INTRODUÇÃOAo longo dos últimos anos, a ocorrência de infecções fúngicas humanas vem apresentando um aumento expressivo, sendo as dermatomicoses as principais infecções responsáveis por esse aumento. Vários fatores estão relacionados ao crescimento dessas infecções fúngicas, entre eles: o melhor diagnóstico laboratorial e clínico, o aumento da sobrevida de pacientes com doenças imunossupressoras e o emprego de medicamentos imunossupressores, utilizados às vezes de forma abusiva, permitindo a instalação de microorganismos convencionalmente saprófitos (Sidrim et al., 1999).Os fungos responsáveis por essas infecções são fungos patógenos (Epidermophyton, Microsporum, Trichophyton, Paracoccidioides, Histoplasma) ou fungos patógenos oportunistas (Candida albicans, Cryptococcus neoformans). O tratamento das micoses humanas não é sempre efetivo, pois os fármacos antifúngicos disponíveis produzem recorrência ou causam resistência, além de apresentarem importante toxicidade. Por esta razão, há uma busca contínua de novos fármacos antifúngicos mais potentes, mas, sobretudo, mais seguros que os existentes. Além das infecções em humanos, os animais também podem ser atacados esporadicamente por fungos muito difíceis de serem combatidos. Além disso, as infecções fúngicas em plantas (espécies de Rhizoctonia, Phytophtora, Sclerotinia, Fusarium, Phomopsis, Colletotrichum, Diaphorte, Macrophomina, Cercospora) representam perdas incalculáveis para a produção agrícola (Zacchino, 2001).Neste contexto, embora a maioria dos antifúngicos existentes no mercado seja de origem sintética, o estudo de produtos naturais voltou a receber a atenção dos cientistas (Yunes, Filho, 2001). Entre as principais ferramentas

Quillaja saponaria Molina represents the main source of saponins for industrial applications. Q. saponaria triterpenoids have been studied for more than four decades and their relevance is due to their biological activities, especially as a vaccine adjuvant and immunostimulant, which have led to important research in the field of vaccine development. These saponins, alone or incorporated into immunostimulating complexes (ISCOMs), are able to modulate immunity by increasing antigen uptake, stimulating cytotoxic T lymphocyte production (Th1) and cytokines (Th2) in response to different antigens. Furthermore, antiviral, antifungal, antibacterial, antiparasitic, and antitumor activities are also reported as important biological properties of Quillaja triterpenoids. Recently, other saponins from Q. brasiliensis (A. St.-Hill. & Tul.) Mart. were successfully tested and showed similar chemical and biological properties to those of Q. saponaria barks. The aim of this manuscript is to summarize the current advances in phytochemical and pharmacological knowledge of saponins from Quillaja plants, including the particular chemical characteristics of these triterpenoids. The potential applications of Quillaja saponins to stimulate further drug discovery research will be provided.

The antidepressant-like effect of a supercritical CO2 (SCCO2) Valeriana glechomifolia extract enriched in valepotriates was investigated in a mice tail suspension test (TST) and forced swimming test (FST). The SCCO2 extract decreased mice immobility in the FST (0.5-20 mg/kg p.o.) and elicited a biphasic dose-response relationship in the TST (1-20 mg/kg p.o.) with no alterations in locomotor activity and motor coordination (assessed in the open-field and rota-rod tests, respectively). The anti-immobility effect of the SCCO2 extract (5 mg/kg, p.o.) was prevented by mice pre-treatment with yohimbine (1 mg/kg, i.p., an α2 adrenoceptor antagonist), SCH 23390 (15 μg/kg, s.c., D1 dopamine receptor antagonist) and sulpiride (50 mg/kg, i.p., D2 dopamine receptor antagonist). However, mice pre-treatments with prazosin (1 mg/kg, i.p., α1 adrenoceptor antagonist) and p-chlorophenilalanine methyl ester (4×100 mg/kg/day, i.p., a serotonin synthesis inhibitor) were not able to block the anti-immobility effect of the SCCO2 extract. Administration (p.o.) of the SCCO2 extract (0.25 mg/kg) and imipramine (10 mg/kg), desipramine (5 mg/kg) and bupropion (3 mg/kg) at sub-effective doses significantly reduced mice immobility time in the FST. These data provide the first evidence of the antidepressant-like activity of V. glechomifolia valepotriates, which is due to an interaction with dopaminergic and noradrenergic neurotransmission.

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