Combinational Effect of Rumex tingitanus (Polygonaceae) Hexane Extract and Bacillus thuringiensis δ-Endotoxin against Spodoptera littoralis (Lepidoptera: Noctuidae).

The increasing insect resistance against Bacillus thuringiensis delta-endotoxins is a serious problem which makes it urgent to look for new eco-friendly strategies. Combining these toxins with other biomolecules is one of the promising strategies against insect pests. In this work, we evaluated the bioinsecticidal potential of Rumex tingitanus extracts and B. thuringiensis strain BLB250 against Spodoptera littoralis (Lepidoptera: Noctuidae) larvae. The chemical composition of the hexane extract, the most active fraction, was analyzed to validate the correlation between chemical composition and biological activity. Among the tested extracts, only the hexanic extract showed toxicity against first and second instar larvae with LC50 of 2.56 and 2.95 mg g-1, respectively. The Bacillus thuringiensis BLB250 delta-endotoxins showed toxicity with an LC50 of 56.3 µg g-1. Therefore, the investigated combinational effect of BLB250 delta-endotoxins and R. tingitanus hexane extract proved significant synergistic effect against S. littoralis larvae. The GC-MS analysis of R. tingitanus hexane extract showed the richness of this extract in phytosterols such as ß and γ-sitosterol (48.91%), campesterol (6.43%), and ß-amyrin (8.92%) which are known for their insecticidal activity. This novel finding highlights the potential use of this combination against insect pests to prevent the appearance of resistance problems.

Antioxidant, Hepatoprotective, and Antidepression Effects of Rumex tingitanus Extracts and Identification of a Novel Bioactive Compound.

Over the last few decades, Rumex species have been recognized as a promising source of new compounds with numerous pharmacological activities. Therefore, the antioxidant activity of Rumex tingitanus (R. tingitanus) leaves extracts was evaluated in vitro and then confirmed in vivo as well as the antidepressant-like and toxicological effects of the extracts. The ethyl acetate fraction (Rt EtOAcF) followed by hydroalcoholic extract (Rt EtOH-H2O) showed a remarkable in vitro antioxidant activity. The hydroalcoholic extract (Rt EtOH-H2O) showed significant hepatoprotective activity against carbon tetrachloride- (CCl4-) induced liver toxicity which is seen from inhibition of the malondialdehyde (MDA) accumulation and enhancement of the liver antioxidant enzymes activities. The Rt EtOH-H2O and Rt EtOAcF extracts were able to reduce the immobility time in mice and then elicited a significant antidepressant-like effect. The ethyl acetate fraction (Rt EtOAcF) was purified and resulted in the identification of a new antioxidant component called 4'-p-acetylcoumaroyl luteolin. The Rt EtOAcF and the 4'-p-acetylcoumaroyl luteolin revealed a strong antioxidant activity using DPPH test with IC50 of 11.7 ± 0.2 and 20.74 ± 0.6 µg/ml, respectively, and AAI of 3.39 and 1.92 better than that of BHT, used as control.

Antibacterial Activity of Onopordum Espinae: Identification of Hispidulin and Dehydromelitensin-8-(4ꞌ-Hydroxy-Methacrylate).

Hexane, ethyl acetate and methanol extracts of Onopordum espinae leaves were investigated for their antibacterial activities against Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, and Salmonella enteritidis. Hexane and ethyl acetate extracts were toxic to Gram-positive bacteria with inhibition zone diameters ranging between 12 and 30 mm. Two products, hispidulin 1, and dehydromelitensin-8-(4ꞌ-hydroxy-methacrylate) 2 were isolated from the ethyl acetate extract of leaves and identified by 2D-NMR for the first time from this species. Ethyl acetate extractꞌs total flavonoid content was the highest, as 78.73 mg quercetin equivalents (QE)/g. The methanol extract showed the highest total phenolic content as 243.43 mg gallic acid equivalents (GAE)/g and gave the most important 2,2-diphenyl-1-picrylhydrazyl (DPPH)scavenging activity (EC50 = 86 µg/mL).

Antimicrobial activity and bioguided fractionation of Rumex tingitanus extracts for meat preservation.

This study was undertaken to investigate the antibacterial and antifungal activities of Rumex tingitanus leaves extracts as well as the identification of bioactive components and their performance in meat preservation. Total phenolics and flavonoids showed the highest content of phenolics and flavonoids in the ethyl acetate fraction (Rt EtOAcF). For antimicrobial efficacy, leaves extract and derived fraction were tested for their capacity to inhibit bacterial and fungal proliferation in vitro and in vivo. The ethyl acetate fraction showed the most potent antibacterial and antifungal activities compared to the others extracts. Thus, the efficacy of this extract to inhibit the proliferation of Listeria monocytogenes in minced beef meat model was examined. This fraction eradicates the L. monocytogenes population in meat in a concentration- and time-dependent manner. A bio-guided purification of the Rt EtOAc fraction resulted in the isolation of the compound responsible for the observed antimicrobial activity. This compound was identified as luteolin by analysis of spectroscopic data. CHEMICAL COMPOUNDS ISOLATED IN THIS ARTICLE: Luteolin (PubChem CID: 5280445); p-iodonitrotetrazolium chloride (PubChem CID: 64957); Amphotericin B (PubChem CID: 5280965); Gentamicin and (PubChem CID: 6419933); Hexane (PubChem CID: 8058); Methanol (PubChem CID: 887); Ethanol (PubChem CID: 702); Dimethylsulfoxide (PubChem CID: 679); Quercetin (PubChem CID: 5280343); Gallic acid (PubChem CID: 370).