Pharmacognosy First Year Pharmacy Students PDF

Pharmacognosy For First Year Pharmacy Students Chapter IV: leaves 1  The leaves The leaf is a lateral outgrowth on the steam from which it differs in structure.it is usually flattened having one or more buds in its axil The leaf is composed...

Pharmacognosy For First Year Pharmacy Students Chapter IV: leaves 1  The leaves The leaf is a lateral outgrowth on the steam from which it differs in structure.it is usually flattened having one or more buds in its axil The leaf is composed of three parts: 1- The leaf-base. 2- The blade (lamina). 3- The stalk (petiole). Leaf blade.leaf lamina usually Expanded and the widest portion 2 Leaf stalk petiole. Distance between nodes and lamina. Connection between lamina and stem Types of leaves: 1- Cotyledons (seed leaves). For storage of reserve food material {protein} 2- - Prophylls (fore -leaves). It is simpler in form and structure from ordinary green leaves 3- Foliage leaves.the ordinary green leaves which carry on normal leaf function 4- Scale leaves.they occur on all subterranean steam and some aerial stems.they are thin membranous and Devoid of chloriphyll 5- Bracts leaves Having a Flower or group of Flower in their Axils 6- Floral leaves.including Sepals and petals stamen and carpels 7- Modified leaves.when the whole the leaf or part of it may be modified into special structure to carry special function It may Modified into 1-Tendrils …Ex. pea 2-Spines ……Ex orange 3-Special Traps for Catching Insects……Ex..drosera 4-May Succulent for storage water …Ex. Zygophyllu 3  Insertion ….position of leaf on steam Foliage leaves may be described as: 1- Radical: the leaves crowded together about the top root at the level of the ground or ju1-st above it. 2- Cauline: the leaves are spread on the elongated aerial stem. 4  Phyllotaxis It is the disposition of the leaves on the stem. Phyllotaxis may be: 1-Alternate (Spiral): when the leaves are inserted singly at the nodes at regular intervals , 2- Opposite: when a pair of leaves is developed at each node and leaf is opposite the other 3- opposite decussate If the leaves are opposite and each pair is inserted at right angle to the pairs immediately above and below it 4- Whorled: when three or more leaves occur at each node 5  Leaf – base Stipules: when the leaf-base itself is small and develops lateral outgrowths. When the stipules are present, the leaf is described as stipulate, when absent it is described exstipulate Petiole or lamina base Petiolate. while when present, sessile, When it is absent 6  Lamina or leaf-blade A-Simple leaf B- Compound leaf A- Simple leaf: 1- Entire …the lamina consists of a continuous, undivided surface. Do not have any lobes 2- Lobed ……when the lamina is cut up into a number of lobes connected with on another by undivided portion a-pinnately-lobed"..if the incision is directed Towards the Midrib b- palmately-lobed….if the incision is directed towards the Top of the petiole. B- Compound leaf the lamina cut up completely into a number of separate leaflets. 1- Binate: with 2 leaflets only 2- Ternate: with 3 leaflets 3-Pinnate: With several leaflets arranged on the rachis. It may paripinnate, with leaflets in 2 rows one on either side of the 7 rachis; imparipinnate like the paripinnate but terminates with a single leaflet. 4-Palmate or digitate: with 5 or more leaflets radiating or coming out from the top of the petiole Shape of the lamina A) When lamina has nearly the same width throughout: 1- Filiform: Thread-like 2- Acicular: Tube-like needle-shaped 3- Tubular: Tube-like as in onion. 4- Linear: Flat and wide with edges parallel near the middle B) When lamina has the widest portion near the base a- Lanceolate: Narrow 8  b- Ovate : Like the egg c- Cordate : Heart shape d- Reniform : Kidney shaped C) When lamina hasthe widest part near the apex 1- Obovate 2- Obcordate 3- Spathulate 9  Apex of lamina 1- Acute 4- Recurved 2- Acuminate 5- Mucronate 3 Obtuse 6- Emarginate Margin 1. Entire.quite smooth 2. Crenate: having numerous minute rounded 3. Denate having teeth pointed straight outwards 4. Serrate having shape teeth directed towards the apex 5. Ciliate: when fringed with hairs 10  Base of lamina 1. symmetric.equal on both side 2. Asymmetric.unequal on both side 3. Decurrent. continuous downwards as wings along the base 4. cordate 11  Venation 1- Parallel.veins are parallel to margin 2- Pinnate. contain only one main vein 3- Palmate. show several divergent main veins arising from the top of the petiole 12  Surface Colour. upper surface is always darker in color 1. Glabrous free from hairs 2. Pubescent. hairy and have two types a- Glandular contain glands for secretion b- Non glandular contain no glands it is function is protection 3. Punctate dotted with oil glands 1. lines on surfaceof coco leaves 2. raised points on belladonna 3. press marks on tinnevelly senna 13  Senna leaf Senna leaflets, Sennae ‫أوراق السنــــــــــــــــــــــــــــــ –أورق‬ folium, Folium sennae. ‫السن مكـي –أ وراق السالميكـ‬ Senna leaf is the dried leaflets of Cassia senna (C. acutifolia), known in commerce as Alexandrian senna leaflets, and of C. angustifolia known in commerce as Tinnevelly senna leaflets Family: (Leguminosae). Collection and preparation: Alexandrian senna: is collected mainly in September, from both wild and cultivated plants. The branches bearing leaves and pods are dried in the sun, the pods and large stalks are first separated, the leaves are then separated, graded, into (1) whole leaves, (2) whole leaves and half-leaves mixed, and (3) sittings. The whole leaves are those usually sold to the public, while the other grades are used for making galenicals. The drug is packed, somewhat loosely, in bales and sent by rail to Port Sudan, from where it is exported. Tinnevelly senna: is obtained from cultivated plants of Cassia angustifolia grown in South India, Pakistan and Jammu. The 14 drug is collected and compressed into bales, few leaflets are usually broken. Macroscopical characters: Senna leaflets bear stout petiolules. The lamina has an entire margin, an acute apex, and a more or less asymmetric base. The surfaces are pubescent. Odor, slight but characteristic; taste, mucilaginous, bitterish and unpleasant. Microscopical characters: Senna leaflets have an isobilateral structure. The epidermal cells have straight walls, and many contain mucilage. Both surfaces bear scattered, unicellular, nonlignified warty hairs up lo 260 m long. The stomata have two cells with their long axes parallel to the pore and sometimes a third or fourth subsidiary cell. The mesophyll consisting of upper and lower palisade layers and median spongy mesopbyll, contains cluster crystals about 15-20 m in diameter. The midrib is biconvex. Below the midrib bundle is a zone of collenchyma. The midrib bundle and larger veins are almost surrounded by a zone of lignified pericyclic fibers and a sheath 15 of parenchymatous cells containing prisms of calcium oxalate 10-20 m long. Vein-islet numbers and stomatal indices can be used lo distin- guish the two species. Senna leaflets. A, Indian senna; B, Alexandrian senna; C, transverse section of leaflet; D-H, elements of the powder; D, leaflet fragment in transverse section; E, F, epidermal fragments in surface view; G, isolated trichomes; H, portion of fiber group with crystal sheath, c, collenchyma; cic, cicatrix; cr1, cr2, calcium oxalate crystals of the cluster and prismatic type respectively; f, fiber groups; l.e. lower epidermis; l.p. lower palisade layer; m, mesophyll; muc, mucilage; m.a. mucronate apex; p.m, press mark, 16  s, stoma; u.e. upper epidermis; u.p. upper palisade layer; xy, xylem. Constituents: 1-Anthranoid (anthraquinone) derivatives (not less than 2.5%): 2-dianthrone glycosides Comparison of Alexandrian and Indian senna leaves Alexandrian senna Tinnevelly senna Macroscopical characters: - Seldom exceed 50 mm in length. - Seldom exceed 40 mm in length. - Yellowish-green. - Grayish-green. - Less asymmetric at base. - More asymmetric at base. - Seldom broken and usually flat - Rather more broken and curled at owing to compression. the edges. - Often shows impressions due to the - Few press markings. midvein of other leaflets. Chemical tests: Ether extract of hydrolysed acid solution of drug gives with methanolic magnesium acetate solution: - a pink color in daylight, - an orange color in daylight, - a pale greenish-orange in filtered - a yellowish-green in filtered ultraviolet light. ultraviolet light. TLC test for naphthalene 17 derivatives: - Tinnevellin glycoside present. - 6-Hydroxymusizin glycoside present. - Adulterants: 1- Palthi senna: derived from Cassia auriculata, has been found Indian senna. It may be distinguished by the long hairs, the crimson color given when boiled with chloral hydrate solution or treated with 80% sulfuric acid and the absence of anthraquinone derivatives. 2- Argel leaves: which are derived from Solenostemma arghel, Family: Asclepiadaceae, were at one time regularly mixed in a definite proportion with Alexandrian senna. The plant occurs in the Sudan, it may be distinguished by the two- or three-celled hairs, each of which is surrounded by about 5 subsidiary cells. 4- Coriario leaves: which are derived from Coriario myrtifolia, Family: Coriariaceae have recently been reported as an 18  adulterant of cut and powdered senna. The adulterant gives positive tests for tannin and microscopically shows an absence of trichomes and crystal idioblasts with differences in quantitative microscopical characters. Action and uses: Senna leaves as well as the purified sennosides are used as laxative, The mixture is more effective than lactulose as a laxative. The pulverized leaves are applied to wounds and burns. Drug interactions: Anthraquinones cause discoloration of the urine which may interfere with diagnostic tests. Hypokalemia (resulting from long-term use of senna) may potentiate the action of cardiac glycosides and interacts with antiarrhythmic drugs, Contra-indications: It is recommended that senna should not be given to patients with intestinal obstruction and stenosis, atony, inflammatory colon diseases (e.g. Crohn's disease, ulcerative colitis), Dosage: Dried leaflets: Small doses of 0.5-2.0g 19  Belladonna Deadly nightshade, Belladonna ‫أوراق ست الحسن – بالدون‬ leaf. Belladonna consists of the dried leaves of Atropa belladonna, Family: Solanaceae. Active Constituents: 1- Alkaloids (0.3-0.60%): the chief of which is hyoscyamine. 2- Flavonoid glycosides. Action and uses Belladonna is drug for all spastic conditions involving the stomach and intestine and is superior to all of the available synthetic drugs. Acute abdominal pain associated with gastric and duodenal ulcers 20  Digitalis Foxglove, Purple foxglove leaves, Digitalis ‫أوراق ديجيتـــ لـــ – اصــــــ‬ leaf, Folium digitalis, Digitalis folium. ‫العذراء – زهر الكشت ت ين‬ Digitalis consists of the dried leaves of Digitalis purpurea, Family: Scrophulariaceae. The foxglove is a biennial or perennial herb, which is very common in the UK and most of Europe, including some Mediterranean regions of Italy, and is naturalized in North America. It is produced commercially in Holland and Eastern Europe Macroscopical characters: Digitalis leaves are usually ovate-lanceolate to broadly ovate in shape, petiolate and about 10-30 cm long and 4-10 cm wide. The dried leaves are of a dark grayish-green color. The lamina is decurrent at the base; apex subacute. The margin is crenate or dentate and most of the teeth show a large water pore. Both surfaces are hairy, particularly the lower, and a fringe of fine hairs is found on the margin. The veins are depressed on the upper surface but very prominent on the lower. The main veins 21 leave the midrib at an acute angle, afterwards branching and anastomosing repeatedly. The drug has no marked odor, but a distinctly bitter taste. Digitalis purpurea leaf. A, First-year leaf ; B, transverse section midrib of first-year leaf; C, upper epidermis; D, lower epidermis; E, trichomes; a.v, Anastomosing veins; c, collenchyma, cic, cicatrix; d.b, decurrent base; d.m, dentate margin; e, endodermis; ep, epidermis; g.t, glandular trichome; g.t1, glandular trichome surface view; m, mesophyll; p, palisade; ph, phloem; s.m, serrate margin; st, stoma; t, trichome base; xy, xylem. 22  Microscopical characters: A transverse section of a foxglove leaf shows a typical bifacial structure and a midrib strongly convex on the lower surface. Stomata and hairs are present on both surfaces, but are more numerous on the lower one. Calcium oxalate is absent. The palisade tissue is interrupted at the midrib. A zone of collenchyma underlies both epidermi in the midrib region. The crescent-shaped midrib bundle is enclosed in an endodermis one or two cells thick developed as a starch sheath. The pericycle is parenchymatous above and collenchymatous below. Sclerenchymatous fibers are absent. Surface preparations show that the upper epidermis consists of polygonal, relatively straight-walled cells, and bears both clothing and glandular hairs. The cells of the lower epidermis are wavy, and the stomata and hairs much more numerous than on the upper surface of the leaf. The stomata are small and slightly raised above the surrounding cells. The clothing hairs are uniserate, 2-7-celled, bluntly pointed, smooth or finely warty, with cells often collapsed alternatively at right angles. The glandular hairs have a unicellular or occasionally a short uniseriate pedicel, with a unicellular or bicellular terminal gland. The cuticle of the hairs and epidermal cells may be stained red with a solution of Sudan Red in glycerin. Active Constituents of Digitalis purpurea: 1- Cardiac glycosides: digitoxin, and gitoxin 2- Anthraquinone derivatives, saponins.flavonoids. 23  Action and uses: Digitalis is cardiotonic. It increases the contractility and improves the tone of the cardiac muscle, both reactions resulting in a slower (negative chronotrope) but much stronger (positive inotrope) heart beat. It is used in most forms of cardiac failure 24  Stramonium leaf Thornapple Leaves; Jimson or Jamestown Weed, ‫أوراق الداتورا‬ Datura. Stramonium leaf consists of the dried leaves of Datura stramonium and its varieties, Family: Solanaceae Active Constituents: 1-Stramonium usually contains 0.2-0.45% of alkaloids 2-a little atropine and hyoscine Action and uses Atropine has a stimulant action on the central nervous system and depresses the nerve endings to the secretory glands and plain muscle. used in the control of motion sickness. Atropine and hyoscine are used to a large extent in ophthalmic practice to dilate the pupil of the eye 25  Buchu leaf Buchu, Bucco, Barosmae folium Buchu is the dried leaves of Agathosma betulina (Bergius) Pill. Family: Rutaceae. Constituents Essential oils (1.0-3.5%, consisting mainly of the monoterpene diosphenol); flavonoids (especially diosmin and rutin), mucilage, resin. Action and uses Traditionally, urinary antiseptic, to treat gravel, inflammation and catarrh of the bladder and acts as a diuretic and diaphoretic. Urinary tract infection (disinfects the urinary tract), dysuria (mild diuretic), cystitis, urethritis and Prostatitis Pregnancy and lactation: contraindicated in pregnancy (contain much higher levels of pulegone in their essential oil). 26  Boldo Boldus, Boldus boldus (Mol.) Lyons. ‫ ال ولـد وة الف غي‬-‫أوراق ال ولـد و‬ Boldo is the dried leaves of Peumus boldus Molina, Family: Monimiaceae Constituents: 1- Isoquinoline alkaloids… boldine 2- Flavonoids, volatile oils (2.5%), Coumarin (0.5%), resin Action and uses: Boldo is used extensively throughout Europe, North America, South America and Latin America as a specific for gallstones and gallbladder inflammation, and for many types of liver, stomach and digestive disorders. 27  Jaborandi leaf Jaborandi is the dried leaflets of Pilocarpus microphyllus Family: Rutaccae Constituents: 1- Alkaloids: pilosine and isopilosine. 2- Volatile oil (about 0.5%). Action, uses and doses: It is used ophthalmically in treatment of glaucoma (rise in intraocular pressure), where it is instilled into the eye as a 0.5 to 4.0% solution Pilocarpine is used orally in the treatment of xerostomia (dry mouth) in patients with malfunctioning salivary gland due to radiotherapy for cancer of head and neck, in 5-10 mg doses. 28  Henna Cypress shrub, Egyptian privet, alkanna, Enah, Folium hennae. ‫أوراق الحن ء‬ Henna consists of the dried leaves of Lawsonia inermis , Family: Lythraceae Active Constituents: Henna contains a coloring matter (naphthoquinones): The plant also contains hennatannin, flavonoids including luteolin and its 7-O-glucoside, fats and resin. Action, uses and doses Henna is commonly used as a dye for the hair, as a cosmetic colorant. An extractive from the plant has strong antimicrobial activity, which has been evaluated as comparable to the antibiotic activity of sulfonamides and penicillin. Lawson exhibits slight antihemorrhagic properties 29  Bearberry Uva ursi. Bearberry is the dried leaves of Arctostaphylos uva ursi (L.) Spreng., Family: Ericaceae. Constituents: 1- Hydroquinone glycosides (4–15%), including arbutin and methylarbutin. 2- Polyphenols , phenolic acids, flavonoids, triterpenes. Action and uses: Uva-ursi possesses diuretic, urinary antiseptic, anti- inflammatory and astringent properties. Can be used for urinary infections such as cystitis, urethritis, Prostatitis, pyelitis; lithuria; diarrhea and intestinal irritations (any condition requiring an astringent action including chronic diarrhea). 30  Green and Black teas Tea consists of the prepared leaves of Thea sinensis (Camellia thea Link., Camellia sinensis), Family: Theaceae Constituents: 1- Alkaloids: 1-5% of caffeine, small quantities of theobromine, theophylline. 2-Tannin (10-24%), volatile oil. Action and uses: Antioxidant, antineoplastic and dental anticariogenic. Aqueous extracts from green and black teas have potent antioxidant activities and exceptional quenching capacity of ultraviolet-induced oxidative DNA damage. Clinical trials in humans suggest that regular tea drinking may reduce the incidence and severity of caries. This could offer a very economical public health intervention. 31