Background Rutin is a common dietary flavonoid which has received great attention in literature, due to their pharmacological properties, including antimicrobial, anti-inflammatory, anticancer, antidiabetic, inter alia . Over 860 products containing rutin are currently marketed in the US. The major disadvantage associated with rutin is its constrained bioavailability, mainly caused by its low aqueous solubility, poor stability and limited membrane permeability. Scope and approach The aim of this contribution is to give an overview of the current methods (conventional and innovative) for the extraction, identification and purification of rutin. Furthermore, recent findings regarding its pharmacological activities and the different approaches to increase rutin solubility in both aqueous and lipid phases will be discussed. Key findings and conclusions Current trends on extraction process have been focused on the discovery and design of green and sustainable extraction techniques to optimize the recovery of rutin. Despite the bioactivity expressed in different in vitro systems, its biological effects in vivo are limited by the poor bioavailability of the flavonoid. The utilization of delivery systems for rutin or its enzymatic or chemical transformation towards highly soluble derivatives have the potential to improve rutin bioavailability, as well as its stability and/or specific biological properties. These novel rutin formulations may bring this promising flavonoid to the forefront of nutraceuticals for the prevention and/or treatment of various chronic human diseases.

Rutin: A review on extraction, identification and purification methods, biological activities and approaches to enhance its bioavailability

A review on plant-based rutin extraction methods and its pharmacological activities

RxList

Enhanced extraction of bioactive natural products using tailor-made deep eutectic solvents: application to flavonoid extraction from Flos sophorae

In recent years, ionic liquids and deep eutectic mixtures have demonstrated great potential in extraction processes relevant to several scientific and technological activities. This review focuses on the applicability of these sustainable solvents in a variety of extraction techniques, including but not limited to liquid- and solid-phase (micro) extraction, microwave-assisted extraction, ultrasound-assisted extraction and pressurized liquid extraction. Selected applications of ionic liquids and deep eutectic mixtures on analytical method development, removal of environmental pollutants, selective isolation, and recovery of target compounds, purification of fuels, and azeotrope breaking are described and discussed.

Ionic liquids and deep eutectic mixtures: sustainable solvents for extraction processes

Determination of rutin and quercetin in Chinese herbal medicine by ionic liquid-based pressurized liquid extraction-liquid chromatography-chemiluminescence detection.

Fast gradient high performance liquid chromatography method with UV detection for simultaneous determination of seven angiotensin converting enzyme inhibitors together with hydrochlorothiazide in pharmaceutical dosage forms and spiked human plasma and urine.

A simple and eco-friendly hydrothermal technique is used to prepare water soluble N and S co-doped carbon quantum dots probe (N,S-CQDs) from thiosemicarbazide and citric acid. Several characterization techniques were performed in order to ensure well- synthesis of highly luminescent N,S-CQDs. The prepared probe exhibited analytical potential as optical nanosensor for the spectrofluorimetric determination of cromolyn sodium (CRO) in its pharmaceutical dosage forms and aqueous humor. The emission intensity of the synthesized N,S-CQDs was measured at 411 nm after excitation at 345 nm. Addition of increasing concentrations of CRO to N,S-CQDs led to quenching of its fluorescence intensity. CRO was investigated within wide concentration range of 10.0 to 150.0 μM with limit of detection of 2.0 μM and limit of quantification of 6.0 μM. The quenching of fluorescent N,S-CQDs occurs through inner filter effect (IFE). The developed spectrofluorimetric method was successfully optimized and validated according to International Council of Harmonization (ICH). Method greenness is proved through using both Eco-scale and AGREE approaches.

Utilization of N,S-Doped Carbon Dots as a Fluorescent Nanosensor for Determination of Cromolyn Based on Inner Filter Effect; Application to Aqueous Humor.

Turn-off fluorescence of nitrogen and sulfur carbon quantum dots as effective fluorescent probes for determination of imatinib. Application to biological fluids.

A facile and simple one-step hydrothermal approach was adopted for fabrication of N and S co-doped carbon quantum dots probe (NSCDs) by using thiosemicarbazide as a dopant and citric acid as a precursor. The prepared NSCDs with a high quantum yield of 0.58 were characterized using UV–visible spectroscopy, IR spectroscopy and high-resolution transmission electron microscopy. The as-obtained NSCDs could be deemed as an effective fluorescent nanosensor for the determination of some anti-hypertensive nitro-calcium channel blockers (Nitro-CCBs) including nicardipine (NIC), nifedipine (NIF) and nimodipine (NIM) whether in pure form or in their pharmaceutical formulations. Measurements of NSCD emission intensity were performed at 416 nm after being excited at 345 nm. Nitro-CCBs could induce quenching in the native fluorescence of NSCDs due to the inner filter effect and static quenching mechanism. The studied compounds were investigated within linear detection range of (10.0–100.0 µM) for NIC, (5.0–60.0 µM) for NIF and (5.0–60.0 µM) for NIM. Correlation coefficients are greater than or equal to 0.9998 and detection limits are ranged between 0.55 and 1.86 µM. The proposed method was extended to estimate the studied compounds in different pharmaceutical samples with high % recoveries ranging from (97.95 to 101.28%) and low % relative standard deviation values (less than 2%). Validation of the developed spectrofluorimetric method was done along with the International Council of Harmonization requirements.

Fawzi Elsebaei

Papers

Determination of rutin and quercetin in Chinese herbal medicine by ionic liquid-based pressurized liquid extraction-liquid chromatography-chemiluminescence detection.

Fast gradient high performance liquid chromatography method with UV detection for simultaneous determination of seven angiotensin converting enzyme inhibitors together with hydrochlorothiazide in pharmaceutical dosage forms and spiked human plasma and urine.

Utilization of N,S-Doped Carbon Dots as a Fluorescent Nanosensor for Determination of Cromolyn Based on Inner Filter Effect; Application to Aqueous Humor.

Turn-off fluorescence of nitrogen and sulfur carbon quantum dots as effective fluorescent probes for determination of imatinib. Application to biological fluids.

Insights for applying N,S-doped carbon dots as a fluorescent nanoprobe for estimation of some nitro-calcium channel blockers