Antidiarrheal activity of dehydroleucodine isolated from Artemisia douglasiana.

Dehydroleucodine (DhL), a sesquiterpene lactone obtained from Artemisia douglasiana, was screened for antidiarrheal effects. DhL inhibited castor oil-induced diarrhea in mice by judged by a decrease in the number of wet faeces in the DhL-treatment groups. DhL significantly reduced intestinal transit in mice. Yohimbine and phentolamine counteracted the inhibitory effect of DhL. It is suggested that alpha2-adrenergic receptors mediate the effect of DhL in intestinal motility. DhL reduced also intraluminal accumulation of fluid. Thus, the antidiarrheal activity of DhL is possibly related, at least in part, to its inhibitory action against gastrointestinal motility and the inhibition of enteropooling property.

Anti-inflammatory properties of plant flavonoids. Effects of rutin, quercetin and hesperidin on adjuvant arthritis in rat.

The anti-inflammatory activities of three flavonoids were investigated in rats using the Mizushima et al. model of acute and chronic inflammation. Intraperitoneal administration of rutin, quercetin (flavonols) and hesperidin (flavanone), given at daily doses equivalent to 80 mg/kg, inhibited both acute and chronic phases of this experimental model of inflammation. Rutin was the most active in the chronic phase.

Antiinflammatory activity from aerial parts of Baccharis medullosa, Baccharis rufescens and Laennecia sophiifolia in mice.

The antiinflammatory activities of ten organic extracts from the aerial parts of Baccharis medullosa DC., Baccharis rufescens S. and Laennecia sophiifolia (Kunth) G. L. Nesom were investigated in mice subjected to carrageenan induced paw oedema. Intraperitoneally administered organic extracts given at doses equivalent to 80 mg/kg of material inhibited the acute phases of inflammation in this model. Our results indicate that the most effective extracts were: n-hexane (I) from B. medullosa, acetone (V) and chloroform (VII) from L. sophiifolia, and acetone (VIII) and chloroform (X) from B. rufescens. All exerted the strongest effect at 5 h after injection of the phlogistic agent.

Phytochemical study and anti-inflammatory properties of Lampaya hieronymi Schum. ex Moldenke.

The chemical study of aerial parts of Lampaya hieronymi Schum. ex Moldenke yielded oleanolic acid, epi-oleanolic acid, epi-maslinic acid, 4'7-dimethoxyapigenin, p-hydroxyacetophenone, and p-hydroxyacetophenone-beta-glucoside. In searching for natural products as potential anti-inflammatory agents, all the compounds, except 4'7-dimethoxyapigenin were evaluated in vivo for their ability to inhibit acute inflammation. Our studies demonstrated that p-hydroxyacetophenone and the triterpenes produced protective effects in carrageenan induced paw edema in mouse, at 1-3 h and 3-5 h, respectively, after the injection of carrageenan. These results indicated that their effects might correlate with the release of histamine, serotonin, kinin and prostaglandins.

Acute and chronic antiinflammatory effects of plant flavonoids.

The antiinflammatory activities of 30 flavonoids isolated from several plants of the Compositae family were investigated using carrageenan-induced mouse paw edema and cotton pellet-induced rat granuloma. Compounds were administered with a unique dose of 75 mg/kg i.p. in the acute test with carrageenan and 25 mg/kg/day in the chronic granuloma test. Flavonoids inhibit the development of the induced granuloma, mostly when a catechol or guaiacol-like B ring is contained in the compound structure, jaceosidin being the most active flavonoid screened. Flavonoids significantly inhibited the maximum edema response in the acute test. We conclude that several of the isolated flavonoids tested here showed antiinflammatory effects, depending on the experimental model used.

Seasonal variations in the testis and epididymis of vizcacha (Lagostomus maximus maximus).

Seasonal changes in reproductive activity in the adult male vizcacha (Lagostomus maximus maximus), a South American rodent, were investigated. Monthly, for 2 yr, the animals were killed and decapitated during the night near their burrows in the vicinity of San Luis, Argentina. The testes, epididymides, and pineal glands were removed and used for biochemical and structural studies. Significant changes associated with seasonal cycles were found. 1) In July-August (winter in South America), a short hibernal period of sexual quiescence, decline in testicular and epididymal weights, arrest of spermatogenesis, and decrease of serum testosterone were observed. The gonads regressed during this period, with regression most pronounced in August. 2) During September-November (spring), a recovery period--without arrest of spermatogenesis--was observed, with significant expression of gonadal activity during April-May (autumn). In this season, gonadal weight was increased and spermatogenesis was complete. These results indicate an increase in sexual activity as well as in the ability to secrete testosterone. A gradual reduction of testicular activity appeared in June-July (early winter). Conversely, in this period, the pineal hydroxyindole-O-methyl transferase activity decreased in contrast to the highest values observed in winter. Our findings indicate that the male adult vizcacha under natural conditions exhibits an annual reproductive cycle. A possible relationship between increased pineal activity and gonadal regression is also suggested.

Pineal serotonin N-acetyltransferase and hydroxyindole-O-methyltransferase activities in vizcacha (Lagostomus maximus maximus) maintained under various photoperiods.

The experiments described in the present paper were aimed to study the vizcacha pineal N-acetyltransferase (NAT) and hydroxyindole-o-methyl-transferase (HIOMT) activities under different lighting regimens. Pineal NAT activity (LD 12:12) exhibits a marked diurnal variation, which decreased during the illumination hours and increased 3-fold after 4 h in darkness. NAT activity of the vizcacha exposed to permanent darkness exhibited an abrupt increase, values being lower during permanent illumination. Vizcacha pineal HIOMT activity (LD 12:12) does not exhibit significant change during the light and darkness phases. In animals exposed continuously to darkness HIOMT activity increased, while under constant illumination a decrease of HIOMT activity to about 1/7 of those under permanent darkness was found. When vizcachas were exposed to natural illumination (day-night), pineal HIOMT activity did exhibit a diurnal rhythm. Either continuous darkness or continuous light abolished the daily variations of vizcacha pineal HIOMT activity. Our results also show that permanent darkness abolished the daily variations of NAT activity suggesting an exogenous rhythm.

Pineal serotonin N-acetyltransferase and hydroxyindole-O-methyltransferase activities in vizcacha (Lagostomus maximus maximus) maintained under various photoperiods.

The experiments described in the present paper were aimed to study the vizcacha pineal N-acetyltransferase (NAT) and hydroxyindole-o-methyl-transferase (HIOMT) activities under different lighting regimens. Pineal NAT activity (LD 12:12) exhibits a marked diurnal variation, which decreased during the illumination hours and increased 3-fold after 4 h in darkness. NAT activity of the vizcacha exposed to permanent darkness exhibited an abrupt increase, values being lower during permanent illumination. Vizcacha pineal HIOMT activity (LD 12:12) does not exhibit significant change during the light and darkness phases. In animals exposed continuously to darkness HIOMT activity increased, while under constant illumination a decrease of HIOMT activity to about 1/7 of those under permanent darkness was found. When vizcachas were exposed to natural illumination (day-night), pineal HIOMT activity did exhibit a diurnal rhythm. Either continuous darkness or continuous light abolished the daily variations of vizcacha pineal HIOMT activity. Our results also show that permanent darkness abolished the daily variations of NAT activity suggesting an exogenous rhythm.

Biological role of the pineal. Responses to the environmental photoperiod.

The pineal of vizcacha (Lagostomus maximus maximus) in specimens collected during winter, has the cytological characteristic of an active organ. In this state the animal is adapted to a prolonged dark environment and its reproductive organs are inactive. During summer, the vizcacha displays its sexual annual cycle of reproduction and the pineal is apparently inactive. These seasonal pineal changes may be related to the natural photoperiod and the gradual exposure to twilight during the long daylight summer period. This photic information may be expressed as changes in the sympathetic tone of the pineal. The vizcacha and rat's pineals may also influence on the pituitary pars intermedia secretion to respond as photoreceptors in the mechanism of adaptation to the natural photoperiod.

Biological role of the pineal.Responses to the environmental photoperiod.

La pineal de la vizcacha (Lagostomus maximus maximus) sacrificadas durnate invierno muestra caracteristicas citologicas de un organo activo. En esta estacion el animal se encuentra adaptado a un prolongado medio ambiente de oscuridad. Sus organos reproductores estan inactivos.Durante el verano la viscacha tiene su ciclo anual reproducto y la pineal esta aparentemente inactiva. Estos cambios estacionales de la glundula pineal pueden relacionarse con el fotoperiodo natural y con la exposicion gradual a la luz crepuscular durante los periodos de luz diarios del verano. Dicha informacion fotica podria expresarse como cambios en el tono simpatico pineal. Las pineales de vizcacha y rata podrian tambien influjir sobre la secrecion de la pars intermedia hipofisaria, las que responderian como fotorreceptores en el mecanismo de adaptacion al fotoperiodo natura

Hydroxyindole-O-methyltransferase (HIOMT), catechol-O-methyltransferase (COMT) and histamine-N-methyltransferase (HNMT) in the pineal gland of the vizcacha (Lagostomus maximus maximus).

The activities of three methylating enzymes HIOMT, COMT, and HNMT were determined in pineal glands from 2 groups of adult vizcachas of both sexes, one (I) maintained under permanent lighting (15 days) and the other (II) kept in darkness. The control determinations (III) were carried out in pineal glands from animals hunted and killed during the night. In (I) the HIOMT activity decreased and the COMT activity increased; no changes were exhibited by HNMT. In (II) showed a diminished HIOMT activity. In captivity illumination affected HIOMT and COMT activites in a similar form to that observed in other species of rodents. The decrease in HIOMT activity in (II) suggests that captivity may affect pineal function, possibly as a consequence of a decrease in locomotor activity.

Hydroxyindole-O-methyl transferase (HIOMT) and serotonin in the pineal gland of the vizcacha (Lagostomus maximus maximus).

Pineal glands of vizcachas collected from their natural habitat were studied. Hydroxyindole-O-methyl transferase (HIOMT) activity showed a great individual dispersion. However, the enzyme activity was significantly higher in males than in females. Serotonin was also assayed in the glands. It did not show significant differences between both sexes. The results are discussed in relation to the natural life conditions of this rodent.

Hydroxyindole-O-methyl transferase (HIOMT) and serotonin in the pineal gland of the vizcacha (Lagostomus maximus maximus)

Pineal glands of vizcachas collected from their natural habitat were studied. Hydroxyindole-O-methyl transferase (HIOMT) activity showed a great individual dispersion. However, the enzyme activity was significantly higher in males than in females. Serotonin was also assayed in the glands. It did not show significant differences between both sexes. The results are discussed in relation to the natural life conditions of this rodent.

Hydroxyindole-O-methyl transferase (HIOMT) and serotonin in the pineal gland of the vizcacha (Lagostomus maximus maximus).

Pineal glands of vizcachas collected from their natural habitat were studied. Hydroxyindole-O-methyl transferase (HIOMT) activity showed a great individual dispersion. However, the enzyme activity was significantly higher in males than in females. Serotonin was also assayed in the glands. It did not show significant differences between both sexes. The results are discussed in relation to the natural life conditions of this rodent.