Abortifacient effects of a unique class of vasoactive lipids from Pinus ponderosa needles.

Pinus ponderosa needle (PN) ingestion by late pregnant cows results in decreased uterine blood flow, premature parturition, and retained placentae. Further, plasma from PN-fed cows increases caruncular arterial tone (i.e., induces prolonged contraction) in an isolated perfused bovine placentome. A novel class of vasoactive lipids was isolated and identified using a bovine placentome assay-guided fractionation of CH2Cl2 extracts of PN. Placentome perfusion tests indicated that 1-12-dodecanedioyl-dimyristate (14-12-14) was the most potent of the PN lipids for increasing caruncular arterial tone. Late pregnant guinea pigs (GP) were used to evaluate the abortifacient activity of these vasoactive lipids. In Study 1, on d 50 of gestation, part of the control diet was replaced with chopped PN (Diet A) or chopped PN subjected to sequential extraction with diethyl ether (Et2O; Diet B); Et2O and CH2Cl2 (Diet C); and Et2O, CH2Cl2, and methanol (Diet D). The GP on Diets A and B exhibited shorter (P<.01) gestation lengths and reduced (P<.01) pig birth weights than GP on the control diet or Diets C and D. Further, only GP on Diets A and B exhibited retained placentae. In Study 2, on d 50 of gestation, part of the control diet was replaced with chopped PN that had been subjected to exhaustive CH2Cl2 extraction and then infiltrated with either CH2Cl2 alone (Diet E), CH2Cl2 containing 14-12-14 (Diet F), or CH2Cl2 containing isocupressic acid (Diet G); then solvents were evaporated. The GP consuming Diet F had shorter (P<.05) gestation lengths and reduced (P<.05) pig birth weights than did GP consuming Diets E or G. The GP consuming Diet F also exhibited a high incidence of retained placentae. These data provide evidence that a unique class of vasoactive lipids in PN exhibit abortifacient activity in guinea pigs.

Gmelinosides A-L, twelve acylated iridoid glycosides from Gmelina arborea.

Besides the known iridoids 6-O-alpha-L-rhamnopyranosylcatalpol (1), 6-O-(3"-O-trans-feruloyl)-alpha-L-rhamnopyranosylcatalpol (14), 6-O-(2"-O-acetyl-3", 4"-O-di-trans-cinnamoyl)-alpha-L-rhamnopyranosylcatalpol (15) and the known phenylpropanoid glycosides verbascoside (acteoside) and martynoside, 12 new acylated iridoid glycosides named gmelinosides A-L (2-13) have been isolated from the leaves of Gmelina arborea. These compounds were structurally characterized using a variety of spectral methods.

Oxidative coupling of mithramycin and hydroquinone catalyzed by copper oxidases and benzoquinone. Implications for the mechanism of action of aureolic acid antibiotics.

The copper oxidases human ceruloplasmin and Polyporous anceps laccase catalyze the oxidative coupling of mithramycin (1) and its aglycone chromomycinone (2) with p-hydroquinone to form new mithramycin-hydroquinone (3) and chromomycinone-hydroquinone adducts (4), respectively. Similar adducts could be formed by the nonenzymatic mimic of this reaction using benzoquinone and these aureolic acids in buffer solutions. FABMS of 3 indicated that the hydroquinone moiety was attached to the aureolic acid aglycone. Acid hydrolysis of 3 yielded a compound with the same chromatographic and spectroscopic characteristics as 4. Structure elucidation of 4 by NMR and MS revealed that the hydroquinone was attached to the C-5 position of the aglycone. NMR evidence indicated that 4 consisted of a mixture of ortho-substituted biphenyl rotamers. The mechanism of the copper oxidase catalyzed adduct formation reaction is presumed to involve radical formation through hydrogen removal at the 8-phenolic position, radical isomerization, and coupling with semiquinone radical also formed during enzymatic and nonenzymatic incubations. Identification of the covalent-hydroquinone adduct provides evidence that aureolic acid antibiotics can be metabolically converted to reactive radical intermediates, and it establishes the C-5 position of aureolic acid as an enzymatically reactive site. Unlike mithramycin, the mithramycin-hydroquinone adducts was inactive in the in vivo P388 leukemic antitumor test system.

Microbial models of mammalian metabolism.

A solid basis for the M4-approach has been developed over the past 10 years. Recent examples of the production of difficult-to-synthesize mammalian metabolites through microbial transformations attest to the utility of the methodology. There is, however, much more to be done. Model studies should be conducted to test parallels between microbial and mammalian S- and N-oxidations, O-glucuronidations, and ester and amide hydrolyses. Subsequently, even greater applications of M4- work can be envisioned. We have been pleased to see our colleagues in industry and academia adopt the M4- approach to solve difficult pharmacological and toxicological problems. In large measure, this has been our greatest reward for efforts initially presented before the membership of the American Society of Pharmacognosy in 1973.