RESUMO
Usnic acid is the best-studied lichen metabolite, presenting several biological activities, such as antibacterial, immunostimulating, antiviral, antifungal, anti-inflammatory, and antiparasitic agents; despite these relevant properties, it is a hydrophobic and toxic molecule. In this context, scientific research has driven the development of innovative alternatives, considering usnic acid as a source of raw material in obtaining new molecules, allowing structural modifications (syntheses) from it. The purpose is to optimize biological activities and toxicity, with less concentration and/or response time. This work presents a literature review with an analogy of the hydrophobic molecule of usnic acid with its hydrophilic derivative of potassium usnate, emphasizing the elucidation and structural characteristics, biological activities, and toxicological aspects of both molecules, and the advantages of using the promising derivative hydrophilic in different in vitro and in vivo assays when compared to usnic acid.
Assuntos
Benzofuranos/química , Benzofuranos/farmacologia , Potássio/química , Analgésicos/química , Analgésicos/farmacologia , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Antiparasitários/química , Antiparasitários/farmacologia , Benzofuranos/toxicidade , Interações Hidrofóbicas e Hidrofílicas , Líquens/metabolismoRESUMO
Chemotherapy for cancer treatment may result in a temporary or long-term gonadal damage resulting in subfertility or infertility. Cyclophosphamide (CY) is a cytotoxic alkylating agent that has been widely used in the treatment of cancer. Recent studies have shown that synthetic resorcinol lipid AMS35AA (3-Heptyl-3,4,6-trimethoxy-3H-isobenzofuran-1-one) may be an important adjuvant chemotherapy that potentiates mutagenic damage and increases apoptosis caused by CY. The present study investigates the action of AMS35AA alone or/in association with CY on testicular function. Animals were divided into four groups: (a) control group: received only water; (b) CY group: received 150 µg/g of CY b.w., i.p.; (c) AMS35AA group: received 10 µg/g of AMS35AA b.w., i.p; and (d) associated group: received 10 µg/g of AMS35AA + 150 µg/g of CY b.w., i.p. Four weeks after the treatment, the results showed that testes weight of CY and associated groups decreased. However, the number of Sertoli cell and Leydig cell per testis was similar in control and treated groups. Our findings provide strong evidence that the AMS35AA alone or in CY association is not toxic to spermatogenesis. The absence of toxicity of AMS35AA supports the view that the resorcinolic lipid could be used associated with CY chemotherapy without causing adverse effects to testes function.
Assuntos
Benzofuranos , Animais , Benzofuranos/toxicidade , Ciclofosfamida/toxicidade , Masculino , Espermatogênese , TestículoRESUMO
To obtain usnic acid potassium salt (PS-UA), the usnic acid (UA) was extracted and purified from the lichen Cladonia substellata, and modified to produce PS-UA. The structure was determined by 1H-NMR, IR and elemental analysis, ratified through computational models, as well as identification the site of K+ insertion in the molecule. Antinociceptive activity was detected through contortions in mice induced by acetic acid and formalin (phases I and II) after treatments with 10 and 20 mg/kg of PS-UA, indicating interference in both non-inflammatory and inflammatory pain. After oral administration at doses of 500, 1000 and 2000 mg/kg, no deaths of mice with treatments below 2000 mg/kg were observed. Except for body weight gain, food and water consumption decreased with treatments of 1000 and 2000 mg/kg, and the number of segmented leukocytes was higher for both treatments. Regarding serum levels, cholesterol and triglycerides decreased, however, there was an increase in hepatic transaminases with both treatments. Liver and kidney histological changes were detected in treatments of 2000 mg/kg, while the spleen was preserved. The PS-UA demonstrated antinociceptive activity while the acute toxicity at the concentration of 2000 mg/kg was the only dose that presented morphological changes in the liver and kidney.
Assuntos
Analgésicos/farmacologia , Benzofuranos/farmacologia , Benzofuranos/toxicidade , Testes de Toxicidade Aguda , Animais , Comportamento Animal/efeitos dos fármacos , Benzofuranos/química , Modelos Animais de Doenças , Comportamento de Ingestão de Líquido , Comportamento Alimentar , Feminino , Camundongos , Conformação Molecular , Especificidade de Órgãos/efeitos dos fármacosRESUMO
BACKGROUND: Benzofurans are heterocyclic compounds with neurotropic activity. Some have been developed for the treatment of acute and degenerative neuronal injuries. OBJECTIVE: The study aimed to evaluate the in silico binding of some promising benzofurans on the GABA receptors, and the in vivo neurotropic activity of benzofuran analogues (BZF 6-10) of gamma-aminobutyric acid (GABA) on a seizure model. METHODS: The ligands with the best physicochemical attributes were docked on two GABA receptors (the alpha-1 subunit of GABAA-R and GBR1 subunit of GABAB-R). Selected benzofuran derivatives were synthesized by a multistep procedure and characterized. To examine the neurotropic effects, mice were pretreated with different concentrations of the compounds prior to PTZ- or 4- AP-induced seizures. We assessed acute toxicity, motor behavior, and the effects on seizures. RESULTS: The tested ligands that complied with Lipinski's rule of five were tested in silico with GABAA-R (ΔG = -5.51 to -5.84 kcal/mol) at the allosteric site for benzodiazepines. They bound to a similar cluster of residues as the reference compound (gaboxadol, ΔG = -5.51 kcal/mol). Synthesis was achieved with good overall yields (42-9.7%). Two compounds were selected for biological tests (BZF-7 and rac-BZF-10) on a mouse model of seizures, induced by pentylenetetrazol (PTZ) or 4-aminopyridine (4-AP). PTZ-induced seizures are associated with GABA receptors, and those 4-AP-induced with the blockage of the delayed rectifier-type potassium channel, which promotes the release of the NMDA-sensitive glutamatergic ionotropic receptor and other neurotransmitters. The biological assays demonstrated that BZF-7 and rac-BZF-10 do not protect against seizures. Indeed, BZF-7 increased the number of PTZ-induced seizures and decreased latency time. The 4-AP model apparently showed a potentiation of seizure effects after administration of the BZF-analogues, evidenced by the incidence and severity of the seizures and reduced latency time. CONCLUSION: The results suggest that the test compounds are GABAergic antagonists with stimulatory activity on the CNS.
Assuntos
Benzofuranos/farmacologia , Estimulantes do Sistema Nervoso Central/farmacologia , Antagonistas de Receptores de GABA-A/farmacologia , Antagonistas de Receptores de GABA-B/farmacologia , Animais , Benzofuranos/síntese química , Benzofuranos/química , Benzofuranos/toxicidade , Estimulantes do Sistema Nervoso Central/síntese química , Estimulantes do Sistema Nervoso Central/química , Estimulantes do Sistema Nervoso Central/toxicidade , Antagonistas de Receptores de GABA-A/síntese química , Antagonistas de Receptores de GABA-A/química , Antagonistas de Receptores de GABA-A/toxicidade , Antagonistas de Receptores de GABA-B/síntese química , Antagonistas de Receptores de GABA-B/química , Antagonistas de Receptores de GABA-B/toxicidade , Humanos , Ligantes , Masculino , Camundongos , Simulação de Acoplamento Molecular , Receptores de GABA-A/química , Receptores de GABA-B/químicaRESUMO
The snail Biomphalaria glabrata is the most important vector for Schistosoma mansoni. Control of this vector to prevent the spread of schistosomiasis is currently performed with the application of a niclosamide molluscicide, which is highly toxic to the environment. Screening of substances that show embryotoxic molluscicidal potential as well as have detrimental effects on cercariae is very relevant for the control of schistosomiasis, as the efficacy of prevention of the disease is increased if it acts as a molluscicide as well as on the cercariae of S. mansoni. The aim of this work was to evaluate the effect of potassium usnate derived from usnic acid on different stages of embryonic development of B. glabrata and on S. mansoni cercariae. After 24 h of exposure, potassium usnate showed embryotoxic activity across all embryonic stages. The values obtained from the LC50 for the embryonic stages were the following: blastula 5.22 µg/mL, gastrula 3.21 µg/mL, trochophore 3.58 µg/mL, veliger 2.79, and hippo stage 2.52 µg/mL. Against S. mansoni cercariae, it had LC90 and 100% mortality at concentrations of 2.5 and 5 µg/mL in 2 h of exposure. In conclusion, this is the first report of potassium usnate toxicity on the embryonic stages of B. glabrata and cercariae of S. mansoni, and this study shows the potassium usnate as a promising agent for the control of mansoni schistosomiasis.
Assuntos
Benzofuranos/toxicidade , Biomphalaria/efeitos dos fármacos , Moluscocidas/toxicidade , Esquistossomose mansoni/prevenção & controle , Animais , Biomphalaria/embriologia , Vetores de Doenças , Potássio/toxicidade , Esquistossomose mansoni/transmissãoRESUMO
PURPOSE: Some phytochemicals have shown the potential of being radiomodifiers, especially phenolic compounds, such as lichenic secondary metabolites. To evaluate the phytochemical usnic acid as a radiomodifier, embryonic cells of molluscs have been used due to their ease of collection, high sensitivity to physical and chemical agents, well-known embryology and low cost for analysis. MATERIALS AND METHODS: This study aimed to assess the radiosensitizing action of usnic acid on Biomphalaria glabrata embryos. Samples were irradiated with 4 Gy of gamma rays from a 60Co source (dose rate 2.906 Gy/h). An acute toxicity test was performed using B. glabrata embryos in the blastula stage, in order to determine the toxicity of usnic acid and to establish the lethal Concentration for 50% (LC50). Subsequently, the radiomodifing capacity of usnic acid was estimated using assays with B. glabrata embryos. RESULTS: Irradiation increased the number of non-viable embryos compared to unirradiated controls. Additionally, it was observed that embryos exposed to a non-toxic concentration of usnic acid (0.6 µg/mL) before irradiation showed a further enhancement in non-viable embryos when compared with exposure to ionizing radiation alone. CONCLUSION: The results presented here indicate that usnic acid makes cells more sensitive to the damaging effects of radiation.
Assuntos
Benzofuranos/farmacologia , Biomphalaria/embriologia , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/efeitos da radiação , Radiossensibilizantes/farmacologia , Animais , Benzofuranos/toxicidade , Radioisótopos de Cobalto , Raios gama , Dose Letal Mediana , Radiossensibilizantes/toxicidadeRESUMO
This study reports the molluscicidal activity of usnic acid isolated from Cladonia substellata Vanio (lichen) on embryos at various stages of development and in adult mollusks of Biomphalaria glabrata. The toxicity of usnic acid was also evaluated through Artemia salina larvae mortality. Usnic acid was extracted with diethyl ether, isolated, purified, and its structure confirmed by analyzing the spectra of proton nuclear magnetic resonance. LC90 for 24â¯h of exposure were 1.62, 4.45, 5.36, and 4.49⯵gâ¯mL-1 for blastula, gastrula, trocophore, and veliger embryonic stages, respectively, and 3.45⯵gâ¯mL-1 for adult snails; LC50 of usnic acid against A. salina was 2.46⯵gâ¯mL-1. LC90 assessed 7â¯days after exposure was 2.56⯵gâ¯mL-1 for adult mollusks. In conclusion, these findings demonstrate that under laboratory conditions usnic acid has teratogenic and molluscicide potential to control the aquatic snail B. glabrata and may prove to be a promising candidate in the search for new molluscicide agents, but further detailed studies on its molluscicidal effect and possible environmental effects are needed.
Assuntos
Benzofuranos/toxicidade , Biomphalaria/efeitos dos fármacos , Embrião não Mamífero/efeitos dos fármacos , Líquens/química , Animais , Artemia/efeitos dos fármacos , Biomphalaria/embriologia , Larva/efeitos dos fármacos , Moluscocidas/toxicidadeRESUMO
In this study, the insecticide potential of eight phthalides derived from furan-2(5H)-one was evaluated against Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) larvae. The potency of the most active phthalides and the susceptibility of six different T. absoluta populations to these compounds were determined. The toxicity of these molecules to two non-target species (Solenopsis saevissima Smith and Tetragonisca angustula Latreille) was also evaluated. Two phthalides (3 and 4) presented insecticide potential against T. absoluta. Phthalide 4 was as toxic as piperine (positive control) and both phthalides exhibited rapid action (LT50 < 2 hours). The variation in the susceptibility of T. absoluta populations to the phthalides 3 and 4 was low. Neither phthalide presented physiological selectivity for non-target species. Therefore, the phthalides 3 and 4 are promising molecules, or at least, a starting point for a chemical optimization program leading to formulations for the management of the tomato leafminer. The application of such products should be conducted according to the principles of ecological selectivity.
Assuntos
Benzofuranos/química , Inseticidas/farmacologia , Inseticidas/toxicidade , Lepidópteros/efeitos dos fármacos , Animais , Formigas/efeitos dos fármacos , Abelhas/efeitos dos fármacos , Benzofuranos/farmacologia , Benzofuranos/toxicidade , Avaliação Pré-Clínica de Medicamentos/métodos , Inseticidas/química , Larva/efeitos dos fármacosRESUMO
This study aimed to evaluate the teratogenic and hepatotoxic potential of the usnic acid encapsulated into PLGA-microspheres. In total, 12 female Wistar rats in pregnancy were randomly distributed in the control group (n= 6) that received 1.0 mL of physiological solution and treatment group (n= 6) that received 25 mg/kg of encapsulated usnic acid by oral administration. All females were euthanized at day 20 of pregnancy and their fetuses were removed and analyzed. During the pregnancy was observed a reduction in weight gain. There was no difference in serum transaminases levels analyzed as well as any difference in liver weight in both groups. The histomorphometric analysis of the liver from the treatment group revealed an increase in number of hepatocytes and a decrease in nuclear area of these cells. Moreover, no alteration was observed in cell area of hepatocytes or number of Kupffer cells. The fetuses had an increase in total number of hepatocytes and a reduction in the amount of megakaryocytes. These results show the hepatotoxic potential of usnic acid during pregnancy. However, its toxicity can be minimized by encapsulation in microspheres.
Assuntos
Ascomicetos/química , Benzofuranos/toxicidade , Feto/efeitos dos fármacos , Ácido Láctico/toxicidade , Líquens/química , Fígado/efeitos dos fármacos , Ácido Poliglicólico/toxicidade , Anormalidades Induzidas por Medicamentos , Animais , Benzofuranos/química , Feminino , Peso Fetal/efeitos dos fármacos , Hepatócitos/efeitos dos fármacos , Ácido Láctico/química , Fígado/patologia , Exposição Materna , Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Gravidez , Distribuição Aleatória , Ratos Wistar , Valores de ReferênciaRESUMO
ABSTRACT This study aimed to evaluate the teratogenic and hepatotoxic potential of the usnic acid encapsulated into PLGA-microspheres. In total, 12 female Wistar rats in pregnancy were randomly distributed in the control group (n= 6) that received 1.0 mL of physiological solution and treatment group (n= 6) that received 25 mg/kg of encapsulated usnic acid by oral administration. All females were euthanized at day 20 of pregnancy and their fetuses were removed and analyzed. During the pregnancy was observed a reduction in weight gain. There was no difference in serum transaminases levels analyzed as well as any difference in liver weight in both groups. The histomorphometric analysis of the liver from the treatment group revealed an increase in number of hepatocytes and a decrease in nuclear area of these cells. Moreover, no alteration was observed in cell area of hepatocytes or number of Kupffer cells. The fetuses had an increase in total number of hepatocytes and a reduction in the amount of megakaryocytes. These results show the hepatotoxic potential of usnic acid during pregnancy. However, its toxicity can be minimized by encapsulation in microspheres.