Tea from Phyllanthus niruri L., Phyllanthaceae, aerial parts is commonly used by Brazilian folk medicine for its benefits on the treatment of genitourinary disorders, for what the polyphenolic compounds are mainly responsible. The yield of such compounds may be influenced by several variables related with the plant growth. The effects of planting periods and harvesting conditions are investigated in this work, including four different seasons. The cultivation was characterized by dry mass yield of aerial parts, and the effect of pruning was analyzed. Leaves, stems and their mixtures were analyzed after drying and milling. Loss on drying and water soluble extractives were used as physical parameters for quality control. Flavonoid content and gallic acid were chosen as chemical markers for this work. The spectrophotometric trial based on the aluminum chloride complexes was applied to evaluate the total flavonoids content. Gallic acid contents were measured from the water extractive solutions by high-performance liquid chromatography. The pruning caused a positive influence on the amount of leaves and stems. The highest flavonoids and gallic acid contents were found in the leaves, which were developed over the summer and the winter, respectively, both from the second harvesting (after pruning). Chomatographic profile by HPLC was characterizes by the presence of gallic acid and two other major peaks (not identified substances), which relation was peculiar to each aerial part. In conclusion, these results suggest that even under less favorable climatic conditions, in winter, the pruning seems to cause a strong influence over the P. niruri polyphenolics production. Indeed, the total flavonoids content, as well as the HPLC profile, can be used as indicative parameters of the ratio of leaves and stem in the vegetal raw material.

Entre as diversas atividades biológicas relatadas para as saponinas, merecem destaque aquelas relacionadas ao aumento da resposta imune e a ruptura das membranas dos eritrócitos. No desenvolvimento de vacinas, ambas as propriedades exercem atividades antagônicas, contudo, as informações sobre as relações estrutura-atividade são relativamente escassas e, às vezes, conflitantes. O presente trabalho visa contribuir no estabelecimento das relações estruturais envolvidas com as atividades imunoadjuvante e hemolítica de saponinas triterpênicas. Para isso, foram selecionadas vinte saponinas de estrutura triterpênica, isoladas das espécies Aesculus hippocastanum, Dolichos lablab e Glycine max. A relação entre grupamentos substituintes do anel triterpênico e as atividades biológicas foi estudada mediante análise de agrupamentos e análise de componentes principais. Os resultados confirmam a importância da presença de açúcares em C-3 para a atividade hemolítica. Porém o efeito causado pela presença de uma hidroxila em C-16, de CH2OH em C-17, de uma acetila em C-22 e de um grupamento acila em C-21 sobre essa atividade parece ser mais acentuado. Já a presença de uma hidroxila em C-21, de uma metila em C-17 e de dois açúcares ligados à aglicona parece ser determinante para a atividade imunoadjuvante. Além disso, observa-se a existência de uma relação inversa entre as atividades hemolítica e imunoadjuvante.

Among the various biological activities reported for saponins, those related with increase immune response and the destruction of the membrane of red blood cells deserve attention. In the development of vaccines, these properties exert antagonistic activities. However, the information about the structure-activity relationships is relatively scarce and sometimes contradictory. This paper aims to contribute to the establishment of structural relations involved with the hemolytic and adjuvant activities of triterpenic saponins by the analysis of the different groups linked to aglycone, with the use of multivariate statistical techniques. For this, we had twenty triterpenic saponins previously isolated from Aesculus hippocastanum, Dolichos lablab. and Glycine max species. Their adjuvant and hemolytic activities are available in the literature. These saponins were analyzed as groups linked to the triterpenic ring and biological activities resulting in an array of date that was submitted to cluster analysis and principal components analysis. The results confirm the importance of sugars in C-3 for hemolytic activity. However, the effect caused by the presence of a hydroxyl in C-16, CH2OH in C-17, acetyl in C-22 and acyl in C-21 on the hemolytic activity seems to be more important. On the other way, the presence of a hydroxyl in C-21, a methyl in C-17 and two sugars linked to aglycone seem determinant for adjuvant activity. Moreover, there is an inverse relationship between adjuvant and hemolytic activities in the set of saponins analyzed.

Saponins are natural soaplike foam-forming compounds widely used in foods, cosmetic and pharmaceutical preparations. In this work foamability and foam lifetime of foams obtained from Ilex paraguariensis unripe fruits were analyzed. Polysorbate 80 and sodium dodecyl sulfate were used as reference surfactants. Aiming a better data understanding a linearized 4-parameters Weibull function was proposed. The mate hydroethanolic extract (ME) and a mate saponin enriched fraction (MSF) afforded foamability and foam lifetime comparable to the synthetic surfactants. The linearization of the Weibull equation allowed the statistical comparison of foam decay curves, improving former mathematical approaches.

O polímero polivinilpirrolidona (PVPP) proporciona uma alternativa analítica ao invés do pó-de-pele e caseína, como um agente complexante na quantificação de taninos. Neste trabalho foi estudado a especificidade do PVPP em complexar com compostos polifenólicos, na presença de rutina. Os ácidos gálico e tânico, catequina e pirogalol foram utilizados como substâncias de referência (PRS), junto com o extrato aquoso das folhas do Psidium guajava L. A especificidade da complexação foi avaliada pelo método espectrofotométrico e por cromatografia líquida de alta eficiência (CLAE) com arranjo de diodos (DAD). As análises para a mistura das PRS e rutina, demonstraram claramente que a complexação com PVPP não é uma reação específica e independe da quantidade de polímero utilizada. As análises por CLAE-DAD do extrato de Psidium guajava revelaram picos característicos de flavonóides, além de catequina e ácido gálico. Todos os picos destes flavonóides, catequina e ácido gálico decresceram quando adicionou-se o PVPP. Isto confirma a falta de especificidade. Desde que a ligação PVPP-polifenóis depende de características estruturais particulares, a extensão desses resultados a outras espécies vegetais deve ser evitada.

Cross-povidone, or polyvinylpyrrolidone (PVPP) affords an analytical alternative instead of hide-powder and casein as binding agent in the content assay of vegetable tannins. In this work we studied the specificity of PVPP to bind polyphenolics in the presence of flavonoids. Gallic acid, tannic acid, catechin and pyrogallol were used as polyphenolic reference substances (PRS), along with an aqueous extract from Psidium guajava L. leaves. The binding specificity was assayed by UV-Vis and High Performance Liquid Chromatography-Photodiode array (HPLC-PDA) methods. The analyses of PRS-rutin mixtures showed clearly that PVPP binding is a non-specific reaction, unrelated to the amount of PVPP used. HPLC-PDA analysis revealed peaks which could be characterized as flavonoids in the Psidium guajava extract, beside catechin and gallic acid. All these flavonoids, catechin and gallic acid peaks decreased as PVPP was added; this confirms the lack of specificity. Since the polyphenolic-PVPP reaction depends on specific structural features, any extensive conclusion should be avoided.