Pharmacognosy-I Lecture 6: Medicinal Leaves

Pharmacognosy-I Lecture 6: Medicinal Leaves

• Lecture covers Senna leaflets, specifically Cassia acutifolia Delile, Cassia angustifolia Vahl, and variations
• Senna leaflets are dried leaves of paripinnate plant
• Senna leaflets belong to the Leguminosae family ( Fabaceae ), Caesalpinoideae subfamily
• Two classifications exist: Alexandrian/Khartoum senna and Tinnevelly/Indian senna
• Senna leaf can be distinguished by leaflet size, midrib impression, symmetry of leaflet base, stomatal index, and vein-islet number.
• Microscopical characteristics for Alexandrian senna include numerous hairs, stomata with two subsidiary cells, vein-islet number between 25.0-29.5 and stomatal index between 11.4-13.0
• Microscopical characteristics for Indian senna include less numerous hairs, stomata with two or three subsidiary cells (ratio approximately 7-3), vein-islet number between 19.5-22.5 and stomatal index between 17.1-20.0.
• Substitutes for Senna includes Cassia obovata (dog senna), Cassia auriculata, Solenstermma argel
• Solenstermma argel is found in upper Egypt, has a bitter taste and wrinkled/twisted leaves; distinguished from Senna by its anthracene free structure

Ginkgo Leaves

• Ginkgo leaves are dried leaves of Ginkgo biloba F. Ginkgoaceae
• Ginkgo leaves are fan-shaped, having a deeply notched apex.
• Leaf margins range from entire (lower portion) to finely notched or crenate (upper portion)
• Leaves have a symmetric base, green to brownish yellow color, and feature a characteristic odor and bitter taste.

Active Constituents of Ginkgo Leaf

• Standardized Ginkgo Leaf extract contains flavonoids (25%), sesquiterpenoids (e.g., bilobalide, 3%), diterpenoids (e.g., gingkolides A-C, 3%), condensed tannins (catechol), and amino acids.

Claimed uses of Ginkgo extract

• Age-related physical and mental deterioration

• Schizophrenia (120-240mg) for 3-6 months.

• Alzheimer's disease and dementia

• Cardiovascular disease (decrease in oxidative stress)

• Cerebral vascular insufficiency.

• Impaired cerebral performance, including loss of memory, alertness, and depressive mood.

• Vertigo and altitude sickness

• Tinnitus (ringing in the ear)

• More research is needed to support Ginkgo's effectiveness due to conflicting results

Hamamelis Leaves (Witch-hazel)

• Dried leaves of Hammamelis virginiana F. Hammamelidaceae

• Active constituents are 10% tannins, including condensed (catechol) and Hamamelis tannins (pyrogallol or hydrolyzable tannins)

• Uses:

  • Astringent for dry/cracked skin
  • Haemostatic for hemorrhoids, minor blood extravasations
  • Calming and healing on irritated red skin
  • Local anti-inflammatory

Hedera Helix Leaf (Ivy)

• Dried leaves of Hedera helix, belonging to the Araliaceae family
• Native to Europe and Western Asia
• Claimed uses (clinical studies): Expectorant and bronchodilator (chesty cough relief)
  • Anti-inflammatory, antispasmodic, antimicrobial activities
• Traditional use in gout and rheumatism.

Active constituents of Hedera Helix Leaf (Ivy)

• Triterpene saponins : hederasaponnins A-I
  • Hederasaponin C (hederacoside c) is a significant compound
• Flavonoid glycosides (rutin and quercetin)
• Phenolic acids
• Alkaloid (emetin)

This lecture focuses on the medicinal properties and classifications of senna leaflets from the Cassia species. It explores the distinctions between Alexandrian and Indian senna through their microscopical characteristics, variations, and substitutes. Ideal for students studying plant pharmacology and medicinal botany.