Habib Mosbah

Hepatoprotective effect of Opuntia microdasys (Lehm.) Pfeiff flowers against diabetes type II induced in rats

Opuntia sp. has long been used as a folk medicine to treat hepatitis and diabetes in Sicile (Italy). To extract the polyphenols from the flower of Opuntia microdasys Lehm. at post flowring stage and evaluate the antidiabetic activity in vitro and in vivo. The hepatoprotective activity of Opuntia microdasys aqueous flowers extract at post flowering stage (OFP) has been tested for their antidiabetic activity. On fructose-alloxan induced diabete in rat model, evaluating the inhibitory effects of OFP on some carbohydrate metabolizing enzymes, pancreatic α-amylase and intestinal α-glucosidase activities in vitro. The OFP extract showed inhibitory activity against α-glucosidase (IC50=0.17±0.012mg/ml) and α-amylase (IC50=2.55±0.41mg/ml). The inhibitory potential of OFP extract on these enzymes suggests a positive and probable role of this extract in the management and treatment of diabetes mellitus, particularly, for type 2. Oral administration of the OFP at 200mg/kg to diabetic male rats for 28days demonstrated a significant protective effect by lowering the levels of glucose (123.21±1.38mg/dL) and hepatic marker enzymes (AST, ALT, LDH, γ-GT, BT, PAL, TC, LDL-C, HDL-C and TG). OFP attenuated oxidative stress by decreasing the SOD, CAT, GPX activity and the levels of PC and MDA in the liver and restored the histological architecture of the rat liver. OFP has protective effects on the protection of liver, thereby reducing some of the causes of diabetes in experimental animals.

Improvement of biomass production and glucoamylase activity by Candida famata using factorial design

To improve biomass production and glucoamylase activity (GA) by Candida famata, culture conditions were optimized. A 23 full factorial design (FFD) with a response surface model was used to evaluate the effects and interactions of pH (X1), time of cultivation (X2), and starch concentration (X3) on the biomass production and enzyme activity. A total of 16 experiments were conducted toward the construction of an empiric model and a first‐order equation. It was found that all factors (X1, X2, and X3) and their interactions were significant at a certain confidence level (P < 0.05). Using this methodology, the optimum values of the three tested parameters were obtained as follows: pH 6; time of cultivation 24 H and starch concentration 7 g/L, respectively. Our results showed that the starch concentration (X3) has significantly influenced both dependent variables, biomass production and GA of C. famata. Under this optimized medium, the experimental biomass production and GA obtained were 1.8 ± 0.54 g/L and 0.078 ± 0.012 µmol/L/Min, about 1.5‐ and 1.8‐fold, respectively, higher than those in basal medium. The (R2) coefficients obtained were 0.997 and 0.990, indicating an adequate degree of reliability in the model. Approximately 99% of validity of the predicted value was achieved.

α-Glucosidase inhibition by Tunisian Scabiosa arenaria Forssk. extracts.

Recent decades have witnessed a sharp increase in the incidence and prevalence of type 2 diabetes mellitus. One antidiabetic therapeutic approach is to reduce gastrointestinal glucose production and absorption through the inhibition of carbohydrate-digesting enzymes such as α-amylase and α-glucosidase. In this study, crude extracts and their corresponding fractions of flowers, fruits, (stems and leaves) and roots of the endemic North African plant Scabiosa arenaria Forssk. were screened for their ability of α-glucosidase inhibition. It was found that the fruits ethyl acetate (EtOAc), the fruits butanolic (n-BuOH) and the flowers ethyl acetate (EtOAc) fractions inhibited α-glucosidase in a non competitive manner with IC50 values of 0.11±0.09, 0.28±0.04 and 0.221±0.01mg/ml, respectively. RP-HPLC analysis indicated that the major components of these active fractions are flavonoid aglycone, cinnamic acid and its derivatives. This result supports the conclusion that the three studied fractions could be a useful natural source for the development of a novel α-glucosidase inhibitory agent against diabetic complications.

Antimicrobial Activity of Scabiosa arenaria Forssk. Extracts and Pure Compounds Using Bioguided Fractionation

The emergence of multidrug resistant pathogens threatened the clinical efficacy of many existing antibiotics. This situation has been recognized globally as a serious concern and justifies further research to discover antimicrobial agents from natural origins including plant extracts. The aim of our work was to evaluate the antimicrobial activities of Scabiosa arenaria Forssk. extracts and pure compounds using a bioguided fractionation, and try to explain some traditional use of this genus. The best antimicrobial activity‐guided fractionation was obtained by BuOH fractions of flowers, fruits and (stems and leaves) against Escherichia coli, Pseudomonas aeruginosa and Candida albicans with minimum inhibitory concentration (MIC) values from 0.0195 to 5 mg/ml. Escherichia coli was the most affected bug, thus the MIC of fruits BuOH extract showed the best anti‐Escherichia coli activity (MIC = 0.0195 mg/ml), followed by the (stems and leaves) and flowers BuOH extracts; MIC = 0.078 and 0.15 mg/ml, respectively. Furthermore, the subfractions obtained from these three mixed fractions showed also an important antimicrobial activity against the three microorganisms, with MIC values between 0.0195 and 0.312 mg/ml. The fractionation of the aerial part BuOH fraction led to the isolation of oleanolic acid (1) and luteolin 7‐O‐glucopyranoside (2) which are reported here for the first time from S. arenaria. Both compounds showed good antimicrobial activities with MIC values ranging from 170 to 683 μm and 86 to 347 μm, respectively. These results support the use of the Scabiosa genus to inhibit the growth of tested pathogenic bacteria and yeasts which may reduce illnesses associated with their exposure.

Partial characterization of a novel amylase activity isolated from Tunisian Ficus carica latex

Context: A large number of plants still need to be investigated through screening of amylases suitable for industry. In the present study, and for the first time, we describe the amylolytic activity of Saint Pedro Ficus carica L. (Moraceae) crude latex of Kahli and Bidhi varieties. Objective: Effects of temperature, pH, metal ions, and inhibitors and compatibility with some commercial detergents were investigated for amylase activity. Materials and methods: Amylase activity was screened in crude latex using the DNS method and potato starch as a substrate. Analyses of amylolytic reaction products by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) were performed. Results: Bidhi and Kahli amylases were active in optimal pH of 6.5 and 7 at 45°C, respectively, displaying a half life of 85 and 60 min, respectively, at 80°C, and they were very stable in a wide range of pH (4–12). Bidhi amylase activity increased to 260% by addition of 10−3 mM Fe2+ or 10−2 mM Cu2+, and was strongly inhibited by Mg2+ and EDTA. In the presence of Ca2+ and Mg2+, Kahli amylase activity was dramatically enhanced by 220 and 260%, respectively. The compatibility of both amylases with certain commercial detergents was also shown to be good as enzymes retained up to 98% of their activities after 30 min of incubation at 80°C. Discussion and conclusion: Analysis of amylolytic reaction products by TLC and HPLC suggested that Kahli amylase was an amyloglucosidase and Bidhi amylase was β-fructose, α(1–4) glucose. Bidhi amylase is a good choice for application in starch, food, detergents and medical industries.

Activity of anti‐inflammatory, analgesic and antigenotoxic of the aqueous flower extracts of Opuntia microdasys Lem.Pfeiff

The aim of this study was to evaluate the analgesic and the anti‐inflammatory activity of Opuntia microdasys at post flowering stage, F3 (OMF3) in rat and, in other hand, its antigenotoxic effects by the Allium cepa test.

Chemical composition and biological activities of Eruca vesicaria subsp. longirostris essential oils

Abstract Context To date, there are no reports to validate the Tunisian traditional and folklore claims of Eruca vesicaria (L) Cav. subsp. longirostris (Brassicaceae) for the treatment of disease. Objective Investigation of the chemical composition antimicrobial and antioxidant activity of essential oils from Eruca longirostris leaves, stems, roots and fruits. Materials and methods The essential oils of E. longirostris from leaves, stems, roots and fruits were obtained after 4 h of hydrodistillation. Chemical compositions were determined using a combination of GC/FID and GC/MS. The in vitro antimicrobial activity of the volatile constituents of E. longirostris was performed in sterile 96-well microplates against three Gram-positive, four Gram-negative bacteria and one strain as yeast. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration values were reported. Furthermore, the antioxidant activity was evaluated by DPPH and ABTS assays. Results The main compound for fruits, stems and roots was the erucin (96.6%, 85.3% and 83.7%, respectively), while β-elemene (35.7%), hexahydrofarnesylacetone (23.9%), (E)-β-damascone (15.4%), erucin (10.6%) and α-longipinene (9.6%) constituted the major compounds in the essential oil of the leaves. The experimental results showed that in all tests, essential oil of fruits showed the better antioxidant activity than the others. On the other hand, the oils of stems, fruits and roots showed significant antimicrobial activity with MIC values ranging from 0.125 to 0.31 mg/mL against Candida species, Gram-positive and Gram-negative bacteria, mainly Salmonella enterica. Conclusions The present results indicate that essential oils of E. longirostris can be used as a source of erucin.

Characterisation of phenolic antioxidants in Scabiosa arenaria flowers by LC–ESI-MS/MS and NMR

This work describes the bioguided fractionation of the flowers ethyl acetate fraction of Scabiosa arenaria Forssk. (Dipsacaceae).

Wild edible Swiss chard leaves (Beta vulgaris L. var. cicla): Nutritional, phytochemical composition and biological activities

Nutritional, soluble carbohydrates and aroma volatile profiles of Tunisian wild Swiss chard leaves (Beta vulgaris L. var. cicla) have been characterized. The chemical composition of an ethanol chard leaves extract, as well as its in vitro antioxidant, α-amylase and α-glucosidase inhibition activities were carefully evaluated. The results of the proximate composition showed that total carbohydrate fraction, mainly as dietary fiber were the major macronutrient (2.43 g/100 g fw), being the insoluble dietary fiber the predominant fraction (2.30 g/100 g). In addition, leaves of Beta vulgaris L. were especially rich in Mg, Fe and Ca (4.54, 2.94 and 2.28 mg/100 g fw) and very poor in Na (0.09 mg/100 g fw). Volatile profile revealed that non-terpene derivatives and sesquiterpene hydrocarbons were the essential classes of volatiles in the chard leaves. Myricitrin, p-cumaric acid and rosmarinic acid were characterized. Moreover, the ethanol extract of wild Swiss chard leaves revealed significant antioxidant capacity. Furthermore, a good enzyme inhibitory effects on α-glucosidase and α-amylase activities were observed. These findings highlighted the potential health benefits of wild Swiss Chard as a source of nutritional and bioactive compounds.