Deep eutectic solvent-ultrasound assisted extraction as a green approach for enhanced extraction of naringenin from Searsia tripartita and retained their bioactivities.

Background: Naringenin (NA) is a natural flavonoid used in the formulation of a wide range of pharmaceutical, fragrance, and cosmetic products. In this research, NA was extracted from Searsia tripartita using an environmentally friendly, high efficiency extraction method: an ultrasound-assisted extraction with deep eutectic solvents (UAE-DES). Methods: Six natural deep eutectic solvent systems were tested. Choline chloride was used as the hydrogen bond acceptor (HBA), and formic acid, ethylene glycol, lactic acid, urea, glycerol, and citric acid were used as hydrogen bond donors (HBD). Results: Based on the results of single-factor experiments, response surface methodology using a Box-Behnken design was applied to determine the optimal conditions for UAE-DES. According to the results, the optimal NA extraction parameters were as follows: DES-1 consisted of choline chloride (HBA) and formic acid (HBD) in a mole ratio of 2:1, an extraction time of 10 min, an extraction temperature of 50°C, an ultrasonic amplitude of 75 W, and a solid-liquid ratio of 1/60 g/mL. Extracted NA was shown to inhibit the activity of different enzymes in vitro, including α-amylase, acetylcholinesterase, butyrylcholinesterase, tyrosinase, elastase, collagenase, and hyaluronidase. Conclusion: Thus, the UAE-DES technique produced high-efficiency NA extraction while retaining bioactivity, implying broad application potential, and making it worthy of consideration as a high-throughput green extraction method.

Ultrasound-Assisted Extraction of Isoquercetin from Ephedra alata (Decne): Optimization Using Response Surface Methodology and In Vitro Bioactivities.

Isoquercetin (ISQ) is reported to be a powerful antioxidant with extremely high bioavailability and structural stability compared to aglycone quercetin. Despite this, it is not well studied due to the limited methods for its extraction. With the growing interest in the research and analysis of ISQ-rich herbs, there is a need to optimize an efficient and rapid method for their extraction. In the present study, the ultrasound-assisted extraction of ISQ from Ephedra alata Decne was optimized by a response surface methodology (RSM) using high-performance liquid chromatography as a separation method. The best possible ranges for extraction time (10-30 min), temperature (50-70 °C), ultrasonic power (60-90 W), solvent-to-solid ratio (50-70 mL/g), and ethanol concentration (50-70%) were determined using a single factor analysis. Subsequently, an optimization of the extraction conditions was performed with RSM using the Box-Behnken design. An ultrasonication time of 10 min, a temperature of 60 °C, a power of 75 W, a solvent-to-solid ratio of 60 mL/g, and an ethanol concentration of 70% were determined to be the optimal conditions for the highest recovery of isoquercetin (1033.96 ± 3.28 µg/g). Furthermore, E. alata powder morphology (using a scanning electron microscope), antioxidant activities, and the inhibition potential of key enzymes involved in skin aging (elastase and collagenase), hyperpigmentation (tyrosinase), diabetes (α-amylase), inflammation (hyaluronidase), and neurodegenerative disorders (cholinesterase) were determined and compared with those using the Soxhlet method. This study established a highly efficient method for ISQ extraction and suggested several potential applications of ISQ in the pharmaceutical and cosmetics industries.

Genus Ziziphus: A comprehensive review on ethnopharmacological, phytochemical and pharmacological properties.

ETHNOPHARMACOLOGICAL RELEVANCE: The genus Ziziphus (Rhamnaceae) contains 58 accepted species that are extensively used by local people and medicinal practitioners in arid and semi-arid regions for the treatment of diarrhoea, dysentery, cholera, diabetic, hypertension, inflammation, intestinal spasm, liver, malaria and other diseases. Aims of this review: This review article documents and critically assesses, for the first time; up to date categorized information about botanical traits, distribution, traditional uses, phytochemistry, pharmacological and toxicological effects of Ziziphus species. METHODS: Information was collected systematically from electronic scientific databases including Google Scholar, Science Direct, PubMed, Web of Science, ACS Publications, Elsevier, SciFinder, Wiley Online Library and CNKI, as well as other literature sources (e.g., books). KEY FINDINGS: The phytochemical investigations of plants of this genus have led to the identification of about 431 chemical constituents. Cyclopeptide alkaloids and flavonoids are the predominant groups. The crude extracts and isolated compounds exhibit a wide range of in vitro and in vivo pharmacologic effects, including antimicrobial, antitumour, antidiabetic, antidiarrhoeal, anti-inflammatory, antipyretic, antioxidant and hepatoprotective activities. Toxicity studies indicate that Ziziphus species seems to be non-toxic at typical therapeutic doses. CONCLUSION: Phytochemical and pharmacological studies have demonstrated that Ziziphus species are important medicinal herbs with prominent bioactivities. The focus so far has only been on ten species; however, plants of this genus can potentially yield a wide range of other products with different properties. Meticulous studies on pharmaceutical standardisation, mode of action of the active constituents and toxicity of Ziziphus species are needed to meet the growing demands of the pharmaceutical industry and to exploit their preventive and therapeutic potential fully.

Application of redox reactions for the determination of valganciclovir hydrochloride in pharmaceuticals

Two simple, selective and sensitive spectrophotometric methods were developed and validated for the determination of valganciclovir hydrochloride (VLGH) in pure drug and tablets. The first method was based on the reduction of iron(III) to iron(II) by VLGH and subsequent formation of iron(III)-ferricyanide complex (Prussian blue) in acid medium which was measured at 730 nm (method A). In the second method (method B), permanganate was reduced by VLGH to bluish green manganate in alkaline medium and the absorbance was measured at 610 nm. The absorbance measured in each case was related to VLGH concentration. The experimental conditions were carefully studied and optimized. Beer's law was obeyed over the concentration ranges of 2.5-20.0 and 2.0-40.0 µg mL-1 for method A and method B, respectively, with corresponding molar absorptivity values of 1.28×104 and 6.88×103 L mol-1 cm-1. The limits of detection (LOD) and quantification (LOQ) were 0.11 and 0.33 µg mL-1 (method A) and 0.21 and 0.64 µg mL-1 (method B). Within-day and between-day relative standard deviations (%RSD) at three different concentrations levels were < 2.4%, and the respective relative errors (%RE) were ≤ 3%. The proposed methods were successfully applied to the determination of VLGH in tablets, and the results confirmed that the proposed methods were equally precise and accurate as the official method.

Application of Cerium (IV) as an Oxidimetric Agent for the Determination of Ethionamide in Pharmaceutical Formulations.

Two simple methods are described for the determination of ethionamide (ETM) in bulk drug and tablets using cerium (IV) sulphate as the oxidimetric agent. In both methods, the sample solution is treated with a measured excess of cerium (IV) solution in H2SO4 medium, and after a fixed standing time, the residual oxidant is determined either by back titration with standard iron (II) solution to a ferroin end point in titrimetry or by reacting with o-dianisidine followed by measurement of the absorbance of the orange-red coloured product at 470 nm in spectrophotometry. In titrimetry, the reaction proceeded with a stoichiometry of 1 : 2 (ETM : Ce (IV)) and the amount of cerium (IV) consumed by ETM was related to the latter's amount, and the method was applicable over 1.0-8.0 mg of drug. In spectrophotometry, Beer's law was obeyed over the concentration range of 0.5-5.0 µg/mL ETM with a molar absorptivity value of 2.66 × 104 L/(mol·cm). The limits of detection (LOD) and quantification (LOQ) calculated according to ICH guidelines were 0.013 and 0.043 µg/mL, respectively. The proposed titrimetric and spectrophotometric methods were found to yield reliable results when applied to bulk drug and tablets analysis, and hence they can be applied in quality control laboratories.