Ferid Limam

Essential Oils, Phenolics, and Antioxidant Activities of Different Parts of Cumin (Cuminum cyminum L.)

Cuminum cyminum L. roots, stems and leaves, and flowers were investigated for their essential oils, total phenolics, flavonoids, and tannins contents, individual phenolic compounds, and antioxidant activities. The essential oil was investigated by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS), whereas identification and quantification of individual target polyphenolic compounds was performed by reversed-phase high-performance liquid chromatography (RP-HPLC). Essential oil yields were 0.03% in roots, 0.1% in stem and leaves, and 1.7% in flowers. Major components of the oils were bornyl acetate (23%), α-terpinene (34%), and γ-terpinene (51%) in roots, stems and leaves, and flowers, respectively. In all C. cyminum organs, total phenolics content ranged from 11.8 to 19.2 mg of gallic acid equivalents per gram of dry weight (mg of GAE/g of DW). Among the polyphenols studied, 13 were identified in roots, 17 in stem and leaves, and 15 in flowers. The major phenolic compound in the roots was quercetin (26%), whereas in the stems and leaves, p-coumaric, rosmarinic, trans-2-dihydrocinnamic acids and resorcinol were predominant. In the flowers, vanillic acid was the main compound (51%). The antioxidant activities of C. cyminum essential oils and acetone extracts obtained from the three organs were assessed using four tests [1,1-diphenyl-2-picrylhydrazyl (DPPH), β-carotene/linoleic acid, reducing power, and chelating power assays]. The acetone extract of flowers was strongly effective as a DPPH radical scavenger, lipid peroxidation inhibitor, and reducing agent, with IC(50) values of 4, 32, and 8 μg/mL, respectively. Moreover, the acetone extract of stems and leaves showed the highest chelating power. However, the essential oils exhibited moderate activities in the different tests.

Drought effects on polyphenol composition and antioxidant activities in aerial parts of Salvia officinalis L.

Salvia officinalis L. is a medicinal plant containing several compounds with important pharmacological activity. In this study, we investigated the effects of water deficit (moderate and severe water deficits) on the contents of total and individual polyphenols of the aerial parts. Also, we studied the effect of drought on the antioxidant activity of methanolic extracts. Our results showed that water deficiency, as estimated by the decrease in water potential, resulted in a reduction of the biomass, plant height and total chlorophyll contents. In general, drought increased the level of total and individual polyphenols and this increase was more pronounced under moderate water deficit. These findings suggest that S. Officinalis is a sensitive species and that a severe water deficit could result in a decline in the activity of enzymes involved in the biosynthesis of phenolic compounds. On the other hand, our results showed an enhancement of reducing power and the radical scavenging activity as assessed using the DPPH assay with increasing stress severity. Finally, the evaluation of the chelating capacity of the extracts was found to be altered significantly under severe treatment by 39.71%. Based on these results, it seems that drought tolerance of S. officinalis is related to the capacity of the plant to modulate its phenolics in order to face to oxidative stress caused by water limiting conditions.

Essential oils and fatty acids composition of Tunisian and Indian cumin (Cuminum cyminum L.) seeds: a comparative study

BACKGROUND Cumin (Cuminum cyminum L.) seeds of two geographic origins, Tunisia (TCS) and India (ICS), were studied regarding their fatty acid and essential oil composition. RESULTS Oil yields were 17.77 and 15.40% for TCS and ICS respectively. Petroselinic acid (C18:1n-12) was the major fatty acid in both varieties, with a higher proportion being found in TCS (55.90% of total fatty acids (TFA)) than in ICS (41.42% TFA). Moreover, the most predominant fatty acids were palmitic, petroselenic and linoleic acids, accounting for more than 91% TFA in both varieties. The unsaturated fatty acid content was high: 70.95% TFA in TCS and 62.17% TFA in ICS. Essential oil yields differed significantly (P < 0.05) between the two varieties: 1.21 and 1.62% for ICS and TCS respectively. A total of 40 compounds were identified, 34 of which were present in both essential oils. The two varieties displayed different chemotypes: γ-terpinene/1-phenyl-1,2-ethanediol for TCS and cuminaldheyde/γ-terpinene for ICS. CONCLUSION The study revealed that the biochemical composition of cumin seeds is origin-dependent and that cumin seeds are rich in an unusual fatty acid, petroselinic acid. Besides, cumin essential oil is a rich source of many compounds, including cuminaldehyde and γ-terpinene. The overall results suggest the exploitation of cumin seeds as a low-cost renewable source for industrial processing in the fields of cosmetics, perfumes and pharmaceuticals.

Anti-candida effect of bacillomycin D-like lipopeptides from Bacillus subtilis B38.

Bacillus subtilis B38, isolated from soil, showed antimicrobial activity against human pathogenic Candida albicans species. Specific PCR primers revealed the presence of the bamC gene, which is involved in the biosynthesis of bacillomycin D. Three anti-Candida compounds designated a(1) , a(2) and a(3) were purified from culture supernatant and identified using matrix-assisted laser desorption/ionization time-of-flight MS as analogues of bacillomycin D-like lipopeptides of 14, 15 and 16 carbon fatty acid long chains, respectively. The compound a(3) displayed the strongest fungicidal activity against pathogenic C. albicans strains. It was even more active than amphotericin B with a lethal concentration of 59.07 vs. 135.26 μM of the antimycotic drug against the pathogenic strain C. albicans sp. 311 isolated from finger nail. Only moderate or weak anti-Candida activity was recorded for a(1) and a(2) compounds. Furthermore, a(3) showed the highest hemolytic activity, reaching 50% hemolysis at 22.14 μM, whereas a(1) and a(2) displayed a limited hemolysis at 68.26 and 37.41 μM, respectively. These findings suggest that the acyl chain length of bacillomycin D-like lipopeptides plays a major role in hemolytic and antifungal activities.

Variation in Phenolic Composition and Antioxidant Activity during Flower Development of Safflower (Carthamus tinctorius L.)

This work was aimed to study the effect of extraction solvent system with varying polarities on polyphenol, flavonoid and proanthocyanidin contents and DPPH scavenging activity. Obtained results showed that phenolic contents and antioxidant activities varied considerably as function of solvent polarity. The extraction with acetone/water (2:8) showed the highest flower polyphenol content (15.09 mg GAE/g DW). Moreover, antiradical capacities against DPPH, chelating power and lipid peroxidation assay were maximal in acetone/water (2:8) of flower extract. Significant variation in antioxidant properties was observed between different development stages of Carthamus tinctorius flowers; the highest antioxidant activity was observed at stage III (full flowering) while phenolic composition reached its maximum at stage II (flower formation). Gallic acid was the most abundant phenolic compound in C. tinctorius orange flowers, accounting for about 102.57 (μg/g DW). Findings underline the potential health benefits as a result of consuming C. tinctorius flowers and suggest that it could be used as valuable flavor with functional properties for food or nutraceutical products on the basis of the high polyphenol contents and antioxidant activities.

Water-deficit impact on fatty acid and essential oil composition and antioxidant activities of cumin (Cuminum cyminum L.) aerial parts.

This study is designed to examine the effect of water deficit on growth, fatty acid and essential oil composition, and antioxidant activities of Cuminum cyminum aerial part extracts. Plants were treated with different levels of water deficit: control (C), moderate water deficit (MWD), and severe water deficit (SWD). Plant growth (height, fresh and dry matter weights) as well as yield components were significantly increased under moderate water deficit and conversely reduced at severe level. Total fatty acid content decreased significantly with severity of constraint. Drought reduced considerably the proportions of major fatty acids and the unsaturated to saturated fatty acid ratio. The essential oil yield was 0.14% (based on the dry weight); it increased by 2.21-fold at MWD but decreased by 42.8% under SWD in comparison to the control. Drought results in the modification of the essential oil chemotype from 1-phenyl-1-butanol to 1-phenyl-1,2-ethanediol. Antioxidant activities of the acetone extracts were determined by two complementary test systems, namely, DPPH and β-carotene/linoleic acid. The highest activity was exhibited by moderately stressed plants and was reduced significantly under SWD. In control plants, the total phenolic amount was 10.23 mg GAE/g DW, which increased by 1.5-fold under MWD and decreased by 42% under SWD.

Chemical Composition and Antioxidant and Antimicrobial Activities of Wormwood (Artemisia absinthium L.) Essential Oils and Phenolics

The aim of this study was to determine the chemical variability of wormwood extracts as affected by the growing region. Antioxidant and antimicrobial activities were also investigated. The essential oil composition variability of A. absinthium L. aerial parts collected from four different Tunisian regions was assessed by gas chromatography (GC/FID) and by gas chromatography mass spectrometry (GC/MS). In addition, total polyphenols, flavonoids, and condensed tannins as well as antioxidant, antibacterial, and antifungal activities of methanolic extract and essential oils were undertaken. Chromatographic analysis of wormwood essential oils showed the predominance of monoterpene hydrocarbons represented mainly by chamazulene. RP-HPLC analysis of wormwood methanolic extract revealed the predominance of phenolic acids. Antiradical activity was region-dependant and the methanolic extract of Bou Salem region has the strongest activity ( µg/mL). Concerning the reducing power, the methanolic extract of Bou Salem, Jerissa, and Boukornine regions was more active than the positive control. Obtained results of antimicrobial activities showed that wormwood essential oil is endowed with important antibacterial activity which was strongly related to the organoleptic quality of oil which appeared strongly region-dependant. A. absinthium L. EOs investigated are quite interesting from a pharmaceutical standpoint because of their biological activities.

Essential Oil Composition of Lavandula dentata, L. stoechas and L. multifida Cultivated in Tunisia

Abstract The chemical composition of the essential oils of dried aerial parts of Lavandula dentata L. stoechas and L. multifida were analyzed by GC and GC-MS. A total of 52 compounds were identified representing 89.62 ± 9.56, 99.94 ± 9.88 and 98.21 ± 10.23 in Lavandula dentata L. stoechas and L. multifida oil, respectively. Essential oil yield varied significantly (P < 0.05) among the three studied Lavandula species and there were (1.96 ± 0.22 %), (1.62 ± 0.15 %) and (1.04 ± 0.11 %) on dry weight basis in L. dentata, L. multifida and L. stoechas, respectively. Essential oil extracted from aerial parts of L. dentata was dominated by linalool (47.30 ± 5.34 %), linalyl acetate (28.65 ± 3.26 %), bicyclogermacrene (3.40 ± 0.41 %), camphor (2.32 ± 0.28 %) and δ-terpineol (1.47 ± 0.16 %). Linalyl acetate (64.30 ± 7.55 %), linalool (20.25 ± 3.21 %) and β-thujone (8.97 ± 0.99 %) were the predominant compounds in L. stoechas essential oil. L. multifida oil was characterized by the predominance of linalool (50.05 ± 6.52 %), camphene (10.06 ± 1.21 %), linalyl acetate (7.30 ± 0.65 %), α-thujene (3.83 ± 0.41 %), bornyl acetate (3.03 ± 0.41 %), β-caryophellene (2.13 ± 0.25 %), nerol (2.01 ± 0.22 %) and terpinolene (2.05 ± 0.23 %). This finding indicates that Lavender was rich in natural component which could be used as a source of natural antioxidants.

Essential oil and aroma composition of leaves, stalks and roots of celery (Apium graveolens var. dulce) from Tunisia

Volatiles of leaves, stalks and roots of Tunisian celery (Apium graveolens var. dulce) were extracted either by hydrodistillation or by maceration in organic solvents. After concentration, essential oils and aroma extracts were studied by gas chromatography (GC) and GC–mass spectrometry (GC–MS). A high proportion of essential oils and aroma extracts consisted of phthalides with 74.6–76.6% in leaves, 56.8–74.1% in stalks and 57.7–79.7% in roots. The studied organs were particularly characterized by appreciable levels of terpene hydrocarbons (17.0–31.5%). Also, results showed that stalks were particularly rich in phenols with 8.7% of total volatiles. The main volatile constituents identified in the different extracts were (Z)-3-butylidenephthalide (27.8–38.4% in leaves, 30.5–38.9% in stalks, 30.5–52.0% in roots), 3-butyl-4,5-dihydrophthalide (34.2–41.0% in leaves, 24.1–27.8% in stalks, 12.3–13.2% in roots) and α-thujene (7.9–9.9% in leaves, 7.5–14.0% in stalks, 7.0–12.4% in roots). The three studied organs of A. graveolens (leaves, stalks and roots) could be considered good sources of phthalides known for their anti-inflammatory, anti-tumor and insecticidal properties. Nevertheless, the efficiency in the extraction of these bioactive compounds depends on both the organ and the method used.

Evaluation of antifungal activity from Bacillus strains against Rhizoctonia solani

In this study, 30 bacterial strains isolated from marine biofilms were screened for their antifungal activity against Rhizoctonia solani by dual culture assay. Two bacterial strains, Bacillus subtilis and Bacillus cereus , showed a clear antagonism against R. solani on potato dextrose agar (PDA) medium. The antagonistic activity of B. subtilis against this pathogen persisted after one month of co-culture. An in vitro antagonistic assay using potato tuber slices was set up allowing both the screening of bacteria for their biocontrol proprieties and for their rotting effect on plant tissues. Potato tuber slices treated with B. cereus showed a heavy tissues rotting, probably due to the secretion of several enzymes. Whereas, B. subtilis did not show any tissues rotting on treated potato tuber slices. In addition, the potato tuber slices treated with B. subtilis and subsequently inoculated with R. solani agar culture showed a reduced fungal infection in comparison to the control tuber slices inoculated with the pathogen only. The crude extract of B. subtilis strain culture in Luria-Bertani (LB) medium at 48 h of incubation showed a high antifungal activity against R. solani growth and no cytotoxic effect on Brine shrimp larvae. Key words: Antagonism, Bacillus spp., biological control, black scurf of potato, marine biofilms.