ABSTRACT
@#Aims: Betanin is a red plant pigment belonging to the group called betalain. This present study aimed at investigating the effect betanin from beetroot (Beta vulgaris subsp. vulgaris) as a potential anti-infective agent against methicillinresistant Staphylococcus aureus (MRSA) using a Caenorhabditis elegans infection model. Methodology and results: The minimum inhibitory concentration of betanin against MRSA strain ATCC 33591 was determined to establish the non-inhibitory concentration. The minimum inhibitory concentration of betanin against MRSA was > 20 mg/mL. C. elegans were then infected with MRSA and treated with betanin at different concentrations (100, 200, 300 and 400 µg/mL). Betanin at 200 µg/mL significantly improved worm survival following infection whereby the mean time to death was extended about 76 h upon treatment. Intestinal colonization by MRSA of worms exposed to betanin extract was similar to non-betanin-treated infected worms. Conclusion, significance and impact of study: The enhanced survival of MRSA-infected worms upon betanin treatment was not a result of the activation of the host antimicrobial mechanism. Betanin from beetroot can be potentially used as a natural anti-infective agent as a mean to reduce antimicrobial resistance of S. aureus or used in combination with established antimicrobials to increase their effectiveness.
ABSTRACT
Among the compounds produced by plants, pigments such as betalains have received attention from both food and pharmaceuticals industries. The Alternanthera sessilis species produces these pigments, though in small quantities, and so it is necessary to increase production. Thus, many studies use elicitors that are capable of triggering physiological or morphological responses in plants. The objective was to establish callus production in A. sessilis grown under different combinations of growth regulators and light qualities and to assess whether these factors can increase betalain and flavonoid production. Leaf and internodal explants in MS medium with different growth regulators were used to obtain calli, which were subsequently transferred to a betacyanin induction medium remaining for 40 days under different light qualities (white, blue, red, and dark). The most suitable treatment for callus formation and subsequent betalain and flavonoid induction was to combine a medium containing 6.7 µmol L-1 2,4-D and 9.0 µmol L-1 BAP and blue light. Physical elicitation by light combined with appropriate concentration of growth regulators on calli can increase production of commercially important metabolites.
Dentre os compostos produzidos pelas plantas, os pigmentos, como as betalaínas, vêm recebendo destaque tanto pela indústria alimentícia como farmacêutica. A espécie Alternanthera sessilis produz esses pigmentos, porém em pequenas quantidades, sendo necessário incrementar a produção. Para isso, muitos estudos utilizam elicitores que são capazes de desencadear respostas fisiológicas ou morfológicas nas plantas. O objetivo do trabalho foi estabelecer a produção de calos de A. sessilis crescidos quando submetidos a diferentes combinações de reguladores de crescimento e qualidades de luz, e avaliar se esses fatores são capazes de incrementar a produção de betalaínas e flavonoides. Foram utilizados explantes foliares e internodais em meio MS com diferentes reguladores de crescimento para obtenção dos calos que, posteriormente, foram transferidos para meio de indução de betacianina, onde permaneceram por 30 dias sob diferentes qualidades de luz (branca, azul, vermelha e escuro). O tratamento mais propício para formação de calos e consequente indução de betalaínas e flavonoides foi a combinação do meio contendo 6,7 µmol L-1 2,4-D e 9,0 µmol L-1 BAP e a luz azul. Conclui-se que a elicitação física pela luz em conjunto com a concentração adequada de reguladores de crescimento em calos é capaz de incrementar a produção de metabólitos de interesse comercial.
Subject(s)
Betalains , Flavonoids , Plants, MedicinalABSTRACT
A manipulação da concentração dos microelementos no meio de cultura representa uma boa estratégia para aumentar a produção de metabólitos secundários em cultura de tecidos. Este trabalho teve por objetivo demonstrar a influência do sulfato de cobre na produção de betacianina e na multiplicação de plantas de Alternanthera philoxeroides (erva-de-jacaré) cultivadas in vitro. Segmentos nodais, obtidos de plantas pré-estabelecidas e após três subcultivos, foram inoculados em meio MS, com diferentes concentrações de CuSO4 (0; 25; 75; 125; 175; 200µM). O delineamento experimental utilizado foi inteiramente casualizado, com seis concentrações de CuSO4 e cinco repetições representadas por um frasco contendo quatro explantes. Os resultados foram submetidos à análise de variância, à regressão polinomial e a análises de correlação entre as variáveis morfológicas e a produção de betacianina. Concentrações acima de 75µM diminuíram a altura das plantas, o número de brotos e gemas e o crescimento radicular, enquanto que, na concentração de 125µM, houve a maior produção de massa fresca. A produção de betacianina aumentou 60 por cento em relação ao controle com 175µM de CuSO4. Ocorreu crescimento das plantas em todas as concentrações de CuSO4 testadas, com exceção de 200µM, sendo esta considerada tóxica.
The manipulation of concentration of trace elements in the culture medium represents a good strategy to increase the production of secondary metabolites in tissue culture. This study aimed to demonstrate the influence of copper sulphate in the production of betacyanin and the multiplication of plants of Alternanthera philoxeroides (alligator weed) cultured in vitro. Nodal segments, obtained from plants pre-stablished and after three subcultures, were inoculated in basic MS with different concentrations of CuSO4 (0, 25, 75, 125, 175, 200µM). The results were subjected to analysis of variance, polynomial regression and correlation analysis between the morphological variables and the production of betacyanin. The experimental design was completely randomized with six concentration of CuSO4 and five replicates represented by a bottle containing four explants. Concentrations above 75µM decreased the height of the plant, number of shoots and buds and root growth, while the concentration of 125µM resulted in the highest fresh mass production. Betacyanin production increased 60 percent over control with 175µM CuSO4. Plant growth occurred in all tested concentrations of CuSO4, with the exception of 200µM which was toxic.