Drugs of Animal Origin

Drugs of Animal Origin

This chapter is prepared for PharmD students in accordance with the officially endorsed curriculum in Pakistan.

October 20, 2024

Chapter outline: Honey; Gelatin; Shellac; Musk; Civet; Ambergris; Cod liver oil; Cantharides; Spermaceti

Honey
» Honey or mel is a saccharine secretion deposited in the cells of a honeycomb by the bee Apis mellifera and other species of Apis (Family Apidae)
» The chief sources of supply of honey are the West Indies, California, Chile, various parts of Africa, Australia, Great Britain, and New Zealand
» Use of honey dates back to ancient times, with Egyptian medical texts (between 2600 and 2200 B.C.) mentioning honey in at least 900 remedies
› Almost all early cultures universally hailed honey for its sweetening and nutritional qualities, as well as its topical healing properties for sores, wounds, and skin ulcers
› During wartime, it was used on wounds as an antiseptic by the ancient Egyptians, Greeks, Romans, Chinese, and even by the Germans as late as World War I
» Honey has been employed as a medicine, it forms an excellent gargle and facilitates the expectoration of viscid phlegm
› Honey has consistently appeared in modern use for the same purposes by the laity (layman) and the medical profession
» Today, bees are commonly kept in Europe, the Americas, Africa, and Asia
› At least 300,000 tons of honey is produced annually

Collection and preparation
» Honey bees reside in colonies
› Every colony essentially has one ‘queen’ or ‘mother bee’
› A huge number of ’employees’ or ‘worker bees’ exist under the command of queen
› Employees are mostly sterile female bees and in certain seasons male bees
» The worker bees, by means of a long hollow tube, take nectar from the flowers they visit and pass it through the esophagus into the ‘honey-sac’ or ‘crop’
Nectar: The sweet liquid that flowering plants produce as a way of attracting the insects and small birds (to assist in pollination)
› The nectar mostly contains an aqueous solution of sucrose (i.e., approximately 25% sucrose and 75% water) and pollens
› In the honey-sac, the nectar is mixed with salivary secretion containing the enzyme ‘invertase’
› Hence, the nectar (sucrose) in the honey sac is hydrolyzed into ‘invert sugar’, also known as ‘invert syrup’
A mixture of glucose and fructose is called inverted sugar. Sucrose is dextrorotatory while a mixture of its hydrolysis products (glucose and fructose) is levorotatory. That is why a mixture of glucose and fructose is called inverted sugar.
› Contents of honey-sac (invert sugar) are partly consumed by the bee for its survival and the balance is carefully stored in a previously prepared cell of the honeycomb
› With the passage of time, the water gets evaporated thereby producing honey (i.e., approximately 80% invert sugar and 20% water)
› As soon as the cell of the honeycomb is filled up completely, the bees seal it with wax to preserve it for off-season utility
» The honey is collected by removing the wax-seal with the help of a sterilized sharp knife
› The pure honey is obtained by centrifugation and filtering through a moistened cheese-cloth
› Invariably, the professional honey collectors smoke away the bees at night, drain-out honey, and warm the separated combs to recover the beeswax
› Honey obtained by expression is liable to be contaminated with the wax
Expression is a process by which the honeycomb is squeezed by hands or in a press. Expression process is also used to obtain fatty oil (fixed oil) from seeds (e.g., sunflower oil, sesame oil, etc.)

Macroscopic characters
» When freshly prepared, honey is a clear, syrupy liquid
» The color is pale yellow or reddish brown
› Odor and taste depend largely on the flowers used in its preparation
» On prolonged storage, it tends to crystallize and become opaque and granular due to the crystallization of dextrose

Chemical constituents
» The average composition of honey constituents is as follows;
› Moisture (14-24%); Dextrose (23-36%); Fructose (30-47%); Sucrose (0.4-6%); Dextrin and Gums (0-7%); Minerals (0.1-0.8%)
» Besides, honey is found to contain small amounts of;
› Essential oil; Bees wax; Pollen grains; Formic acid; Acetic acid; Succinic acid; Maltose; Dextrin; Coloring pigments; Vitamins; An admixture of enzymes (diastase, invertase, and inulase)
» Interestingly, the sugar contents in honey vary widely from one country to another as it is exclusively governed by the source of the nectar and also the enzymatic activity solely controlling the conversion of nectar into honey

Uses
» Demulcent (definition of demulcent)
› Being a demulcent, it is recommended for coughs, colds, and sore throats. It is a component of linctuses and cough mixtures.
» Emollient (definition of emollient)
› Being an emollient, honey is an important ingredient in certain lotions, cosmetics, soaps, creams, balms, etc.
» Nutrient
› Because of its natural content of easily assimilable simple sugars, it is globally employed as a good source of nutrients for infants, elderly persons, and, convalescing patients
» Antibacterial
› Because of its antibacterial potential, honey has been used to treat open and burn wounds. It will stop infection, stimulate skin regeneration, and keep the burned area moist. Honey is better for burns than nearly all medical interventions, even for third-degree burns.
» Adsorbent (definition of adsorbent)
› Because of its anti-bacterial and adsorbent properties, honey is useful in diarrhea
» Laxative (definition of laxative)
› Honey is also used as a mild laxative
» Sweetening agent
› It is used as a sweetening agent in food and medicines

Adulterant and substitutes
» Due to the relatively high price of pure honey, it is invariably adulterated either with artificial invert sugar or simply with cane-sugar syrup

♦ Which honey brands are available in Pakistan and which one do you prefer and why?
♦ What is the difference between a ‘demulcent’ and an ’emollient’?
♦ Can diabetic people consume honey? If yes, how much quantity?

♦ And your Lord inspired the bee, saying make your homes (hives) in the mountains, in the trees, and also in the structures which men erect. Then feed on every kind of fruit and keep treading the ways of your Lord which have been made easy. From its belly comes a drink with different colors which provides healing (shifa) for mankind. Indeed, in this, there is a sign for people who give thought. [Quran, Surah Nahal, Verse 68,69]
♦ The Prophet Muhammad (PBUH) prescribed honey to treat stomach upset. [Sahih Bukhari, Hadees number 5684]

Gelatin
» Gelatin is a mixture of reversible gel-forming proteins
» Gelatin is obtained by partial hydrolysis of collagen; derived from the skin, white connective tissue, and bones of animals
» Commercially, gelatin is prepared from the suitable byproducts of slaughtered cattle, sheep, and hogs

Preparation
» The initial stages of the preparation vary with the starting material
› For example, bones are defatted with an organic solvent and decalcified by treatment with an acid (e.g. HCl)
› Materials are extracted with boiling water and steam under pressure until the collagen is hydrolyzed
› The solution is then filtered by electro-osmosis, concentrated under reduced pressure, allowed to gel, and rapidly dried on netting (mesh) in currents of warm air
› When to use in the manufacture of capsules or for coating of tablets, gelatin may be colored with a certified color
» Two types of gelatin are characterized in the British Pharmacopeia/European Pharmacopeia
› Type A: Obtained by partial acid hydrolysis of animal collagen
› Type B: Obtained by partial alkaline hydrolysis
› Mixtures of both types are also permitted

Macroscopic characters
» Gelatin occurs in sheets, flakes, shreds, or as a coarse or fine powder
» It is faintly yellow or amber colored
» Possesses slight characteristic odor and taste
» When dry, it is stable in air
» When moist or in solution form, gelatin is subjected to bacterial decomposition
» Insoluble in cold water
› Swells and softens in cold water, gradually absorbing from 5 to 10 times its weight of water
» It dissolves on heating and a 2% solution forms a jelly on cooling
› Soluble in hot water
» The gelatinizing power of gelatin is reduced by long boiling
» Insoluble in volatile and fixed oils
» The quality of gelatin is largely judged by its ‘jelly strength’ or ‘Bloom strength’ which is determined by a ‘Bloom gelometer’
» There are two types of gelatin;
› Type A has isoelectric points in the ranges pH 6.0-9.5
› Type A is not compatible with anionic substances
› Type B has isoelectric points in the ranges pH 4.7-5.6
› Type B is compatible with anionic substances (e.g., natural gums)
The isoelectric point is the pH at which a molecule carries no net electrical charge or is electrically neutral in the statistical mean

Chemical constituents
» Amino acids
» Chondrin (gelatinizing agent)
» Gelatin is an incomplete nutritional protein because tryptophan is absent and other important amino acids are present only in traces

Uses
» Joint health
› Gelatin supplements are used to improve joint health (may help reduce symptoms of osteoarthritis and other degenerative joint disorders by supporting cartilage repair and reducing inflammation)
» Bone health
› Gelatin is the most convenient way to ingest the important amino acids of collagen. So, gelatin can help maintain bone health.
» Skin, hair, and nail health
› Gelatin is believed to enhance skin elasticity and hydration, potentially reducing the appearance of wrinkles. It also strengthens hair and nails due to its collagen content
» Blood plasma substitutes
› In some medical situations, gelatin is used as a plasma substitute in emergency treatments to maintain blood volume during shock or trauma
» Pharmaceutic aid
› Encapsulating agent
› Suspending agent
› Tablet binder
› Coating agent
› As a vehicle and in the manufacture of suppositories
» Zinc oxide is added to form zinc gelatin
› Zinc gelatin is used as a topical protectant
» As a nutrient, gelatin is used for the preparation of commercial food products and bacteriological culture media

Absorbable gelatin sponge
» Absorbable gelatin sponge is a sterile, absorbable, water-insoluble, gelatin-base sponge
› Absorbable gelatin sponge is a local hemostatic
› It is applied topically in operative wounds

Absorbable gelatin film
» Absorbable gelatin film is a specially prepared gelatin product used in neurosurgery and in thoracic and ocular surgery
› When moistened by immersion in a salt solution, it is easily cut into the shape needed to fit into the contours of the incision

Microfibrillar collagen
» Microfibrillar collagen is a fibrous, water-insoluble material prepared from purified bovine collagen
› It is an absorbable, topical hemostatic agent that is used in surgical procedures when control of bleeding by ligature or other conventional means is ineffective or impractical
› It is applied dry and directly onto the bleeding surface
› The microfibrillar collagen attracts platelets that adhere to the fibrils and trigger the formation of thromb

♦ Is, gelatin produced in non-Muslim countries, Halal?
♦ Are, capsules and gelatin-containing eatables produced in non-Muslim countries, Halal?

Lac/Shellac
» Shellac is a resinous substance prepared from the excretion of the scale insect Lucifer lacca (Family Coccidae)
› Produced in India, Thailand, China, and Pakistan

Collection and preparation
» The insects live on the juices of various trees
› The insects suck the juice of the tree and excrete ‘stick lac’ almost continuously (Figure 1A)
› Stick lac is found most abundantly on the smaller branches and twigs
» Twigs/branches are broken off
› Stick lac is scrapped with the help of curved knives
› Scrapped stick lac is ground to powder
» The ground stick lac undergoes an extraction process (with water or a dilute alkali solution) 
› The obtained extract is dried and is called ‘lac dye’ (Figure 1C)
› Lac dye is used as a coloring matter
› After extraction of the ground stick lac, the exhausted stick lac, in dried form, is known as ‘seed lac’ (Figure 1B)
» Seed lac is melted in a long sausage-shaped bag suspended over a charcoal fire and the lac is squeezed out (Figure 1D)
› This lac (squeezed out from the sausage-shaped bag) is processed in three ways, as follows;
1. It is cooled and then stretched into a large sheet
› The large sheets are then broken up to produce ‘flake shellac’ (Figure 1E)
2. Sometimes, lac is poured into circular molds, and on cooling, stamped with the maker’s name
› This form is known as ‘button lac’ (Figure 1F)
3. Lac is bleached with chlorine
› It is known as ‘bleached shellac’ 

Macroscopic characters
» Shellac occurs in thin, very brittle, yellowish, translucent sheets or powder
» Soluble in alcohol, ether, benzene, and petroleum ether
» Insoluble in water

Main constituents
» Resin (70-85%)
» Wax (6%)
» Red coloring matter (6.5%)
» Laccaic acid
» Few insects remain
» Vegetable debris

Uses
» Shellac is reported to be used as a protective barrier on the skin to shield wounds or irritated skin from environmental factors
» Used in dentistry, as a binding agent for dentures, restorations, and moldings, and for training purposes in dental schools
» Used in tablet coating 
» Coating of citrus fruits with shellac reduces the loss of water and volatile flavoring components
» Finishing leather
» In lacquers (polishes) and varnishes in the furniture industry
» Shellac has also been used as an ingredient in hair spray and other cosmetics, like mascara and lipstick
» To manufacture buttons and sealing wax

Musk (کستوری)
» Musk is the dried secretion from the preputial follicles of the male musk deer (not female) Moschus moschiferus
› The preputial follicles are located in the musk pod, a sac under the skin of the abdomen between the genitals and the navel
› The musk-containing sacs are brown, about 5-7 cm in diameter, weigh up to 30 g, and contain musk, about half of their weight
› The musk pod is normally obtained by killing the male deer
› Farming of musk deer is becoming a vital way to protect musk deer and the only legal way to obtain the natural musk
› This deer is found in China and the Himalayas
› To date, seven species of musk deer have been discovered in the aggregate worldwide

Main constituents
» When distilled, musk yields about 1.4% of dark brown volatile oil
› The chief odorous principle of the oil is ‘muscone’
» Other constituents
› Steroidal hormones; Mscopyridine; Alkaloids; Peptides

Uses
» Musk acts like the male sex hormones (androgens) and is considered an aphrodisiac (definition of aphrodisiac)
› In traditional medicines, musk is considered a symbol of health (especially male health), power, and vitality
› This is the reason for its use in traditional medicines as a tonic to resolve all health issues
» In China, musk has been utilized as a kind of medicine to treat stroke, coma, neurasthenia, convulsions, heart diseases, ulcerous sores, and other conditions for 2000 years
» Musk is also used as a fixative in the perfume industry (stabilizing or preservative agent)
› Also an important ingredient of many high-class perfume

♦ The Prophet Muhammad (PBUH) was asked about musk and he said: It is the best of your perfumes. [Jamia Tirmizi, Hadees number 992]

Civet

» Civet is the odorous secretion obtained from highly specialized scent glands in the region of the external reproductive organs of male and female civet cats, Viverra zibetha (Family Viverridae)
› Civet cats are widely found in Africa, South East Asia, and Southern Europe
› Civet cats can be distinguished from ordinary cats by their fine-toed hind feet, longer muscles, and shorter limbs
› Civets are omnivorous in diet 

Macroscopic characters
» A pale-yellow semi-liquid
» Has an obnoxious odor, but when diluted becomes very pleasant
› Taste is bitter
» Partly soluble in hot alcohol and ether
› Insoluble in water

Main constituents
» Civetone
› Civetone is a cyclic ketone closely related to muscone
» Civetol
» Propylamine

Uses
» Wound healing
› In certain cultures, civet has been applied to wounds or cuts to promote healing, due to its believed antiseptic and healing properties
» Aphrodisiac
› Civet has historically been regarded as an aphrodisiac
» Anti-inflammatory
› In folk medicine, civet was applied topically to treat skin conditions and reduce inflammation. It was sometimes used for conditions like rashes or swelling
» Perfume and aromatherapy
› Civet’s strong musky odor has been used in perfumes and incense. Its scent was thought to have mood-enhancing properties, providing a calming and comforting effect when inhaled.

Ethical considerations
» Musk and civet are obtained from animals, often in ways that are considered cruel
» There are significant ethical concerns about the use of musk and civet
» Synthetic analogs are now considered an alternative to avoid animal exploitation

♦ What do you know about ‘civet coffee’?

Ambergris (عنبر)
» Ambergris is a pathological product found in the intestine of sperm whale Physeter macrocephalus (Family Physeteridae)

Production of ambergris
» The main part of the sperm whale diet is ‘squid’ (a type of fish)
› After ingestion, the sperm whale cannot digest the beaks of squids
› Indigested beaks of squids cause injury in the intestine of the sperm whale and in turn, stimulate the formation of ambergris
» So, ambergris consists of a soft, waxy mass that builds up in the intestine of the sperm whale
› Ambergris is a very expensive aromatic substance
› Ambergris is found floating on the oceans or collected from the shores of many countries around the world
› Sometimes, the masses weighing 1 kg to 10 kg or more are found floating at a time

Macroscopic characters
» Grey to black waxy mass
» Soluble in hot alcohol, chloroform, ether, fats, and volatile oil
› Insoluble in water
» It volatilises at 100 °C into white vapors

Main constituents
» Ambrein (a triterpene alcohol)

Uses
» Considered aphrodisiac
» Sometimes used to treat digestive disorders
» Ambergris has been employed as a remedy for nervous system disorders, including treating headaches, migraines, and anxiety
» Anticonvulsant
» Heart tonic
» Mood Enhancer
» Anti-inflammatory
» Creating perfume and fragrance much like musk

Cod liver oil
» Cod liver oil is a fixed/fatty oil prepared from the fresh liver of the cod (a type of fish), Gadus morrhua and from other species of Gadus (Family Gadidae)

Preparation
» The cod are caught by ship and their livers, which contain approximately 50% oil, are removed
» The cod livers are then transferred to steamers (at the ship) in which the oil is released from the tissue, or
› The cod livers are stored in chilled conditions (at the ship) for later processing at a shore station

» Following are the principal stages in the preparation of the medicinal oil;
» Refining
› Refining is carried out under air-free conditions to avoid oxidation
› Refining is carried out in a continuous, automatic, hermetic refining plant consisting of a battery of mixers linked to centrifuges
› The crude oil is rapidly heated to 77 °C in a heat exchanger and passed to disc-type mixers
› In these disc-type mixers controlled addition of an aqueous reagent takes place which removes impurities and causes further dissolution of the small amount of liver tissue present
› Oil and water phases are separated in a hermetic separator (centrifuge: 7000 rpm) without contact with air
› The refined oil is then mixed with water and reheated; and the separation process is repeated in a second and third set of centrifuges
» Drying
› Drying is done in a vacuum drying tower
› It continuously evaporates any small amount of residual water
› Produces a clear, bright, and highly refined oil
» Winterization
› All medicinal oil and veterinary oils are cooled to about 0°C
› It causes stearin (triglycerides with a higher saturated fatty acid content) to separate
› The solid is removed by cold filtration
› A polyunsaturated (enriched) product is left
» Deodorization
› Final deodorization is achieved by steaming under vacuum
› It removes aldehydic and ketonic impurities
› This process establishes the palatable flavor of the finished oil
» Standardization
› The medicinal oil is finally standardized for vitamin content by blending
› The BP/EP oil is required to contain in 1 g, 600 to 2500 International Units of vitamin A and 60 to 250 International Units of vitamin D₃
» Storage
› The oil should be kept in well-filled airtight containers, protected from light, and in a cool place

Characters
» Medicinal cod liver oil is a very pale yellow liquid with only a slightly fishy odor and taste
» The acid value should not exceed 2.0 but varies with age
» The iodine value, as may be inferred from the constituents, is high (150-180)

Main constituents
» The medicinal properties of cod-liver oil are mainly due to vitamin A and vitamins of the D group
» The main antirachitic activity appears to be due to D₃ (cholecalciferol)
» The oil consists of glycerides of unsaturated (about 85%) and saturated (about 15%) acids
» Evidence is increasing that these polyunsaturated acids are significant for human health

Uses
» Joint health and rheumatoid arthritis
› Cod liver oil has been widely used to reduce inflammation and alleviate symptoms of rheumatoid arthritis. Its omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have anti-inflammatory properties, helping to relieve joint pain, stiffness, and swelling.
» Bone Health
› The high vitamin D content in cod liver oil supports calcium absorption and bone health, making it beneficial for preventing or managing conditions such as osteoporosis. It helps maintain bone density and reduces the risk of fractures, particularly in older adults.
» Cardiovascular health
› The omega-3 fatty acids in cod liver oil promote heart health by reducing triglyceride levels, lowering blood pressure, and improving cholesterol profiles
» Eye health
› Vitamin A, found abundantly in cod liver oil, is essential for maintaining healthy vision
» Cognitive function
› Cod liver oil’s omega-3 fatty acids are critical for brain development and function
» Skin health
› Cod liver oil has been traditionally used to improve skin conditions such as eczema, psoriasis, and dry skin
» Cod liver oil has extensive veterinary use as well

♦ How does vitamin D regulate calcium in our body?
♦ Why unsaturated fatty acids are considered healthy?
♦ Which are omega-3 fatty acids and why are they named ‘omega-3’?

Cantharides (ہسپانوی مکھیاں)
» Cantharides, Spanish flies, Russian flies, or blistering flies consist of the dried insect, Cantharis vesicatoria (Family Meloidae)

Preparation
» The insects are found on certain shrubs of the Caprifoliaceae and Oleaceae families that grow in Southern and Central Europe
» Mature insects are brilliant green with a metallic luster
» These usually appear in June or July
» In the early morning, when the insects are still sluggish from the cold of night, the shrubs are shaken or beaten with poles and the insects are collected on cloths spread on the ground
› Insects are killed by plunging into dilute vinegar; by exposure to the fumes of hot vinegar, ammonia, sulfur dioxide; or by means of ether, chloroform, or similar drugs
› After the killing, insects are carefully dried at a temperature not higher than 40 °C
› Drug should be stored in dried containers
› A few drops of chloroform or carbon tetrachloride should be added occasionally to preserve the drug from attack by other insects

Main constituents
» Cantharidin (0.6-1.0%)
» Fat (12%)

Uses
» Irritant (Definition of irritant)
» Vesicant (Definition of vesicant)
» Rubefacient (Definition of rubefacient)
» If taken internally, it is excreted by the kidney, irritates the urinary tract, and can result in priapism
› This accounts for the drug’s popular reputation as an aphrodisiac in humans and male livestock
Priapism is a medical disorder in which there is persistent, often painful erection of the penis in the absence of sexual interest
» Internal administration is potentially dangerous
» Wart and mole removal (solution of cantharidin, applied topically)

♦ What is meant by irritant, vesicant, and rubefacient?
♦ Are such characteristics of a drug beneficial for health, and how?

Spermaceti

» Spermaceti is a waxy substance obtained from the head of the sperm whale Physeter macrocephalus (Family Physeteridae)
› Sperm whales are found mainly in the Pacific, Atlantic, and Indian oceans
› The sperm whale is an endangered species and spermaceti is no longer available
› Efforts to find a substitute for spermaceti have led to the use of a synthetic spermaceti

Preparation
» Sperm oil is secreted in a large special cavity above the right nostril in the jaw of sperm whale
› The cavity is emptied after the animal is captured
› The oil on cooling deposits a crystalline mass known as spermaceti
› Sperm whales die during this process

Macroscopic characters
» Spermaceti is odorless and tasteless
» Becomes yellow on exposure to air
» It is soluble in oils, chloroform, carbon disulfide, and boiling alcohol
› It is insoluble in petroleum ether and water

Main constituents
» Cetyl palmitate
› It is the main component of spermaceti
› It is an ester of palmitic acid and cetyl alcohol
» Fatty alcohols
› Spermaceti contains long-chain fatty alcohols such as ‘cetyl alcohol’ and ‘stearyl alcohol’
» Triglycerides
› Small amounts of triglycerides can also be found in spermaceti

Uses
» Skin softener and emollient
› Spermaceti was commonly used in the treatment of dry skin, burns, and chapped lips
› Its high content of cetyl palmitate and fatty alcohols gave it excellent emollient properties, making it an effective ingredient in creams, ointments, and lotions to soften and moisturize the skin
» Wound healing
› Spermaceti was applied to minor wounds, burns, and abrasions as a soothing agent
› Its ability to form a protective barrier over the skin was believed to promote healing and protect wounds from infection
» Lubricant for eyes and ears
› In certain medical practices, spermaceti was used as a lubricant for dry eyes and in preparations for treating ear conditions such as earwax buildup
› Its smooth, waxy texture made it ideal for use in delicate areas like the eyes and ears
» Cosmetic use
› Spermaceti was widely used in the manufacture of cosmetics, such as face creams, lip balms, and hair conditioners
› Its moisturizing and smoothing properties made it a popular ingredient in beauty products before the advent of synthetic substitutes

» With the decline in sperm whale populations and increased awareness of ethical concerns, the use of spermaceti in pharmaceuticals and cosmetics has largely been replaced by synthetic alternatives, such as synthetic cetyl palmitate and synthetic esters
› These alternatives replicate many of the beneficial properties of spermaceti without harming whale populations

Reading References

» Ahmad M et al. Textbook of Clinical Pharmacognosy. BCC&T Press, University of Karachi, 1^st edition, 2016.
» Evans WC. Trease and Evans Pharmacognosy. Elsevier, 16^th edition, 2009.
» Kar A. Pharmacognosy and Pharmacobiotechnology. New Age International Publishers. 2^nd edition.
» Kokate CK, Purohit AP, Gokhale SB. Pharmacognosy. Nirali Prakashan, 55^th edition.
» Shah BN, Seth AK. Textbook of Pharmacognosy and Phytochemistry. Elsevier, 1^st edition, 2010.
» Tyler VE, Brady LR, Robbers JE. Pharmacognosy. Lea & Febiger, 9^th edition, 2003.
» http://www.bskoshellac.com/stick-lac.htm [Accessed: October 20, 2024].
» https://www.flipkart.com/hmr-button-lac-gala-rich-reddish-brown-wood-varnish/p/itm52cb043cc7253 [Accessed: October 20, 2024].
» https://mapacademy.io/article/lac-dye/ [Accessed: October 20, 2024].
» https://www.rockler.com/liberon-blonde-dewaxed-shellac-flakes-250g [Accessed: October 20, 2024].
» https://www.shellac.net/seed_shellac.html [Accessed: October 20, 2024].
» https://www.youtube.com/watch?v=ALToZ4kB0fc [Accessed: October 20, 2024].

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