Antiviral activity of castor oil plant (Ricinus communis) leaf extracts.

ETHNOPHARMACOLOGICAL RELEVANCE: Ricinus communis L., commonly known as castor oil plant, is a precious traditional medicine with a history of thousands of years in the world. Castor oil plant has high traditional and medicinal values for treating liver infections, stomach ache, flatulence, constipation, inflammation, warts, colic, enteritis, fever, headache, and as a counter irritant. Its diverse phytochemicals have a wide range of valuable medicinal activities including hepatoprotective, anti-nociceptive, antioxidant, antiulcer, anticancer, anti-inflammatory, central analgesic, antidiabetic, antimicrobial, antiviral, and wound healing activity. AIM OF THE WORK: To provide a complete characterization of the composition of Ricinus communis leaves using ultra-performance liquid chromatography coupled with hybrid triple time-of-flight mass spectrometry (UPLC-Triple TOF-MS/MS) and different chromatographic techniques and to evaluate its antiviral potential using three mechanisms against three common viruses. MATERIALS AND METHODS: R. communis leaves were extracted with 70% methanol and further partitioned with solvents of increasing polarities: petroleum ether, dichloromethane (CH2Cl2), ethyl acetate, and n-butanol. The CH2Cl2 and n-butanol fractions were subjected to repeated chromatographic separation to isolate the phytochemicals, and their structures were elucidated using nuclear magnetic resonance spectroscopy. UPLC-Triple TOF-MS/MS was performed to determine the different phytochemicals in the ethyl acetate fraction. The antiviral activity of the extracts was investigated using the maximum nontoxic concentration of each against the challenge dose of the virus (CDV) and 1/10 and 1/100 dilutions of the CDV for Coxsackie B virus type 4 (COXB4), herpes simplex virus type 1 (HSV1), and hepatitis A virus (HAV) using Vero cell cultures that were treated according to three protocols to test for anti-replicative, protective, and anti-infective antiviral activity. Cell viability was evaluated using the MTT colorimetric assay and each experiment is repeated three times independently of each other. RESULTS: R. communis leaves possessed antiviral activity. Evaluation of the anti-replicative activity showed that all extracts possessed high anti-replicative activity against HAV especially methanol and methylene chloride fractions and moderate activity against COXB4; butanol > methylene chloride and ethyl acetate > methanol. All extracts showed protective activity against HAV, especially butanol extract, while methanol extracts showed higher non-significant antiviral protective activity against HSV1 vs Acyclovir. Almost no anti-infective effects were recorded for any extract against the studied viruses. CONCLUSION: The discriminatory effect against each virus by different mechanisms suggests the presence of different chemical compounds. The alkaloid and phenolic derivatives of the extracts of R. communis leaves may help develop a drug to prevent or treat common viral infections. Further investigations are recommended to define the bioactive antiviral properties of R. communis leaves.

Scaling up of levan yield in Bacillus subtilis M and cytotoxicity study on levan and its derivatives.

This study focused on kinetics of levan yield by Bacillus subtilis M, in a 150 L stirred tank bioreactor under controlled pH conditions. The optimized production medium was composed of (g/L): commercial sucrose 100.0, yeast extract 2.0, K2HPO4 3.0 and MgSO4⋅7H2O 0.2; an increase in both carbohydrates consumption and cell growth depended on increasing the size of the stirred tank bioreactor from 16 L to 150 L. The highest levansucrase production (63.4 U/mL) and levan yield of 47 g/L was obtained after 24 h. Also, the specific levan yield (Yp/x) which reflects the cell productivity increased with the size increase of the stirred tank bioreactor and reached its maximum value of about 29.4 g/g cells. These results suggested that B. subtilis M could play an important role in levan yield on a large scale in the future. Chemical modifications of B. subtilis M crude levan (CL) into sulfated (SL), phosphorylated (PL), and carboxymethylated levans (CML) were done. The difference in CL structure and its derivatives was detected by FT-IR transmission spectrum. The cytotoxicity of CL and its derivatives were evaluated by HepGII, Mcf-7 and CaCo-2. In general most tested levans forms had no significant cytotoxicity effect. In fact, the carboxymethylated and phosphrylated forms had a lower anti-cancer effect than CL. On the other hand, SL had the highest cytotoxicity showing SL had a significant anti-cancer effect. The results of cytotoxicity and cell viability were statistically analyzed using three-way ANOVA.