Pharmacognosy and Phytochemistry of Ephedra : An Amino Alkaloid / Proto-alkaloid

 Synonym

Ma-Huang (Ma-Astringent taste, Huang -Yellow)

Biological source
It consists of dried young stems of Ephedra gerardiana, E. nebrodensis (India), Ephedra sinica, Ephedra equisetina (China) Family: Gnetaceae / Ephedraceae.

Geographical source

China, Pakistan, North India, Australia, Kenya, Spain etc.

Morphological features

Fig.1: Ephedra Plant and its Stems

• This is an evergreen shrub which can grow up to 60 cm high.
• Ephedra has many different species.
• This plant is differentiated into 3 parts: root, stem and leaves.
• The plant is spread by the use of rhizomes.
• Stems are green, leaves are opposite in arrangement and whorled.
• The shape of leaves are scale like and have no resin canals.
• Seeds are yellow to dark brown in colour.
• The branches of this plant are slender, more or less broken aerial stems which are woody in nature and branched only at the base.

Macroscopic Characters of Ephedra gerardiana

·        Woody, cylindrical.

·        Colour: Grey to greenish

·        Taste: Bitter

·        Stems contain numerous, fine and longitudinal ridges.

—  It has Nodes, internodes, scaly leaves and terminal buds.

·        Shows internodes at 3-4 cm distance.

·        The diameter of node is about 1-2 mm and diameter of internode is 3-6 cm.

Microscopy

Fig. 2: Schematic diagram of transverse section of ephedra stem

Fig. 3: Detailed histological diagram of transverse section of ephedra stem

 

·        Epidermis: Single layered, quadrangular cells, with thick and smooth cuticle. Vertical rows of sunken stomata present between many vertical ridges on the stem.

·        Cortex: Many layers of thin-walled cellulosic parenchyma. Below epidermis, two or three layers of loosely arranged palisade like cells are present. Cortex shows both lignified and unlignified fibers.

i) Unlignified fibers: like bunch of grapes occur below the ridges where no palisade cells are present.

ii) Fibres: Scattered, isolated or in groups of two to four cells lignified.

·        Pericyclic fibers: lignified, crown the phloem on its outer side

·        Vascular bundle: Around 10, collateral, conjoint, open and arranged in ring. Contains phloem and xylem

i) Phloem: It consists of sieve tubes and companion cells

ii) Xylem: It is made up of vessels, tracheid’s, parenchyma and fibro tracheids.

·        Pith: Large, thin walled, lignified parenchyma with intercellular space. Some cells contain dark brown mucilaginous substance (Brown matter).

 

Cultivation and Collection

—  The plant favors light (sandy) and medium (loamy) soils and requires well-drained soil. The plant prefers acid, neutral and basic (alkaline) soils.

—  It cannot grow in the shade. It requires dry or moist soil and can tolerate drought.

—  Seeds are sown as soon as they are ripe in the autumn in a greenhouse.

—  It can also be sown in spring in a greenhouse in sandy compost.

—  Seedlings are transferred into individual pots as soon as they are large enough to handle and grown them for at least their first winter in a greenhouse.

—  Drug is collected in autumn since it contains maximum percentage of alkaloids.

—  Green slender twigs are collected in autumn, dried and packed loose in bags. Sometimes the twigs are pressed tightly.

Chemical constituents
 

—  It contains Amino-alkaloids. Ephedra’s contain about 0.5 – 2.0 % of alkaloids.

—  Chief Constituent: Ephedrine

—  Norephedrine

—  N-methyl ephedrine

—  Pseudoephedrine

—  Root Contains Macrocyclic alkaloid: Ephedradine

—  Oxazolidone

—  Tannins are also found in mostly ephedra species.

—  Also contains flavonoids and polysaccharides.

Chemical test

Ephedrine + Water + dil.HCl + CuSO₄ + NaOH. The solution gives blue colour. If shaken with solvent ether:  Organic Layer-Purple, Aq. Layer – Blue colour

 

Therapeutic Uses

—  Ephedra shows sympathomimetic activity.

—  In allergic conditions like hay fever, bronchitis, Woophing cough.

—  To correct the low BP because of its peripheral contraction of arterioles.

—  It has anti- inflammatory, anticancer, antibacterial, antioxidant properties.

—  Pseudoephedrine is decongestant, cough suppressant and nor-pseudoephedrine is peripheral vasodilator used to treat angina.

—  It is used as hepatoprotective, anti-obesity and antiviral.

—  It also exhibits diuretic activity.

—  Ephedra is used in the treatment of asthma (Bronchodilator) and hay fever.

—  Ephedrine has more prolonged action than adrenalin as it is slowly hydrolyzed by MAO and also can be administered by mouth.

—  It has anti-sudorific action.

 

Substituents and Allied Species

Ephedra sinica 

·        Thickness: 4–7 mm

·        Length: up to 30 cm of branches

·        Leaves: 2–4 mm long, opposite, decussate and subulate.

·        Leaf, base is reddish-brown, apex acute and recurved and lamina white in colour. 

Ephedra equisetina

·        Stems are woodier and more branched 

·        Length:  25–200 cm of branches and 1–2.5 cm of internodes,

·        Outer surface: Grey to pale green and smooth.

 Ephedra nebrodensis 

·        Stems are 15–35 cm long; 1–2 mm thick,

·        Cylindrical,

·        Colour: greenish-yellow

·        Nodes are brownish and distinct and fractured surface is fibrous in the cortex but pith contains brownish powdery mass.

·        Leaves: Brownish to whitish-brown in colour, scaly, connate, opposite and decussate, acute, agreeable and slightly aromatic odour and taste is astringent and bitter.

 

MULTIPLE CHOICE QUESTIONS (Answers are marked bold)

1. Ephedra gerardiana belongs to which one of the family…………..

(a) Apocyanaceae

(b) Leguminoceae

(c) Liliaceae

(d) Gnetaceae

 

2. The principal constituent of ephedra is ……

(a) Oxazolidon

(b) Pseudoephedrine

(c) Ephedradine

(d) Ephedrine

 

3. Characteristics of ephedra leaves include………..

(a) Scale like

(b) Opposite in arrangement

(c) Whorled

(d) All of the above

 

4. The important features of ephedra stem includes………

(a) Contain longitudinal ridges

(b) Woody

(c) Branched only at once

(d) All of the above

 

5. Ephedra contains ………..

(a) Amino alkaloids

(b) Tropane alkaloids

(c) Indole alkapoids

(d) Purine alkaloids

 

6. Ephedra used as……….

(a) Hepatoprotective

(b) Decongestant

(c) Bronchodilator

(d) All of the above

 

7. …….is one of the important diagnostic features of ephedra powder.

(a) Lignified parenchyma

(b) Cork cell

(c) Calcium oxalate crystal

(d) Brown matter

 

Pharmacognosy and Phytochemistry of Kurchi Bark - A Drug Containing Steroidal Alkaloid

Synonyms

 Holarrhenna; Kurchi; Kuda

 Biological Source

 Kurchi bark consists of dried stem bark of Holarrhena antidysenterica Wall, belonging to family Apocynaceae.

 Geographical Source

 The plant is found throughout India.

 Cultivation and Collection

•        Kurchi is a shrub.

•        It is a deciduous laticiferous shrub or small tree having height of 9-10 m.

•        The bark is small and recurved both longitudinally and transversely.

•   The bark is collected from the tree by making suit-able transverse and longitudinal incisions.

•    The alkaloidal content is high soon after the rains when new shoots are produced which declines during winter months.

 Characteristics

·    Bark is small and recurved both longitudinally and transversely.

·  Colour: Outer surface is buff to reddish brown, inner surface cinnamon-brown, longitudinally striated

·   Size: Vary from piece to piece. and bears numerous prominent circular or transversely elongated horizontal lenticels and longitudinal wrinkles.

·     Odour is not distinct.

·     Taste:  Acrid and bitter

   

Fig. 1: Kurchi Bark

Microscopy: Transverse section

 ·         Cork is made up of uniformly arranged several layers of tangentially elongated cells.

·         Cortex is composed of thin-walled, irregular, polygonal parenchymatous cells containing starch grains and prismatic calcium oxalate crystals.

·         Groups of sclereids are scattered in the cortex; individual sclereid cells are more or less rounded-oval, thick-walled with numerous pits.

·         Phloem consists of phloem parenchyma similar to cortex, traversed longitudinally by medullary rays at regular intervals.

·         Medullary rays are narrow, one to two cells wide and almost straight.

Fig. 2:  Schematic Diagram of Transverse section of Kurchi Bark

Fig.3: Detailed Histological Diagram of Transverse section of Kurchi Bark

Chemical Constituents

·         Total Alkaloidal Content:  Vary from 1.1% to 4.72%.

·         Chief Constituent: Steroidal alkaloid - Conessine (20–30%).

·         Other alkaloids: Conarrhimine, conimine, conamine, conessimine, isoconessimine, dimethyl conkurchine and holarrhimine.

·         Other constituents: Gum, resin, tannin, lupeol and digitenol glycoside holadysone.

 

Fig. 4: Chemical Structure of Conessine

 Uses

• The bark of kurchi is used as stomachic, astringent, tonic and antidysentery.

·         It also has property of febrifuge and anthelmintic.

·         It helps to treat dropsy by rubbing the bark over the body.

·         It also helps to treat amoebic dysentery and diarrhoea.

  Adulterants

 Wrightia tinctori is an adulterant of kurchi.

 Marketed Products

§  Diarex PFS, Diarex Vet. (Himalaya Drug Company),

§  Mahamanjishthadi kwath (Patanjali)

§  Mahamanjisthadyarishta (Dabur)

§  Amree plus granules and Purodil capsules (Aimil Pharmaceuticals).

 MULTIPLE CHOICE QUESTIONS (MCQ)

1. Kurchi belongs to the family…………..
(a) Apocynaceae
(b) Asteraceae
(c) Lamiaceae
(d) Violaceae

2. Which part of the Kurchi plant is medicinally active………….
(a) Leaves
(b) Stem
(c) Bark
(d) Flower

3. The colour of the bark of Kurchi
(a) Yellow
(b) Brown
(c) Buff to reddish brown
(d) Red

4. Chemically, Kurchi bark is classified under a broad category of ………..
(a) Steroidal Alkaloid
(b) Steroidal Lactone
(c) Steroidal Triterpenoids

(d) Steroidal Glycosides

5. The principal constituents of Kurchi is………….

(a) Conessine
(b) Gum
(c) Resin
(d) Tannin

6. Kurchi bark is mainly used as…………
(a) Stomachic
(b) Astringent
(c) Anti-dysenteric
(d) Tonic

7. Kurchi bark contains one of the following microscopic character

(a) Stone cell
(b) Brown matter

(c) Cystolith

(d) Pitted xylem

8. Adulterant of kurchi bark is …………
(a) Wrightia tinctori
(b) Piper nigrum

(c) Cinchona officinalis
(d) Withania somnifera