Cytotoxic/antiproliferative and nutraceutical activity of aqueous and ethanolic extracts of green and mature Averrhoa carambola.

Averrhoa carambola L. presents in its composition diversity of nutrients and vitamins. The present study aimed to extract water and fat-soluble compounds from this fruit at different stages of maturation (green and mature), perform the physical-chemical characterization as well as evaluate its cytotoxicity against hepatoma cells of Rattus norvegicus (HTC). The physicochemical results showed that the pH and molar acidity is influenced by the fruit maturation state. The fruit presented high percentage of moisture, while the percentage of total minerals (ash) increased according to its maturation stage. The results of the phytochemical screening showed that star fruits present phenolic compounds. The antioxidant activity showed greater potential for the ethanolic extracts of the green and mature star fruit. For HTC cells treated with ethanolic extract of green and mature star fruit the data show absence of cytotoxic effect. The tests with the aqueous extract showed cytotoxic/antiproliferative effect of green and mature star fruit extract, in 24, 48 and 72 hours. The presence of nutraceutical compounds and the cytotoxic/antiproliferative activity were more expressive in the aqueous extract, being an option of easily accessible solvent economic and not harmful to organisms.

Cytotoxicity of isolated compounds from Picrasma crenata (Vell.) Engl. in animal tumor cell (HTC).

The study aim was to evaluate the cytotoxic activity, using the MTT test [3-(4,5-Dimethilthiazol-2-yl)-2,5-diphenil tetrazolium bromide], from the crude extract of Picrasma crenata (Pau Tenente) and its isolated compounds, quassin and parain, in culture of rat liver tumor cells (HTC). The test was carried out exposing the cells for 24, 48 and 72 hours to concentrations of 5, 10, 50, 100, 200, 300, 400, 500 and 1000 µg of crude extract of Pau Tenente/mL of culture medium and 1, 5, 10, 15, 20, 40, 60, 80 and 100 µg of quassin or parain compounds/mL of culture medium. The absorbances averages results obtained showed that the crude extract did not present cytotoxicity for the HTC cells in all the concentrations and evaluated times. For quassin, the concentrations of 80 and 100 µg/mL were cytotoxic, after 72 hours of treatment. For parain, the concentrations of 1, 5, 20, 40, 60, 80 and 100 µg/mL, in 72 hours, were cytotoxic, revealing a new activity for this compound. Thus, the results demonstrate a first indication of the cytotoxic activity of compounds quassin and parain, adding an important social and economic value to them, and may have application in future research and in pharmaceutical industry.

Cytotoxicity of capsaicin and its analogs in vitro.

Capsaicin (CAP) is the main compound responsible for the spicy flavor of Capsicum plants. However, its application can be inhibited due to its pungency and toxicity. This study aimed to evaluate and compare the cytotoxic effect of CAP and its analogs N-benzylbutanamide (AN1), N-(3-methoxybenzyl) butanamide (AN2), N-(4-hydroxy-3-methoxybenzyl) butanamide (AN3), N-(4-hydroxy-3-methoxybenzyl) hexanamide (AN4) and N-(4-hydroxy-3-methoxybenzyl) tetradecanamide (AN5) on the hepatoma cells of Rattus norvegicus using the MTT test. The results showed cytotoxicity of CAP at concentrations of 100, 150, 175, and 200 µM (24 hours), AN1 at 150 and 175 µM (48 hours), AN2 at 50 µM (24 hours) and 10, 25, 50, and 75 µM (48 hours), AN4 at 175 µM (24 hours), and AN5 at 50 µM (48 hours). Removing the hydroxyl radical from the vanillyl group of capsaicin, together with reducing the acyl chain to 3 carbons, which is the case of AN2, resulted in the best biological activity. Increasing the carbon chain in the acyl group of the capsaicin molecule, which is the case of AN5, also showed evident cytotoxic effects. The present study proves that the chemical modifications of capsaicin changed its biological activity.

Cytotoxicity of extracts and compounds isolated from Croton echioides in animal tumor cell (HTC).

The search for compounds with anticancer effects is of paramount importance today due to the high incidence of the disease. The Euphorbiaceae family is known for having compounds with therapeutic properties, one of its genera being Croton. It has several species, which contain compounds already known for their biological activities, presenting anti-inflammatory, antimicrobial and anticancer properties. Thus, the cytotoxicity/antiproliferative activity of semi-purified fractions and compounds isolated from Croton echioides in liver tumor cells of Rattus norvegicus (HTC) was evaluated by the MTT test. The semi-purified fractions showed cytotoxicity at concentrations above 200 µg/mL, at 24, 48 and 72 hours, reaching cell viability of 24.78% [400 µg/mL] at 24 hours, 12.79% [500 µg/mL] at 48 hours and 10.57% [300 µg/mL] at 72 hours. For the isolated compounds, lupeol had a cytotoxic effect in all concentrations (1, 5, 10, 15, 20, 40, 60, 80 and 100 µg/mL) and tested times (24, 48 and 72 hours), reaching minimum viability of 4.37% [100 µg/mL], within 72 hours. The clerodan diterpenes CEH-1 and CEH-4 also showed antiproliferative activity, with minimum viability of 36.19% [100 µg/mL] over 72 hours and 21.33% [100 µg/mL] over 48 hours, respectively. However, the clerodan diterpenes CEH-2 and CEH-3 did not shows a cytotoxic effect for HTC cells. Thus, there is a cytotoxic/antiproliferative potential of C. echioides against tumor cells, with targeted to mitochondrial enzymes, associated with cell proliferation, indicating that this species deserves prominence in the search for new molecules for the treatment of cancer.

Cytotoxicity of iodine-131 radiopharmaceutical in tumor and non-tumor human cells and radioprotection by integral juices of Vitis labrusca L.

Iodine-131 (I-131) radioisotope it causes the formation of free radicals, which lead to the formation of cell lesions and the reduction of cell viability. Thus, the use of radioprotectors, especially those from natural sources, which reduce the effects of radiation to healthy tissues, while maintaining the sensitivity of tumor cells, stands out. The objective of the present study was to evaluate the cytoprotective/radioprotective effects of whole grape juices manufactured from the conventional or organic production systems, whether or not exposed to ultraviolet (UV-C) light irradiation. The results showed that I-131 presented a cytotoxic effect on human hepatocellular cells (HepG2/C3A) at concentrations above 1.85 MBq/mL, after 24 and 48 hours of treatment, though all concentrations (0.0037 to 7.40 MBq/mL) were cytotoxic to non-tumor human lung fibroblast (MCR-5) cells, after 48 hours. However, grape juices (10 and 20 µL/mL) did not interfere with the cytotoxic effect of the therapeutic dose of I-131 on tumor cells within 48 hours of treatment, while protecting the non-tumor cells, probably due to its high antioxidant activity. In accordance with their nutraceutical potential, antioxidant and radioprotective activity, these data stimulate in vivo studies on the use of natural products as radioprotectants, such as grape juice, in order to confirm the positive beneficial potential in living organisms.

Degradation of estriol (E3) and transformation pathways after applying photochemical removal processes in natural surface water.

Steroidal hormones such as estriol (E3), are resistant to biodegradation; hence their removal by conventional treatment systems (aerobic and anaerobic) facilities is limited. These substances are detected in surface water, and present risks to the aquatic ecosystem and humans via potential biological activity. Photochemical treatments can be used to remove E3; however, just a few studies have analyzed the kinetics, intermediates, and E3 degradation pathways in natural surface water. In this study, the behavior of E3 under ultraviolet irradiation associated with H2O2, O3 or TiO2 was investigated to determine the degradation potential and the transformation pathways in reactions performed with a natural surface water sample. E3 degradation kinetics (200 ppb) fitted well to the pseudo-first-order kinetics model, with kinetic constant k in the following order: kUV/O3 > kUV/TiO2 > kUV/H2O2 > kUV. The mechanism of degradation using different advanced oxidative processes seemed to be similar and 12 transformation byproducts were identified, with 11 of them being reported here for the first time. The byproducts could be formed by the opening of the aromatic ring and addition of a hydroxyl radical. A possible route of E3 degradation was proposed based on the byproducts identified, and some of the byproducts presented chronic toxicity to aquatic organisms, demonstrating the risks of exposure.

Assessment of phytoremediation potencial of Allium cepa L. in raw sewage treatment / Avaliação do potencial de fitorremediação da Allium cepa L. no tratamento do esgoto bruto

Abstract Whereas the effects of the substances found in domestic sewage on live organisms is important to evaluate the use of plants to remove pollutants from the environment. The objective of this study was to assess the phytoremediation activity of Allium cepa L. (onion) roots exposed to raw sewage, as well as the acute toxic activity of this effluent for the bioindicators A. cepa, through a cytotoxicity test, and Artemia salina L., through a mortality/immobility test. The physicochemical assessments of the sewage were conducted in two scenarios: immediately after collection and after being in contact with onion roots (phytoremediation) for 24 hours. The physicochemical data indicate there was a reduction in nitrogen and phosphorus levels and in biochemical oxygen demand in sewage treated. The results from the cytotoxicity test with A. cepa indicated a reduction in the mitotic cell divisions of the onions treated with the raw sewage. The mortality/immobility test with A. salina indicated that the concentrations with 50 and 100% of raw sewage induced the mortality of the nauplii. Thus, the data suggest new studies that seek greater efficiency, efficacy and viability of onion phytoremediation.

Resumo Considerando os efeitos das substâncias encontradas no esgoto doméstico em organismos vivos, é importante avaliar o uso de plantas para remover poluentes do meio ambiente. O objetivo deste trabalho foi avaliar a atividade de fitorremediação de raízes de Allium cepa L. (cebola) expostas ao esgoto bruto, bem como a atividade tóxica aguda desse efluente para os bioindicadores A. cepa, através de um teste de citotoxicidade, e Artemia salina L., através de um teste de mortalidade/imobilidade. As avaliações físico-químicas do esgoto foram realizadas em dois cenários: imediatamente após a coleta e após contato com raízes de cebola (fitorremediação) por 24 horas. Os dados físico-químicos indicam que houve redução nos níveis de nitrogênio e fósforo e na demanda bioquímica de oxigênio no esgoto tratado. Os resultados do teste de citotoxicidade com A. cepa indicaram uma redução nas divisões celulares mitóticas das cebolas tratadas com o esgoto bruto. O teste de mortalidade/imobilidade com A. salina indicou que as concentrações com 50 e 100% de esgoto bruto induziram a mortalidade dos náuplios. Assim, os dados sugerem novos estudos que busquem maior eficiência, eficácia e viabilidade de fitorremediação das cebolas.

Assessment of phytoremediation potencial of Allium cepa L. in raw sewage treatment.

Whereas the effects of the substances found in domestic sewage on live organisms is important to evaluate the use of plants to remove pollutants from the environment. The objective of this study was to assess the phytoremediation activity of Allium cepa L. (onion) roots exposed to raw sewage, as well as the acute toxic activity of this effluent for the bioindicators A. cepa, through a cytotoxicity test, and Artemia salina L., through a mortality/immobility test. The physicochemical assessments of the sewage were conducted in two scenarios: immediately after collection and after being in contact with onion roots (phytoremediation) for 24 hours. The physicochemical data indicate there was a reduction in nitrogen and phosphorus levels and in biochemical oxygen demand in sewage treated. The results from the cytotoxicity test with A. cepa indicated a reduction in the mitotic cell divisions of the onions treated with the raw sewage. The mortality/immobility test with A. salina indicated that the concentrations with 50 and 100% of raw sewage induced the mortality of the nauplii. Thus, the data suggest new studies that seek greater efficiency, efficacy and viability of onion phytoremediation.

In vivo antimutagenic activity of the medicinal plants Pfaffia glomerata (Brazilian ginseng) and Ginkgo biloba.

Complementary and alternative therapies, including the use of medicinal plants, have become almost standard among the world's population. Pfaffia glomerata (PG), popularly known as Brazilian ginseng, is widely used as a restorer of vital functions, increasing mental balance, and is used for the treatment of diabetes and rheumatism. Ginkgo biloba (GB) is one of the oldest known gymnosperms, whose leaves are widely used for its potentiating action on the nervous system. The biological activities of these plants were determined on bone marrow cells of Wistar rats treated in vivo. For cytotoxic and mutagenic acute analysis, plant extracts were administered by gavage at concentrations of 0.15, 1.5, and 15 mg PG/mL water and 1, 2, and 3 mg GB/mL water. For antimutagenic analysis, plant extracts aqueous solution (PG, 1.5 mg/mL or GB, 2 mg/mL) were administered by gavage before (pretreatment), simultaneous to (simultaneous treatment), or after (post-treatment) the administration of cyclophosphamide (1.5 mg/mL, intraperitoneally). Both plant extracts have no cytotoxic or mutagenic potential, and they significantly reduce the percentage of chromosomal aberrations induced by the cyclophosphamide given simultaneously (PG, 87%; GB, 75%), pretreatment (PG, 98%, GB, 78%) and post-treatment (PG, 99%, GB, 75%). This beneficial antimutagenic property of the medicinal plants P. glomerata and G. biloba presented here, with no cytotoxic or mutagenic activity, can efficiently contribute to improvements in quality of life and recovery for people undergoing chemotherapeutic treatment, or those looking for health and preventive habits.

Influence of processing and storage of integral grape juice (Vitis labrusca L.) on its physical and chemical characteristics, cytotoxicity, and mutagenicity in vitro.

Integral grape juice is extracted from the grape through processes that allow the retention of their natural composition. However, due to the severity of some processes, fruit juices can undergo changes in their quality. The present study evaluated the cytotoxic and mutagenic effects of integral grape juice by a cytokinesis-blocked micronucleus assay in Rattus norvegicus hepatoma cells (HTC) in vitro. Vitis labrusca L. (variety Concord) were produced organically and by a conventional system, and their juice was extracted by a hot extraction process. The organic grapes were subjected to ultraviolet-type C radiation (UV-C). Experiments were performed after production and after 6 months in storage. Physicochemical analyses revealed that UV-C irradiation of organic grapes, the juice production process, and storage resulted in nutraceutical alterations. However, none of the juice concentrations were cytotoxic to HTC cells by the cytokinesis-blocked proliferation index results or were mutagenic, because the formation of micronucleated cells was not induced. In general, juice induced cell proliferation, possibly due to the presence of vitamins and sugar content (total soluble solid). The data increased the understanding of food technology and confirmed the quality and safety consumption of these juices.

Assessment of phytoremediation potencial of Allium cepa L. in raw sewage treatment

Abstract Whereas the effects of the substances found in domestic sewage on live organisms is important to evaluate the use of plants to remove pollutants from the environment. The objective of this study was to assess the phytoremediation activity of Allium cepa L. (onion) roots exposed to raw sewage, as well as the acute toxic activity of this effluent for the bioindicators A. cepa, through a cytotoxicity test, and Artemia salina L., through a mortality/immobility test. The physicochemical assessments of the sewage were conducted in two scenarios: immediately after collection and after being in contact with onion roots (phytoremediation) for 24 hours. The physicochemical data indicate there was a reduction in nitrogen and phosphorus levels and in biochemical oxygen demand in sewage treated. The results from the cytotoxicity test with A. cepa indicated a reduction in the mitotic cell divisions of the onions treated with the raw sewage. The mortality/immobility test with A. salina indicated that the concentrations with 50 and 100% of raw sewage induced the mortality of the nauplii. Thus, the data suggest new studies that seek greater efficiency, efficacy and viability of onion phytoremediation.

Resumo Considerando os efeitos das substâncias encontradas no esgoto doméstico em organismos vivos, é importante avaliar o uso de plantas para remover poluentes do meio ambiente. O objetivo deste trabalho foi avaliar a atividade de fitorremediação de raízes de Allium cepa L. (cebola) expostas ao esgoto bruto, bem como a atividade tóxica aguda desse efluente para os bioindicadores A. cepa, através de um teste de citotoxicidade, e Artemia salina L., através de um teste de mortalidade/imobilidade. As avaliações físico-químicas do esgoto foram realizadas em dois cenários: imediatamente após a coleta e após contato com raízes de cebola (fitorremediação) por 24 horas. Os dados físico-químicos indicam que houve redução nos níveis de nitrogênio e fósforo e na demanda bioquímica de oxigênio no esgoto tratado. Os resultados do teste de citotoxicidade com A. cepa indicaram uma redução nas divisões celulares mitóticas das cebolas tratadas com o esgoto bruto. O teste de mortalidade/imobilidade com A. salina indicou que as concentrações com 50 e 100% de esgoto bruto induziram a mortalidade dos náuplios. Assim, os dados sugerem novos estudos que busquem maior eficiência, eficácia e viabilidade de fitorremediação das cebolas.

In vivo antimutagenic effects of the Barbados cherry fruit (Malpighia glabra Linnaeus) in a chromosomal aberration assay.

Barbados cherry (BC) (Malpighia glabra Linnaeus) is a functional fruit that is consumed to prevent disease. It is used as an adjuvant in the treatment of several diseases, and acts as an antianemic, an appetite stimulant, a wound healer, an anti-inflammatory, a mineralizer, an antifungal, and an antioxidant agent. Several chemotherapeutic agents, such as cyclophosphamide, may result in undesirable side effects, and generate mutations in normal cells. Thus, the present study evaluated the antimutagenic potential of the fresh (BCN) and frozen (BCF) juices of BC pulp, with and without concomitant administration of cyclophosphamide, using a chromosomal aberration test system in the bone marrow cells of Wistar rats treated in vivo for 24 h. The results showed that neither the BC juice (0.4 mg/mL) alone, nor that with concomitant cyclophosphamide (1.5 mg/mL), were cytotoxic. BC has potential as an antimutagenic, and statistically reduced the percentages of chromosomal alterations induced by cyclophosphamide when administered simultaneously (BCN: 80.75%; BCF: 88.26%), pre-treatment (BCN: 86.85%; BCF: 87.32%), or post-treatment (BCN: 90.14%; BCF: 86.85%). This was due to the antioxidant activity of the fruit and the action of its bioactive compounds, which may have inhibited cyclophosphamide metabolism or scavenged the free radicals generated by this compound. Thus, attenuation of cyclophosphamide-induced mutagenicity suggests that the consumption of fresh or frozen BC should be encouraged for the prevention of disease, and for the maintenance and promotion of health.

Antimutagenic and radioprotective activities of beta-carotene against the biological effects of iodine-131 radiopharmaceutical in Wistar rats.

Radioactive iodine-131 (131I) is used in the treatment and diagnosis of thyroid gland injuries. However, because it emits ionizing radiation, it causes harmful effects to cells. Given that beta-carotene (BC) has antioxidant and antigenotoxic properties, this study aimed to investigate its radioprotective and antimutagenic activity in relation to 131I at the dose that is used to treat hyperthyroidism using a test system of bone marrow cells from Wistar rats (Rattus norvegicus). The doses were 0.2 mL of 8 mg BC/mL corn oil and 25 µCi 131I per 100 g body weight, and they were given via gavage in acute and subchronic treatments. Treatment groups included simultaneous, pre-treatment, post-treatment, and continuous treatment types. In all antimutagenic acute treatments, BC had a significant antimutagenic/radioprotective activity in relation to 131I. In subchronic antimutagenic treatments, BC reduced the damage that was caused by the radioisotope; however, this reduction was not statistically significant because of the relatively low percentage of chromosomal abnormalities that were observed with only 131I compared to the acute treatment. These results demonstrate the radioprotective and antimutagenic activity of BC, indicating its use by the population, which inevitably is exposed to mutagenic agents, as a means of health protection.

Cytotoxicity and mutagenicity of fluoxetine hydrochloride (Prozac), with or without vitamins A and C, in plant and animal model systems.

Fluoxetine, commonly known as Prozac, is the first representative of the so-called new generation of antidepressants that promise efficacy, with few side effects, against deep depression, nervous bulimia, and anxiety. As there is a growing number of people suffering from anxiety and depression; consequently, the use of fluoxetine is also increasing. Verifying absence of drug effects such as cytotoxicity or mutagenicity is of great importance. Certain vitamins, such as vitamin A (retinol, retinoids) and vitamin C (ascorbic acid) protect and are extremely active against mutagens. We evaluated the cytotoxic and mutagenic activity of fluoxetine, with and without concomitant administration of vitamin A or C, in Allium cepa meristem cells and Wistar rat bone marrow cells. The A. cepa meristem cells showed fluoxetine cytotoxicity; concomitant treatment with vitamin A or C proved non-protective. Treatment of Wistar rats with fluoxetine intraperitoneally or via gavage did not affect cell division or cause clastogenic effects. Vitamin A and C did not affect the cytotoxicity or mutagenicity of fluoxetine in the rat cells.

Cytotoxic and mutagenic effects of iodine-131 and radioprotection of acerola (Malpighia glabra L.) and beta-carotene in vitro.

The radioisotope iodine-131 [(131)I] can damage DNA. One way to prevent this is to increase the amount of antioxidants via dietary consumption. The goal of this study was to evaluate the radioprotective effect of fresh acerola pulp and synthetic beta-carotene in Rattus norvegicus hepatoma cells (HTC) in response to [(131)I] exposure in vitro. Cellular DNA damage was subsequently assessed using a cytokinesis block micronucleus assay. The mutagenic and cytotoxic activities of doses of [(131)I] (0.1, 0.5, 1, 5, and 10 µCi), acerola (0.025, 0.125, and 0.25 g acerola pulp/mL), and beta-carotene (0.2, 1, and 2 µM) were evaluated. Radioprotective tests were performed by simultaneous treatment with acerola (0.25 g/mL) plus [(131)I] (10 µCi) and beta-carotene (0.2 µM) plus [(131)I] (10 µCi). Acerola, beta-carotene, and low concentrations of [(131)I] did not induce micronucleus formation in HTC cells; in contrast, high concentrations of [(131)I] (10 µCi) were mutagenic and induced DNA damage. Moreover, neither acerola nor beta-carotene treatment was cytotoxic. However, acerola reduced the percentage of [(131)I]-induced damage, although beta-carotene did not show a similar effect. Thus, our results suggest that acerola diet supplementation may benefit patients who are exposed to [(131)I] during thyroid diagnostics and therapy.

Reconhecimento e uso de plantas medicinais pelos idosos do Município de Marmeleiro - Paraná / Recognition and use of medicinal plants by the elderly in the city of Marmeleiro - Paraná

O consumo de plantas medicinais tem base na tradição familiar e tornou-se prática generalizada na medicina popular. Neste sentido, este trabalho teve como objetivo verificar o grau de reconhecimento e uso de espécies medicinais utilizadas por 35 idosos do município de Marmeleiro - Paraná. Os resultados das entrevistas mostraram que todos os idosos conheciam, das vinte plantas medicinais apresentadas, a babosa, a camomila, a erva-cidreira, a macela, a malva, a manjerona, a noz-moscada, a pata-de-vaca e a sálvia. Além disso, 94% dos mesmos faziam o uso de plantas medicinais, sendo que 71,4% destes, utilizavam frequentemente, enquanto 94,2% foram influenciados principalmente pelos familiares (pais e avós). As plantas medicinais consumidas diariamente pelos idosos eram a erva-cidreira (48,6%), a malva (34,3%), o quebra-pedra (34,1%), a sálvia (25,7%), a camomila (22,9%), o guaco (20%), a carqueja e a macela (14,3%), a pata-de-vaca e o alecrim (8,6%) e a babosa (2,9%), preparadas na forma de chá (decocção) ou infusão. Vale destacar que a forma de obtenção das plantas medicinais era principalmente em plantações próprias (88,6%). Desta forma, informações acerca das plantas medicinais devem retornar para a população, em especial a mais idosa, enfatizando o modo de cultivo e colheita, através de técnicas desconhecidas por eles, bem como a melhor forma de utilização de cada espécie medicinal, estimulando seu uso, com maior eficacia e segurança.

The use of medicinal plants is based on family tradition and became a common practice in popular medicine. Therefore, this study aimed to verify the level of recognition and use of medicinal plants used by 35 elderly in the city Marmeleiro - Paraná. The results of the interviews showed that all elderly knew, from twenty medicinal plants presented, aloe vera, chamomile, lemon balm, camomile, mallow, marjoram, nutmeg, paw-of-cow and sage. Besides that, 94% of them used medicinal plants, 71.4% of these frequently, influenced mainly by the family (parents and grandparents) (94.2%). Medicinal plants consumed daily by the elderly were the lemon balm (48.6%), mallow (34.3%), shatterstone (34.1%), sage (25.7%), chamomile (22.9 %), guaco (20%), gorse and camomile (14.3%), paw-of-cow and rosemary (8.6%) and aloe vera (2.9%), prepared as tea (decoction) or infusion. We should note that the form to obtain the plants was mainly from their own gardens (88.6%). We conclude that the information about medicinal plants should be available to the public, especially the elderly, emphasizing the methods of cultivation and harvesting, with techniques still unknown to them, and the best way to use each medicinal species, encouraging their use, but with no damage to health.

In vitro contraction of the pupillary sphincter by substance P and its stable analogs.

The effects of substance P and substance P analogs have been studied quantitatively by use of an isolated preparation of bovine pupillary sphincter muscle. Substance P contracts the pupillary sphincter in a dose-dependent manner with a value for median effective dose (ED50) of 1.0 X 10(-6) M. The effects of substance P result from its interaction with a specific receptor in the pupillary sphincter. These results strengthen the view that substance P is involved in the oculopupillary reflex.