A novel optimized eco-friendly simple spectrofluorimetric method for the determination of total catechins in green tea extract: Application to commercial tablet.

Green tea extract (GTE) contains antioxidants that are present in green tea. The active constituents of green tea extract are catechins. This study demonstrates a spectrofluorimetric method for measuring GTE's catechin concentration based on its native fluorescence. To design a quick, sensitive, and ecological spectrofluorimetric approach, all features were investigated and adjusted. This method relies on determining the GTE ethanolic solution's native fluorescence at 312 nm after excitation at 227 nm. The calibration graph displayed a linear regression for values between 0.05 and 1.0 µg mL-1. The detection and quantification limits of the proposed technique were 0.008 and 0.026 µg mL-1, respectively. Two pure catechins present in GTE, (-)-epicatechin and (-)-epigallocatechin gallate, were examined by the proposed method. The analytical estimation of GTE in the pharmaceutical tablet was achieved effectively using this approach. An adequate degree of agreement was found when the findings were compared to those obtained by the comparative technique. Therefore, the novel strategy may be used in the GTE quality control study with minimal risks to people or the environment. The quantum yields of catechins were estimated. The validated technique was accepted by the International Council of Harmonization criteria.

Exhausted Grape Seed Residues as a Valuable Source of Antioxidant Molecules for the Formulation of Biocompatible Cosmetic Scrubs.

Grape seed of Obeidi, a white Lebanese autochthonous variety, was previously tested in different studies as a valuable source of bioactive molecules such as polyphenols, oils, and proteins by means of extraction procedures for the development of cosmetic and therapeutic products. However, an un-valorized, exhausted grape seed residue remains as "secondary waste" after the extraction processes. In this study, the exhausted seeds have been further exploited to produce cosmetic scrubs capable of releasing antioxidant molecules during the exfoliation process, in accordance with the principles of the circular economy and going toward a zero-waste process. The deep characterization of the exhausted seeds confirmed the presence of antioxidant phenolic molecules including gallic acid, catechins and protocatechuic acid (0.13, 0.126, and 0.089 mg/g of dry matter DM), and a high phenolic content (11.85 mg gallic acid equivalents (GAE)/g of dry matter (DM)). Moreover, these residues were shown to possess a sandy texture (Hausner ratio (HR): 1.154, Carr index (CI): 0.133, and angle of repose: 31.62 (°) degrees), similar to commercial natural exfoliants. In this respect, exhausted Obeidi grape seed residues were incorporated at increasing concentrations (0.5, 1, 1.5, and 2% w/w) in a cosmetic scrub, and stored for 5 weeks at 4, 25, and 50 °C for stability testing. All tested scrub formulations exhibited good spreadability with a spread diameter of 3.6-4.7 cm and excellent physical stability, as no phase separation or color change were observed after four cycles of heat shock at 4 and 50 °C. Finally, an in vivo skin irritation test showed that the scrub enriched with 1.5% of exhausted Obeidi grape seed residues was the most promising formulation, as it possessed a high amount of phenolic molecules (0.042 ± 0.001 mg GAE/mL of scrub) and good stability and could be safely applied to the skin with no irritation phenomena. Overall results underlined that exhausted grape seed residues can be transformed into promising systems for both physical and chemical exfoliation, thus confirming the importance of the effective exploitation of agro-industrial by-products for the development of high value cosmeceutics towards a more sustainable and zero-waste approach.

Multi-Step Biomass Fractionation of Grape Seeds from Pomace, a Zero-Waste Approach.

Grape seeds are the wineries' main by-products, and their disposal causes ecological and environmental problems. In this study seeds from the pomace waste of autochthonous grape varieties from Lebanon, Obeidi (white variety) and Asswad Karech (red variety) were used for a multi-step biomass fractionation. For the first step, a lipid extraction was performed, and the obtained yield was 12.33% (w/w) for Obeidi and 13.04% (w/w) for Asswad Karech. For the second step, polyphenols' recovery from the defatted seeds was carried out, resulting in 12.0% (w/w) for Obeidi and 6.6% (w/w) for Asswad Karech, with Obeidi's extract having the highest total phenolic content (333.1 ± 1.6 mg GAE/g dry matter) and antioxidant activity (662.17 ± 0.01 µg/mL of Trolox equivalent). In the third step, the defatted and dephenolized seeds were subsequently extracted under alkaline conditions and the proteins were isoelectric precipitated. The recovered protein extract was 3.90% (w/w) for Obeidi and 4.11% (w/w) for Asswad Karech seeds, with Asswad Karech's extract having the highest protein content (64 ± 0.2 mg protein/g dry matter). The remaining exhausted residue can be valorized in cosmetic scrubs formulations as a replacement for plastic microbeads. The designed zero-waste approach multi-step biomass fractionation has the potential to improve the valorization of the side products (grape seeds) of these two Lebanese autochthonous grape varieties.

Stability and Antioxidant Activity of Hydro-Glyceric Extracts Obtained from Different Grape Seed Varieties Incorporated in Cosmetic Creams.

Grape seeds are agro-industrial by-products, which if improperly managed, may be responsible for socioeconomic and environmental problems. Nevertheless, it is possible to effectively valorize them by means of extraction of the bioactive compounds, especially the antioxidant phenolic molecules, using a safe, green, and environmentally-friendly extractive medium (i.e., hydro-glyceric solution). In the present study, the extraction was performed using seeds from two Lebanese varieties, Obeidi and Asswad Karech, and three international varieties, Marselan, Syrah, and Cabernet Franc. The type and amount of phenolic compounds were identified by High-Performance Liquid Chromatography (HPLC). Marselan was the extract richer in catechins (132.99 ± 9.81 µg/g of dried matter), and it also contained a higher amount of phenolic compounds (49.08 ± 0.03 mg of gallic acid equivalent/g of dry matter and 10.02 ± 0.24 mg of proanthocyanidin content/g of dry matter). The antioxidant capacity of the extracts was assessed using three different colorimetric assays including 2,2-DiPhenyl-1-PicrylHydrazyl (DPPH), CUPRIC ion Reducing Antioxidant Capacity (CUPRAC), and Ferric Reducing Antioxidant Power (FRAP). As expected, Marselan exhibited the highest antioxidant activity; as well, the total phenolic and proanthocyanidin content were the highest. The stability of the Marselan extract incorporated into a commercial cream, was performed at three different temperatures (4, 25, and 50 °C), and four different concentrations (5, 4, 3, 2%), over a period of 4 months, using different methods such as centrifugation, Heat-Shock Cycles, pH, and viscosity. All Marselan hydro-glyceric extract formulations were proven to be stable over the entire 4 months, where the highest stability was achieved at 4 °C and the least at 50 °C. This study supports the suitability of the incorporation of phenolic extracts into commercial creams to enrich the cosmetic industry with effective, natural, and safe skincare products.