Comparison of antioxidant and antimicrobial activities of two cultivated Cistus species from Tunisia

Hela Mahmoudi,Margaret Gruber,Nesrine Ben Hamida,Chedia Aouadhi,Rym Kaddour,Karim Hosni,Mouhiba Ben Nasri,Wafa Zaouali,Hanene Zargouni,Zeineb Ouerghi

doi:10.14393/bj-v32n1a2016-30208

Abstract

The secondary metabolite composition, antioxidant activities, and microbial inhibition properties of leaves of two Cistus species ; C. monspeliensis and C. salvifolius were investigated using three solvent extracts (ethanol, hexane and distilled water). Ethanol extracts were most efficient at extracting phenolics, flavonoids and condensed tannins compared to hexane and distilled water for both Cistus species. A total antioxidant test (TAA) and two radical scavenging tests (DPPH and ABTS) indicated that the 70% ethanolic extract from C. salvifolius leaves had stronger antioxidant activity compared to the C. monspeliensis 70% ethanol extract, while the aqueous extract of C. monspeliensis was much stronger than the aqueous extract or the 70% ethanol extract of C. salvifolius . Overall, the polar extracts were more active in both species than the non-polar extracts. Thus aqueous ethanol extracts of the leaves of each Cistus species were tested for their ability to inhibit seven pathogenic microbial strains, including Escherichia coli ATCC 8739, Salmonella typhimurium NCTC 6017, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 29213, Enterococcus faecalis , Aspergillus niger , and Candida albicans . Leaf ethanol extracts from both species were active against each microbial species, but the C. monspeliensis leaf ethanolic extract was much more active against several microbial species than that of C. salvifolius. For example, the C. salvifolius 70% ethanol extract showed its highest antimicrobial activity against P. aeruginosa and A. niger (MIC 3.1 mg/ml and MBC 6.3 mg/ml for both), while the C. monspeliensis extract showed much higher overall activity against E. coli , P. aeruginosa and C. albicana. (MIC 6.25 mg/ml and MBC 12.5 mg/ml for all three). In conclusion, maceration with 70% ethanol was the most efficient method for extracting total polyphenols, flavonoids, and condensed tannins from the two Cistus species, and the aqueous-ethanol extracts displayed the highest antioxidant and antimicrobial activities. Hence, the aqueous-ethanolic extracts of both species may be considered as potential sources of natural antioxidants and antimicrobial agents.

Highlights

The Cistaceae family includes the genus Cistus, which comprises about 20 shrub species found broadly throughout the entire Mediterranean region (COMANDINI et al, 2006, TOMAS-MENOR et al, 2013) In Mediterranean folk medicine, Cistus species have been used as general remedies (BARRAJÓNCATALÁN et al, 2010) and for their antiinflammatory (DEMETZOS et al, 2001), antiulcerogenic, wound healing, anti-microbial (DEMETZOS et al.,1999), antifungal (BAYOUB et al, 2010), antiviral, anti-tumor (DIMAS et al, 2000), cytotoxic (BEN JEMIA et al, 2013) and antinociceptive (BARRAJÓN-CATALÁN et al, 2010)properties
We report on the effectiveness of three different solvents in the extraction of antioxidant activity, secondary metabolite levels, and antimicrobial activities from leaves of two Cistus species
The values we obtained for total leaf phenol contents in these two Cistus species were in the concentration range found for C. ladanifer (40-57 mg gallic acid equivalents (GAE)/g dry weight (DW)) and C. libanotis (40-44 mg EGA/g DW) collected in eastern Morocco in May (ZIDANE et al, 2013)

Summary

Introduction

The Cistaceae family (consisting of eight genera and 175 species) includes the genus Cistus, which comprises about 20 shrub species found broadly throughout the entire Mediterranean region (COMANDINI et al, 2006, TOMAS-MENOR et al, 2013) In Mediterranean folk medicine, Cistus species have been used as general remedies (BARRAJÓNCATALÁN et al, 2010) and for their antiinflammatory (DEMETZOS et al, 2001), antiulcerogenic, wound healing, anti-microbial (DEMETZOS et al.,1999), antifungal (BAYOUB et al, 2010), antiviral, anti-tumor (DIMAS et al, 2000), cytotoxic (BEN JEMIA et al, 2013) and antinociceptive (BARRAJÓN-CATALÁN et al, 2010)properties. Tea prepared from C. salvifolius L. herb (AL-KHALIL, 1995) has traditionally been used for the treatment of gout KHALIL, 1995) and ulcers (YESILADA et al, 1999). In Morocco, C. salvifolius has been found to exhibit anti-bacterial activity against Mycobacterium aurum and Mycobacterium smegmatis (HAOUAT et al, 2013). Cistus incanus spp. tauricus contains a specific polyphenol-rich extract (called CYSTUS052) that has demonstrated antiviral activity against influenza A virus infections (EHRHARDT et al, 2007). The antimicrobial activity of many plant species is related to their phenolic compounds (RAUHA et al, 2000), and these types of antioxidant compounds are widely distributed in the plant kingdom and are considered as potential therapeutic. J., Uberlândia, v. 32, n. 1, p. 226-237, Jan./Feb. 2016

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