RESUMO
Five Oudneya Africana (OA) leaves extracts were screened for their total phenolic (TPC), total flavonoid (TFC), condensed tannins (CTC) content, as well as their antioxidant capacity. The highest amount of TPC (661.66 ± 0.08 mg GAE/g), TFC (344.68 ± 0.44 mg QE/g) and TCT (90.18 ± 0.49 mg CE/g) was recorded to ethanol, acetone, and dichloromethane extracts, respectively. For 2,2-diphenyl-1-picrylhydrazyl (DPPH) (22.00 ± 0.03 µg/mL) and Reducing Power Assay (FRAP) (269.00 ± 0.01µg/mL) assays, ethanol extract showed the potent activity, while with ABTS test, acetone extract was the most active (761.15 ± 0.09 µg/mL). HPLC-MS analysis of acetonic and ethanolic extracts reveals the predominance of quinic acid, chlorogenic acid, 4-O-caffeoylquinic acid, and rutin compounds. The addition effect evaluation of OA extracts in beef burger preservation demonstrates the powerful effect (p < 0.05) of acetonic and ethanolic ones (0.03%) to inhibit lipids oxidation during storage for 10 days, given by the lowest increase in Thiobarbituric Acid-reactive Substances (TBARS) values as compared to the (-) control with a significant difference between free thiols values. In addition, these two extracts appear to be effective (p < 0.05) for pH stability, color, and sensory parameters as compared to (+) and (-) controls and aqueous extract. Hamburger odour was considered as a dependent variable in multiple linear regression analysis, where the models results showed that physicochemical parameters determine more burger odour than sensorial ones.
RESUMO
This study aimed to investigate the antimicrobial and cytotoxic activities of essential oil isolated by the hydro-distillation of aerial parts of Thymelaea hirsuta. The antimicrobial activity of the oil was evaluated against eight bacterial and three fungal pathogenic strains. The results revealed that the essential oil exhibited a moderate-to-potent anti-microbial activity against all the microorganisms tested. Gram-positive bacteria were noted to be more sensitive to the oil than gram-negative bacteria and yeasts. In vitro cytotoxicity evaluation against HeLa cell lines showed that the essential oil exhibited moderate cytotoxicity on human tumor cells, with a high IC50 value of 175µg/mL. To the author's knowledge, this is the first study reporting on the antimicrobial and cytotoxic activities of Thymelaea hirsuta essential oil. Overall, the results indicate that the T. hirsuta essential oil has a number of attractive properties that might open new promising opportunities for the control or prevention of a wide range of microbial infections and cancers and can facilitate the use of essential oils as natural preservatives against spoilage microorganisms in food systems.