The effect of drying temperature and the application of ultrasound on drying kinetics of Lawsonia inermis (henna) leaves and the extraction of lawsone from the dried samples was addressed. Indeed, henna leaves were dried with and without the application of ultrasound (21.7 kHz, 30.8 kW/m³) at 40, 50 and 60 °C with a constant air velocity (1 m/s). As expected, both the increase of temperature and the application of ultrasound decreased the drying time and increased the rate of extraction of the lawsone. The values of the effective diffusion coefficients obtained were used to quantify this influence showing the value increases with higher drying temperature and the application of ultrasound. Moreover, the influence of temperature was quantified by the estimation of the activation energy from an Arrhenius-type equation (46.25 kJ/mol in the case of drying without ultrasound application and 44.06 kJ/mol in the case of ultrasonically-assisted drying). Regarding the influence of studied variables on lawsone extraction yield, the higher is the temperature, the lower is the yield, probably linked with lawsone degradation reaction due to thermal treatment. On the contrary, the application of ultrasound improved the extraction yield mainly at the lower drying temperature tested of 40 °C.

Background: Natural products possess interesting biological activities, which attracted several researchers to their elucidation to provide knowledge that will lead to the advancement medicine. Chenopodaceae is an important plant family in the world; it contains a number of phytochemicals and has been used to treat a wide range of human diseases. The aim of this work was to carry out qualitative analyses of secondary metabolites and an antimicrobial investigation on the crude extracts from Atriplex halimus (Chenopodaceae) growing in Algerian Sahara. Methods: In this laboratory investigation during 2021-2022, phytochemical screening based on staining and precipitation tests was carried out using some solvents of different polarities. The antibacterial essay was carried out by the disc diffusion method on solid medium, using seven bacterial strains chosen for their high pathogenicity. Result: The secondary metabolites detected in the various extracts were essentially flavonoids, tannins, saponins and terpenoids. The antibacterial investigation made it possible to know that the aqueous extract from Atriplex halimus showed a significant inhibition against all bacteria tested. Diethyl ether and chloroform exracts had only one activity against Enterococcus faecalis and Listeria monocytogenes, respectively, whereas the methanolic extract exhibited the highest inhibition of Pseudomonas aeruginosa.

Background: This study is part of the contribution to the development of the medicinal plant Ephedra alata from the region of Bechar, Algeria. This work aimed to measure yields, total phenols, total flavonoids, antioxidant capacity and antibacterial evaluation. Methods: In this laboratory investigation during March 2023 to December 2023, the samples were macerated; total phenolic and flavonoids contents were analyzed using a colorimetric method, while antioxidant capacity was assessed through DPPH. The antibacterial essay was carried out by the disc diffusion method on a solid medium using Muller Hinton. Result: Phytochemical screening confirms the presence of alkaloids, flavonoids, free quinones, reducing sugars, saponins, sterols, tannins and terpenes. Methanol extract represents the highest yield (4.41%), followed by butanol extract (3.3%), ethyl acetate extract (1.25%) and dichloromethane extract (0.69%). The dosage carried out revealed the content of plyphenols and flavonoids in the methanol extract was (175.73±0.25 μg EAG/mg DE) and (35.2±0.17 μg QE/mg DE), respectively. The evaluation of the antioxidant effect of the crude extracts by free radical scavenging DPPH gave the IC50 values of the extracts methanol, butanol, ethyl acetate and dichloromethane (0.170, 0.244, 0.324 and 2.23 mg/mL), respectively. The investigation into antibacterial activity revealed that the methanol extract significantly inhibited all tested bacteria, while the dichloromethane extract showed the lowest inhibition of Escherichia coli.

Introduction: The continuously growing number of commercial Lawsonia inermis (henna) powders and the wide variability of their quality necessitate verifying as well as controlling their level of lawsone, the main active ingredient. The purpose of this study is to examine the effect of drying on the level of lawsone. Methods: The leaves of henna were dried at different temperatures (40°C, 50°C, and 60°C) with both modes (air and ulrasons). We extracted lawsone from leaves by a Soxhlet extractor using methanol and water as solvents, respectively. This natural pigment was isolated, purified, and analyzed by thin-layer chromatography (TLC), high-pressure liquid chromatography (HPLC), and ultra-violet (UV) spectrophotometer. Results: The drying temperature highly affected the extraction yield (Re). Therefore, drying henna leaves at low temperatures allows for a higher yield of lawsone extracts. Conclusion: We recommend ultrasonically assisted drying of henna leaves to facilitate both the reduction of drying temperatures in order to conserve energy as well as the increase of the yield of lawsone extraction.