Impurities in Active Pharmaceutical Ingredients and Drug Products: A Critical Review.

The presence of impurities in active pharmaceutical ingredients (APIs) and drug products represents a risk to patients' health. Such substances are related to diverse side effects and may have mutagenic potential. That's why it is necessary to establish acceptable limits for these by-products, to minimize the risk associated with medicinal therapy.

Synthesis of new trypanocidal agents from the hybridisation of metronidazole and eugenol analogues.

Nitroimidazole compounds are well-known bioactive substances, and the structural activity relationship has been reported whereby the position of the nitro group within the imidazole ring has a large influence on the activity. This study focuses on synthesising new trypanocidal agents from the hybridisation of metronidazole with different natural phenols (eugenol, dihydroeugenol and guaiacol). Two different coupling methodologies have been explored in order to analyse the influence of the connector on bioactivity: i) classic direct esterification (AD compounds) and ii) "click" chemistry using a triazole connector (AC compounds).

Discovery of a new dihydroeugenol-chalcone hybrid with cytotoxic and anti-migratory potential: A dual-action hit for cancer therapeutics.

Cancer still represents a serious public health problem and one of the main problems related to the worsening of this disease is the ability of some tumors to develop metastasis. In this work, we synthesized a new series of chalcones and isoxazoles derived from eugenol and analogues as molecular hybrids and these compounds were evaluated against different tumor cell lines. This structural pattern was designed considering the cytotoxic potential already known for eugenol, chalcones and isoxazoles.

Combining eugenol and dihydroeugenol with a piperazine moiety to create new antimicrobial agents that are effective against resistant species.

Historically, the piperazine moiety has been demonstrated to possess pharmacophoric properties, and has subsequently been incorporated in many drugs that have antitumor, antimalarial, antiviral, antibacterial and antifungal properties. Derivatives of eugenol and dihydroeugenol have also been reported as being bioactive compounds. This study reports the synthesis of a range of eugenol/dihydroeugenol - piperazine derivatives which have been tested as antimicrobial compounds against Gram positive, Gram negative and rapid-growing mycobacteria (RGM).

Evaluation of antiplasmodial activity in silico and in vitro of N-acylhydrazone derivatives.

N-acylhydrazones are considered privileged structures in medicinal chemistry, being part of antimicrobial compounds (for example). In this study we show the activity of N-acylhydrazone compounds, namely AH1, AH2, AH4, AH5 in in vitro tests against the chloroquine-resistant strain of Plasmodium falciparum (W2) and against WI26 VA-4 human cell lines. All compounds showed low cytotoxicity (LC > 100 µM).

Synthesis of New Hybrid Derivatives from Metronidazole and Eugenol Analogues as Trypanocidal Agents.

Background: The search for new drug compounds is always challenging and there are several different strategies that involve the most varied and creative approaches in medicinal chemistry. One of them is the technique of molecular hybridisation: forming a hybrid compound from two or more pharmacophoric subunits. These hybrids may maintain the characteristics of the original compound and preferably show improvements to its pharmacological action, with reduced side effects and lower toxicity when compared to the original components.

Synthesis of eugenol-derived glucosides and evaluation of their ability in inhibiting the angiotensin converting enzyme.

We report here a series of glucosides which are active as inhibitors of the angiotensin converting enzyme (ACE). They are structurally related to the natural compound eugenol and exhibited significant inhibition values. Their syntheses were expeditious and we could obtain informative docking plots of them complexed to this enzyme.