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X Lozoya

Publications and source records attributed to X Lozoya.

At least 19 recordsLinked to original sources

An experimental model of stress-induced immunosuppression produced by electrical stimulation of the brain in the rat.

The present paper reports a model of stress induction, based on electrical stimulation of the brain in normal Wistar rats. Stress-related stimulation of the hypothalamic-pituitary-adrenal axis produced a rise in circulating corticosterone levels that correlated significantly with the impairment of some immunological parameters, such as delayed hypersensitivity reactions to dinitrofluorobenzene and to sheep red blood cells, together with changes in splenocyte proliferation and phagocytic activity of peritoneal macrophages. This experimentally elicited stress in the rat is proposed as a suitable model of immunosuppression that could be used for the evaluation of drugs with potential immunomodulatory properties.

Animals↗

Immunomodulatory activity of Chilean Cyttaria species in mice with L5178Y lymphoma.

The immunomodulatory effect of hydrosoluble extracts of four Chilean Cyttaria species (Discomycetes, Fungi) was assessed in mice with L5178Y lymphoma. Oral administration of 100 mg extract per day for 7 days enhanced the percentual phagocytosis and phagocytosis index in animals receiving Cyttaria berteroi, Cyttaria darwinii, Cyttaria espinosae and Cyttaria harioti extracts. Differences in the digestion index were observed in mice treated with C. darwinii and C. berteroi. In the delayed-type hypersensitivity model, only C. harioti was able to modify the immune response. The results suggest that intake of Cyttaria can improve the immune system of consumers.

Adjuvants, Immunologic↗

Phenytoin and electric shock-induced apoptosis in rat peripheral blood lymphocytes.

The apoptotic index (AI) of peripheral blood lymphocytes (PBL) and plasma corticosterone (CS) levels were determined in Wistar rats treated with phenytoin (PHT) at therapeutic and toxic doses (100 or 200 mg/kg/day, respectively, over a period of 7 days) and stressed by bifrontal electric shock (60 Hz/40 mA/0.2 seg). The values of CS and AI were found to be significantly higher in rats submitted to electric shock (ES) and in rats treated with therapeutic and toxic doses of PHT plus ES, than in rats treated only with PHT (P<0.001). The plasma concentrations of PHT were found to be significantly higher in rats treated with toxic doses than in those treated with therapeutic doses (P<0.001), while the control group (without treatment) and vehicle group (propilenglycol-ethanol-water, 40:10:50), showed low levels of CS, and less than 1% of AI. The DNA analysis by electrophoresis in agarose in all the groups was positive, displaying the ladder pattern characteristic of apoptotic process (200 bp), except in the control groups (no treatment and vehicle treated). Our results demonstrate that chronic stress, caused by ES, produces an elevation of CS. The values of apoptosis were correlated with the CS levels, suggesting that the apoptotic inductor process is a consequence of an increase in the concentration of corticosterone in plasma, in response to the hypothalamic-pituitary-adrenals (HPA) axis activation, while phenytoin at therapeutic doses is only a moderate apoptosis inductor.

Animals↗

Antimicrobial compounds detected in Bocconia arborea extracts by a direct bioautographic method.

BACKGROUND: Among the numerous in vitro methods for studying the antimicrobial activity of plant drugs, bioautography has found widespread applications, especially for the detection of new compounds in complex plant extracts. METHODS: This paper describes the results obtained during the application of the bioautographic method to detect antimicrobial compounds in a chloroformic extract of leaves and stems of Bocconia arborea, a plant used profusely in traditional medicine for the treatment of diverse infectious diseases. RESULTS AND CONCLUSIONS: The methods allows for the detection of spots of growth inhibition of cultures directly in the extract thin layer chromatographic plate previously dispersed with a broth culture containing the microorganisms. The procedure also allowed for the detection of the presence of several products in the B. arborea extract with considerable activity against five different microorganisms. Additionally, the method allowed the determination that the antimicrobial activity is due to compounds of probable alkaloid origin.

Anti-Infective Agents↗

Antimicrobial evaluation of some plants used in Mexican traditional medicine for the treatment of infectious diseases.

Twelve methanolic plant extracts from botanical species used in traditional medicine in Morelos, México to cure infectious diseases have been subjected to a screening study to detect potential antimicrobial activity against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. The antimicrobial activity of the products was evaluated using colonies growing in solid medium, establishing the minimal concentration required to inhibit their in vitro growth (MIC). The results showed that extracts from Eucalyptus globolus Labill, Punica granatum L., Artemisia mexicana Wild., and Bocconia arborea Watt. possess strong in vitro antimicrobial activity against the tested microorganisms.

Candidiasis↗

Survival of cultured plant cells grafted into the subcutaneous tissue of rats (preliminary report).

To evaluate the survival of plant tissue in an animal environment, cultured calli from a Mexican medicinal plant (Mimosa tenuiflora Poir.) were transplanted under sterile conditions into the subcutaneous tissue of rats. Microscopic studies of grafted areas were carried out at the 30th, 60th and 120th days after transplantation. Histological evidence of plant graft survival was found in specimens of all groups. during the first month of subcutaneous grafting a moderate inflammatory reaction around the callus was observed characterized by the presence of polymorphonuclear cells and some macrophages and the formation of a fibrous capsule. Nevertheless, the plant grafts remained viable and a decrease of the inflammatory reaction around the callus was observed in the specimens during the following months. In the fourth month specimens the formation of blood vessels inside the grafted plant tissue was observed. Once removed from rats, plant tissues showed high viability according to the fluorescein test. These calli were then transferred to the original in vitro medium showing growth capacity during the following weeks. These results demonstrate, for the first time, that cultivated cells of higher plants survive in an animal environment, suggesting the possibility to utilize pharmacologically active plant transplants in animals, a technique proposed here as inter-regni transplants. Further studies are required to explore this new field of research that opens numerous questions about plant-animal cellular interaction.

Animals↗

Archives of Medical Research: an historical and subject coverage overview.

A bibliometric study about the subject content of the articles published in the Mexican scientific journal Archives of Medical Research is reported. The journal, published by the Mexican Institute of Social Security (IMSS), is comprised of 100 regular issues and 12 special supplements giving a total amount of 1,424 reports on medical research performed in Mexico during the last 25 years. According to the type of studies published during this period, we found that there is a similar percent of biomedical and clinical reports in the journal (47 and 42%, respectively) and a low proportion of epidemiological and medical educational reports (8 and 3%, respectively). Six thematic areas of research have been permanently published in this journal: investigations on infectious and neurological diseases being the areas mainly represented (34% of the total, corresponding to 17% in each area), followed by studies in reproductive biology (10%) and endocrine (7%), oncological (5%) and cardiovascular (3%) diseases. The tendency of the subjects covered by the journal during this period shows an increment in reports on infectious and parasitic disorders together with an increase in publications related to medicinal plant pharmacology; reproductive biology and endocrine studies show also an increasing tendency. On the other hand, a moderate decrease in studies related to neurological, oncological and cardiovascular diseases is observed. The origin of contributions during the last five years has balanced the proportion of papers published from IMSS scientists, other Mexican biomedical researchers and foreign contributions, thus reflecting favorably the recent changes in the journal's policies. This journal represents a clear example of a scientific publication edited in a developing country, originating as a national publication that evolved progressively into an international biomedical journal.

Animals↗

Two decades of Mexican ethnobotany and research in plant drugs.

A renewed interest in the systematic study of indigenous medicines and associated medicinal plants arose in the 1970s. In Mexico the government established a national pharmaceutical industry to make use of the valuable colonial heritage of traditional practices combined with European medical concepts and resources. In 1975 the Mexican Institute for the Study of Medical Plants was created to integrate botanical, chemical and pharmacological studies on the Mexican flora. It compiled a database on ethnobotanical information relating to Mexican medicinal plants from the medical literature of the 16th to 19th centuries. A second database contained information on medicinal plants in current use. A medicinal herbarium was established. Taxonomical studies led to classification of the 11,000 voucher specimens in the herbarium and cross-referencing of the information with other databanks. A core group of 1000 plants used in traditional medicine throughout Mexico for almost 400 years was identified. Most of these are used to treat common diseases or basic health problems, usually given orally as decoctions or infusions. 95% of the plants used traditionally are from wild species. Information was collected from almost 3000 small Indian communities over four years on three aspects of traditional medicine--the healer, the disease categories recognized and the therapeutic resources in use. Plants with reported medicinal activity were selected for laboratory screening according to the frequency and commonality of their use, geographical distribution and seasonal availability. Screening involves a collaboration between chemists and pharmacologists: plant extracts are sequentially assayed and fractionated until the pure compound is isolated. Several active compounds are usually obtained from the same extract, frequently from the aqueous fractions. Ethnomedical information influences which plants are selected for screening and the type of assay used.

Medicine, Traditional↗

Calcium-antagonist effects of quercetin on aortic smooth muscle.

Relaxation induced by quercetin was studied on aortic rings depolarized with KCl and on Ca2+ dependent aortic contraction. Quercetin's actions as a cyclooxygenase inhibitor were compared with those of indomethacin. To determine the possible effects of quercetin on internal Ca2+ mobilization, it was assayed on aortic muscle contracted with caffeine. Quercetin relaxes aortic smooth muscle contracted with KCl (RC50 = 1.8 x 10(-4) M) and induces a rightward displacement of Ca2+ curves. The relaxation induced by quercetin is higher than that produced by indomethacin, suggesting that its action is independent of cyclooxygenase inhibition. Caffeine-induced aortic contraction was not modified by quercetin, suggesting that its effect should not involve internal calcium modulation. Our results further support the thesis that the spasmolytic action of quercetin arises from its negative modulation of calcium entry to the smooth muscle.

Animals↗

Quercetin glycosides in Psidium guajava L. leaves and determination of a spasmolytic principle.

The traditional herbal remedy from Psidium guajava leaves has been medically proposed in Mexico as effective treatment of acute diarrhea. A methanolic leaf extract was subjected to a bioassay-guided isolation of spasmolytic constituents. Six fractions were separated on a polyvinylpolypyrrolidine (PVPP) column using a water methanol-gradient. The fraction containing flavonols inhibited peristalsis of guinea pig ileum in vitro. A trace of quercetin aglycone together with five glycosides was isolated from this active fraction and identified as quercetin 3-O-alpha-L-arabinoside (guajavarin); quercetin 3-O-beta-D-glucoside (isoquercetin); quercetin 3-O-beta-D-galactoside (hyperin); quercetin 3-O-beta-L-rhamnoside (quercitrin) and quercetin 3-O-gentobioside. Biological activity of each pure compound was studied in the same bioassay. Obtained results suggest that the spasmolytic activity of the Psidium guajava leaf remedy is mainly due to the aglycone quercetin, present in the leaf and in the extract mainly in the form of five flavonols, and whose effect is produced when these products are hydrolyzed by gastrointestinal fluid.

Animals↗

Calcium-antagonist effect of quercetin and its relation with the spasmolytic properties of Psidium guajava L.

The antidiarrheal properties of water and methanolic extracts of Psidium guajava leaves have been demonstrated with anteriority and their spasmolytic effect was attributed to quercetin, a flavonoid contained in this plant. The present paper reports the intestinal smooth muscle relaxation produced by quercetin on isolated guinea pig ileum previously contracted by a depolarizing KCl solution. Quercetin also inhibited intestinal contraction induced by different concentrations of calcium, shifting the contraction curve to the right showing a clear calcium-antagonistic effect. Quercetin effect on ileal and aortic smooth muscles are compared, the ileum being more sensitive to this flavonoid. The calcium-antagonist property of quercetin is discussed and also its contribution to explain the spasmolytic effect of this popular herbal remedy.

Animals↗

Solanum chrysotrichum (Schldl.) a plant used in Mexico for the treatment of skin mycosis.

An ethnobotanical field study carried out in 200 rural communities determined that the leaves of Solanum chrysotrichum Schldl. are used in Mexican traditional medicine for the treatment of skin mycosis, being particularly recommended to cure Tinae pedis. Clinical trials were performed using a cream containing 5% of a methanolic leaf extract of this plant. Results showed that 45% of the patients were completely cured after 4 weeks of topical treatment. The rest of the cases improved notably in comparison with the control group of patients using the habitual miconazole treatment. The same plant extract inhibited the growth in vitro of the dermatophytes Trychophyton mentagrophytes, T. rubrum and Microsporum gypseum at MICs under 15 mg/ml.

Antifungal Agents↗

Effect of Galphimia glauca methanolic extract on neuropharmacological tests.

Galphimia glauca Cav. (Malpighiaceae) is used in Mexican traditional medicine for the treatment of nervous excitement. A methanolic extract from its aerial parts (MEGA) was tested in several neuropharmacological animal models including among others: hypothermic activity, barbiturate potentiation, protection against strychnine- and leptazol-induced convulsions. The combined data obtained from all biological models demonstrate the sedative property of this plant product.

Animals↗

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Americas↗

The in vitro effect of grandiflorenic acid and zoapatle aqueous crude extract upon spontaneous contractility of the rat uterus during oestrus cycle.

Montanoa tomentosa (zoapatle) is a Mexican plant popularly used for antifertility purposes and with promising characteristics for the development of a new oral contraceptive agent with uteroevacuant properties. In a previous pharmacological report we established the ambivalent myometrial response to zoapatle leaves aqueous extract (ZACE) depending on the animal species used and on the existence or absence of pregnancy. This fact could be useful in determining an appropriate medical use of zoapatle and suggests an interesting possible hormonal dependence in its mechanism of action. To elucidate the ZACE effect upon the pattern of uterine contractility in different hormonal stages, the rat uterus in vitro during oestrus cycle was studied. The aqueous crude extract of Montanoa tomentosa leaves produced different (or even opposite), effects on uterine motility during the distinct phases of the oestrus cycle in the rat. Furthermore, pure grandiflorenic acid (GA), obtained from the phytochemical work up of this plant reproduced the uterine responses induced by ZACE. The action of zoapatle is discussed in relation to hormonal stage and to a probable adrenergic mechanism involved.

Abortifacient Agents↗

The zoapatle II--botanical and ecological determinants.

A collection of Montanoa (Cerv) specimens was conducted throughout Mexico. Twenty-one specimens were classified, some of them grown in the greenhouse and transplanted in an agricultural experimental field station in the Valley of Mexico. In vitro uterotonic potency was assayed and the results expressed as equivalents of oxytocine, by using estrogenized guinea pig uterine strips. A great variation of uterotonic potency was observed among the wild plants. A clear decrease and uniformity of uterotonic potency was found in plants grown in the experimental field. The study points out the importance of ecological variations in expression of the plant's biological activity.

Altitude↗

The zoapatle III--biological and uterotonic properties of aqueous plant extract.

Differences in uterotonic activity were observed between zoapatle Montanoa (Cerv.), plants growing in their natural habitat and plants growing in an experimental agricultural plot. Details of an in vitro analogic model for assaying uterotonic potency in guinea pig strips is described. Important species differences on the uterine response to zoapatle aqueous crude extract were noticed in rats, hamsters, guinea pigs, cats and Rhesus monkeys. The need for proper biological evaluation of chemical substances already isolated from zoapatle specimens, is mentioned, and the advantages of working with zoapatle specimens grown under controlled ecological conditions are pointed out.

Animals↗

The zoapatle IV--toxicological and clinical studies.

The zoapatle aqueous crude extract has been used in Mexico for the last 5 centuries for the induction of labor, treatment of post-partum bleeding problems, and as a menses inducer. Today, it is sold in street markets, and its long documented history of use by humans could be taken as indirect evidence of a lack of toxicity. Rigorous pharmacological and clinical studies described here, fully confirm the empirical observations.

Animals↗