Dihydroagarofuran sesquiterpene alkaloids from Maytenus putterlickoides.

Two new dihydroagarofuran sesquiterpene alkaloids, putterines A (2) and B (3), and a known alkaloid, mayteine (1), were isolated from the root of Maytenus putterlickoides. The structures of these compounds were elucidated by various spectroscopic techniques, including 1H and 13C NMR, COSY, ROESY, HMBC, and high-resolution FABMS.

New sucrose phenylpropanoid esters from Polygonum perfoliatum.

Five diferuloyl esters of sucrose, 6'-acetyl-3,6-diferuloylsucrose (helonioside B) (1); 2',4',6'-triacetyl-3,6-diferuloylsucrose (2); 1, 2',4',6'-tetraacetyl-3,6-diferuloylsucro se (3); 1,2',6'-triacetyl-3, 6-diferuloylsucrose (4); and 2',6'-diacetyl-3,6-diferuloylsucrose (5), were isolated, along with the 1,3,6-tri-p-coumaroyl-6'-feruloylsucroses, vanicoside A and vanicoside B, from the whole plant of Polygonum perfoliatum by various chromatographic methods. The structures of these phenylpropanoid glycosides were determined on the basis of their NMR and mass spectroscopic data. Compound 1 is a known compound, but 2-5 are new members of this class.

Neoflavonoids from Polygonum perfoliatum.

Four neoflavonoids, 3,4-dihydro-4-(4'-hydroxyphenyl)-5,7-dihydroxycoumarin (1), 3,4-dihydro-5-hydroxy-7-methoxy-4-(4'-methoxyphenyl)coumarin (2), 3,4-dihydro-5-hydroxy-4-(4'-hydroxyphenyl)-7-methoxycoumarin (3), and 3,4-dihydro-5,7-dihydroxy-4-(4'-methoxyphenyl)coumarin (4), were isolated from the whole plant of Polygonum perfoliatum. Neoflavonoids 1, 2, and 4 were known compounds, but 3 is a new member of this class.

Vanicosides C-F, new phenylpropanoid glycosides from Polygonum pensylvanicum.

The isolation of the protein kinase C inhibitors, vanicoside A (1) and vanicoside B (2), from Polygonum pensylvanicum prompted continued interest in the active principles of this plant. A new, more efficient isolation procedure has been developed to facilitate separation of homologues of vanicosides A and B from the complex extract. Several new phenylpropanoid glycosides have since been isolated. The structures of these principles were determined to be 2'-O-acetylhydropiperoside (4), 6'-O-p-coumarylhydropiperoside (5), 4'-O-acetylvanicoside A (6), and 3'-O-acetylvanicoside B (7) using negative ion FABMS, 1H NMR, and 2D NMR techniques.

5-Benzoyl-5-deacetylwilforidine: a new sesquiterpene nicotinoyl alkaloid from Maytenus buchananii.

A new sesquiterpene nicotinoyl alkaloid has been isolated from Maytenus buchananii (Loes.) R. Wilczek and identified as 5-benzoyl-5-deacetylwilforidine (1). This appears to be the first sesquiterpene nicotinoyl alkaloid based on hydroxywilfordic acid with a benzoyl group at C-5.

Dihydrolicoisoflavone, a new isoflavanone from Swartzia polyphylla.

Fractionation of an ethanolic extract of Swartzia polyphylla, guided in part by an assay for inhibition of protein kinase C, led to the isolation of the known flavonoids biochanin A, dihydrobiochanin A, ferreirin, dalbergioidin, and naringenin, and one new prenylated isoflavonone, dihydrolicoisoflavone [1].

Vanicosides A and B, protein kinase C inhibitors from Polygonum pensylvanicum.

Two new protein kinase C inhibitory glycosides, vanicosides A [1] and B [2] were isolated from Polygonum pensylvanicum (Polygonaceae) by chromatographic techniques guided by bioassays for PKC inhibition. The structures of these glycosides were established primarily by analysis of 1H- and homonuclear correlated nmr and high-resolution fab mass spectra of 1 and 2 and the derived octaacetate, 3. Both glycosides were found to have p-coumaryl esters at the 1, 3, and 6 carbons of sucrose and a feruloyl ester at the 6' carbon. Vanicoside A [1] also had an acetate group at the 2' carbon.

4-Hydroxy-25-desoxyneorollinicin, a new bistetrahydrofuranoid acetogenin from Rollinia papilionella.

4-Hydroxy-25-desoxyneorollinicin, a new linear bistetrahydrofuranoid acetogenin, has been isolated from Rollinia papilionella. The structure was elucidated from high resolution mass spectral and nmr data. The relative stereochemistry of six of the eight stereogenic centers was established by analysis of the 1H-nmr spectra of the triacetate of 2. In addition, the relative stereochemistry of seven of the eight stereogenic centers of rollinicin, a previously reported bistetrahydrofuranoid acetogenin, was established by analysis of the 1H nmr spectra of the triacetate of 1 and the mass spectra of the tristrimethylsilyl ether of 1.

Characterization of decomposition products of maytansine.

Analysis of outdated clinical samples of maytansine formulated in mannitol indicated that approximately 40% of the original maytansine content had decomposed. Chromatographic examination of these samples showed the presence of one major and multiple minor decomposition products. The major decomposition product was found to be maysine, a naturally occurring maytansinoid resulting from hydrolytic elimination of the C-3 ester side chain. Four minor decomposition products were isolated with the use of HPLC. All of these decomposition products were found to possess the C-3 ester side chain. However, other structural modifications were noted, especially in the region of the C-9 carbinolamide. Two of the minor decomposition products were tentatively identified as 10-epimaytansine and 9-epimaytansine. One minor decomposition product was found to contain a hydroxyl group at the benzylic C-15 position.

New macrocyclic trichothecenes from Baccharis megapotamica.

The isolation and structural elucidation of biologically active baccharinoids B1 [11a], B2 [12a], B3 [5a], and B7 [6a] are reported with crystal structure determinations of baccharinoid B7 and of the triacetate of baccharinoid B2. All four compounds are isomeric with 11a/12a and 5a/6a being epimeric at C13'.

Maquiroside A, a new cytotoxic cardiac glycoside from Maquira calophylla.

Maquiroside A, a new cardiac glycoside, was isolated from the Peruvian plant Maquira calophylla. The structure was established using spectroscopic methods, and the aglycone was found to be cannogenol. The sugar portion was identified as D-cymarose. Maquiroside A demonstrated activity against the KB cell culture.

Preparation of glucosidic derivatives of steganol.

Glucoside derivatives of steganol analogous to the semisynthetic podophyllotoxin derivative, VP 16-213, were prepared. Glucosidation of steganol with 2, 3, 4, 6-tetra-O-benzylglucopyranose gave the alpha-anomer of the glucoside as the major product. Subsequent removal of the benzyl groups and reaction with acetaldehyde dimethyl acetal gave the ethylidene derivative 10. The beta-anomer of the glucoside was similarly converted to 12. All derivatives prepared were screened for activity in the DNA breakage assay.

Neoisostegane, a new bisbenzocyclooctadiene lignan lactone from Steganotaenia araliacea.

Neoisostegane, the first naturally occurring steganin without a functional group at C-5, was isolated from two different collections of Steganotaenia araliacea. The structure of neoisostegane, which contained five aromatic methoxyl groups rather than the more usual three methoxyls and one methylenedioxy moiety, was elucidated by comparison of the pmr coupling constants with those of synthetic steganes and by selective decoupling experiments. The structure was confirmed by cmr data, by preparation of a derivative having five aromatic methoxyl moieties from stegane, which was compared spectroscopically to neoisostegane, and by thermal isomerization experiments.

Rollinone, a new cytotoxic acetogenin from Rollinia papilionella.

Rollinone, a new member of a series of cytotoxic, linear acetogenins bearing a bistetrahydrofuran moiety and a gamma-lactone, has been isolated from Rollinia papilionella. The structure elucidation of rollinone was achieved by interpretation of the pmr and cmr data and mass spectral fragmentation patterns.

Psorospermin, a new antileukemic xanthone from Psorospermum febrifugum.

An ethanolic extract of Psorospermum febrifugum was fractionated with antileukemic activity in vivo in the P388 lymphocytic leukemia in mice and in vitro in the KB cell culture system used as a guide. The new antileukemic xanthone psorospermin 1 was isolated, and its structure was elucidated. The chlorohydrin of O-methylpsorospermin 2 was also isolated after treatment of the fraction containing psorospermin chlorohydrin 6 with diazomethane. Psorospermin 1 was demonstrated to have significant antitumor activity in the P388 in vivo system as well as cytotoxicity against the KB in vitro system.