Browsing by Subject "piperine"

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  • Mgbeahuruike, Eunice Ego; Fyhrquist, Pia; Vuorela, Heikki; Julkunen-Tiitto, Riitta; Holm, Yvonne (2018)
    Piper guineense is a food and medicinal plant commonly used to treat infectious diseases in West-African traditional medicine. In a bid to identify new antibacterial compounds due to bacterial resistance to antibiotics, twelve extracts of P. guineense fruits and leaves, obtained by sequential extraction, as well as the piperine and piperlongumine commercial compounds were evaluated for antibacterial activity against human pathogenic bacteria. HPLC-DAD and UHPLC/Q-TOF MS analysis were conducted to characterize and identify the compounds present in the extracts with promising antibacterial activity. The extracts, with the exception of the hot water decoctions and macerations, contained piperamide alkaloids as their main constituents. Piperine, dihydropiperine, piperylin, dihydropiperylin or piperlonguminine, dihydropiperlonguminine, wisanine, dihydrowisanine and derivatives of piperine and piperidine were identified in a hexane extract of the leaf. In addition, some new piperamide alkaloids were identified, such as a piperine and a piperidine alkaloid derivative and two unknown piperamide alkaloids. To the best of our knowledge, there are no piperamides reported in the literature with similar UV absorption maxima and masses. A piperamide alkaloid-rich hexane leaf extract recorded the lowest MIC of 19 mu g/mL against Sarcina sp. and gave promising growth inhibitory effects against S. aureus and E. aerogenes as well, inhibiting the growth of both bacteria with a MIC of 78 mu g/mL. Moreover, this is the first report of the antibacterial activity of P. guineense extracts against Sarcina sp. and E. aerogenes. Marked growth inhibition was also obtained for chloroform extracts of the leaves and fruits against P. aeruginosa with a MIC value of 78 mu g/mL. Piperine and piperlongumine were active against E. aerogenes, S. aureus, E. coli, S. enterica, P. mirabilis and B. cereus with MIC values ranging from 39-1250 mu g/mL. Notably, the water extracts, which were almost devoid of piperamide alkaloids, were not active against the bacterial strains. Our results demonstrate that P. guineense contains antibacterial alkaloids that could be relevant for the discovery of new natural antibiotics.
  • Mgbeahuruike, Eunice Ego; Stålnacke, Milla; Vuorela, Heikki; Holm, Yvonne (2019)
    Microbial resistance to currently available antibiotics is a public health problem in the fight against infectious diseases. Most antibiotics are characterized by numerous side effects that may be harmful to normal body cells. To improve the efficacy of these antibiotics and to find an alternative way to minimize the adverse effects associated with most conventional antibiotics, piperine and piperlongumine were screened in combination with conventional rifampicin, tetracycline, and itraconazole to evaluate their synergistic, additive, or antagonistic interactions against Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. The fractional inhibitory concentration index was used to estimate the synergistic effects of various combination ratios of the piperamides and antibiotics against the bacterial and fungal strains. Both piperine and piperlongumine showed synergistic effects against S. aureus when combined at various ratios with rifampicin. Synergistic interaction was also observed with piperine in combination with tetracycline against S. aureus, while antagonistic interaction was recorded for piperlongumine and tetracycline against S. aureus. All the piperamide/antibacterial combinations tested against P. aeruginosa showed antagonistic effects, with the exception of piperine and rifampicin, which recorded synergistic interaction at a ratio of 9:1 rifampicin/piperine. No synergistic interaction was observed when the commercial compounds were combined with itraconazole and tested against C. albicans. The results showed that piperine and piperlongumine are capable of improving the effectiveness of rifampicin and tetracycline. Dosage combinations of these bioactive compounds with the antibiotics used may be a better option for the treatment of bacterial infections that aims to minimize the adverse effects associated with the use of these conventional antibacterial drugs.
  • Gasques Rocha Pinheiro, Beatriz (Helsingin yliopisto, 2020)
    Geometric isomers are of extreme importance due to the different properties of E and Z compounds. The interconversion between these forms allow to explore a vast amount of applications since their use in perfume and food industry until the development of photoactive drugs and advanced polymers. Included in this scenario are the E/Z isomers of pepper alkaloids, whose broad range of desirable pharmacological activities, such as anti-inflammatory, antioxidant and anti-cancer effects, makes them a focus in multidisciplinary research. Black pepper contains several of these alkaloids, among which piperine is the most abundant. Its properties have been studied for many years, with highlight for its pungency and flavour, in addition to medicinal applications that date from the development of ancient Indian and Chinese medicine. Piperine and structure-related compounds undergo rapid double bond isomerization in the presence of light, equilibrating to a mixture of four geometrical isomers, due to the two conjugated double bonds present in their structures. The biological activity of these isomers differs from those of the natural abundant E/E molecules. Thus, emphasizing the importance of having reliable analytical assays for their separation, detection and quantification. The current project pursued the development of a robust HPLC assays for isomers separation for piperine and some analogues. The effort included the extraction of piperine from black pepper and its use for the synthesis of highly pure piperylin and piperlonguminine standards. Piperine extraction kinetics was also studied to optimize the extraction procedure. The standards of alkaloids were isomerized using sunlight and then HPLC separation methods on chiral stationary phases were successfully established to resolve their E/Z isomers. Isocratic runs were also developed for piperine, piperylin and piperlonguminine, with the goal of adapting these methods to LC/MS application in the future. These last separations could be accomplished within 25 minutes with critical resolutions values larger than 1.8.