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The main objective of this work was to investigate antioxidant, antibacterial and antidiabetic activities as well as to explore the chemical composition of the stems barks essential oils from Ficus caricacollected in three maturation periods, namely summer, autumn, and winter. The obtained essential oils were analyzed through the use of GC/FID and GC/MS techniques. A total of 19 compounds representing 99.13 to 99.58% of the total oils were identified, exhibiting qualitative and quantitative differences. The major compounds values were eugenol 75.31% for essential oil obtained in summer and 40.56% for essential oil obtained in winter, undecan-2-one 37.97% and carvacrol 17.11% for the essential oil obtained in autumn. The antioxidant activity of the Ficus caricaessential oils was assessed using 2, 2-DiPhenyl-1- PicrylHydrazyl (DPPH), and total antioxidant capacity assays. Essential oil recovered in winter displayed a great antioxidant activity with IC50= 0.04 mg/mL, followed by essential oil extracted in autumn (0.06 mg/mL) and essential oil obtained in summer (0.0646 mg/mL) compared to the standard vitamin C (IC50= 0.03 mg/mL). Additionally, essential oils were evaluated for their nitric oxide chelating activity and presented an important scavenging effect with IC50of 0.032, 0.033 and 0.045 mg/mL for essential oil extracted in winter, essential oil recovered in autumn and essential oil obtained in summer, respectively. Furthermore, the IC50values of essential oils against α-amylase amounted to 24.58, 35.85 and 38.15 µg/mL for essential oil recovered in summer, essential oil obtained in autumn and essential oil recovered in winter, respectively. These values were suggestive of a powerful anti-diabetic effect comparable to that of acarbose (IC50 = 16.82 µg/mL). The obtained essential oils were equally evaluated for their antibacterial activity against five bacteria. Moderate results were reported compared to the positive control Gentamicin.

AbstractIn this study, we investigated the chemical composition, antioxidant and antibacterial activities of essential oil and aqueous extract from Thymus algeriensisBoiss. & Reut growing in Tunisia. GC/MS analysis of essential oil from the aerial part of the plant led to identifying 54 constituents representing 96.87 % of the total oil composition. Monoterpenes represented the major components of the essential oil. On the other hand, the aqueous extract and the essential oil were screened for their antioxidant and antibacterial activities. The latter was assessed against Gram-negative and Gram-positive bacterial strains using the broth dilution micro method for the determination of antibacterial activity. The antioxidant activity was evaluated using the DPPH scavenging activity and Ferric Reducing/Antioxidant Power (FRAP) assays. The essential oil was found to be more active in antibacterial screening (MIC = 0.54 μg/mL). Whereas the aqueous extract exhibited the most potent antioxidant activity with (IC50= 0.04 μg/mL). UHPLC ESI(-)-HRMS/MS analysis of the aqueous extract allowed tentative identification of its constituents and showed that it is rich in phenolic compounds. Luteolin-glucuronide was found to be the most abundant compound followed by Vicenin-2 and Apigenin-diglucuronide.

Oleaster (Olea europaeavar. sylvestris) is a wild olive tree distributed in the Mediterranean area. It is known to possess several biological activities due to their richness in polyphenols. However, enhanced autophagic activity in human cells by using this plant has not been studied before. The objective of the present study was to determine the phytochemical composition of the fruits paste from Tunisian Oleaster, and evaluate its antioxidant activity using the DPPH•and ABTS•+methods as well as the evaluation of its effect on autophagy activity. The extraction conditions were optimized using response surface methodology (RSM) leading to the best phenolic extract yield. It was noted that ethyl acetate extract presented the highest amount of total phenols and the best solvent for extraction of phenolic compounds. After optimization, the ethyl acetate extract was fractionated into 15 fractions by silica gel column chromatography. The most phenolic components in the fifth and sixth fractions (F5 and F6) were identified using UPLC-ESI(-)-HRMS analysis. Accordingly, F6 was the richer fraction in polyphenols. In vitro antioxidant activity evaluation showed that F6 exhibited a strong ability to scavenge DPPH and ABTS radicals. Furthermore, this fraction was also the most effective to induce autophagic activity in Human foreskin fibroblasts (HFF) cells. These results could be presumably due to the presence of oleuropein aglycon in this fraction which is absent in fraction F5. Oleaster fruits paste would be used as a natural source of bioactive compounds useful in various pharmaceutical drugs.

This paper deals with the analysis of seed and seed oil of Linum usitatissimumof Tunisian origin in terms of physicochemical properties, fatty acid, sterol and triacylglycerol compositions, thermal characteristics UV/Vis, DSC profile, IR and NMR spectroscopic analysis. Some of these properties were compared to those of linseed and linseed oil from other countries. The contents of moisture, ash, protein, and carbohydrates in the seeds were 3.60, 3.17, 14 and 48.16%, respectively. The physicochemical properties of LOT included: acid value (0.9 mg KOH/g of oil), iodine value (142.12 g/100 g of oil), peroxide value (3.5 meqO2/kg) and saponification number (200.5). Linolenic acid (58.59%), oleic acid (16.67%), linoleic acid (15.50%) and palmitic acid (5.44%) were the major fatty acids in LOT. The dominant polyunsaturated triacylglycerols found in LOT are LnLnLn, LnLLn, LnOLn, LnLnP (Ln: Linolenic; L: Linoleic; O: Oleic and P: Palmitic acids). The main sterol found in LOT was β-sitosterol (51.31%). The DSC melting curve reveals that the melting point of LOT is −32.96 °C and the melting enthalpy is 22.79 J/g. This study has shown that L. usitatissimumseed and seed oil from Tunisia is useful in different fields such as nutrition, cosmetic by its richness in linoleic acid (ω-3) and paint products due to its rapid drying as well as pharmaceutical area.

In the present study, the growth conditions and accumulation of ectoines (ectoine and hydroxyectoine) by Paludifilum halophilumDSM 102817Tunder salt stress conditions have been investigated. The productivity assay of this strain for ectoines revealed that the highest cellular content was reached in the minimal glucose sea water medium (SW-15) within 15% salinity. The addition of 0.1% (w/v) aspartic acid to the medium allowed an average of four times higher biomass production, and a dry mycelial biomass of 1.76 g L-1was obtained after 6 days of growth in shake flasks at 40 °C and 200 rpm. Among the inorganic cations supplemented to the glucose SW-15 medium, the addition of 1 mM Fe2+yielded the highest amount of mycelial biomass (3.45 g L-1) and total ectoines content (119 mg g-1), resulting in about 410 mg L-1of products at the end of exponential growth phase. After 1 h of incubation in an osmotic downshock solution containing 2% NaCl, 70% of this content was released by the mycelium, and recovering cells maintained a high survival, with a maximal growth rate (µmax) of about 93% of the control population exposed to 15% NaCl. During growth at optimal salinity and temperature (15% NaCl and 40 °C), P. halophilumdeveloped a compact and circular pellets that were easy to separate by simple decantation from both fermentation media and after hypoosmotic shock. Overall, the ectoines excreting P. halophilumcould be a promising resource for ectoines production in a commercially valuable culture medium and at a large-scale fermentation process.