Kalanchoe fedtschenkoi R. Hamet & H. Perrier, a non-conventional food plant in Brazil: HPLC-DAD-ESI-MS/MS profile and leaf histochemical location of flavonoids

Kalanchoe fedtschenkoi (Crassulaceae) is a non-commercial food species in Brazil, whose leaves are used in several aqueous preparations. Their morphology and potential nutraceuticals (e.g., antioxidant phenolics) have been poorly studied. Anatomical features are useful for the correct identification of plants, avoiding their misuse. We describe the anatomy and tissue flavonoid location of K. fedtschenkoi leaves, as well as the phenolic composition and the antioxidant activity of their aqueous extracts. The succulent leaves have a unistratified epidermis with anisocytic or helicocytic stomata, collateral vascular bundles, and phenolic idioblasts throughout the leaf blade. NP-reagent tests suggested the presence of kaempferol derivatives (yellow fluorescence) in the regular epidermis cells, subsidiary cells, and leaf mesophyll. An orange color, assigned to quercetin derivatives, was detected in stomata guard-cells and below the epidermis. The HPLC-DAD-ESI-MS/MS evidenced the presence offlavonoids, mostly kaempferol glycosides (especially sagittatin A), some of them firstly described as constituents of K. fedtschenkoi. The extracts also showed high antioxidant activity. We report, for the first time, the complete anatomical description of K. fedtschenkoi leaves, the tissue location of flavonoids, and the flavonoid composition of the extracts. The high flavonoid content and antioxidant activity of K. fedtschenkoi leaves can be an advantage for their consumption as a food, in addition to being a possible source of nutraceuticals

Bioavailability of phenolic compounds: a major challenge for drug development?

Made available in DSpace on 2017-06-01T19:33:54Z (GMT). No. of bitstreams: 2 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) 7.pdf: 588587 bytes, checksum: 88e3c4dba59a6f534592745229219511 (MD5) Previous issue date: 29Universidade Federal do Rio de Janeiro. Centro de Ciências da Saúde. Instituto de Pesquisas de Produtos Naturais. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Centro de Ciências da Saúde. Instituto de Pesquisas de Produtos Naturais. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Centro de Ciências da Saúde. Instituto de Pesquisas de Produtos Naturais. Rio de Janeiro, RJ, Brasil.As substâncias fenólicas constituem uma importante classe de metabólitos secundários, amplamente distribuídas no reino vegetal. Diversas atividades biológicas in vitro são atribuídas a essa classe de substâncias. Entretanto, algumas dessas substâncias não apresentam o mesmo perfil de atividade nos ensaios in vivo. Parte disso pode ser explicada pela baixa biodisponibilidade dessas substâncias. As principais razões encontradas para este fato podem ser a baixa solubilidade em meio aquoso, a fraca estabilidade gastrointestinal, a dificuldade em atravessar membranas e a rápida e extensa metabolização. Os metabólitos produzidos na biotransformação pela microbiota intestinal e por enzimas hepáticas poderiam explicar a baixa eficácia dessas substâncias. Em contrapartida, a biotransformação também pode originar metabólitos potencialmente mais ativos que as substâncias originais. Diante da relevância do tema, este artigo tem como objetivo abordar os impactos da metabolização das substâncias fenólicas sobre o efeito farmacológico. Adicionalmente, serão apresentadas estratégias que podem ser utilizadas para aumentar a bioeficácia dessas substâncias, e consequentemente, contribuir para o aproveitamento dessa classe química no desenvolvimento de fármacos de origem vegetal.Phenolic substances are an important class of secondary metabolites widely distributed in the plant kingdom. Several biological activities in vitro are assigned to this class of substances. However, some of these substances do not have the same profile of activity in in vivo assays. This fact could be partially explained by the low bioavailability of these substances. The main reasons for this low bioavailability may be low aqueous solubility, poor gastrointestinal stability and difficulty crossing membranes. The rapid and extensive metabolism by the intestinal flora and by some liver enzymes of phenolic substances after oral administration, may explain the poor bioavailability. In contrast, biotransformation can also lead to metabolites potentially more active than the original substances. Given the importance of the topic, this article aims to address the impacts of metabolism of phenolic substances on their pharmacological effects. Additionally, we show strategies to improve the bioefficacy of these substances, contributing to their use in the development of drugs of vegetal origin

The Potential of Allelochemicals from Microalgae for Biopesticides

Improvements in agricultural productivity are required to meet the demand of a growing world population. Phytopathogens, weeds, and insects are challenges to agricultural production. The toxicity and widespread application of persistent synthetic pesticides poses a major threat to human and ecosystem health. Therefore, sustainable strategies to control pests are essential for agricultural systems to enhance productivity within a green paradigm. Allelochemicals are a less persistent, safer, and friendly alternative to efficient pest management, as they tend to be less toxic to non-target organisms and more easily degradable. Microalgae produce a great variety of allelopathic substances whose biocontrol potential against weeds, insects, and phytopathogenic fungi and bacteria has received much attention. This review provides up-to-date information and a critical perspective on allelochemicals from microalgae and their potential as biopesticides

Potential Therapeutic Effects of Underground Parts of Kalanchoe gastonis-bonnieri on Benign Prostatic Hyperplasia

Benign Prostatic Hyperplasia (BPH) affects mainly older men. It is estimated to affect 50% of 51-60-year-old men and 70% of 61-70-year-old men. BPH is a nonmalignant proliferation of epithelial and stromal cells of the prostate gland regions. Despite the use of conventional pharmacological therapy, herbal medicines are used in BPH therapy, and several mechanisms of action have been suggested based on their complex chemical composition. Considering the ethnomedicinal uses of Kalanchoe gastonis-bonnieri (KGB), we evaluated the inhibitory effects on the proliferation of stromal cells from primary benign prostatic hyperplasia (BPH) of four different aqueous extracts from this plant: underground parts from specimens in flower (T1 treatment), leaves from specimens in flower (T2 treatment), and flowers (T3 treatment) and leaves from specimens not in flower (T4 treatment). T1, T2, T3, and T4 treatments at 250 μg/ml for 72 hours inhibited BPH cells by 56.7%, 29.2%, 39.4%, and 13.5%, respectively, showing that the KGB underground parts extract (T1 treatment) was the most active. Our findings show that the extract of the KGB underground parts (150 and 250 μg/ml) stimulates important changes in the BPH cells, modulating crucial processes such as proliferation, viability, and apoptosis. HPLC-DAD-MS/MS analysis provided a tentative identification of glycosylated syringic acid derivatives, glycosylated forms of volatile compounds, and lignans in this extract. Finally, these results suggest that there is a potential therapeutic use for KGB in BPH, which could improve the clinical management of the disease

Development of Microalgae Biodiesel: Current Status and Perspectives

Microalgae are regarded as a promising source of biodiesel. In contrast with conventional crops currently used to produce commercial biodiesel, microalgae can be cultivated on non-arable land, besides having a higher growth rate and productivity. However, microalgal biodiesel is not yet regarded as economically competitive, compared to fossil fuels and crop-based biodiesel; therefore, it is not commercially produced. This review provides an overall perspective on technologies with the potential to increase efficiency and reduce the general costs of biodiesel production from microalgae. Opportunities and challenges for large-scale production are discussed. We present the current scenario of Brazilian research in the field and show a successful case in the research and development of microalgal biodiesel in open ponds by Petrobras. This publicly held Brazilian corporation has been investing in research in this sector for over a decade