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Biomedical subjects

J M Miguel del Corral

Publications and source records attributed to J M Miguel del Corral.

13 recordsLinked to original sources

Podophyllotoxin: distribution, sources, applications and new cytotoxic derivatives.

Several podophyllotoxin derivatives modified in the A, B, C, D and E rings were prepared from podophyllotoxin and methyl isoxazopodophyllic acid and evaluated for their cytotoxicity on several neoplastic cell lines. Chemical transformations performed on these compounds have yielded derivatives more potent and more selective that the parent compound. Most of the compounds maintained their cytotoxicity at the microM level. Distribution, biosynthesis, production, biotechnology, applications and synthesis have also been reviewed.

Cytotoxins↗

Cytotoxic cyclolignans related to podophyllotoxin.

The cyclolignan family of natural products includes compounds with important antineoplastic and antiviral properties such as podophyllotoxin and two of their semisynthetic derivatives, etoposide and teniposide. The latter are included in a wide variety of cancer chemotherapy protocols. Due to these biological activities, cyclolignans have been the objective of numerous studies focused to prepare better and safer anticancer drugs. Several cyclolignans related to podophyllotoxin have been prepared and evaluated for their cytotoxic activities on four neoplastic cell lines (P-388, A-549, HT-29 and MEL-28); some of them have antiviral and immunosuppressive activities.

Aldehydes↗

New antineoplastic prenylhydroquinones. Synthesis and evaluation.

Several prenylhydroquinones have been prepared through Diels-Alder condensation, further functionalized or degraded chemically and then evaluated for their cytotoxic activity against some neoplastic cultured cell lines. A number of them have shown IC50 values under the microM level.

Antineoplastic Agents↗

Structure- and species-dependent insecticidal effects of neo-clerodane diterpenes.

Several natural neo-clerodane diterpenoids isolated from Linaria saxatilis and some semisynthetic derivatives were tested against several insect species with different feeding adaptations. The antifeedant tests showed that the oliphagous Leptinotarsa decemlineata was the most sensitive insect, followed by the aphid Myzus persicae. The polyphagous Spodoptera littoralis was not deterred by these diterpenoids; however, following oral administration, some of these compounds did have postingestive antifeedant effects on this insect. In general terms, the antifeedant effects of these compounds were species-dependent and more selective than their toxic/postingestive effects. The study of their structure-activity relationships showed that both the decalin moiety and the chain at C-9 determined their bioactivity. Furthermore, the presence of a 4,18-epoxy/diol moiety was an important feature for both the antifeedant and the toxic/postingestive effects.

Animals↗

Inhibition of human sPLA2 and 5-lipoxygenase activities by two neo-clerodane diterpenoids.

The inhibitory effect of two neo-clerodane diterpenoids, E-isolinaridial (EI) and its methylketone derivative (EIM), isolated from Linaria saxatilis var. glutinosa, on PLA2 and other enzyme activities involved in the inflammatory process was studied. Both compounds inhibited human synovial sPLA2 in a concentration-dependent manner with IC50 values of 0.20 and 0.49 microM, respectively, similar to scalaradial. Besides, these compounds decreased the cell-free 5-lipoxygenase activity and A23187-induced neutrophil LTB4 biosynthesis. Another function of human neutrophils, such as receptor-mediated degranulation, was also significantly reduced. In contrast, none of the compounds affected superoxide generation in leukocytes, or cyclooxygenase-1, cyclooxygenase-2 and inducible nitric oxide synthase activities in cell-free assays.

Diterpenes↗

Immunosuppressive cyclolignans.

The immunosuppressive activity of several lactonic, nonlactonic, and heterocycle-fused cyclolignans has been demonstrated for the first time by use of a T-cell-mediated immune response. Of the compounds tested, 4'-demethyldeoxypodophyllotoxin (8), beta-apopicropodophyllin (6), and the isoxazoline-fused cyclolignan 15 are the most potent with respect to their suppression of activated splenocytes.

Animals↗

Methyl ethers of podophyllotoxin-related cyclolignans.

Methyl ethers of podophyllotoxin [1] and its epimers at positions 7 and 8' were obtained through the corresponding chlorinated or brominated derivatives at position 7. Additionally, the corresponding diol methyl ethers were obtained by reducing the lactone with LiAlH4. 7-O-Methylepipicropodophyllotoxin [12], 7-O-methylpicropodophyllotoxin [13], the diol methyl ethers 15-18 and the corresponding diacetates are described here for the first time. Most of the cyclolignans obtained were evaluated for their cytotoxic activity.

Animals↗

Antineoplastic and antiviral activities of podophyllotoxin related lignans.

28 cyclolignans, most of them derived from podophyllotoxin, have been evaluated for their antineoplastic and antiviral activities. They were subjected to screening against P-388 murine leukemia, A-549 human lung carcinoma, and HT-29 colon carcinoma, while antiviral assays were performed on herpes simplex virus type I infecting fibroblasts of monkey kidney (HSV/CV-1) and on vesicular stomatitis virus infecting fibroblasts of hamster kidney (VSV/BHK). A number of substances were active in both groups of assays at concentrations below 1 microM; deoxypodophyllotoxin (1) being the most potent compound in all cases.

Animals↗

Pharmacological and phytochemical studies of Cephäelis axillaris.

The most significant effect, observed in the preliminary pharmacological evaluation of the whole ethanol extract and the alkaloidal fraction of Cephäelis axillaris, was the hyperemia of ears and external mucosas which was most probably due to an alpha-adrenergic blocking activity. In addition, both samples also induced a marked hypotension in normotensive as well as hypertensive (SHR) rats and inhibited the increases of blood pressure induced by i.v. administration of noradrenaline in pithed rats. The structures of the major alkaloidal components of the extract were elucidated on the basis of chemical characterization assays and IR, UV, 1H and 13C one and two-dimensional NMR analyses.

Animals↗

Antineoplastic and antiviral activities of some cyclolignans.

Nineteen cyclolignans of varied structures, most of them isolated from Juniperus sabina leaves, were evaluated for their antineoplastic and antiviral activities. They were subjected to screening against P-388 murine leukemia, A-549 human lung carcinoma, and HT-29 colon carcinoma, while the antiviral assays were performed on herpes simplex virus type 1 infecting fibroblasts of monkey kidney (HSV-1/CV-1) and on vesicular stomatitis virus infecting fibroblasts of hamster kidney (VSV/BHK). A number of substances were active in both types of assays at concentrations below 1 microgram/ml; deoxypodophyllotoxin and beta-peltatin A methyl ether being the most potent compounds in all cases, with IC50 values in the range 2.5-4 ng/ml for the three neoplastic systems.

Animals↗

Abietane acids: sources, biological activities, and therapeutic uses.

The biological activities of natural abietane acids and their derivatives have been reviewed from 1967 to 1992. Antimicrobial, antiulcer, and cardiovascular activities are the most representative for this class of diterpenoids, while others like allergenic, antiallergic, filmogenic, surfactant, antifeedant, etc. activities, which determine several uses of abietane acids, have also been reported.

Animals↗

Synthesis and antineoplastic activity of cyclolignan aldehydes.

Several aldehydes related to methyl 9-deoxy-9-oxo-alpha-apopicropodophyllate, a selective antitumour agent against the HT-29 colon carcinoma, have been prepared and evaluated for their cytotoxic activities on four neoplastic cell lines (P-388, A-549, HT-29 and MEL-28). All of them lacked the lactone ring but maintained their cytotoxicity at, or under, the microM level.

Aldehydes↗