Comics

Biomolecular Characterization of Wild Sicilian Oregano: Phytochemical Screening of Essential Oils and Extracts, and Evaluation of Their Antioxidant Activities

Description
Biomolecular Characterization of Wild Sicilian Oregano: Phytochemical Screening of Essential Oils and Extracts, and Evaluation of Their Antioxidant Activities
Categories
Published
of 23
All materials on our website are shared by users. If you have any questions about copyright issues, please report us to resolve them. We are always happy to assist you.
Related Documents
Share
Transcript
  Biomolecular Characterization of Wild Sicilian Oregano: PhytochemicalScreening of Essential Oils and Extracts, and Evaluation of Their AntioxidantActivities by  Teresa Tuttolomondo a ),  Salvatore La Bella a ),  Mario Licata a ),  Giuseppe Virga a ),  Claudio Leto b ), Antonella Saija c ),  Domenico Trombetta c ),  Antonio Tomaino c ),  Antonio Speciale c ), Edoardo M. Napoli d ),  Laura Siracusa d ),  Andrea Pasquale d ),  Giusy Curcuruto d ), and Giuseppe Ruberto* d ) a ) Dipartimento dei Sistemi Agro-Ambientali (SAGA), Universita ` di Palermo, Viale delle Scienze 13,I-90128 Palermo b ) Co.Ri.S.S.I.A. Consorzio di Ricerca per lo Sviluppo di Sistemi Innovativi Agroambientali,Via Liberta ` 203, I-90100 Palermo c ) Dipartimento Farmaco-Biologico, Universita ` di Messina, Contrada Annunziata, I-98128 Messina d ) Istituto del C.N.R. di Chimica Biomolecolare, Via Paolo Gaifami 18, I-95126 Catania(phone:  þ 39-0957338347; fax:  þ 39-0957338310; e-mail: giuseppe.ruberto@icb.cnr.it)An extensive survey of wild Sicilian oregano was made. A total of 57 samples were collected fromvarious sites, followed by taxonomic characterization from an agronomic perspective. Based onmorphological and production characteristics obtained from the 57 samples, cluster analysis was used todivide the samples into homogeneous groups, to identify the best biotypes. All samples were analyzed fortheir phytochemical content, applying a cascade-extraction protocol and hydrodistillation, to obtain thenon volatile components and the essential oils, respectively. The extracts contained thirteen polyphenolderivatives,  i.e ., four flavanones, seven flavones, and two organic acids. Their qualitative and quantitativecharacterization was carried out by LC/MS analyses. The essential oils were characterized using acombination of GC-FID and GC/MS analyses; a total of 81 components were identified. The majorcomponents of the oils were thymol,  p -cymene, and  g -terpinene. Cluster analysis was carried out on bothphytochemical profilesand resultedin the division ofthe oregano samples into differentchemical groups.The antioxidant activity of the essential oils and extracts was investigated by the  Folin  Ciocalteau  (FC)colorimetric assay, by UV radiation-induced peroxidation in liposomal membranes (UV-IP test), and bydetermining the O .  2  -scavenging activity. 1. Introduction.  – Plants produce a wide and diverse range of organic compounds,which are not directly involved in the growth and development of the plant, butperform vital ecological functions, such as the creation of protective barriers againstherbivores and microbial infections, the attraction of pollinators, the production of allelopathic substances affecting competition from other organisms,  etc . [1–3]. Thesecompounds, known as secondary metabolites, are recognized for their numerousbiological properties, which are used in a range of industrial and pharmaceuticalapplications [4–11].A further powerful tool offered by the study of secondary metabolite pathways istheir use in establishing the quality and typicalness of a living organism. Environ-mental factors often influence these pathways (a typical example of this might be seenin the chemical profile of an essential oil), and, for this reason, profiling often allows us CHEMISTRY & BIODIVERSITY – Vol. 10 (2013) 411  2013 Verlag Helvetica Chimica Acta AG, Zrich  to acquire precious information on the srcin and the intrinsic typicalness of a plantand a food.In the Mediterranean basin, the Lamiaceae family assumes a role of particularinterest [12][13] as oregano is one of the most commonly used species in the area. Dueto variations in the chemical and aroma composition, oregano has a wide range of uses,not only as a culinary herb and as flavoring in food products and alcoholic beverages[14][15], but also as an antibacterial, antioxidant, antithrombin, and antihyperglycae-mic agent [16–19], due to its pharmacological properties.There has been an ongoing interest in the study of   Origanum  species, mainlydirected at the essential-oil composition and as a potential source of antimicrobial andantioxidant natural agents. As a consequence of considerable research in this area andtaking the main compounds into consideration,  Origanum  taxa can be divided in threegroups:  i ) a linalool, terpinen-4-ol, and sabinene hydrate group ( Group A ),  ii ) acarvacrol and/or thymol group ( Group B ), and  iii ) a sesquiterpene group ( Group C  )[20]. Much less attention has been given to phytochemical studies on the non-volatilecomponents of this genus, although recent studies have shown that different classes of polyphenols constituted the most common non-volatile compounds in the genus Origanum  [21][22].The aim of this study was to provide a systematic analysis of the phenotypicvariability of oregano plants within a large population of biotypes, collected fromvarious sites in Sicily, focusing on biomorphological characteristics, production, andqualitative chemical evaluation, in order to identify those biotypes best suited for thelocal development. Given its central position in the Mediterranean region and its vastplant heritage, the island of Sicily is ideally placed for a planned resource developmentof this kind. Furthermore, this study and its results contribute to generating interest inthe biodiversity of the Mediterranean area, in which Sicily plays a crucial role. On thebasis of the abovementioned considerations, the cultivation and technologicalutilization of medicinal plants are emerging as a profitable alternative income in thecrop-production sector. 2. Results and Discussion.  – 2.1.  Agronomic Characteristics.  Research on wildoregano populations carried out over a number of sites in Sicily led to the collection of 57 biotypes. These were found mainly in hilly and mountainous areas and on slopingland that was mostly limestone, rich in rock particles, and with low production potential( Table 1 ).Cluster analysis based on morphological characteristics and biomass production of all 57 biotypes resulted in their division into four main groups, as reported in  Table 2 ,showing the average and the coefficient of variability for each characteristic analyzed.These values are only descriptive and seek merely to better illustrate the morphologicaland production characteristics of the biotypes as grouped by the analysis.The first cluster ( Group 1 ) consisted of 38 biotypes, the second ( Group 2 ) of 5, thethird ( Group 3 ) of 13, and the fourth ( Group 4 ) of only 1 biotype. This latter biotype( Sample 50 ), found in the province of Ragusa, exhibited the highest biomass-production levels, making it of particular interest for further study.The first agronomic cluster contained the largest number of samples (38), all of which demonstrated relatively good bioproduction characteristics in addition to good CHEMISTRY & BIODIVERSITY – Vol. 10 (2013)412  average essential-oil yields (4.2% ( v / w )). Biotypes belonging to the second cluster (fivesamples) were characterized by a high productivity, making them of particular interestfor biomass-production purposes. It is worth noting that these biotypes, in addition tohaving a high average plant weight, showed higher average flower-stratum values andaverage inflorescence weights, making them particularly suited for the production of essential oils – an aspect, which is confirmed by the higher essential-oil yield (averagevalue of 4.8%). The third cluster, containing 13 biotypes, showed the lowest values foreach agronomic characteristic examined, in addition to a lower average value of essential-oil yield (3.7%). The highest biomass-production levels ( Table 2 ) were foundin the fourth cluster, represented by a single sample ( Sample 50 ), however, theessential-oil yield of this sample was not found to be particularly high (2.3%).Considering the effects that climatic factors have on the vegetative and productioncycle of plants, an analysis of the location of the collection sites in relation to biotype CHEMISTRY & BIODIVERSITY – Vol. 10 (2013) 413 Table 1.  Location  (Province)  and Altitude of the Collection Sites of the 57 Sicilian Oregano SamplesSample  Province a ) Altitude [m.a.s.l.]  Sample  Province a ) Altitude [m.a.s.l.] 01  RG 210  31  PA 605 02  AG 356  32  CL 546 03  AG 511  33  CL 542 04  ME 502  34  PA 612 05  PA 610  35  PA 115 06  TP 705  36  CL 596 07   PA 796  37   TP 398 08  PA 498  38  CL 547 09  PA 589  39  PA 694 10  PA 823  40  AG 748 11  PA 711  41  PA 792 12  ME 601  42  PA 935 13  CL 535  43  CL 548 14  PA 758  44  CL 551 15  CL 547  45  CL 559 16  CL 565  46  PA 847 17   CL 598  47   CL 559 18  CL 587  48  ME 67 19  PA 591  49  PA 798  20  PA 815  50  RG 597  21  PA 804  51  PA 647  22  PA 698  52  RG 394  23  CL 689  53  PA 386  24  PA 794  54  CL 568  25  PA 789  55  PA 661  26  CL 598  56  PA 962  27   CL 587  57   AG 289  28  CL 598  29  CL 579  Range 67–962  30  PA 698  Average 601 a ) Abbreviations of the provinces of srcin: AG ¼ Agrigento, CL ¼ Caltanissetta, ME ¼ Messina, PA ¼ Palermo, RG ¼ Ragusa, TP ¼ Trapani.  behavior is of particular interest. With this in mind, an evaluation of the relationshipbetween the altitude and the dry-biomass production was carried out on each of thebiotypes in the cluster-analysis groups ( Table 2 ).  Fig. 1  shows the results of thisanalysis: the most productive group ( Group 2 ) contained biotypes collected at altitudesranging between 210 and 698 m.a.s.l, whereas the least productive group ( Group 3 )included biotypes collected at higher altitudes (502–962 m.a.s.l). The first group,characterized by intermediate production values, consisted of biotypes found along theentire altitude range of the study (67–935 m.a.s.l.). These results show that the biomassproduction of the biotypes tended to improve as we moved from the higher altitudes tolower ones. Fig. 1.  Relationship between altitude and biomass production of the 57 samples of wild oregano  (groupdivision from  Table 2 ) CHEMISTRY & BIODIVERSITY – Vol. 10 (2013)414 Table 2.  Morphological and Biomass-Production Characteristics of the Four Groups of Sicilian OreganoSamples Obtained by Cluster Analysis Based on these Characteristics Characteristic  Group 1  ( n ¼ 38) a )  Group 2  ( n ¼ 5)  Group 3  ( n ¼ 13)  Group 4  ( n ¼ 1)Plant height [cm] 51.2 (13.5%) b ) 60.7 (9.5%) 50.0 (12.2%) 52.6Flower stratum height [cm] 14.3 (14.0%) 16.8 (10.6%) 14.2 (13.2%) 12.5Fresh weight [g] 1226.1 (13.7%) 1657.3 (4.2%) 690.4 (19.0%) 2204.5Dry weight [g] 471.5 (14.4%) 685.3 (9.6%) 302.3 (31.3%) 905.9Stems/plant 400.1 (37.6%) 494.9 (38.9%) 248.0 (24.6%) 598.3Branches/plant 283.8 (13.5%) 319.7 (13.2%) 255.2 (7.0%) 212.3Inflorescences [g] 118.8 (21.9%) 151.2 (28.5%) 78.0 (31.1%) 200.5Leaves [g] 114.7 (20.9%) 137.2 (14.6%) 68.7 (15.7%) 205.2Stems [g] 238.0 (17.6%) 396.9 (12.9%) 155.7 (49.9%) 500.2 a ) Composition of the Groups:  Group 1 ,  Samples 05–10 ,  13 ,  15 ,  16 ,  18 ,  19 ,  21 ,  23 ,  24 ,  26 ,  28–30 ,  32 ,  34– 38 ,  41–46 ,  48 ,  49 ,  51–55 , and  57  ;  Group 2 ,  Samples 01–03 ,  12 , and  22 ;  Group 3 ,  Samples 04 ,  11 ,  14 ,  17  ,  20 ,  25 ,  27  ,  31 ,  33 ,  39 ,  40 ,  47  , and  56 ;  Group 4 ,  Sample 50 .  b ) Results are given as average values withcoefficients of variation in parentheses.  However, it is important to note that the production parameters, such as biomassand essential-oil accumulation, are the results of not only the genetic characteristics of the species, but also of a combination of different abiotic factors, which can vary even ingeographically close areas. This might explain why biotypes collected from neighboringor the same geographical areas were attributed to different groups; an observation,which is magnified in Sicily by the complex morphology and varying soil and climateconditions found throughout the island.2.2.  Phytochemical Profiles.  2.2.1.  Essential-Oil Composition. Table 3  lists the yieldof essential oil (obtained by hydrodistillation) and the number of oil componentsidentified in 51 of the 57 samples included in this study. For six samples, the isolation of essential oil was not possible, because of insufficient plant material. The essential-oil CHEMISTRY & BIODIVERSITY – Vol. 10 (2013) 415 Table 3.  Yield and Number of Components of the Essential Oils and Yields of the AcOEt and EtOH Extracts of the Sicilian Oregano SamplesSample  Essential oil Yield of extracts [%] a )  Sample  Essential oil Yield of extracts [%] a )Yield [%] b )  N  c ) AcOEt EtOH Yield [%] b )  N  c ) AcOEt EtOH 01  4.1 52 3.77 10.57  30  n.a. d ) n.a. 2.37 12.47 02  5.8 52 3.37 6.93  31  2.7 47 1.77 8.40 03  5.4 52 2.63 6.83  32  4.6 38 2.00 9.73 04  3.0 51 3.07 7.90  33  4.2 51 2.78 7.53 05  5.2 52 4.17 9.23  34  2.7 46 3.30 6.50 06  6.4 53 3.33 8.53  35  4.6 47 3.60 11.77 07   2.8 51 2.87 5.73  36  4.0 50 1.80 5.47 08  5.1 51 2.47 7.03  37   2.4 46 3.27 11.67 09  3.6 50 2.93 5.47  38  4.5 41 1.87 5.60 10  5.4 52 3.17 6.73  39  3.3 44 2.03 9.80 11  4.2 50 2.63 10.07  40  n.a. n.a. 3.53 7.93 12  3.3 43 1.87 6.23  41  n.a. n.a. 3.03 7.53 13  5.6 47 3.20 8.90  42  2.4 44 3.03 6.77 14  2.7 48 3.70 12.07  43  3.4 42 2.37 9.13 15  3.7 44 2.30 8.33  44  n.a. n.a. 4.40 11.03 16  5.9 43 2.77 6.50  45  4.5 52 3.10 5.20 17   5.6 47 2.73 11.00  46  4.0 47 3.23 12.23 18  3.5 41 2.97 7.97  47   2.2 51 2.40 12.47 19  4.0 44 2.13 8.83  48  3.9 50 3.50 11.50  20  4.0 48 3.13 10.37  49  4.7 47 3.37 11.57  21  4.5 54 3.67 8.93  50  2.3 49 4.40 7.93  22  5.6 39 2.43 10.43  51  3.2 45 3.07 13.83  23  5.6 39 3.73 10.50  52  3.1 44 5.90 11.30  24  2.8 47 3.07 8.30  53  6.2 34 3.87 16.43  25  4.9 46 2.40 7.80  54  4.0 43 2.37 5.03  26  4.1 45 4.37 8.07  55  6.6 39 4.23 9.83  27   3.6 51 3.20 6.20  56  n.a. n.a. 3.13 6.23  28  4.4 44 2.63 8.10  57   n.a. n.a. 2.57 10.17  29  1.8 47 2.67 13.20  Average 4.1 47 3.05 8.98 a ) The extract yields are given as percentage ( w / w ) based on the dry weight.  b ) The essential oil yields aregiven as percentage ( v / w ).  c )  N:  Number of essential oil components identified.  d ) n.a.: Not available(insufficient plant material).
Search
Related Search
We Need Your Support
Thank you for visiting our website and your interest in our free products and services. We are nonprofit website to share and download documents. To the running of this website, we need your help to support us.

Thanks to everyone for your continued support.

No, Thanks
SAVE OUR EARTH

We need your sign to support Project to invent "SMART AND CONTROLLABLE REFLECTIVE BALLOONS" to cover the Sun and Save Our Earth.

More details...

Sign Now!

We are very appreciated for your Prompt Action!

x