Actividad in vitro anti-Leishmania (Trypanosomatidae) del epóxido trans-Z-&-bisaboleno y del Safrol, en frutos de Piper auritum (Piperaceae) / Anti-Leishmania (Trypanosomatidae) activity of trans-Z-&-bisabolene epoxide and isolation of safrole, in fruits of Piper auritum (Piperaceae)

Resumen La leishmaniasis es una enfermedad con una alta incidencia en el ser humano, que puede ser controlada, pero como los tratamientos tienen efectos secundarios importantes se han realizado estudios de diversas plantas con el fin de encontrar compuestos con actividad antileishmaniásica que presenten pocos efectos nocivos para el ser humano. El presente estudio consistió en realizar un tamizaje fitoquímico de la planta, para identificar la presencia de cumarinas, terpenos, triterpenos y azúcares reductores. El objetivo fue encontrar componentes químicos puros con actividad contra el parásito Leishmania sp. Por tal razón se purificaron los compuestos: trans-Z-alfabisaboleno y el Safrol, a los que se les realizaron pruebas del efecto anti parasitario que presentaron un CI50 de 50.0 µg/mL y 0.0 µg/mL, respectivamente. Además, se discute la importancia de estos nuevos hallazgos. El compuesto mayoritario presente en los aceites esenciales (Safrol) no es el componente que presentó la actividad. Es importante realizar estudios sobre su proyección en el tratamiento de la leishmaniasis.

Abstract The leishmaniosis disease incidence is high in tropical regions, and its current treatment has shown severe secondary effects. Considering this problem, many studies have focused on plants, looking for chemical components that have anti-leishmanial activity, and are free of adverse effects for human beings. The purpose of this work was to find a chemical component with this kind of activity in Piper auritum. In a phytochemical screening of this plant, we found some cumarins, terpens, triterpens and reducing sugars; and later, we identified the components trans-Z-α-bisabolene epoxide and Safrol. The first component presented a CI50 of 50.0 µg/mL of anti-Leishmania activity. The Safrol, which is the major component of the essential oils of this plant, did not show antiparasitic activity. These results are discussed considering treatment of leishmaniasis. Rev. Biol. Trop. 66(2): 826-835. Epub 2018 June 01.

Epilepsy treatment. Targeting LDH enzymes with a stiripentol analog to treat epilepsy.

Neuronal excitation is regulated by energy metabolism, and drug-resistant epilepsy can be suppressed by special diets. Here, we report that seizures and epileptiform activity are reduced by inhibition of the metabolic pathway via lactate dehydrogenase (LDH), a component of the astrocyte-neuron lactate shuttle. Inhibition of the enzyme LDH hyperpolarized neurons, which was reversed by the downstream metabolite pyruvate. LDH inhibition also suppressed seizures in vivo in a mouse model of epilepsy. We further found that stiripentol, a clinically used antiepileptic drug, is an LDH inhibitor. By modifying its chemical structure, we identified a previously unknown LDH inhibitor, which potently suppressed seizures in vivo. We conclude that LDH inhibitors are a promising new group of antiepileptic drugs.

Toxic phytochemicals and their potential risks for human cancer.

Consuming plants for their presumed health benefits has occurred since early civilizations. Phytochemicals are found in various plants that are frequently included in the human diet and are generally thought to be safe for consumption because they are produced naturally. However, this is not always the case and in fact many natural compounds found in several commonly consumed plants are potential carcinogens or tumor promoters and should be avoided.

To investigate antihyperglycemic and antihyperlipidemic potential of safrole in rodents by in-vivo and in-vitro study.

In the present investigation anti-diabetic and in-vitro antioxidant potential of safrole were evaluated (100 and 200 mg/kg p.o.) in acute and chronic Streptozotocin-nicotinamide (STZ) induced antihyperglycemic rat model. The oral administration of safrole for 30 days affects the level of blood glucose, glycosylated hemoglobin (HbA1C), total cholesterol (TC), triglycerides (TG), phospholipids, high density lipoprotein (HDL), body weight, insulin level, liver glycogen content, antioxidant parameters, lipase, α-amylase in normal and STZ induced diabetic rats. The oral administration of safrole at dose 100 & 200 mg/kg p.o. significantly improve the diabetic condition in Streptozotocin-induced diabetic rats. In enzymatic assay, the IC50 value of the safrole for α-amylase and lipase was found to be 702.78 and 861.35 µg/ml respectively which was found comparable with the standard drug (ascorbic acid) as 252.12 µg/ml. Further studies can be performed on safrole for mechanistic and toxicological aspects so that it can be investigated as a new substance for the management of various diseases.

Safrole suppresses murine myelomonocytic leukemia WEHI-3 cells in vivo, and stimulates macrophage phagocytosis and natural killer cell cytotoxicity in leukemic mice.

Many anticancer drugs are obtained from phytochemicals and natural products. However, some phytochemicals have mutagenic effects. Safrole, a component of Piper betle inflorescence, has been reported to be a carcinogen. We have previously reported that safrole induced apoptosis in human oral cancer cells in vitro and inhibited the human oral tumor xenograft growth in vivo. Until now, there is no information addressing if safrole promotes immune responses in vivo. To evaluate whether safrole modulated immune function, BALB/c mice were intraperitoneally injected with murine myelomonocytic WEHI-3 leukemia cells to establish leukemia and then were treated with or without safrole at 4 and 16 mg/kg. Animals were sacrificed after 2 weeks post-treatment with safrole for examining the immune cell populations, phagocytosis of macrophages and the natural killer (NK) cells' cytotoxicity. Results indicated that safrole increased the body weight, and decreased the weights of spleen and liver in leukemic mice. Furthermore, safrole promoted the activities of macrophages phagocytosis and NK cells' cytotoxicity in leukemic mice when compared with untreated leukemic mice. After determining the cell marker population, we found that safrole promoted the levels of CD3 (T cells), CD19 (B cells) and Mac-3 (macrophages), but it did not affect CD11b (monocytes) in leukemic mice. In conclusion, safrole altered the immune modulation and inhibited the leukemia WEHI-3 cells in vivo.

Safrole induces apoptosis in human oral cancer HSC-3 cells.

Phytochemicals have been used as potential chemopreventive or chemotherapeutic agents. However, there are data suggesting a mutagenic effect of some phytochemicals. We hypothesized that safrole would have anticancer effects on human oral squamous cell carcinoma HSC-3 cells. Safrole decreased the percentage of viable HSC-3 cells via induction of apoptosis by an increased level of cytosolic Ca(2+) and a reduction in the mitochondrial membrane potential (ΔΨ(m)). Changes in the membrane potential were associated with changes in the Bax, release of cytochrome c from mitochondria, and activation of downstream caspases-9 and -3, resulting in apoptotic cell death. In vivo studies also showed that safrole reduced the size and volume of an HSC-3 solid tumor on a xenograft athymic nu/nu mouse model. Western blotting and flow cytometric analysis studies confirmed that safrole-mediated apoptotic cell death of HSC-3 cells is regulated by cytosolic Ca(2+) and by mitochondria- and Fas-dependent pathways.