Syzygium

1
Syzygium

• Riley Hollenbach

2
Overview

• Taxonomy
• Ecology
• History
• Cultivation
• Human Uses
• Biochemistry

3
Taxonomy

• Kingdom Plantae
• Division Magnoliophyta
• Class Magnoliopsida
• Order Myrtales
• Family Myrtacea
• Genus Syzygium

4
Taxonomy

• Many Syzygium species classified under Eugenia
  (Schmid, 1972)
• Differ in floral anatomy
• Multiple synonyms for single species
• Syzygium should be considered a higher taxonomic
  group (Biffin et al, 2006)
• DNA sequencing doesnt support traditional
  generic separations

5
Taxonomy

• S. aromaticum has such problematic nomenclature
• Multiple synonyms
• Common name is the clove tree
• Cloves are the dried, unopened buds
• Clove comes from Latin root clavus, meaning nail

6
Ecology

• Found in subtropical and tropical Old World
  regions
• Mainly Australasia and Indonesia
• Phloem found on both sides of xylem
• Leaves arranged in opposite pattern
• The Greek word syzygios means opposite
• Glabrous
• Oils glands on lower surface

7
Ecology

• Flowers are in parts of 5
• Multiple stamens
• Brightly coloured petals
• Found in terminal clusters of 3 or 4
• Fleshy Fruits
• Commonly eaten out-of-hand
• In form of drupes or berries
• Frugivores disperse seeds

8
Ecology

• S. aromaticum originated in the Moluccas
• Grows between 8-30 meters tall
• Conical shape
• Flowers are bright red
• Emit a strong, penetrating fragrance
• Fruit is referred to as mother of clove

9
History

• Found in ceramic vessels located in Syria 1700 BC
• Chinese have been using cloves since 500 BC
• Subjects required to chew 2 cloves before meeting
  with the Emperor
• Referred to as chicken tongue spice in ancient
  Chinese scripture
• Ancient Romans and Arabs traded cloves 2000 years
  ago

10
History

• Age of Exploration
• Spanish and Portuguese first to visit the Spice
  Islands in the 16th century
• Dutch established a monopoly of the clove trade
  in the 17th century
• Destroyed any clove tree found outside their
  range of control (Amboina and Ternate)
• Native population grew to detest the Dutch

11
History

• French ended Dutch monopoly in 1788
• Smuggled clove trees to islands of Zanzibar and
  Pemba
• Elihu Yale (1649-1721)
• Born in Boston, raised in England
• Traveled to India to become a spice merchant
• Amassed a small fortune which he used to create
  the institute known as Yale University

12
Cultivation

• Propagation through seeds
• Gathered from trees at least 15 years old
• Must produces regular crop yields
• Clove trees grow very slowly
• 7 years to yield fruits
• Another 8-12 years to reach full potential
• Can live up to 100 years old

13
Cultivation

• Harvesting of buds occurs when calyx turns from
  green to red
• Must be picked very carefully by hand
• If branches become damaged, crop yield will be
  affected years after
• Once harvested, unopened buds are laid out to dry
• Done on mats or concrete surface
• Takes 4-5 hours to properly cure
• When done correctly, cloves are brown and crisp

14
Cultivation

• Indonesia is the world largest exporter
• Produces 50-60 thousand tonnes yearly
• Saudi Arabia, U.S., and India are largest
  importers
• Pests and diseases
• Sudden Death (Valsa eugeniae)
• Stem Borer (Sahydrassus malabaricus)
• Leaf Rot (Cylindrocladium quinquiseptatum)

15
Human Uses

• Spice in culinary arts
• Spicy yet sweet taste
• Used extensively in Indian and Chinese cuisine
• Not as popular in Europe or North America
• Folk medicine
• Fungal and bacterial infections
• Digestive ailments
• Parasites

16
Human Uses

• Early American Eclectic physicians first to
  extract essential oil from cloves
• Clove oil used in dentistry to treat gum and
  toothaches
• Disinfectant when performing oral surgery
• Antioxidant
• Pound for pound cloves are the most powerful
  natural antioxidant (American Institute for
  Cancer Research, 2007)
• Potential to prevent degenerative diseases

17
Human Uses

• Anticarcinogenic agent
• Clove oil causes apoptosis of cancerous cells
  (Namiki, 1994)
• Antimutagenic properties reduce incident of
  cancer (Miyazawa and Hisama, 2001)
• Aromatic cigarettes
• Smoked by over 90 of Indonesian population
• 50 of worldwide clove production used to make
  kretek cigarettes
• 60 tobacco and 40 ground cloves

18
Biochemistry

• Main active ingredient in the essential oil of
  cloves is eugenol
• Comprises 89 (Chaieb et al, 2007)
• Gives cloves its pleasant spicy aroma
• Eugenol is a phenolic compound
• Responsible for anesthetic, antioxidant, and
  antiseptic properties of cloves

19
Biochemistry

• Eugenol as an anesthetic (Cascales et al, 1998)
• Alters structure of plasma membrane
• Direct effect on proteins embedded in membrane
• Works especially well in fish
• Eugenol as an antioxidant (Ogata et al, 2000)
• Interferes with chain reactions caused by oxygen
  radicals
• Free radical scavenger

20
Biochemistry

• Eugenol as an antiseptic (Gill and Holley, 2004)
• Interacts with cell membrane of microbes
• Causes ion leakage and inhibits ATP production
• Microbes unable to regulate chemical gradients
• Leads to inhibition of growth and eventually cell
  death