Suppression of migration inhibition factor (MIF) production by mitomycins in vitro.

The effects of a series of mitomycins in a modified version of the Migration Inhibition Factor (MIF) test were investigated. This modified assay, which uses monocytes of the mouse cell line WEHI3 as target cells for MIF, discriminates between effects on the migrating monocytes, the production of MIF by lymphocytes and the activity of the produced MIF. The 7-methoxy mitomycins were found to be more active than the 7-amino and 7-hydroxy derivatives in suppressing both the spontaneous migration of target monocytes and the MIF production by lymphocytes. Neither of the compounds had a significant effect on the activity of produced MIF. A relationship between the activities of the mitomycins and their lipophilicity and polarographic half-wave potential is discussed. Further attention is paid to the stability of the mitomycins under the test conditions and additional advantages of the modified MIF assay over related in vitro tests for cell-mediated immunity.

Decomposition of mitomycin and anthracycline cytostatics in cell culture media.

The chemical stability of members of two groups of cytostatics, mitomycins and anthracyclines, has been studied in four different cell culture media enriched with serum. Stability was determined with the use of high performance liquid chromatography. In the group of mitomycins, the 7-aminomitosanes appeared to be relatively stable during a seven days incubation period at 37 degrees C when compared to the 7-methoxy congeners. The anthracycline derivatives, 4-demethoxy-daunorubicin, doxorubicin and its 4'-analogues showed half-lives of about 10-20 hours. Doxorubicinol and daunorubicin were found to be more stable. Anthracycline degradation products could be traced with the use of thin layer chromatography. All main degradation products originate from hydrolytic reactions. No enzymatic conversions could be observed. These observations may be of importance for the correct interpretation of the effects of mitomycins or anthracyclines on cells incubated in a cell culture medium.

In vitro immunosuppressive activities of recently developed anthracycline cytostatics.

The effects of a series of seven anthracycline cytostatics on various human leukocyte functions, namely the production of Migration Inhibition Factor (MIF) by lymphocytes and the production of chemiluminescence by activated polymorphonuclear leukocytes (PMNs), as well as on classical and alternative pathways of activation of human complement were investigated. In addition, lipophilic and electrochemical properties of the compounds were determined, by measuring their High Performance Liquid Chromatography (HPLC) capacity ratio (k') and half-wave reduction potential (E1/2). The antitumor agents under investigation suppressed, in most cases, lymphocyte and PMN functions, whereas complement activity remained unaffected. The extent of suppressive effects showed a good correlation with the lipophilicity of the compounds, while no correlation with reduction potentials was found.

Immunomodulatory activity of an aqueous extract of Azadirachta indica stem bark.

The interference of an aqueous extract of the stem bark of Azadirachta indica with different parts of the human immune system was investigated. The extract showed strong anticomplementary effects which were dose-and time-dependent and most pronounced in the classical complement pathway assay. Moreover, a dose-dependent decrease in the chemiluminescence of polymorphonuclear leukocytes was observed and a dose-dependent increase in the production of migration inhibition factor by lymphocytes.

Ethnopharmacognostical survey of Azadirachta indica A. Juss (Meliaceae).

Literature data on respectively botany, chemistry, ethnopharmacology, pharmacology and toxicology of Azadirachta indica A. Juss. (Meliaceae) are reviewed and evaluated. In traditional literature, preparations of the tree are claimed to be vulnerable in wide spectrum of diseases. Especially for inflammation-related diseases a good correlation is found with the results of recent experimental investigations. In addition, a variety of other biological activities are reported. Most frequently the effects can be attributed to compounds representing the structural classes of the limonoids, phenolics and macromolecules. Reported toxicity of preparations and isolated compounds are low, except for the seed oil. In conclusion, A. indica can be regarded as a valuable plant source for the rationalisation of its use in traditional medicine and for modern drug development.

Characterization of anti-complement compounds from Azadirachta indica.

The crude aqueous extract of Azadirachta indica bark possesses an inhibitory activity on both classical (CP) and alternative pathway (AP) activation of human complement. Purification of the compounds with the guidance of the AP-inhibitory activity involved extraction with methanol, dialysis, ion-exchange procedures and gel-permeation chromatography. This sequence yielded two polymers, NB-I and NB-II, one a highly active compound with a relatively low molecular weight (NB-II) and the other a less active compound with a high molecular weight (NB-I). The polymers were characterized by using colour reactions, TLC, GLC and HPLC after hydrolysis and gel-permeation chromatography as peptidoglycans. The carbohydrate part consisted predominantly of glucose. Arabinose, galactose and mannose were present in minor amounts (NB-II) or only as traces (NB-I). Protein was present for 5.5% in NB-I and for 9.8% in NB-II.

Gentiogenal, a conversion product of gentiopicrin (gentiopicroside)*.

The structure of gentiogenal, (+/-)5-formyl-6-methyl-3,4-dihydro-1H,6H-pyrano-[3,4-c-]-pyran-1-one, a conversion product of the aglucone of gentiopicrin (gentiopicroside), isolated from BLACKSTONIA PERFOLIATA (Gentianaceae), was elucidated by (1)H- and (13)C NMR spectroscopic, mass spectrometric and X-ray diffraction methods. In a TLC bioassay gentiogenal showed fungitoxicity towards PENICILLIUM EXPANSUM.

Activity-guided isolation and identification of Azadirachta indica bark extract constituents which specifically inhibit chemiluminescence production by activated human polymorphonuclear leukocytes.

The A. indica crude aqueous bark extract inhibits the generation of chemiluminescence by activated human polymorphonuclear leukocytes (PMN). Guided by this activity the responsible compounds were purified by extraction with different organic solvents and HPLC. Gallic acid, (+)-gallocatechin, (-)-epicatechin, and (as a 2:1 mixture) (+)-catechin and epigallocatechin were isolated and identified by means of HPLC, TLC, MS, 1H-NMR, UV, and CD data. Commercial samples of gallic acid, (+)-catechin and (-)-epicatechin showed the same effects. To our knowledge the identified catechins have never been described as constituents of A. indica.

An ethnopharmacognostic approach to the search for immunomodulators of plant origin.

The search for immunomodulating plant constituents through basic and field inquiries into the literature and practices of traditional Indian medicine is treated. The strategy of data collecting proceeds through aspects of an ethnobotanical, an ethnopharmaceutical, an ethnopharmacological, and an ethnomedical nature. In the experimental immunopharmacognostic phase, immunomodulatory compounds are isolated and purified through action-guided fractionation procedures. The results described here refer to activities found on human complement activation and on PMN leucocytes activation. The immunomodulating plant compounds included in this report were isolated from Azadirachta indica bark, Woodfordia fructicosa flowers, Picrorhiza kurroa roots, and Jatropha multifida latex.