Chemical composition and in vitro antibacterial activity of essential oils from Murraya paniculata (L.) Jack (Rutaceae) ripe and unripe fruits against bacterial genera Mycobacterium and Streptococcus

This study aims to investigate chemical composition of essential oils from Murraya paniculata (L.) Jack (Rutaceae) ripe and unripe fruits and determine their in vitro antibacterial activity. Essential oils were extracted by hydrodistillation from Murraya paniculata (L.) Jack ripe and unripe fruits collected in the Cerrado, in Rio Verde, southwestern Goiás, Brazil. They were analyzed by gas chromatography with flame ionization detector (GC-FID) and by gas chromatography-mass spectrometry (GC-MS). Sesquiterpenes, which represent the most abundant class of compounds in oils, predominated in both ripe and unripe fruits. Major constituents of essential oils extracted from ripe fruits (RF-EO) were β-caryophyllene (21.3%), α-ylangene (13.3%), germacrene-D (10.9%) and α-zingiberene (9.7%) whereas the ones of unripe fruits (UF-EO) were sesquithujene (25.0%), α-zingiberene (18.2%), germacrene-D (13.1%) and α-copaene (12.7%). In vitro antibacterial activity of essential oils was evaluated in terms of its minimum inhibitory concentration (MIC) values by the broth microdilution method in 96-well microplates. Both essential oils under investigation showed moderate anti-streptococcal activity against the following bacteria: Streptococcus mutans, S. mitis, S. sanguinis, S. sobrinus and S. salivarius. MIC values ranged between 100 and 400 µg/mL. Regarding the antimycobacterial activity, essential oils from M. paniculata (L.) Jack unripe and ripe fruits were active against Mycobacterium kansasii (MIC = 250 µg/mL), moderately active against M. tuberculosis (MIC = 500 µg/mL) and inactive against M. avium (MIC = 2000 µg/mL). This study was pioneer in revealing similar chemical profiles of both essential oils extracted from Murraya paniculata (L.) Jack unripe and ripe fruits, besides describing their in vitro anti-streptococcal and antimycobacterial activities

Evaluation of the antimicrobial activity of curcuminoids and study of their gas phase fragmentation reactions by sequential mass spectrometry

Neste trabalho, uma série de curcuminoides monocetônicos foram sintetizados por meio da condensação entre acetona e 11 diferentes aldeídos aromáticos. Esses curcuminoides foram posteriormente convertidos em seus álcoois e cetonas saturados correspondentes por meio de reações de hidrogenação catalítica. Os compostos obtidos foram avaliados quanto às suas atividades antimicrobianas frente a um painel representativo de bactérias cariogênicas empregando o método de microdiluição em microplacas. Além disso, as vias de fragmentação em fase gasosa dos curcuminoides monocetônicos protonados foram investigadas por espectrometria de massas sequencial com ionização por eletrospray (ESI-MS/MS) em combinação com dados de massas acuradas, dados de experimentos de espectrometria de massas de estágios múltiplos (MSn) e de troca de deutério, bem como em dados termoquímicos estimados por Química Computacional. Dentre os 31 curcuminoides avaliados, a curcumina A (10), 1E,4E)-1,5-bis(4-hidroxifenil)penta-1,4-dien-3-ona, e o (1E,4E)-1,5-bis(4-hidroxifenil)penta-1,4-dien-3-ona (11), apresentaram a atividade antimicrobiana mais efetiva, com valores de concentração inibitória mínima (CIM) de 50 g/mL contra Streptococcus mutans e de 50 g/mL contra Streptococcus mitis. Os valores de CIM obtidos foram menores que os valores de CIM previamente relatados para a curcumina, que é o análogo -dicetônico do composto 10. As relações estrutura-atividade inferidas sugerem que o grupo hidroxila ligado aos aneis aromáticos e a ligação dupla entre C2-C3 e C2-C3 e o grupo carbonila e C1 são as características responsáveis pela atividade antimicrobiana. Os resultados mostraram que o íon H e o íon acílio D, resultantes de dois rearranjos de hidrogênio competitivos, são os mais intensos no espectro de íons produtos dos curcuminoides protonados. Além da identificação de alguns íons diagnósticos, este trabalho comprovou que a formação de alguns íons produtos ocorreu a partir de um íon intermediário resultante de uma ciclização de Nazarov da molécula protonada, cuja ocorrência foi reportada previamente na literatura. Os dados termoquímicos suportaram as estruturas dos íons propostos e mostraram que a posição da hidroxila fenólica no anel aromático desempenha um papel fundamental sobre a ciclização de Nazarov. Os resultados deste trabalho poderão contribuir futuramente na identificação dos produtos resultante do metabolismo dos estudos in vitro e in vivo sem a necessidade de padrões ou isolamento desses metabolitosIn this work, a series of monoketone curcuminoids were synthesized by condensation between acetone, and 11 (eleven) different aromatic aldehydes. These curcuminoids were subsequently converted to their corresponding saturated alcohols and ketones by means of catalytic hydrogenation reactions. The obtained compounds were evaluated for their antimicrobial activities against a representative panel of cariogenic bacteria using microdilution plating method. In addition, the gas-phase fragmentation pathways of the protonated monoketone curcuminoids were investigated by ionization tandem mass spectrometry (ESI-MS/MS) in combination with accurate mass data, multi-stage mass spectrometry (MSn), and deuterium exchange experiments, as well as in thermochemical data estimated by Computational Chemistry. Among the 31 curcuminoids evaluated, curcumin A (10), (1E,4E)-1,5-bis(4-hydroxyphenyl)penta-1,4-dien-3-one, and (1E,4E)5-bis(4-hydroxyphenyl)penta-1,4-dien-3-one (11) showed the most effective antimicrobial activity, with minimum inhibitory concentration (MIC) values of 50 g/mL against Streptococcus mutans and 50 g/mL against Streptococcus mitis. MIC values of curcumin A (10) were lower than the previously reported MIC values for its -diketone analog of compound 10. The inferred structure-activity relationships indicated that the hydroxyl group attached to the aromatic rings and the double bond between C2-C3 and C2\'-C3 \'and the carbonyl group and C1 are the characteristics responsible for the antimicrobial activity. The results showed that the ion H and the acylium ion D, resulting from two competitive hydrogen rearrangements, are the most intense in the spectrum of proton curcuminoids product ions. Besides the identification of some diagnostic ions, this work proved that the formation of some product ions occured from an intermediate ion resulting from a Nazarov cyclization of the protonated molecule, whose occurrence has been previously reported in the literature. The thermochemical data supported the structures of the proposed ions and showed that the position of the phenolic hydroxyl in the aromatic ring plays a key role in the Nazarov cyclization. The results of this work may contribute in future to the identification of products from the in vitro and in vivo metabolism studies without the need for standards or isolation of these metabolite

Evaluation of the antibacterial and antiparasitic activities of artepillin C and its prenylated analogs and study of their gas-phase fragmentation reactions using tandem mass spectrometry

O artepillin C é um dos principais componentes da própolis verde. Várias atividades biológicas têm sido atribuídas ao artepilin C, com destaque para a atividade antimicrobiana. Neste trabalho, o artepillin C e 14 análogos prenilados e seus derivados foram sintetizados e avaliados quanto às suas atividades antibacteriana frente a bactérias cariogênicas, esquistossomicida e leishmanicida. Além disso, as reações de fragmentação em fase gasosa dos compostos sintetizados foram investigadas por espectrometria de massas sequencial com ionização por eletrospray (ESI-MS/MS). Apesar de o uso de micro-ondas ter reduzido a etapa de prenilação do p-cumaroato de metila de 24 h para 10 min, não foi possível evitar a formação de três subprodutos prenilados, que também haviam sido formados nas condições da literatura. Nenhum dos 15 compostos sintetizados apresentou atividades esquistossomicida contra vermes adultso de Schistosoma mansoni ou leishmanicida contra formas promastigotas de Leishmania amazonensis promissoras. Por outro lado, os compostos 5 (plicatina B) e 6 (2\',3\',7,8-tetraidroplicatina B) apresentaram atividade antibacteriana promissora frente a um painel representativo de bactérias cariogênicas, com valores de concentração inibitória mínima (CIM) entre 32,2 e 62,5 µg/mL. Dados obtidos por docking molecular demonstraram que os compostos 5 e 6 possuem parâmetros físicoquímicos, biodisponibilidade e farmacocinética que atendem a todos os critérios para serem considerados como promissores. Os estudos por espectrometria de massas mostraram que compostos C-prenilados podem ser diferenciados de O-prenilados pelas perdas de C4H8 e C5H8, respectivamente. Além disso, a utilização de varredura por monitoramento de reações múltiplas (MRM) utilizando as transições 301→259, 301→245 e 301→203 para o artepillin C (5) e 247→205, 247→191, e 247→159 para a plicatina B (6) possibilitou a identificação desses compostos em uma amostra comercial de própolis utilizando cromatografia de ultraperformance acoplada à espectrometria de massas sequencial com ionização por eletrospray (UPLC-ESI-MS/MS).Artepillin C is one of the main components of true propolis. Several biological activities have been attributed to artepilin C, and the antimicrobial activity has been highlighted. In this work, artepillin C and 14 prenylated analogues and their derivatives were synthesized and evaluated for their antibacterial, schistosomicidal and leishmanicidal activities. Furthermore, the gas phase fragmentation reactions of the synthesized compounds were investigated by sequential electrospray ionization mass spectrometry (ESI-MS/MS). Although the use of microwave irradiation reduced the time of prenylation step of methyl p-coumaroate from 24 h to 10 min, it was not possible to avoid the formation of three prenylated by-products, which had also been formed under conditions in the literature. None of the 15 compounds synthesized showed promising schistosomal against adult Schistosoma mansoni worms or leishmanicidal activity against Leishmania amazonensis promastigote forms. On the other hand, compounds 5 (plicatin B) and 6 (2\',3\',7\',8\'- dihydroplicatin B) showed promising antibacterial activity against a representative panel of cariogenic bacteria, with minimum inhibitory concentration (MIC) values between 32.2 and 62.5 µg/mL. Data obtained by molecular docking demonstrated that compounds 5 and 6 meet all the physicochemical, pharmacokinetic, and bioavailability criteria to be considered as promising. Mass spectrometry studies showed that C-prenylated compounds can be differentiated from O-prenylated compounds by the losses of C4H8 and C5H8, respectively. Moreover, the use of multiple reaction monitoring (MRM) scan mode based on the transitions 301→259, 301→245 and 301→203 for artepillin C (5) and 247→205, 247→191, and 247→159 for plicatin B (6) allowed for the identification of these compounds in a commercial sample of green propolis using ultra-performance chromatography coupled with sequential mass spectrometry with ionization by electrospray (UPLC-ESI-MS/MS)

Chemical constituents of essential oil from Murraya paniculata leaves and its application to in vitro biological control of the fungus Sclerotinia sclerotiorum

ABSTRACT Besides their value as therapeutic resources, medicinal plants may also be used as sources of active ingredients against phytopathogens. Fungi can grow and cause spoilage in food, thus, resusting in decrease in its quality and quantity. This research aimed at evaluating the effect of essential oil from Murraya paniculata (ML-EO) leaves on mycelial growth of Sclerotinia sclerotiorum, a fungus that poses high risk to several cultures, mainly soybean. Essential oil from M. paniculata (Rutaceae) leaves was obtained by hydrodistillation which was carried out by a Clevenger-type apparatus while its chemical composition was analyzed by GC-FID and GC-MS. β-Caryophyllene (23.8%), α-zingiberene (21.0%) and β-cubebene (10.2%) were the main constituents found in ML-EO leaves. In vitro antifungal activity showed that ML-EO, at a 300 µL dose, inhibited 91.2% of mycelial growth of Sclerotinia sclerotiorum . This is the first report of the antifungal activity of ML-EO against S. sclerotiorum and results suggest that the essential oil under evaluation has good potential to control this phytopathogenic fungus