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العنوان
Taxonomic Studies on Family Lauraceae and Its Antibacterial Effect /
المؤلف
Hamad, Wafa Ahmed Mahmoud.
هيئة الاعداد
باحث / وفاء احمد محمود حمد
مشرف / مجدي مـحـمـد مراد
مشرف / ايناس حامد الشطوري
مشرف / الصفا حسن محمد
تاريخ النشر
2017.
عدد الصفحات
312 p. :
اللغة
الإنجليزية
الدرجة
الدكتوراه
التخصص
علوم النبات
تاريخ الإجازة
1/1/2017
مكان الإجازة
جامعة عين شمس - كلية العلوم - علوم النبات
الفهرس
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Abstract

Taxonomic relationships among eight taxa of Lauraceae representing three tribes, four genera and seven species have been studied on the basis of information derived from macro- micromorphological and molecular characters as well as extracted chemical compounds of essential oils and its antibacterial effect.
The highlights of the current study can be summarized as follows:
I. Macro-micromorphological characteristics
The most obvious variation of macromorphological characters are:
A. Leaf shape elliptic in Apollonias barbujana and Laurus nobilis, oblong ovate in Cinnamomum glanduliferum, or ovate in the rest of the studied taxa. Leaf apex, acuminate in Cinnamomum camphora and Cinnamomum glanduliferum, or acute in the rest of the studied taxa. Leaf base was, concave in Cinnamomum verum, straight in Apollonias barbujana, Cinnamomum glanduliferum and Laurus nobilis, or convex in the rest of the studied taxa.
B. The presence of epidermal cells with straight or sinuous anticlinal walls
C. The most diagnostic lamina vein architecture are:

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• Acrodroums superabasal primary vein category in Cinnamomum camphora and C. verum, pinnate in the rest of the studied taxa.
• Brochidromous secondary vein category in C. glanduliferum, weak brochidromous in C. verum and festooned brochidromous in the rest of the studied taxa.
• Dichotomizing fifth vein category was found in persea americana var. americana where those of the rest of the studied taxa are regular polygonal reticulate as well as the freely ending ultimate veins of leaf which was unbranched in all taxa except p. americana var. americana was recorded two or more branched.
II. Micromorphological characteristics
The most distinctive features are:
A. Outline of petiole: In basal part five outline features were recorded viz. half- circular (in L. azorica), heart (in L. nobilis), cresentiform (in Persea americana var. americana), arc shape in (in P. americana var. drymifola) or terete in the rest of the studied taxa. In middle part four outline features were scored viz. terete (in P. americana var. drymifola), cresentiform (in C. glanduliferum), shallow cresentiform (in C. camphora and C. verum) or half circular in the rest of the studied taxa. .In the top part four outline features were showed viz. winged (in A.
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barbujana), half-circular (in L. azorica), cresentiform (in
C. verum and L. nobilis) or shallow cresentiform in the rest of the studied taxa.
B. Occurrence of secretory cells of phloem: In basal part, present in C. camphora only. In middle part, present in both C. camphora and C. glanduliferum. While in top part, present in the three species of Cinnamomum.
C. Hypodermis detected in L. azorica, L. nobilis and two varieties of P. americana or wanting in the rest of studied taxa. Trichomes are abaxially eglandular unicellular in two varieties of P. americana or absent in the rest taxa.
D. Palisade extended at mid rib region in two varieties of P. americana or absent of the rest taxa.
E. The existence of secretory cells are obviously different in their distribution density among the species in lauraceae. Secretory cells are solitary, isolated or bigger than the adjacent cells and are present in all taxa in wing region. The highest number were recorded in A. barbujana, L. azorica and L. nobilis, while the lowest number are scored by the rest of taxa. Concerning the midrib region, only A. barbujana detected the presence of secretory cells. Regarding the phloem tissues, secretory cells scored in L. azorica and L.nobilis, and absent in phloem of the rest of taxa.
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F. The dendrogram utilizing 118 macro& micro- morphological character states showed groping of Persea americana var. americana and P. american var. drymifoliain series I . While series II contain the rest of taxa which involved in two clusters one of them contains Laurus azorica, L. nobilis and Apollonia barbujana. While the other contains all Cinnamomum spp. This result is in agreement with (Kostermans, 1957) who allocated taxonomic position of Cinnamomum spp. in tribe Cinnamomeae and Laurus spp. in tribe Litseeae.
II. Molecular studies
A. ISSR-PCR analysis was used to eight species; utilizing 13 primers were as follows:
• Total number of bands was 209 bands, which 165 were polymorphic.
• The number of 23 out of 209 was scored as specific markers.
• The largest number of markers was generated by primer ISSR7 (6markers) while lowest number of markers was generated by primers ISSR9 and ISSR10 (1marker each).
B. The dendrogram constructed based on 165 molecular data showed distribution of Cinnamomum spp. on several groups
and close similarity between C. camphora &C. glanduliferum.
This claim is also supported Kamel and Loutfy (2001). Cluster
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analysis showed the close relationships between the two varieties of Persea americana, and also nearby relationships between the two species of Laurus. This is in harmony with Kamel and Loutfy (2001).
III. Combined data based on morphological and molecular characters
The collective dendograms showed the close relationships between the two varieties of Persea americana and the two species of Laurus. Also the collective dendogram grouped Cinnamomum spp. together while the most current system distribute them in different groups and reject it as homogenous genus
IV. Chemical compounds of essential oils and its antibacterial activity.
The essential oils were extracted from the plants under investigation by the Clevenger apparatus. The chemical compounds were identified by GC-MS and their antibacterial effect was studied using the Minimum Inhibitory Concentration (MIC).
• The detected compounds of essential oils of the studied eight taxa ranged from 41to 65compounds.
• In laurel leaf of the studied taxa, six major compounds were common in all the studied taxa viz. butyl acetate; α-
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pinene; β-pinene; toluene; norbornane or cyclopentane ethyl.
• The laurel essential oils of the studied taxa were capable of inhibiting the growth of tested pathogenic bacteria viz. Streptococcus pneumoniae, Staphylococcus aureus (two strains), Escherichia coli and Klebsiella pneumoniae.
• Pseudomonas aeruginosa was resistant to essential oil of the studied taxa.
• The essential oils of the two varieties of Persea americana
inhibit only Klebsiella pneumoniae and Escherichia coli.
• The highest antibacterial activity of essential oils was achieved by Cinnamomum glanduliferum followed by C. verum, Laurus azorica, Apollonias barbujana, L. nobilis and C. camphora, while the lowest activity was recorded by the two varieties of Persea americana.
• The presence of oxygenated and non-oxygenated monoterpenes especially Cineole responsible for the antibacterial activity of essential oils except Apollonias barbujana it activity is due to α-phellandrene rather than cineole.
In general, the antibacterial effect is in agreement with that of the combined analysis and also in accordance with the dendrogram based on macro-micromorphological characters. Both suggest that the genus Cinnamomum is better include
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together (have potency activity against the five tested bacteria). The close relationship between the two varieties of Persea americana (they have antibacterial activity against only two bacteria K. pneumoniae and E. coli) and the two species of Laurus (mild antibacterial activity against the five tested bacteria).