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Questions and Answers
What is the maximum height that a clove tree can reach?
What is the maximum height that a clove tree can reach?
During which months are clove flower buds typically collected?
During which months are clove flower buds typically collected?
What color are cloves when they are fully dried?
What color are cloves when they are fully dried?
Which part of the clove is primarily responsible for its strong, fragrant odor?
Which part of the clove is primarily responsible for its strong, fragrant odor?
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What happens to clove buds if they are left too long on the tree?
What happens to clove buds if they are left too long on the tree?
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What is the primary height of the pyrethrum plant?
What is the primary height of the pyrethrum plant?
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Which part of the pyrethrum flower head is surrounded by an outer ring of white ray florets?
Which part of the pyrethrum flower head is surrounded by an outer ring of white ray florets?
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Which of the following species is NOT a source of insecticides from pyrethrum?
Which of the following species is NOT a source of insecticides from pyrethrum?
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What is the diameter of an open pyrethrum flower head?
What is the diameter of an open pyrethrum flower head?
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Which of the following chemical constituents is largely responsible for the rapid knock-down action of pyrethrum?
Which of the following chemical constituents is largely responsible for the rapid knock-down action of pyrethrum?
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What type of cells are often found containing aggregate crystals in the microscopy of pyrethrum powder?
What type of cells are often found containing aggregate crystals in the microscopy of pyrethrum powder?
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What feature characterizes the ray florets of the pyrethrum flower?
What feature characterizes the ray florets of the pyrethrum flower?
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Which structure is described as having longitudinal striations in the context of pyrethrum?
Which structure is described as having longitudinal striations in the context of pyrethrum?
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Which structure is characterized by having a central columella supported by air spaces?
Which structure is characterized by having a central columella supported by air spaces?
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What type of cell wall feature is observed in the anther wall of the clove's reproductive structure?
What type of cell wall feature is observed in the anther wall of the clove's reproductive structure?
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Which component is NOT a characteristic of the hypanthium in the clove?
Which component is NOT a characteristic of the hypanthium in the clove?
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What is the primary function attributed to the tannins found in cloves?
What is the primary function attributed to the tannins found in cloves?
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Which of the following is a significant chemical constituent of the clove?
Which of the following is a significant chemical constituent of the clove?
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What type of crystals are predominantly found within the placenta of the clove ovary?
What type of crystals are predominantly found within the placenta of the clove ovary?
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Which aspect of the sepals and petals demonstrates variation in stomatal presence?
Which aspect of the sepals and petals demonstrates variation in stomatal presence?
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What is the range of volatile oil concentration found in cloves?
What is the range of volatile oil concentration found in cloves?
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Study Notes
Flower Drugs: Clove and Pyrethrum
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Clove:
- Dried flower buds of Syzygium aromaticum (syn. Eugenia caryophyllus)
- Part of the Myrtaceae family
- Tree, 10-20 m high
- Indigenous to clove islands
- Cultivated in Zanzibar, Madagascar, Brazil
- Flower buds collected between August and December when they turn from green to crimson
- If left too long on the tree, buds open, petals fall off (blown cloves), and fruits (mother cloves) are produced
- Dried in open air, separated from peduncles (clove stalks)
- 10-17.5 mm long, blackish to reddish brown
- Head with calyx teeth (sepals), imbricated petals, numerous incurved stamens
- Bilocular ovary with ovules on axile placentae
- Strong, fragrant, spicy odour
- Pungent, aromatic taste
- Sinks in water
- Exudes oil when pressed
- Exhausted cloves do not exude oil
- Varieties: Penang & Amboyna (larger, plumpest, reddish-brown); Zanzibar (smaller, leaner, blackish-brown)
- Hypanthium below the ovary with epidermal layer, stomata, radially arranged parenchyma, oil glands, calcium oxalate crystals, ring of vascular bundles, lignified fibers, aerenchyma zone
- Inner epidermis forms ovary wall; dissepiment is parenchymatous, placentae is rich in cluster crystals of calcium oxalate and vascular bundles.
- Sepals and petals have simplified leaf structure; sepal epidermis has stomata; petals lack stomata
- Stamens have filament, connective and anther; filament has numerous oil glands, anther wall has lignified thickening, pollen grains (15-20 µm)
- Chemical constituents:
- 14-21% volatile oil (colourless/pale yellow, slightly heavier than water; darkens with FeCl3)
- Potassium eugenate crystals with alcoholic KOH (due to eugenol)
- Tannins (10-13%)
- Acids, esters, glycosides
- Uses: Stimulant aromatic, flavouring agent, spice, antiseptic (volatile oil)
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Pyrethrum:
- Dried flower heads of Chrysanthemum cinerariifolium (Trev.) Vis.
- Part of the Asteraceae family
- Synonyms: Tanacetum cinerariifolium, Pyrethrum cinerariifolium
- Perennial plant, about 1 m high
- Kenya is the largest exporter
- Favourable conditions for cultivation: Altitude (1900-2700 m), Annual rainfall (76-180 cm), Low night temperature (5-15°C)
- Only flowers collected (contain ~90% insecticidal activity) - dried, powdered, or standardized into liquid extracts; non-toxic to insects before drying
- Flower head composed of florets on slightly convex receptacle; disk florets (yellow center), ray florets (white outer ring)
- Tubular corolla, small calyx, five stamens (filaments), anthers forming a cylinder, style rises from ovary (two lobes)
- Ray florets (10-20 mm), central one being very small; closed flower head(6-9 mm), open flower head(9-12 mm)
- Yellowish, lanceolate hairy bracts (involucre)
- Short peduncle with longitudinal striations
- Microscopy shows: Parenchyma (aggregate crystals), T-shaped hairs, numerous spherical pollen grains, sclerenchyma cells, tracheids, epidermal cells (striated papillose cuticle)
- Insecticidal properties due to six esters: Pyrethrin I (lethality), Jasmolin I, Cinerin I, Pyrethrin II (rapid knock-down), Jasmolin II, Cinerin II
- Pyrethrum extract B.P. (Vet.) contains 24.5-25.5% pyrethrins
- Synthetic analogues are more common in domestic sprays due to: higher insecticidal activity (over 1000x that of pyrethrin I), greater photostability, similar low mammalian toxicity
- Uses: Contact poison for insects in food processing plants, insecticidal spraying of edible fruits and vegetables before harvest
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Description
Explore the fascinating world of clove and its uses in traditional medicine. Learn about the characteristics, cultivation, and processing of dried clove buds from Syzygium aromaticum. This quiz covers their origins, varieties, and unique properties.
