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The chemical composition of the essential oil (EO) from fresh cocklebur (Xanthium strumarium L.) leaves was investigated by GC-MS. The antimicrobial activity of the EO was tested against Gram-positive and Gram-negative bacteria and fungi. Scolicidal activity was assayed against Echinococcus granulosus protoscolices. In total, 34 compounds were identified, accounting for 98.96% of the EO. The main compounds in the EO were cis-β-guaiene (34.2%), limonene (20.3%), borneol (11.6%), bornyl acetate (4.5%), β-cubebene (3.8%), sabinene (3.6%), phytol (3.1%), β-selinene (2.8%), camphene (2.2%), α-cubebene (2.4%), β-caryophyllene (1.9%), α-pinene (1.8%) and xanthinin (1.04%). The antibacterial and antifungal screening of the EO showed that all assayed concentrations significantly inhibited the growth of Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger (MIC = 0.5 ± 0.1, 1.3 ± 0.0, 4.8 ± 0.0, 20.5 ± 0.3, 55.2 ± 0.0 and 34.3 ± 0.0 µg/mL, respectively). The scolicidal assay indicated that the EO exhibited a significant activity against E. granulosus protoscolices. To the best of our knowledge, this is the first report on the scolicidal activity of X. strumarium. Because of the emergence of antimicrobial drug resistance, the study of new effective natural chemotherapeutic agents, such as the X. strumarium EO, possibly with low side effects, represents a very promising approach in biomedical research.

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The present study examined the effects of Allium paradoxum (M.B.) G. Don. and Eryngium caucasicum Trauve. extracts on the lipid oxidation and quality deterioration indices, microbiological as well as sensory characteristics in silver carp (Hypophthalmichthys molitrix) fillets during storage at 4 °C ± 1. Treatments applied in the study including the following: control (without plant extracts), 2% and 4% (w/v) plant extracts. The addition of plant extracts significantly delayed oxidative deterioration in silver carp fillets during refrigerated storage as shown by the PV, TBARS, Acid Value and TVB‐N data (P < 0.05). The results also showed that natural compounds from A. paradoxum and E. caucasicum extracts resulted in lower bacterial growth in fish fillets during the refrigerated storage period. Comparing to the control samples, the psychrophilic bacterial counts (PTC) and total viable count (TVC) values for the E. caucasicum (2.0%) and E. caucasicum (4.0%), A. paradoxum (2.0%), A. paradoxum (4.0%) treatments were above the acceptability limit (7 log10 colony‐forming unit/g) at the end of 6, 9, 12, 9 and 15th day of storage, respectively. It was observed that addition of A. paradoxum at 4% to fish fillets increased its shelf‐life while the addition of E. caucasicum at 4.0% made a positive effect on sensory quality. These results suggested that A. paradoxum and E. caucasicum extracts have the potential to be used as natural preservatives for shelf‐life extension of fish products. Practical Applications The exploration of naturally occurring antimicrobials in food preservation receives increasing attention because of consumer awareness of natural food products. Biopreservatives are useful in extending the foods shelf‐life, reducing or eliminating pathogenic bacteria and increasing the overall quality of food products. In this work, we evaluated the effects of two natural extracts, from Allium paradoxum and Eryngium caucasicum, on the fish product quality, such as rancidity indices, microbiological and sensory qualities during refrigerated storage. To our knowledge, the application of A. paradoxum and E. caucasicum extracts in shelf‐life extension of fish product has not been studied previously. The present study showed that both E. caucasicum, A. paradoxum extracts, regarding to their antioxidant and antibacterial properties, could efficiently retard microbial growth, delay chemical deterioration, maintain or improve sensory attributes and extend the shelf‐life of the silver carp fillets during refrigerated storage.

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