Seòrsaichean Tì Uaine is Dubh

• Tea comes from Thea sinensis L. (Camellia thea Link.) Family Theaceae, and the parts used are the two adjacent young leaves together with the stem and bud

Tea Types

• Green tea is made through rapid drying and high temperature processing
• Green tea processing stops/destroys the oxidase enzyme, leading to no fermentation
• Green tea processing prevents oxidation of tannins, and there is no change in chlorophyll color
• Black tea is made through slow drying and no high temperature processing
• Black tea undergoes complete oxidation by oxidase enzyme, leading to complete fermentation
• Black tea processing leads to oxidation of tannins and a change in chlorophyll color to dark

Active Constituents

• Both green and black tea contain caffeine-phlobatannins
• Green tea's caffeine-phlobatannins complex is soluble because the oxidase enzyme is destroyed
• Black tea contains insoluble phlobaphenes (tannins) and free caffeine due to complete hydrolysis of the complex during fermentation by oxidase enzyme
• Green tea contains tannins in the form of a complex with caffeine that is soluble
• Black tea contains tannins in the form of phlobaphenes that are insoluble after hydrolysis
• Green tea contains less caffeine and more tannins
• Black tea contains more caffeine and less tannins
• Both types of tea contain traces of theobromine and theophylline alkaloids, volatile oil, and saponin glycosides
• Green tea is an antioxidant and antitumor due to a higher concentration of flavonoids

Confirmatory Chemical Tests for Tea

Murexide test

• Used to test for caffeine
• Aqueous decoction is evaporated, and the residue is mixed with concentrated hydrochloric acid (HCl) + H₂O and evaporated to dryness
• A yellow color forms and turns crimson red
• Adding vapors of ammonia results in a violet color

Ferric chloride test

• Used to test for tannins
• Aqueous extract mixed with FeCl3 produces a green color

KOH test

• Used to test for flavonoids glycosides
• Acidic extract mixed with KOH produces a yellow color

Froth test

• Used to test for saponin glycosides
• Powdered drug is shaken with water to give persistent froth that remains for 5 minutes

Medicinal Uses of Tea

• Caffeine in tea acts as a CNS stimulant, diuretic, and weak smooth muscle relaxant
• Tannins in tea act as an antidiarrheal drug (constipating agent)
• Green tea is an antioxidant and anticancer

Precautions of taking large doses of tea

• Can cause gastritis, nervous irritability, anemia, constipation, a habituation syndrome, and an increase in heart rate

Digitalis (Foxglove)

• The leaves of Digitalis purpurea and Digitalis lanata(Family Scrophulariaceae) plants are the what the drug is derived from

Active Constituents of Digitalis

• Cardiac glycosides: Digoxin, Digitoxin, Lanatoside A, and Lanatoside C
• Saponin glycosides are also present

Confirmatory Chemical Tests for Digitalis

Baljet test

• Used to test for Cardiac glycosides
• Alcoholic extract mixed with Baljet reagent (Picric acid +10% NaOH = Sodium picrate) produces an orange-yellow color compared with a blank

Keller–Killiani test

• Used to test for deoxy sugar in glycone part
• Acetic acid extract with FeCl + Conc H₂SO₄ produces a reddish-brown ring at the junction of the two layers, and the upper layer turns bluish-green

Froth test

• Used to detect the presence of Saponin glycosides
• Powdered drug is shaken with water to check for the formation of persistent froth that remains for up to 5 minutes

Medicinal Uses of Digitalis

• Digitalis has a cardiotonic action on a diseased heart
• Digitalis strengthens the heartbeat, increases the force of contraction, and enables the heart to beat more strongly, slowly, and regularly without requiring more oxygen

Precautions for Digitalis Use

• Cardiac glycosides in Digitalis are excreted very slowly which can cause cumulative effects, which may be fatal.
• Digitalis is preferred as a long-term medication

Digitalis Leaf Morphology

• The petiole is petiolate

Leaf Blade

• Apex is acute
• Shape is lanceolate and decurrent
• Margin is entire but ciliated at the base
• Form (Type) is simple
• Venation is reticulate anastomosing near the margin
• Apex is exstipulate symmetric, decurrent
• Phyllotaxis is alternate

Key Elements Found in Digitalis Powder

• Fragments of epidermal cells with beaded anticlinal walls and anomocytic stomata with striated cuticle
• Three types of glandular hairs: bicellular biserriate head unicellular stalk, unicellular head unicellular stalk (capitate hair), and unicellular head multicellular uniserriate stalk
• Two types of non-glandular hairs: collapsed hair and multicellular uniserriate
• Does not contain any type of calcium oxalate

Senna (Alexandrian & Indian Senna)

• Senna is derived from the dried leaflets of Cassia acutifolia (Alexandrian Senna) and Cassia angustifolia (Indian Senna) Family Leguminosae.

Active Constituents of Senna

• Anthraquinones glycosides: Sennoside A, B, C, D upon hydrolysis yield Sennidin A, B, C, D
• Mucilage (carbohydrates)

Confirmatory Chemical Tests for Senna

Borntrager's test

• Used to test for free anthraquinones
• A chloroformic extract mixed with NH4OH produces a rose (pink) to intense red color in the aqueous layer

Modified borntrager's test

• Used to test for combined anthraquinones
• A chloroformic extract mixed with NH4OH produces a rose (pink) to intense red color in the aqueous layer

Medicinal Uses of Senna

• Senna is used as a laxative and powerful cathartic in the treatment of constipation due to the presence of anthraquinones glycosides

Precautions for Senna Use

• Senna should not be taken for more than 10 days because it can weaken the large bowel muscles
• This is due to the presence of anthraquinones glycosides

Side Effects of Senna

• Due to presence of anthraquinones glycosides, Senna can cause a slightly bitter taste and nausea
• Senna causes gripping and colic, so it is mixed with other aromatic, carminative herbs that relax the intestinal muscles, such as Mentha, anise, cardamom, clove, antispasmodic (belladonna)

Contraindications for Senna Use

• Senna should not be taken during pregnancy, as it causes muscle contraction which may lead to abortion due to the presence of anthraquinones glycosides
• It also should not be taken when breastfeeding

Senna Leaf Morphology

• The petiole is petiolate

Leaf Blade

• Shape is obovate, lanceolate
• Margin is entire
• Form (Type) is compound, pinnate, paripinnate (even number)
• Venation is reticulate (netted) and pinnately reticulate
• Phyllotaxis is alternate

Key Elements Found in Senna Powder

• Palisade cells (leaf organ) with longitudinal colenchyma
• Upper and lower epidermal cells with paracytic stomata (leaf organ)
• Warty hair: nonglandular, unicellular, thick wall, curved and covered with a warty cuticle
• Crystal sheath with prisms of Ca-Oxalate
• Clusters of calcium oxalate
• Fibers can sometimes be seen due to the crystal sheath being transparent

Leaf Histology

• The ordinary leaf consists of upper and lower epidermis, mesophyll, cortical tissues, and a vascular system
• Upper and lower epidermis is present
• Mesophyll tissues lie in between the two layers of epidermis
• Cortical tissues surround the vascular bundle
• Vascular system is present

Microscopic Characteristics of Leaves

• Includes form and number of stomata
• Trichomes: including Secretory (glandular hairs) and covering trichomes (non-glandular hairs)
• Presence of crystals such as calcium oxalate

Leaf Arrangement

• Alternate: Leaves on at each node (1 leaf per node)
• Opposite: Nodes are opposite each other on the stem (2 leaves per node)
• Opposite Decussate: Special case where each successive pair of leaves is at a right angle to the previous pair
• Whorled: Three or more leaves originate from one node

Forms of Leaves

• Simple: Leaves that have blades that are not divided into distinct morphologically separate leaflets, but form a
• Entire (single) blade: the leaf is not divided
• Lobed or deeply lobed
• Pinnately lobed: lobes are arranged on the sides of a central axis, like a feather
• Palmately lobed: lobes spread radially from a point, like a finger on a hand
• Compound: Each blade is divided into smaller leaflets to form either
• Pinnate: leaflets arise along sides of the rachis which is the extension of the petiole
• PariPinnate: The leaflets are in even number.
• ImpariPinnate: The leaflets are in odd number.
• Palmate: the leaf is divided into 5 or more leaflets radiating from the top of the petiole

Venation

• Parallel venation is a characteristic feature of monocotyledons
• Veins run approximately parallel to each other
• Multicostate venation: there are multiple main veins or ribs that radiate from the base of the leaf
• Unicostate venation: a single main vein runs through the center of the leaf blade
• Netted venation is a characteristic feature of dicotyledons

Types of Netted Venation

• Pinnately netted: Veins branch off or radiate from a central mid vein
• Palmately netted: Several major veins radiate out from a point

Morphological Structure of a Dicot Leaf

• Leaves consist of several parts
• Petiole (optional): Attaches blade to stem
• Lamina/Blade: Broad, flat in shape and collects light for photosynthesis
• Veins: Contains vascular tissue
• Axil: The point of attachment of the leaf at the node of the stem, and it is the intersection of petiole and stem and sometimes has axillary bud
• Stipules (optional): Outgrowths at base of the leaf

Parts of Leaves

• Tip and Base
• Apex
• Margin

Different Kinds of Leaves

• Cotyledons (seed leaves): Leaves of the embryo, serving for storing of food
• Foliage leaves: Ordinary green leaves (photosynthesis)
• Floral leaves: Reproductive parts of the flower, which include sepals, petals, stamens, and carpels
• Bract leaves: Leaves having a flower in their axils
• Scale leaves: Occur on subterranean stems (thin, membranous, and devoid of chlorophyll)
• Modified leaves: When the leaf is modified into special structure for the purpose of carrying out special function