Kaouther Majouli

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.

Polyphenolic contents, antioxidant activities and UPLC–ESI–MS analysis of Haplophyllum tuberculatum A. Juss leaves extracts

The aim of this study is to determine the phytochemical profile, the total polyphenolic contents and the antioxidant activities of Haplophyllum tuberculatum leaves extracts. The most active extracts were analyzed by ultra-high performance liquid chromatography coupled to electrospray ionization mass spectrometry. Antioxidant activities were screened by the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) test and measured by the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and β-carotene bleaching inhibition assays. Phytochemical screening of the extracts revealed the presence of various secondary metabolites. The ethyl acetate extract was the richest extract in phenolics and flavonoids with 262mg gallic acid equivalents/g and 99.1mg quercetin equivalent/g of dry weight, respectively. The same extract showed an important scavenging effect on DPPH, ABTS and β-carotene/linoleic acid with IC50 of 0.020mg/mL, 0.029mg/mL and 0.022mg/mL, respectively. The correlations between the antioxidant capacities and the polyphenolic content were ranging between 0.889 and 0.256 and occasionally found to be significant. The UPLC-ESI-MS analysis showed the presence of polyphenolic and alkaloid compounds. Arabelline, majidine, dictamine and a qudsine derivative are found for the first time in H. tuberculatum. The results indicate that polyphenolic and alkaloid compounds may be major contributors to the antioxidant activity of these extracts.

Biological properties of Hertia cheirifolia L. flower extracts and effect of the nopol on α-glucosidase

In screening for antioxidant and α-glucosidase inhibitors from the extracts of Hertia cheirifolia L. flowers, the petroleum ether extract showed interesting antioxidant activity and inhibitory effect on the activity of α-glucosidase. The fractionation of this extract resulted in the isolation of a compound which is characterized by NMR and ESI-MS as a nopol. The nopol exhibited potent α-glucosidase inhibitory potential with IC50 value of 220μM. The kinetic evaluation indicated that it acts as a non-competitive inhibitor. A molecular docking study proved that the nopol presented a strong affinity with amino acid residues of α-glucosidase.

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.

Two new alkaloids and a new polyphenolic compound from Cotula coronopifolia

Two new alkaloid derivatives of the 3-benzazocine skeleton (cotuzine A and B) and a new polyphenolic substance (3-(1,3-dihydroxyprop-2-yl)-4-hydroxyanisol) (corimen) have been isolated from the aerial part (stems, leaves) of the plant Cotula coronopifolia (L.). These three new structures were established by spectroscopic procedures (1H, 13C, one- and two-dimensional NMR). The stereochemistry of the new alkaloids was established based on different NOE effects revealed on the NOESY spectrum. Mass spectrometry and IR spectroscopy were used to confirm these structures.

Phytochemical and Pharmacological Properties of Hertia L. Genus

The genus Hertia L. contains 12 species distributed all over south and North Africa and Southwest Asia. Some species of these plants are used traditionally for pain of stomach and to reduce hyperglycemia. It has been found that the species belonging to this genus possesses a rich phytochemical content and a wide range of pharmacological activities such as acaricidal, spasmolytic, anti-inflammatory, cytotoxic, anthelmintic, antibacterial, antioxidant effects and α-glucosidase inhibition. In an aim to highlight the importance of Hertia, this study evaluated its phytochemical and pharmacological properties.

Anti-inflammatory activity and gastroprotective effect of Hertia cheirifolia L. roots extract

ETHNOPHARMACOLOGICAL RELEVANCE Hertia cheirifolia L. is used traditionally to treat rheumatic pains and known as a medicinal plant having several pharmaceutical and biological activities. The present study evaluated in vivo the anti-inflammatory and gastroprotective effects of the methanolic extract from H. cheirifolia L. MATERIALS AND METHODS Reverse phase high-performance liquid chromatography (RP-HPLC) was performed to identify various chemical components of the plant extract. Anti-inflammatory and gastroprotective activities were assessed on carrageenan-induced paw edema and HCl/ethanol-induced gastric lesions in rats, respectively. RESULTS (RP-HPLC) analysis indicated that coumarin is the abundant component in the extract (53.80%). Intraperitoneal administration of the methanolic extract at different doses showed interesting activities in rats in a dose-dependent manner. At 100 mg/kg, this extract showed the highest acute anti-inflammatory activity and an important inhibition of gastric lesions with inhibition percentage of 79.41% and 88.53%, respectively. CONCLUSION Altogether, the results of this study reveal the anti-inflammatory and gastroprotective effects of H. cheirifolia extract and promote the traditional use of this plant in the treatment of different pain and inflammatory diseases.

Pharmacological activities of the organic extracts and chemical fatty acids composition of the petroleum ether extract from Haplophyllum tuberculatum leaves

ETHNOPHARMACOLOGICAL RELEVANCE Haplophyllum tuberculatum is used in traditional medicine to treat many disorders including inflammation and pain. The aim of this study is to investigate the organic extracts from H. tuberculatum leaves against inflammation, gastric ulcer and pain. MATERIALS AND METHODS Acute toxicity was studied in vivo to determine the toxic doses of the organic extracts. Anti-inflammatory activity was also evaluated in vivo using carrageenan-induced paw edema in Wistar rats. Gastroprotective activity was tested using the HCl/ethanol-induced gastric ulcer test in rats. Peripheral and central analgesic activities were assessed using the acetic acid-induced writhing test and the hot-plate method, respectively. The chemical composition of the fatty acids in the petroleum ether (PE) extract was determined with GC-MS. RESULTS At 25, 50 and 100mg/kg PE extract was the most active against inflammation. Percentages inhibition 5h after carrageenan-injection were 51.12; 86.71% and 96.92%, respectively. The same extract at 100mg/kg showed good analgesic activities using the acetic acid-induced writhing test and the hot-plate method. The chloroform, ethyl acetate (EtOAc) and butanolic (n-BuOH) extracts exhibited strong anti-inflammatory, gastroprotective and analgesic activities at 100mg/kg. The GC-FID analysis revealed that the PE extract was rich in γ-linolenic acid (45.50%) followed by palmitic acid (18.48%), linoleic acid (10.73%), erucic acid (4.72), stearic acid (3.96%) and oleic acid (2.57%). CONCLUSION The results of the present study support the traditional use of the leaves of H. tuberculatum and may possibly serve as prospective material for further development of safe new phytochemical anti-inflammatory, gastroprotective and/or analgesic agents.