Mol2Net-04 Assessment of antioxidant and antibacterial properties of - PDF document

Mol2Net-04 , 2018 , BIOCHEMPHYS-01 (pages 1- x, type of paper, doi: xxx-xxxx http://sciforum.net/conference/mol2net-4 SciForum Mol2Net-04 Assessment of antioxidant and antibacterial properties of some Tunisian plants Manel Ben Ali 1, 2 *, Houda Hmani 1, Lobna Daoud 1 , Mouna Jlidi 1, Adel Hadj Brahim 1 , Samir Bejar 1 and Mamdouh Ben Ali 1,2 1 Laboratory of Microbial Biotechnology and Engineering Enzymes (LBMIE), Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour km 6, PO Box 1177 Sfax 3018, Tunisia E-Mails: houda_enis@yahoo.fr (Houda hmani); lobna.daoudm@gmail.com (Lobna daoud); jlidimanno@yahoo.fr (Mouna Jlidi); adelhadjibrahim@gmail.com (Adel Hadj brahim); samir.bejar@cbs.rnrt.tn (Samir Bejar) 2 Astrum Biotech, Business incubator, Center of Biotechnology of Sfax (CBS), University of Sfax, Road of Sidi Mansour km 6, PO Box 1177 Sfax 3018, Tunisia; E-Mail: mamdouh.benali@cbs.rnrt.tn; * Corresponding author: E-Mail: manel.benali@gmail.com Received: / Accepted: / Published: Abstract: This study is a screening of antioxidant and antibacterial activities of a multitude of Tunisian plants extracts. Total phenolic and total flavonoid contents were also determined. Results showed that total phenolic and flavonoid contents of the samples as well as antioxidant activities varied greatly among different plant parts and suggest that many plants are rich in antioxidant compounds. Interest will be taken to promising active plants particularly those which combine antioxidant properties with antimicrobial activities. Keywords: Tunisian plants; total phenolics; flavonoids; antioxidant activity; antibacterial activity 1. Introduction Scientists have focused on plants as sources of food deterioration during storage and processing [3] , many studies have reported their natural antioxidants since they can protect the human body from free radicals. The antioxidant antimicrobial activities and some of them are properties of plant extracts have been attributed classified as Generally Recognized Safe Substances (GRAS) [4] . to their metabolites Particularly polyphenol contents [1, 2] . The objective of this work was to screen a Medicinal plant parts (roots, leaves, number of Tunisian plant extracts by evaluating branches/stems, barks, flowers, and fruits) are their total phenolics and flavonoid contents, commonly rich in phenolic compounds. In antioxidant (free radical-scavenging and ß- addition with the capacity of these compounds to carotene) and antibacterial activities. suppress lipid oxidation, the major factor causing 2. Results and Discussion 2-1. Antioxidant activity by DPPH free radical- 80%. Methanolic extract of Amaranthus hybridus scavenging activity stalks (IP = 19.13%), Citrillus colocynthis fruit Methanol extracts of the studied plants were the (IP = 26.76%) and Chenopodium humile leaves most effective DPPH radical scavengers. Twenty (IP = 33.53%) contained remarkably lower eight of the investigated methanol extracts, amounts of radical scavenging compounds inhibited DPPH absorption with percentages over according to their lower IP values. Ten ethyl

Mol2Net , 2015 , 1( Section A, B, C, etc. ), 1- x, type of paper, doi: xxx-xxxx 2 acetate extracts, which are considerably less into 4 classes: very high (>300 mg GAE/g), medium high (100 – 300 mg GAE/g), medium effective radical scavengers compared to the corresponding methanol extracts, exhibited low (50-100 mg GAE/g ), low (10-50 mg GAE/ inhibition percentages higher than 80%. In g) and very low ( <10 mg GAE/ g). addition, radical scavenging activities of ethyl Most of the extracts showed medium high level acetate extracts of Pelargonium roseum flowers of TPC. The highest amounts were found in the and Salvia officinalis were similar to those of methanolic extracts, especially of S. officinalis methanol extracts of the same plant parts. leaves and flowers (respectively 852.2 mg However, the ethyl acetate extract of C. humile GAE/g and 557.5 mg GAE/g), P. roseum leaves (IP = 62.03%) was more effective than its (891.8 mg GAE/g), R. officinalis leaves (553.5 mg GAE/g) and Artimisia absinthium stalks methanol extract (IP = 26.76%). Ten ethyl acetate extracts and sixteen methanol (588.51 mg GAE/g). extracts have radical scavenging activity with It was noticed that some leaves had higher TPC IC 50 < 100 µg/ml. free radical-scavenging than flowers and stalks of the same species, i.e. activity of methanol S. officinalis leaves extract TPC of leaves methanolic extracts of A. hybridus , Atriplex mollis, C. colocynthis , is the strongest ( IC 50 = 3.34 µg/ml) tested extract followed by methanol extracts of Marribium alysson , Rosmarinus officinalis, S. P. roseum leaves (8.25 µg/ml) and stalks (10.4 officinalis and P. roseum were significantly µg/ml). IC 50 value of methanol extract of higher than their respective flowers and stalks S.officinalis stalks was also noteworthy methanolic extracts. Although TPC of Ocimum basilicum flowers extract was found to be higher (13.04 µg/ml) when compared to the synthetic antioxidant BHT (7.7 µg/ml) used in this study than that of his corresponding leaves. This as positive control. observation is valid for stalks ethyl acetate 2-2. Determination of antioxidant activity by- β - extracts of R. officinalis, S. officinalis carotene bleaching method and P. roseum. Differences in antioxidant In the β -carotene / linoleic acid system oxidation distribution in the leaves, flowers and Stalks of linoleic acid was effectively inhibited by could be explained by the following observations. Siddhuraju and coworkers [5] have overall tested extracts with inhibition percentages values greater than 70%. Consequently, there reported that the production of anthraquinones, was no much difference in the antioxidant xanthones, flavonol and proanthocyanidins in potential of the extracts prepared by increasing of leaves would lead to higher antioxidant activity. Del Bano et al. [6] have found that some solvent polarity. Both extracts, ethyl acetate of Juncus maritimus antioxidative compounds were selectively (92.86%) and methanol of P. roseum stalks biosynthesized by the leaves but the compounds (92.66%), displayed the greatest antioxidative do not exist in flowers. In addition, it has been properties in emulsion, while A.hybridus seeds reported that the amount of total phenolics vary with respect to families and varieties [7,8] . In this demonstrated the lowest activity (9.029%) at plant material. work we calculated the total flavonoid contents Different bleaching rates were demonstrated for in units of mg quercetin equivalent. Existence of the common antioxidants, BHT (84.06%) higher total flavonoid amount was observed in and α -tocopherol (87.27%). When compared to the methanolic extracts prepared the aerial parts both ethyl acetate and methanol extracts, twelve of each species. However, in some cases, the extracts are stronger in linoleic peroxidation ethyl acetate extract of some plant parts exceeded activity than these antioxidants. This result its methanolic extract. The content of flavonoids indicates that compounds with the strongest (mg/g extract) in quercetin equivalents varied antioxidant activity in the β -carotene-linoleate from 1.5 to 184.9 mg Q/g extract. The highest assay system can be of medium or high polarity. amounts of flavonoids were found in methanolic 2-3. Total phenolic and flavonoid contents extracts of A . mollis leaves (166.3), A. mollis The amount of Total phenolic Compounds (TPC) stalks (184.9) and A. Tenuifolius flowers (156.9). of the selected plants, ranged from 12.03 to Lowest amounts are in ethyl acetate extracts of 852.24 mg GAE/g extract, could be categorized Salsola suaeda (1.8) and C. colocynthis (2.1 mg