Search PubMed⌕ Search

Biomedical subjects

A San Feliciano

Publications and source records attributed to A San Feliciano.

At least 19 recordsLinked to original sources
PubMed2005

Analgesic-antiinflammatory properties of Proustia pyrifolia.

The antiinflammatory (per os and topic) and analgesic (per os) properties of the aerial part of Proustia pyrifolia a species in danger of extinction were investigated, and the major compounds of two of its active extracts were isolated. In addition, the evaluation of cytotoxicity in three tumoral cell lines and the acute toxicity of the crude methanol extract were also assayed, together with the antioxidant activity for the different extracts of this species. The results of the evaluation of the topic antiinflammatory activities induced by arachidonic acid, and phorbol 12-myristate 13-acetate of the different extracts showed that this species possesses active constituents that could diminish cyclo-oxygenase and lipoxygenases activities, the enzymes that allow the synthesis of proinflammatory endogenous substances as prostaglandin E(2) and leukotrienes, respectively. Our results corroborate the antiinflammatory and analgesic effects of Proustia pyrifolia, and could justify its use in folk medicine for the treatment of rheumatic and gout illnesses. From bio-active extracts beta-sitosterol, quercetin and dihydroquercetin were obtained, and these compounds could explain in part the antiinflammatory, analgesic and antioxidant activities of this species. The crude methanol extract did not present acute toxicity or cytotoxic activity, however only this extract exhibited antioxidant activity.

Analgesics↗
PubMed2004

Synthesis and cytotoxicity of hydrophobic esters of podophyllotoxins.

Diverse norbornenecarboxylate esters of podophyllotoxin and its epimers and diastereoisomers have been prepared through Diels-Alder cycloaddition by treating the dienophilic acrylates of cyclolignans with cyclopentadiene. Their cytotoxicities against several cancer cell lines have been evaluated and the results compared with those found for other lignan esters. Podophyllotoxin adducts showed a one-fold increase in activity when compared to the natural product. The preparation of more hydrophobic esters, which showed less cytotoxicity, demonstrated that this activity is not primarily due to the lipophilic factor, but mainly to the spatial arrangement of the bulky moiety, which could contribute to increase the binding to the target site.

Animals↗
PubMed2004

Anti-inflammatory activity of leaf extract and fractions of Bursera simaruba (L.) Sarg (Burseraceae).

Seeking for new medicinal compounds in plants used in traditional medicine, which grow in Venezuela, we investigated the anti-inflammatory activity of the leaf hexane extract (HE) and several fractions obtained from sp. Bursera simaruba (L.) Sarg. (Indio desnudo) using carrageenan-induced paw edema inflammation. Oral administration of leaf HE as well I (91-100) fraction, and compounds VIII 25-26 and VIII 29, inhibited the carrageenan-induced paw edema with different capacity and time course, over a period of 7h. The anti-inflammatory effect was comparable to that of the reference drug phenylbutazone (80 mg/kg, p.o.). Included in fraction I (91-100), Vitamin E was identified as one of its components and compound VIII 29 was identified as a methyl-beta-peltatin A. The comparison of the anti-inflammatory activity of VIII 29 fraction with the corresponding standard of methyl-beta-peltatin A, suggest that this compound could be one of the active principles involved in the anti-inflammatory activity of Bursera simaruba (L.) Sarg. leave. Our results contribute to the pharmacological support of the use of Bursera simaruba (L.) Sarg. as anti-inflammatory in the ethnomedicinal practice.

Administration, Oral↗
PubMed2001

Anti-Trypanosoma activity of some natural stilbenoids and synthetic related heterocyclic compounds.

We report the anti-Chagasic activity of the natural dihydrostilbenoid isonotholaenic acid and several simple derivatives, as well as that of some representative compounds of related synthetic series, with basic structures of benzalphthalides, dihydrostilbamides, isoindoles, phthalazin-1-ones, imidazo[2,1-a]isoindoles and pyrimido[2,1-a]isoindoles. The evaluation was performed in vitro on cultures of epimastigote and trypomastigote forms of Trypanosoma cruzi. Some of the tested compounds resulted to be as potent as benznidazole (epimastigotes), and others were shown to be more active than gentian violet (trypomastigotes), used as reference drugs.

Animals↗
PubMed2001

Leishmanicidal activity of some stilbenoids and related heterocyclic compounds.

We have evaluated the leishmanicidal activity of some natural and semisynthetic dihydrostilbenoids and several compounds of other series of dihydrostilbamides, isoindoles, phthalazinones, imidazoisoindoles and pyrimidoisoindoles. The evaluation was performed in vitro, on cultures of cutaneous, mucocutaneous and visceral strains of Leishmania spp. The most potent and selective compounds of these series were the dihydrostilbene piperidides.

Animals↗
PubMed2001

New selective cytotoxic diterpenylquinones and diterpenylhydroquinones.

A new series of diterpenylquinone/hydroquinones has been prepared by Diels-Alder cycloaddition between three labdanic diterpenoids (myrceocommunic acid, methyl myrceocommunate, and myrceocommunyl acetate) and p-benzoquinone or 1,4-naphthoquinone. Influences of the quinone/hydroquinone fragment and other structural features, such as the different functionalities in the terpenic core, are considered in relation to the cytotoxicity toward neoplastic cells and the selectivity of these diterpenylnaphthoquinones/hydroquinones and anthraquinones. Several compounds showed IC50 values under the micromolar level, and four of these derivatives were evaluated at the NCI screening panel. The results showed an important selectivity toward renal cancer lines, identifying these compounds as a very promising group of antineoplastics.

Animals↗
PubMed2001

Trypanosoma cruzi: inhibition of parasite growth and respiration by oxazolo(thiazolo)pyridine derivatives and its relationship to redox potential and lipophilicity.

Chagas' disease constitutes a therapeutic challenge because presently available drugs have wide toxicity to the host and are generally ineffective in the chronic stages of the disease. A series of oxazolo(thiazolo)pyridene derivatives were studied on Trypanosoma cruzi epimastigote growth and oxygen consumption and their electrochemical (redox) potentials and lipophilicity. The derivatives produced different degrees of parasite growth and respiration inhibition on CL Brener, LQ, and Tulahuen strains of T. cruzi epimastigotes. Respiratory chain inhibition appears to be a determinant of the trypanosomicidal activity of these compounds, since a significant correlation between respiration and culture growth inhibition was found. A similar correlation was found, within the different structural subfamilies, between toxic effects and the ability of the compounds to be oxidized in aqueous media. The inhibition of respiration and of parasite growth in culture increases with the lipophilicity of the substituents on the oxazolopyridine nucleus. No difference in the action of these derivatives was found among the different parasite strains. It is concluded that these compounds may have a potential usefulness in the treatment of Chagas' disease.

Animals↗
PubMed2001

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↗
PubMed2000

Synthesis and enzyme inhibitory activities of a series of lipidic diamine and aminoalcohol derivatives on cytosolic and secretory phospholipases A2.

We have synthesised some lipidic diamines and aminoalcohols and examined their behaviour as inhibitors of secretory and cytosolic PLA2. Some structure-activity relationships considerations have been deduced. Compound 14 was a potent and selective inhibitor of cPLA2 and compound 4 showed a dual inhibitory profile against both types of PLA2 while no cytotoxicity at 10 microM on human neutrophils or on murine macrophage line was observed for both.

Amino Alcohols↗
PubMed2000

Effects of 3-chloro-phenyl-1,4-dihydropyridine derivatives on Trypanosome cruzi epimastigotes.

A series of 3-chloro-phenyl-1,4-dihydropyridine derivatives produced different degrees of inhibition of parasite growth and respiration on clone Brener, LQ and Tulahuen strains of Trypanosome cruzi epimastigotes. Respiratory chain inhibition appears to be a posible determinant of the trypanosomicidal activity of this compounds. No difference in the action of these derivatives was found among the different parasite strains. For comparative purposes, the inhibitory effects of felodipine and nicardipine are also reported. A good correlation between toxic effects and the easiness of oxidation of the dihydripyridine ring was found. The presence of a fused ring on the dihydropyridine moiety significantly diminished the inhibitory effects.

Animals↗
PubMed2000

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↗
PubMed2000

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↗
PubMed1999

Leishmanicidal activity of combretastatin analogues and heteroanalogues.

We have investigated the in vitro leishmanicidal activity of representative members from series II-V of combretastatin analogues and heteroanalogues. Most of them exhibited different degrees of activity against various strains of Leishmania spp. The diaryl(heteroaryl)ethane system or the more complex fused heterocyclic stilbenoids, constitute useful skeletal bases to support some kind of antiparasitic activity. Particularly, the incorporation of 2-furyl substituents led to potent antileishmanial compounds, which have been selected for in vivo testing on murine models.

Animals↗
PubMed1999

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↗
PubMed1998

Hydroindenic-guanylhydrazones. Synthesis and evaluation as inotropic agents.

The synthesis and inotropic activity of two families of hydroindenic compounds are described. Among them, a bis-guanylhydrazone derivative has demonstrated to produce an interesting positive inotropic effect on guinea pig atria, displaying at higher dosis a similar effect to that elicited by digoxin.

Animals↗
PubMed1997

Antihypertensive effect of some oxazolo[3,2-a]pyridines, thiazolo[3,2-a]pyridines and pyrido[2,1-b]oxazines in conscious spontaneously hypertensive rats.

The antihypertensive activity of eighteen 'oxazolo[3,2-a]pyridine, thiazolo[3,2-a]pyridine and pyrido[2,1-b]oxazine derivatives has been evaluated in conscious spontaneously hypertensive rats (SHRs), and compared with that of nifedipine, used as reference. At a dose of 50 mg kg-1 (i.p.) eleven compounds resulted in a significant reduction in mean arterial blood pressure; four of the eleven were particularly effective, resulting in significant hypotension more than 6 h after administration and an effect that was still apparent after 24 h. The hypotension induced by nifedipine gradually decreased, disappearing 6-8 h after administration. The long-lasting activity shown by these compounds is, in general, not accompanied by reflex tachycardia. Intraperitoneal administration of two oxazolo[3,2-a]pyridine derivatives and two pyrido[2,1-b]oxazine derivatives resulted in potent and long-lasting antihypertensive action in SHRs. Further studies on the mechanism of action of these derivatives might help the determination of better structure-activity correlations and the design, synthesis and evaluation of better antihypertensive agents.

Animals↗