tannin-containing topoisomerase inhibitory plant samples were subjected to one or more of seven tannin removal procedures, and the resulting products were subsequently evaluated for topoisomerase inhibitory activity. In most of the samples investigated, the initial activity was lost after tannin removal. It was concluded that the activity initially observed was primarily due to tannins. Procedures are presented for routinely obtaining tannin-free organic and aqueous fractions.

Isolation and structure identification of an active DNA strand-scission agent, (+)-3,4-di-hydroxy-8,9-methylenedioxypterocarpan.

A new pterocarpan, (+)-3,4-dihydroxy-8,9-methylenedioxypterocarpan [1], was isolated from the flowers of Petalostemon purpureus by a DNA strand-scission assay-guided fractionation procedure. Compound 1 demonstrated activity in a standard in vitro DNA strand-scission assay, and cytotoxicity toward a KB tumor cell line. Two other related pterocarpans [2, 3] isolated from same plant were found to be moderately active for KB cells, but were inactive in the DNA strand-scission assay. (+)-4-Hydroxy-3-methoxy-8,9-methylenedioxypterocarpan [2] has not been reported previously as a natural product, while (+)-maackiain [3] has been isolated only as an optically inactive racemate along with its optical antipode, the (-)-isomer.

Gummiferol, a cytotoxic polyacetylene from the leaves of Adenia gummifera.

A new polyacetylenic diepoxide compound, gummiferol [1] was isolated from the leaves of Adenia gummifera by KB cytotoxicity-guided fractionation. Compound 1 exhibited significant activity against the KB human cell line and a broad cytotoxic spectrum against other human cancer cell lines. The structure of 1 was established primarily on the basis of its spectral data.

Isolation and structural elucidation of pentacyclic triterpenoids from Maprounea africana.

Pentacyclic triterpenoids based on the taraxer-14-ene skeleton with a C-28 attached carboxylic acid group have been isolated from the roots of Maprounea africana. These compounds were identified as 1 beta,2 alpha-dihydroxyaleuritolic acid 2,3-bis-p-hydroxybenzoate [1], 2 alpha-hydroxyaleuritolic acid 3-p-hydroxybenzoate [2], 2 alpha-hydroxyaleuritolic acid 2,3-bis-p-hydroxybenzoate [4], aleuritolic acid 3-p-hydroxybenzoate [5], aleuritolic acid [6], and aleuritolic acid 3-acetate [7]. Compounds 1 and 2 are new triterpene esters. Compound 3 was previously reported as 7 beta-hydroxymaprounic acid 3-p-hydroxybenzoate [13]. However, based on detailed nmr studies, its structure has been revised.

Cytotoxic constituents of Baccharis gaudichaudiana.

Three new labdane diterpenes, gaudichaudols A-C [1-3], a new clerodane diterpenoid, gaudichaudone [4], and the known clerodane, articulin acetate [5] have been isolated from the aerial parts of Baccharis gaudichaudiana, together with the known compounds, apigenin, hispidulin, spathulenol, and ursolic acid. Through the application of 1D- and 2D nmr spectroscopy, the structures of the new diterpenoids [1-4] were, in turn; elucidated as 15,16,18,19-tetrahydroxylabd-5-ene, 15-O-acetyl-16,18,19-trihydroxylabd-5-ene, 16-O-p-trans-coumaroyl-15,18,19-trihydroxylabd-5-ene, and 2 beta-hydroxy-15,16-epoxycleroda-1(10),15,16-trien-18,19-olide++ +. The isolated compounds were evaluated in P-388 lymphocytic leukemia cells as well as a battery of human cancer cell lines. Among the diterpenoids, gaudichaudol C [3], gaudichaudone [4], and articulin acetate [5] exhibited significant cytotoxic activity against certain cancer cells.

Plant antitumor agents. 31. The calycopterones, a new class of biflavonoids with novel cytotoxicity in a diverse panel of human tumor cell lines.

Three new biflavonoids to which we have accorded the trivial names calycopterone (1), isocalycopterone (2), and 4-demethylcalycopterone (3) and the known flavone 4',5-dihydroxy-3,3',6,7-tetramethoxyflavone (4) were isolated as cytotoxic constituents from the flowers of Calycopteris floribunda Lamk. (Combretaceae). Compounds 1-3 showed a wide range of activity against a panel of solid tumor cell lines. Among the biflavonoids, calycopterone (1) is the major constituent.