The frequent occurrences of antibiotic-resistant biofilm forming pathogens have become global issue since various measures that had been taken to curb the situation led to failure. Euphorbia hirta, is a well-known ethnomedicinal plant of Malaysia with diverse biological activities. This plant has been used widely in traditional medicine for the treatment of gastrointestinal, bronchial and respiratory ailments caused by infectious agents.

Background: The escalating dominance of resistant Pseudomonas aeruginosa strains as infectious pathogen had urged the researchers to look for alternative and complementary drugs. Objective: The objective of this study is to address the biological targets and probable mechanisms of action underlying the potent antibacterial effect of the isolated compounds from Euphorbia hirta (L.) against P. aeruginosa. Materials and Methods: The action mechanisms of caffeic acid (CA) and epicatechin 3-gallate (ECG) on P. aeruginosa cells were investigated by several bacterial physiological manifestations involving outer membrane permeabilization, intracellular potassium ion efflux, and nucleotide leakage. Results: The findings revealed that ECG and CA targeted both cell wall and cytoplasmic membrane of P. aeruginosa. The cellular membrane destruction and ensuing membrane permeability perturbation of P. aeruginosa had led to the ascending access of hydrophobic antibiotics, release of potassium ions, and leakages of nucleotides. Conclusion: The overall study concludes that ECG and CA isolated from E. hirta possess remarkable anti-infective potentials which can be exploited as drug template for the development of new antibacterial agent against resistant P. aeruginosa pathogen. Abbreviations used: ECG: Epicatechin 3-gallate; CA: Caffeic acid; E. hirta: Euphoria hirta.

Nutmeg (Myristica fragrans Houtt.) is the seed kernel of inside the fruit. It has been studied to having number of ethnopharmacological properties. Essential oils are secondary metabolites which originated from different parts of plants and made up of volatile compounds. In the present study, the essential oil extracted from nutmeg was investigated for its in vitro cytotoxicity on Vero cell line (normal cell line) and anti-parasitic activity against Toxoplasma gondii parasite. Nutmeg essential oil showed very low cytotoxic activity against Vero cells with IC50 value of 24.83μg/mL. In the in vitro anti-T.gondii assay, the oil extract showed significant inhibiting activity with EC50 value of 24.45μg/mL. This result was comparable to the standard drug clindamycin (EC50=16.57μg/mL.). Based on the promising results, nutmeg essential oil may be further studied for its mechanism of action against T.gondii and to isolate the bioactive compound(s) to treat toxoplasmosis

The present study was aimed at evaluating the antimicrobial and cytotoxic activities of various extracts of Euphorbia hirta. The ethanolic extract exhibited the strongest antimicrobial activity against Salmonella typhi with MIC value of 0.031mg/ml. In contrast, hexane extract appeared to be the least active extract as its inhibition potency was been observed only on Proteus vulgaris. Dichloromethane and ethyl acetate extracts demonstrated moderate activities with MIC values in the range between 1- 0.5mg/ml. Interestingly, all the extracts exhibited no cytotoxic effect against Vero cell line. The results showed E.hirta extracts possess promising antimicrobial properties