Browsing by Author "Chammakhi, Yosra"
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- Development of semi-solid formulations containing Juglans regia L. leaves extracts for tropical applicationPublication . Besrour, Nermine; Chammakhi, Yosra; Pinela, José; Mezni, Mohamed; Caleja, Cristina; Pereira, Carla; Abreu, Rui M.V.; Alves, Maria José; Taofiq, Oludemi; Barros, Lillian; Ferreira, OlgaNowadays, cosmetic brands are urged to follow sustainable development strategies via circular economy and low carbon footprint processes. Using ingredients from agri-food waste to generate new cosmetic products and environmentally friendly solvents are one of the paths to meet those challenges [1]. In this regard, glycerol and alkanediols can be seen as alternative solvents to extract phytochemicals from plant material due to their potential application in the cosmetics area. In this work, the leaves of walnut trees (Juglans regia L.) were studied as a source of bioactive compounds. Their extracts are already used in traditional herbal medicine but can be further valorised as potential bioactive ingredients in the cosmeceutical area. The extracts were obtained using aqueous solutions of ethanol or 1,2-propanediol, and diverse bioactivity studies (antioxidant, cytotoxic, anti-inflammatory, antimicrobial, anti-tyrosinase, and photostability) were carried out. Better results were obtained with the hydroethanolic extracts in the anti-tyrosinase, antioxidant, and anti-inflammatory dimensions. In the antimicrobial assay, both extracts showed similar microbial properties. The main phytochemicals identified in both extracts were 3-O-caffeoylquinic acid, quercetin-O-pentoside, taxifolin-O-pentoside isomer, quercetin 3-O-glucoside, and 3-p-coumaroylquinic acid. After, the propanediol and hydroethanolic extracts were incorporated in a commercial base cream, aiming to design a formulation for topical application. The following parameters were studied to evaluate the stability of the final formulation: pH, colour, phenolic compounds content, and antioxidant activity. The formulation containing the hydroethanolic extract was the best to conserve the identified phenolic compounds for 30 days, at different temperature conditions (5 ºC, 20 ºC, and 40 ºC). The formulation containing the propanediol extract should be redesigned by incorporating higher amounts of extract. Both formulations presented relevant antioxidant activity and a favourable pH range of 3.8 to 4.7. These preliminary results suggest the potential application of J. regia extracts as an ingredient for incorporation into skin care products as they showed a very satisfactory chemical and physical stability at the studied time and temperature storage conditions. Nevertheless, additional studies will be performed not only to evaluate their stability over longer periods of time, but also their safety and toxicity.
- Valorization of Aloe vera leaf rind extracts through partition studies and the development of a cosmetic formulationPublication . Chammakhi, Yosra; Ferreira, Olga; Pinela, José; Caleja, Cristina; Oludemi, TaofiqAloe vera (Aloe barbadensis Mill.) is a succulent xerophytic medicinal plant that has assumed, in the last decades, great importance in the industrial sector due to its bioactive properties, which is why it is used in the development of cosmeceuticals, functional foods and food supplements. In this work, the focus is on the green rind of the Aloe vera leaf, which is usually considered a waste part of the plant. The main objectives were to obtain the partition coefficients of the main anthrones and chromones present in the extracts to support the design of fractionation processes using centrifugal partition chromatography (CPC), to develop a semi-solid formulation for topical use containing glycerol (G), propylene glycol (PG) and water (W) extracts, and characterize the bioactive properties and shelf stability of the final formulation. The chemical characterization of aloesin-rich extracts showed that the highest content of phenolic compounds was detected in W extract and the most abundant compounds were aloeresin B and aloin A. The G extract presented the best DPPH radical scavenging activity followed by W and PG extracts. The G and W extracts were the most stable when exposed to UVA and UVB radiation at different tested skin pH (3-6). Also, the three extracts had a MIC = 5 mg/mL against the bacterial pathogen of the skin Enterococcus faecalis, which can be beneficial for application in the cosmeceutical field. Antibacterial results showed that the PG extract presented broad spectrum antibacterial activity against Gram-positive and Gram-negative bacteria. PG and G extracts also presented anti-inflammatory activity. After incorporation of the extracts in a base cream, the final formulations presented higher antioxidant activity compared to the base cream (control). The antioxidant activity was evaluated at different storage condition along time and the results showed that the extracts retained its functionality (antioxidant capacity) after being incorporated in the base cream. The colour and pH analysis showed that the final formulations had good physicochemical stability when stored during 14 days at different temperatures. Finally, regarding the partition coefficients studies of the main anthrones and chromones present in the extracts, depending on the target compounds, very promising results were obtained using binary or ternary mixtures of the biphasic system water + butan-1-ol + ethyl acetate.