Green and Cost-Effective Extraction Techniques of Quercetin from Mixture of Nutraceuticals with Yield Analysis via Spectrophotometry and High-Performance Liquid Chromatography Methods.

BACKGROUND: Extraction is the leading critical stage in the analysis of nutraceuticals. Ginkgo biloba (GB) has gained interest because of its therapeutic usages. OBJECTIVES: The aim was to develop four cost-effective extraction techniques for the extraction of quercetin from GB in a sachet containing a mixture of nutraceuticals. These techniques are solid-phase extraction (SPE), liquid-liquid extraction, inverted dispersive liquid-liquid microextraction, and the QuEChERS (quick, easy, cheap, effective, rugged, and safe) method. METHOD: Direct spectrophotometry was used to monitor the recovery of the standard quercetin throughout the optimization steps. The HPLC-UV method of analysis was optimized to quantify the yields from the extracts present in the complicated contents of the sachets. The present study was assessed by analytical Eco-Scale assessment (ESA) and the National Environmental Method Index (NEMI) for greenness in comparison with the literature. RESULTS: SPE showed the best cleanup outcomes. ESA and NEMI showed an adequate greenness of the proposed extraction protocol. CONCLUSIONS: Quercetin (marker for GB) extraction from market nutraceutical sachets is considered an exemplar for analysis in the QC of nutraceuticals. Regarding the greenness results, the proposed method of extraction is better even with adequate greenness as the extraction was a one-step process, in comparison with multistep processes of previously published protocols. Accordingly, it is recommended for use in routine extraction and analysis of such nutraceuticals. HIGHLIGHTS: Four extraction protocols have been developed. For GB ternary-mixture sachets, proper recovery was obtained using C18 SPE. The assessment of greenness of the proposed protocol guaranteed the superiority of the presented method. Safer sorbents and chemicals are favored for use in routine extraction of nutraceuticals.

Correlation of In Vivo and In Vitro Assay Results for Assessment of Free Radical Scavenging Activity of Green Tea Nutraceuticals.

Green tea (GT)-derived catechins; epigallocatechin gallate (EGCG) in particular are commonly used nutraceuticals for their free-radical scavenging activity (FRSA). The influence of photodegradation on the protective power of GT nutracenticals against oxidative stress was thoroughly explored. Photodegradation of GT extracts was carried out and monitored using orthogonal stability-indicating testing protocol; in vitro and in vivo assays. Total polyphenol content (TPC) and FRSA were determined spectrophotometrically while EGCG was selectively monitored using SPE-HPLC. In vivo assessment of photodegraded samples was investigated via measuring a number of biomarkers for hepatic oxidative stress and apoptosis (caspase-3, inducible nitric oxide synthase, nitric oxide, mitogen-activated protein kinase, glutathione, thiobarbituric acid reactive substances, nuclear factor kappa beta, and nuclear factor erythroid 2-related factor) as well as liver damage (alanine transaminase and aspartate transaminase) in serum of rats previously subjected to oxidative stress. Results showed complete degradation of EGCG in photodegraded green tea samples with no correlation with either TPC or FRSA. On the other hand, in vivo assay results revealed not only loss of activity but formation of harmful pro-oxidants. Photostability was found crucial for the protective effect of GT extract against lead acetate insult. Results confirmed that careful design of quality control protocols requires correlation of chemical assays to bioassays to verify efficacy, stability, and most importantly safety of nutraceuticals.

Stability of catechins in green tea nutraceutical products: application of solid phase extraction-thin layer chromatography densitometry.

Epigallocatechin gallate (EGCG) is a powerful antioxidant and commonly used nutraceutical. Accelerated stability of EGCG in tablet formulations was investigated. LLE and SPE were employed for sample clean-up and enrichment of EGCG over caffeine. Samples were analysed after spiking with fixed concentration of gallic acid (GA), in order to verify reproducibility of analysis. A TLC-densitometric assay was developed and validated for determination of % loss EGCG. EGCG, GA and caffeine were resolved with Rf values 0.54, 0.69 and 0.80, respectively. LC-MS/MS was used to verify identity and purity of the EGCG band. Determination was carried out over a concentration range of 0.50-5.00µg/band and 0.20-2.40µg/band for GA and caffeine, respectively. Results showed significant reduction in EGCG content after one, three and six months: 24.00%, 28.00% and 52.00% respectively. Results continue to demonstrate that stability of nutraceutical products should be investigated in-depth using industry-oriented protocols before granting marketing authorisation.