Antioxidant potential of various solvent extract from Morus alba fruits and its major polyphenols composition / Potencial antioxidante de vários extratos de frutos de Morus alba e de sua composição majoritária de polifenóis

ABSTRACT: Extraction conditions are an important factor in the process of obtaining bioactive compounds from plant matrix. These compounds differ structurally. Structures of phyto-compounds and their interactions with other food ingredient are not fully known, while these two aspects should play a significant role in extrahents choice and determination of extraction process conditions. Mulberry (Morus alba) is a plant growing in Asia, which fruits are rich in bioactive ingredients and high anti-oxidative potential. In our study we analyzed mulberry fruits extracts differing in the extra hent applied: acetone, methanol, ethanol and water. All tested extracts possessed rich polyphenolic composition and radical scavenging ability. The significant differences among the extracts in phenolic acids and flavonoids compositions were noticed, where the highest values were observed for acetone extract. The extrahent applied affects the antioxidative profile of tested samples, as well. The highest scavenging activity against ABTS was observed for acetone and ethanol extracts, while the poorest activity had water extract. Similar results were provided for ferrous ion reducing test and Fe chlating activity (acetone>ethanol>methanol>water). These results are helpful when selecting solvents with appropriate bioactive compounds compositions and high phytochemical profiles to be used as ingredients in supplements, as well as in functional foods.

RESUMO: As condições de extração são um fator importante no processo de obtenção de compostos bioativos da matriz vegetal. Estes compostos diferem-se estruturalmente. As estruturas de fito conjugações e suas interações com outros ingredientes alimentares não são totalmente conhecidas, enquanto esses dois aspectos devem desempenhar um papel significativo na escolha de extrações e na determinação das condições do processo de extração. A amoreira (Morus alba) é uma planta que cresce na Ásia, cujos frutos são ricos em ingredientes bioativos e com alto potencial antioxidante. Em nosso estudo, analisamos extratos de frutos de amoreira diferindo no extraente aplicado: acetona, metanol, etanol e água. Todos os extratos testa dos possuíam composição polifenólica rica e capacidade de eliminação de radicais livres. As diferenças significativas entre os extratos em composições de ácidos fenólicos e flavonóides foram observadas, em que os maiores valores foram observados para o extrato de acetona. O extraente aplicado afeta também o perfil antioxidante das amostras testadas. A maior atividade de eliminação contra o ABTS foi observada para a acetone e etanol extração, enquanto a atividade mais pobre tinha água. Resultados semelhantes foram fornecidos para teste de redução de íons ferrosos e atividade de aglutinação de Fe (acetona>etanol>metanol>água). Estes resultados são úteis na seleção de solventes com composições apropriadas de compostos bioativos e altos perfis fitoquímicos para serem usados como ingredientes em suplementos, bem como em alimentos funcionais.

The effect of high concentrations of glycerol on the growth, metabolism and adaptation capacity of Clostridium butyricum DSP1

Background The production of biofuels from renewable energy sources is one of the most important issues in biotechnology today. The process is known to generate various by-products, for example glycerol that is obtained in the making of biodiesel from rapeseed oil. Crude glycerol may be utilized in many ways, including microbial conversion to 1,3-propanediol. The main drawback of that technology is the use of high concentrations of glycerol, which inhibits the growth of bacterial cells. Results This study investigated the impact of crude glycerol on Clostridium butyricum DSP1 and its ability to adapt to an environment of high osmotic pressure. It was found that a crude glycerol concentration of up to 70 g/L did not have an inhibitory effect on C. butyricum DSP1. Adaptation procedures involving the passage of metabolically active biomass from a fermentation medium with a lower concentration of crude glycerol to one with a greater substrate concentration allowed breaking the barrier of high osmotic pressure (150 g/L crude glycerol) and receiving a 1,3-PD concentration of 74 g/L in a batch culture operation. The work looked into intracellular modifications shown by proteomic profiling in order to explain the mechanisms underlying the response and adaptation of bacterial cells exposed to unfavorable environmental conditions. Conclusions This study of the effect of glycerol on the growth and metabolism of C. butyricum DSP1 demonstrated that the maximum substrate concentrations that do not inhibit the metabolic activity of bacterial cells are 90 g/L and 70 g/L for pure and crude glycerol, respectively.

Biotechnological potential of Clostridium butyricum bacteria

In response to demand from industry for microorganisms with auspicious biotechnological potential, a worldwide interest has developed in bacteria and fungi isolation. Microorganisms of interesting metabolic properties include non-pathogenic bacteria of the genus Clostridium, particularly C. acetobutylicum, C. butyricum and C. pasteurianum. A well-known property of C. butyricum is their ability to produce butyric acid, as well as effectively convert glycerol to 1,3-propanediol (38.2 g/L). A conversion rate of 0.66 mol 1,3-propanediol/mol of glycerol has been obtained. Results of the studies described in the present paper broaden our knowledge of characteristic features of C. butyricum specific isolates in terms of their phylogenetic affiliation, fermentation capacity and antibacterial properties.