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Nowadays, herbal extracts are considered to be a potential source for developing new drugs that will overcome resistance to conventional chemotherapeutic agents. This study was aimed to explore the efficacy of several Egyptian plant extracts against Toxoplasma gondii infection in vitro for future development of a new, safe, and effective compound for T. gondii. Methanol extracts from Matricaria chamomilla (German chamomile), Laurus nobilis, Citrullus colocynthis, Cinnamum camphora, Boswellia scara, and Melissa officionalis plants and oil extracts (either essential or fixed oils) of some plants such as: lemon grass (Cymbopogon citratus), marjoram (Origanum majorana), watercress (Nasturtium officionale), wheat germ (Triticum aestivum), sesame (Sesamum indicum), rosemary (Salvia rosmarinus), citronella (Cymbopogon nardus), clove (Syzygum aromaticum), jojoba (Simmondsia chinesis), and basil (Ocimum basilicum) were investigated for their anti-Toxoplasma activities. The methanol extracts from C. colocynthis and L. nobilis and the oil extracts from lemon grass and marjoram were active against T. gondii with half maximal inhibitory concentrations (IC 50) of 22.86 µg/ml, 31.35 µg/ml, 4.6 µg/ml, and 26.24 µg/ml, respectively. Their selectivity index (SI) values were < 10. Interestingly, the methanol extract from M. chamomilla and oil from citronella had the lowest IC 50 values for T. gondii (3.56 µg/ml and 2.54 µg/ml, respectively) and the highest SI values (130.33 and 15.02, respectively). In conclusion, methanol extract from M. chamomilla and oil from citronella might be potential sources of novel therapies for treating toxoplasmosis.

Objectives: Searching for new antiviral compounds is important due to continuous appearance of new viral strains that resist the commonly used drugs and due to toxic side effects of some of these drugs. This current study was designed to investigate some herbs to discover new natural antiviral agents. Methods: Eight herbal extracts were screened for antiviral activities against Hepatitis A, Herpes Simplex-1 and Coxsackie viruses. Bio guided fractionation of the active extracts using different solvents and further investigation of the bioactive one using various chromatographic techniques including normal phase column chromatography, poly amide column and preparative TLC led to isolation and identification of twelve compounds. Structural elucidation of these compounds was done using different spectroscopic techniques including IR, HR-MS, 1D and 2D-NMR. The antiviral activities of the isolated compounds were assessed by MTT assay that depends on mixed treatment assay which test inactivation of virus particles in the virus suspension by samples. The concentration of samples which inactivate virus particles in virus suspension by 50% compared with untreated control was determined for each sample and was compared with IC 50 of positive control, Acyclovir. Findings: Twelve known compounds were isolated from the bioactive fractions of Cleome droserifolia and Lotus creticus. Nine compounds (1-9) from methylene chloride and ethyl acetate fractions of Cleome droserifolia and four compounds (10-13) from ethyl acetate and butanol fractions of Lotus creticus. Teuclatriol (4) was the most potent, with IC 50 value of 4.89 ±0.061µM against HSV-1 and a selective index (SI) value of 4.8. Moreover, the pentamethoxyflavone (3) was the most active against HAV with IC 50 value of 9.52±0.329 µM and SI of 3.4. The potent activity against Cox. B4 virus with IC 50 of 13.054 ±0.348 µM and SI of 3.4 exhibited by β-sitosterol 3-O-β-D-glucoside (6, 12). Novelty: The results highlight that these compounds are candidates for the development of new lead antiviral compounds. This is the first report for proving antiviral activities of these compounds.

Highlights• Topp-Leone inverse Lomax is proposed as a new model.• Structure properties of the new model are provided.• Reliability and parameter estimators are obtined from complete and Type II censored samples.• Simulation as well as data analysis is worked out.