Smail Aazza

This study aims to provide new data on the chemical composition and biological properties of Corrigiola telephiifolia, demonstrating the influence of different extraction solvents and geographic locations on these properties. It presents novel findings on the phytochemical contents, antioxidant...

This study delves into the influence of varying solvent compositions on the extraction of Total Phenolic Compounds (TPC) and the antioxidant activities of extracts from Mentha suaveolens subsp. timija leaves and stems. The extraction process is conducted using ultrasound-assisted extraction via...

Acetylcholinesterase (AChE), hydrolyzes acetylcholine to choline and acetate, thereby terminating this neurotransmitter effect at cholinergic synapses. Therefore, AChE inhibition is used for counterbalance the cholinergic deficit in Alzheimer’s disease (AD) patients. In the present work, in order to find new plant acetylcholinesterase inhibitors, the hydroalcoholic extracts from seventeen medicinal plant species were screened for their acetylcholinesterase inhibition activity, as well as total phenolic (TPC) and flavonoids contents (TFC) and antioxidant activity using ORAC (Oxygen Radical Absorbance Capacity) assay, and their ability to inhibit lipid peroxidation. The results revealed that Rumex acetosa, Taraxacum officinaleand Hypericum perforatumextracts possessing the highest TPC and TFC, were the most effective in terms of ORAC antioxidant activity, and acetylcholinesterase inhibition, in addition to their ability to inhibit liposomes peroxidation, suggesting that those plant species may provide a substantial source of secondary metabolites, which act as natural antioxidants and acetylcholinesterase inhibitors, and may be beneficial in the treatment of AD.

Tribulus terrestris fruit has been used as a traditional and popular medicine for the prevention and treatment of several diseases, including sexual dysfunction, atherosclerosis and hypertension. The aim of this study was to evaluate the antioxidant, lipoxygenase and α-glucosidase inhibitory activities of an ethanol extract from Brazilian T. terrestris and its fractions sequentially partitioned into n-hexane, dichloromethane, ethyl acetate and n-butanol. The antioxidant capacities were determined by DPPH and ABTS scavenging free radicals, chelating metal ions, reducing power and total antioxidant activity by using phosphomolybdenum. High-performance liquid chromatography with diode array detection (HPLC-DAD) fingerprint analysis and quantitation of total phenolics were performed on the samples. The dichloromethane fraction showed the most complex HPLC-DAD chemical profile. The ethyl acetate and butanol fractions revealed the best phenolic compound and flavonoid recovery from T. terrestris. Concerning antioxidant activity, the ethyl acetate fraction presented better capacity for scavenging DPPH, ABTS and hydroxyl radicals, reductive power, total antioxidant capacity (TAC) and α-glucosidase inhibitory activity than the other fractions. These results correlated closely with the levels of phenolic compounds and flavonoids. The hexane fraction showed the best metal chelating power and lipoxygenase inhibitory activity. The anti-diabetic and anti-inflammatory potential of Brazilian Tribulus terrestris depend on the method of preparation.

Garlic is a health promoter that has important bioactive compounds. The bioactive extraction is an important step in the analysis of constituents present in plant preparations. The purpose of this study is to optimize the extraction with the best proportion of solvents to obtain total phenolic compounds (TPC) and thiosulfinates (TS) from dried garlic powder, and evaluate the antioxidant activities of the optimized extracts. A statistical mixture simplex axial design was used to evaluate the effect of solvents (water, ethanol, and acetone), as well as mixtures of these solvents, after two ultrasound extraction cycles of 15 min. Results showed that solvent mixtures with a high portion of water and pure water were efficient for TPC and TS recovery through this extraction procedure. According to the regression model computed, the most significant solvent mixtures to obtain high TPC and TS recovery from dried garlic powder are, respectively, the binary mixture with 75% water and 25% acetone and pure water. These optimized extracts presented oxygen radical absorbance capacity. Pure water was better for total antioxidant capacity, and the binary mixture of water–acetone (75:25) was better for DPPH scavenging activity. These optimized extracts can be used for industrial and research applications.

A statistical simplex centroid design methodology was applied to determine the effects of different solvents and their mixtures on the yield, total polyphenol content, 22-dipheny-l-picrylhydrazyl (DPPH) radical scavenging activity, and ferric reducing antioxidant power (FRAP) of extracts from the waste of Cannabis sativa. The different extractor solvents (ethanol, methanol, water, and hexane) and their binary and ternary combinations were evaluated. The experimental results and their response surface models showed that the highest TPC yield values occur with the binary interaction between water and ethanol around the proportion of (ethanol, 70; water, 30). The desirability function showed that the optimal conditions were for TPC extraction ternary mixtures which consisted of 75 ethanol, 12.5 methanol, and 12.5 water. Ternary mixtures including water and binary mixture (ethanol 50 to 75) yielded extracts with the best DPPH antioxidant activity, whereas pure methanol was the best solvent for extracting molecules with FRAP antioxidant capacity. The desirability function including all responses showed that the optimal solvent mixture consisted of 25 ethanol and 75 methanol.

Honey is a natural food product very famous for its health benefits for being an important source of antioxidant and phenolic compounds. Euphorbia honeys obtained from different regions of Morocco were evaluated for their ability to inhibit acetylcholinesterase, lipoxygenase, tyrosinase and xanthine oxidase activities. Their antioxidant properties were evaluated using the: 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging capacity, nitric oxide scavenging activity (NO) and scavenging ability of superoxide anion radical. Then, the phenolic extracts of the same entire honey samples were evaluated by liquid chromatography coupled to diode array detection and mass spectrometry (LC-DAD-MS) and tested for the biological activities previously evaluated on the entire honeys, in order to conduct a comparative study between both (honey and phenolic extracts). The chromatographic profiles for the studied Euphorbia honey extracts were different. Phenolic compounds gallic acid, 4-hydroxybenzoic acid and p-coumaric acid were detected in all samples, whereas kampferol was only present in two samples. Physicochemical parameters and total phenolic content were also determined. Entire honey that recorded the highest rate of phenols was sample M6 (E. resinifera) = 69.25 mg GAE/100 g. On the other hand, the phenolic extracts had better antioxidant and enzyme inhibitory activities than the entire honeys, regardless the monofloral honey type. In conclusion, the studied Euphorbia honeys may have a great potential as antioxidant, anti-inflammatory and anti-tyrosinase sources for pharmaceutical and cosmetic applications.

Summary: This study aims to determine the chemical composition of hemp (Cannabis sativa L.) seeds of two varieties cultivated in four different regions of northern Morocco. The content of protein, insoluble fibre, ash, total phenols and flavonoids was found to be 19.25%–24.18%, 26.40%–37.40%, 3.72%–5.39%, 134.57–199.90 mg 100g⁻¹ and 39.40–69.54 mg 100g⁻¹ respectively. Oil contents ranged from 26.42 to 35.19 g 100 g⁻¹ of seeds in the four collection sites with variable oxidative stability at 100°C from 9.73 to 15.42 h. Total tocopherol content was between 376.46 and 796.06 mg kg⁻¹ of oil, with a dominance of γ‐tocopherol. Fatty acids consisted mainly of unsaturated fatty acids (87.30‐88.96%) with a predominance of linoleic acid (48.26%–55.39%). Triacylglycerols (TAGs) composition analysis revealed the presence of 18 TAGs with an equivalent carbon number of 38–48. The composition of TAGs was predominated by LLL (14.34%–22.62%), OLL (12.77%–18.78%) and LLLn (12.32%–18.59%). Furthermore, the majority of the evaluated parameters were strongly influenced by the varietal factor, growing area and their interaction. The knowledge of this composition variability in seeds of non‐industrial Cannabis sativa varieties cultivated in northern Morocco could be useful in new Cannabis variety breeding programmes potentially valuable as non‐conventional oil in cosmetic and agro‐industry.