Favipiravir (FVP), a pyrazine analog, has shown antiviral activity against a wide variety of viruses. It is considered to be worth further investigation as a potential candidate drug for COVID-19. It is not officially available in any pharmacopoeia. A rapid, simple, precise, accurate, and isocratic high performance liquid chromatography (HPLC) method has been developed for routine quality control of favipiravir in pharmaceutical formulations. Separation was carried out by C18 column. The mobile phase was a mixture of 50 mM potassium dihydrogen phosphate (pH 2.3) and acetonitrile (90:10, v/v) at a flow rate of 1 mL min⁻¹. The ultraviolet (UV) detection and column temperature were 323 nm, and 30 °C, respectively. The run time was 15 min under these chromatographic conditions. Excellent linear relationship between peak area and favipiravir concentration in the range of 10–100 μg mL⁻¹ has been observed (r², 0.9999). Developed method has been found to be sensitive (limits of detection and quantification were 1.20 μg mL⁻¹ and 3.60 μg mL⁻¹, respectively), precise (the interday and intraday relative standard deviation (RSD) values for peak area and retention time were less than 0.4 and 0.2%, respectively), accurate (recovery, 99.19–100.17%), specific and robust (% RSD were less than 1.00, for system suitability parameters). Proposed method has been successfully applied for quantification of favipiravir in pharmaceutical formulations.

UV spectrophotometric and HPLC methods have been developed and validated for the quantitative determination of remdesivir in pharmaceutical formulations. The HPLC analyzes have been performed on a C-18 column with a mobile phase consisting of 20 mM KH₂PO₄ solution and acetonitrile (50:50, v/v), at a flow rate of 1.2 mL min⁻¹. UV spectrum has been recorded between 200 and 800 nm using deionized water as solvent and the wavelength of 247 nm has been selected. These methods have been validated according to the procedures described in ICH guidelines Q2(R1). Both methods demonstrated good linearity, precision and recovery. No spectral and chromatographic interferences from non-medicinal ingredients were found in both methods. Correlation coefficients were greater than 0.999 within a concentration range of 10–60 mg mL⁻¹. Therefore both analytical methods gave the most reliable results for the quantification of remdesivir in pharmaceutical formulation.

There is no currently successful method to treat Covid-19 infection. Nevertheless, previously licensed pharmaceuticals to treat other virus infections are used on an off-label basis either alone or in combination. One of them is favipiravir. Favipiravir, also known as favilavir, is an antiviral drug that is active against many viruses. Spectrophotometric and liquid chromatographic methods have been developed and validated for the quantitative determination of favipiravir in pharmaceutical formulations. Chromatographic method has been performed using reverse-phase technique on a C-18 column with a mobile phase consisting of sodium acetate solution (pH adjusted to 3.0 with glacial acetic acid) and acetonitrile (85:15, v/v) at 30 oC. The mobile phase flow rate was 1.0 mL min-1. For the determination of favipiravir, UV spectrum has been recorded between 200 and 800 nm using deionized water as solvent and the wavelength of 227 nm has been selected. Both methods have been validated in terms of their specificity, linearity, limits of detection and quantification, precision, accuracy, and robustness. Both methods have demonstrated good linearity, precision and recovery. No spectral and chromatographic interferences from the tablet excipients were found in spectrophotometric and liquid chromatographic methods. In both methods, correlation coefficients were greater than 0.999 within a concentration range of 10-60 mg mL-1 using spectrophotometry and chromatography. Intra-day and inter-day precision were observed with low relative standard deviation values. The accuracy of the methods were within the range 99.57-100.10% for LC and from 99.83-100.45% for UV. Therefore, both methods gave the most reliable outcomes for the determination of favipiravir in pharmaceutical formulation.

Colchicum autumnale L. also known as the autumn crocus, contains colchicine alkaloid having antifungal properties. The tuber of this plant is rich in terms of colchicine. In this research an ultrasound-assisted extraction (UAE) method was optimized for the extraction of colchicine from Colchicum autumnale L. bulbs before high-performance liquid chromatography with UV detection (HPLC-UV). Optimization of various extraction parameters was performed using response surface methodology (RSM) to evaluate the maximum colchicine yield from Colchicum autumnale L. bulbs. The Box-Behnken design (BBD) and RSM were used to investigate the effect of three key parameters (extraction time (20-60 min), extraction temperature (40-80 °C) and ultrasound power (500-700 W) on extraction efficiency. The variance analysis suggested that the dependent response variable of yield of colchicine may be expressed by a quadratic polynomial model. The optimal theoretical extraction conditions were found to be an ultrasonication power of 602.4 W, an extraction time of 42 min and a temperature of 64 °C. Under these conditions, the optimum foreseen yield was 0.237%. The experimental colchicine yield obtained by following the optimized conditions was found to be 0.238%. These values are very well compatible with each other.

Melatonin acts as a seed germination activator, plant growth regulator, leaf senescence retardant, and, in general, has a multifunctional role as a ‘defence molecule’; furthermore, by interacting with other molecules, such as phytohormones and gaseous molecules, it greatly enhances plant adaptation to different environments. However, there are not enough studies about the use of melatonin on horticultural crops, and even fewer studies have outlined the differences related to this phytohormone use between protected environment and in open field. The two latter systems have different growing conditions that could lead to diversified application doses. As the choice of melatonin dose depends on all crop system components, the present research aimed to assess the effects of three melatonin concentrations (1 ppm, 5 ppm and 10 ppm) plus an untreated control, on yield, quality, and antioxidants of four strawberry cultivars (i.e., Kabarla, Fortuna, Sweet Ann, Festival) grown either in greenhouse or in open field. Research was conducted to assess the yield parameters were better affected by greenhouse than open field, and mean fruit weight was the highest in cultivar Sweet Ann. In open field 10 ppm showed the highest values of fruit number and yield, but in greenhouse did not differ from 5 ppm which led to the highest fruit number. At all melatonin doses, cultivar Kabarla demonstrated the highest yield, compared to the other cultivars, with the maximum value of about 46 t·ha⁻¹. Plant dry weight was 90% higher under greenhouse than in open field conditions, and 52% or 132% higher with cultivar Kabarla in comparison with Fortuna and Sweet Ann, respectively. The melatonin dose of 10 p.p.m showed 56% higher plant dry weight in comparison to the untreated control. Fortuna showed higher values of fruit dry matter, soluble solids, and glucose than Sweet Ann. The fruit dry matter was 7% lower at 10 ppm melatonin than in the untreated control. Fructose was higher under 1 ppm melatonin with 245 mg·g⁻¹ d.w. compared to the untreated control with 220 mg·g⁻¹ d.w. in Festival, whereas in Fortuna was the highest in the control fruits, the latter also showing the highest titratable acidity in Fortuna and Sweet Ann. The highest phenolics content was recorded under 10 ppm melatonin in open field, and with 5 ppm in greenhouse; the phenolics content was the highest under 1 ppm melatonin dose in Kabarla and 5 ppm in Fortuna. Under the protected environment 5 and 10 p.p.m. melatonin elicited the highest accumulation of ascorbic acid; 10 ppm were more effective in Fortuna and Sweet Ann, and 5 ppm in Festival. The most enhanced antioxidant activity was recorded under 5 p.p.m. melatonin dose in Fortuna and Festival. The present study confirms that the dose of melatonin to apply to strawberry crop closely relates both to cultivar and crop system.

The effects of acute exposure to 250 mg/kg malathion and the protective effects of 20 mg/kg oleuropein, both administered intraperitoneally, were evaluated in Wistar male rats. Malathion administration increased malondialdehyde, nitric oxide, 8-hydroxy-2′-deoxyguanosine, total oxidant status, and DNA damage, yet decreased total antioxidant activity, superoxide dismutase, and catalase activities in blood, liver, and kidney. Administration of oleuropein reversed malathion-induced oxidative stress, lipid peroxidation, DNA damage, and antioxidant enzyme activity.