European Journal of Forensic Sciences
DOI: 10.5455/ejfs.174977www.ejfs.co.uk
Eur J Forensic Sci ● Apr-Jun 2015 ● Vol 2 ● Issue 2 15
INTRODUCTION
The primitive man, in his quest for food, must have come across plants containing poisonous substances. By trial and error, humans in the early times learn to distinguish between the parts of a poisonous plant that could be harmful or even fatal and the others that could be ingested safely. Hence with time, poisoning was developed as a method for murder and suicide.
Cases have been reported in which criminals have used toxic or irritating plants to cause harm to their victims [1] even death [2‑4], if a small quantity of their stem, leaves, seeds, fruits, roots or any other part is ingested [5] either immediately or by reason of cumulative action of the toxic property due to presence of known or unknown chemical substances in them and not by mechanical action [6]. The poisonous nature of whole plant or any part of it is due to production of toxic substances. Some other plants are normally harmless, but they may become toxic if preparations from them are taken in excess in strong doses or for a long period of time as suggested by Qurush et al. [2]. Small amounts of compounds in some plants may be used in medicines.
It has been reported that [7] there are no physical characteristics that allow a plant to be automatically identified as being potentially poisonous. However, the presence of some chemical substances or compounds makes them poisonous plant.
There are more than 20 groups of chemical constituents or compounds, primarily alkaloids, glycosides, saponins, resinoids, oxalates photosensitizing compounds and mineral compounds accumulated from the soil, which make a plant or its part poisonous.
Plants containing alkaloids often produce unpleasant or dangerous reactions in the nervous system. Examples are paralysis (hemlock), hallucinations (thorn apple) or heart block (yew). A lot of work has been reported on toxicology of plants, but no work has been done specially on study of chemical constituents of plants in terms of forensic context. In the present study, a review has been performed on most of the poisonous plants of India to report the basic details of the plants poisonous parts, toxic chemical constituents, etc.
PLANT POISONING
There are more than 4000 species of medicinal plants growing as herbs, shrubs and trees in world, many of which are poisonous when administered in large doses. Suicide or murder by poisoning is common in world as poison can be easily obtained, and many poisonous plants grow in wild, e.g. dhatura, oleanders, aconite, nux vomica, etc. Moreover, many persons consider the taking of life by blood‑shed a greater crime than poisoning, strangling, etc. Accidental poisoning occurs from the use of philters or love potions and quack remedies containing poisonous drugs. The
Plants and their toxic constituent’s forensic approach: A ReviewRitika Gupta, Vinod Dhingra
Review Article
Department of Toxicology, Regional Forensic Science Laboratory, Gwalior, Madhya Pradesh, India
Address for correspondence: Vinod Dhingra, Regional Forensic Science Laboratory, Gwalior 474009, Madhya Pradesh, India. E-mail: [email protected]
Received: December 13, 2014
Accepted: February 16, 2015
Published: April 15, 2015
ABSTRACTPlants contain a large number of biologically active chemicals. Some of these have been found to be extremely useful for treating various human and animal diseases (e.g. digitoxin, colchicines and atropine). However, some plant chemical constituents produce adverse health effects following exposure. Fortunately, among thousands of plants in the environment of animals, relatively few cause acute, life-threatening illnesses when ingested. The diversity of chemical substances in plants is quite amazing.There are a number of broad categories of toxicologically significant plant chemical constituents. These include alkaloids, proteins, glycosides and resins. The present review is an effort to collect all the facts regarding poisonous plants, toxic constituents and their chemical tests for forensic analysis.In the present review, an effort has been made to highlight various poisonous chemical constituents of the plants. Scattered literature regarding classification of plant’s chemical constituents, methods of analysis of poisonous chemical constituents have been thoroughly received and collected from journals, analytical procedure manuals and text books to make this review useful to all specialists of different discipline especially it has been design to provide an essential information of analytical approach. In this review, an effort has been made to include common poisonous plants, their harmful chemical constituents used as a weapon of crime.
KEY WORDS: Forensic sciences, forensic toxicology, chemical tests, forensic testing, plant poisoning
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incidence of poisoning in India is among the highest in the world, and it is estimated that more than 50,000 people die every year from toxic exposure [2]. The causes of poisoning are many ‑ civilian and industrial, accidental and deliberate [8]. The toxic principle of a poisonous plant may be a single substance, a number of substances with different chemical properties or the toxic compounds that may not have been yet characterized. The vast variety of chemical compounds synthesized within the plant kingdom can be classified as primary metabolites and secondary metabolites. Poisonous substances in plants are secondary plant metabolites.
Classification of Plant Poisons
Plant poisons are the chemical constituents or substances of “organic nature”, which are formed in plants through the activity of their individual cells. The plants are able to convert the simple chemical substances into complex organic compounds with the help of enzymes. It is essential to take cognizance of the fact that overuse or abuse of the medicinal constituents of plants can cause danger [9]. Plants containing glucosides, acids or alkaloids are used as medicines. Thus, when taken in excess often have an adverse effect.
According to their chemical constituents, plant poisons are broadly classified in four groups, which are sub‑divided on the basis of their chemical structure and pharmacological action.
CLASSIFICATION OF POISONOUS PLANTS ON THE BASIS OF THEIR CHEMICAL CONSTITUENTS
Alkaloids
The alkaloids are a heterogenous group of compounds “alkaloids can be generally defined as basic, nitrogen containing heterocyclic compounds of plant origin.” Alkaloids contain one or more nitrogen atoms usually as a part of a cyclic system, but alkaloids such as ephedrine and mescaline contain nitrogen, which is not present in cyclic form, colchicine is an exception to the above definition as like alkaloid is not basic in nature. The alkaloids are found in various parts of the mature plants as illustrated by some examples of drugs: In seeds (strychnos), in fruits (piper), in leaves (belladonna), in roots (rauwolfia).
Chemical Classification
This classification is universally adopted and depends on the fundamental ring structure carbon‑nitrogen skeleton. According to these two main groups
1. Non‑heterocyclic Alkaloids: In this group of alkaloid not has any one Heterocyclic ring in their structure. E.g., Hordenine
(Hordeum vulgare), Ephedrine (Ephedra gerardiana) Genateceae.
2. Heterocyclic Alkaloids: According to heterocyclic ring the alkaloids are sub‑divide in following: ‑
Pyridine-piperidine alkaloids
Alkaloids are containing pyridine‑piperidine, α‑propyl piperidine and derivative of nicotinic acids. Heterocyclic ring in their structure. Reduction of pyridine converts it into piperidine. This group includes alkaloids containing piperidine. e.g., nicotine, lobaline, piperidine, ricinine.
Tropane alkaloids
Tropane is a bicyclic structure in which pyrrolidine and piperidine systems fused through a common nitrogen atom. Alkaloid is containing tropone ring. The alcohol corresponding to tropen is tropine. Its ester with organic acids like tropic acid or benzoic acid constitutes tropane alkaloids. e.g., Family Solanaceae (belladonna hyoscyamus) and Erythroxylaceae, Hyoscyomine, Atropine Hyoscine ‑ Solanaceae Cocain - Coca spp.
Quinoline alkaloids
The alkaloids are containing the quinoline as their basic nucleus structure is obtained from the bark of Cinchona species. The major alkaloids of this group are quinine, quinidine. (Cinchona bark) Cinchonine, Cinchonidine and cusparin ‑ (cusparia bark). e.g., Cinchona officinalis Linn.
Isoquinoline alkaloids
Alkaloids are containing is quinoline ring in their chemical structure. The alkaloids containing isoquinoline are obtained from the plant such as opium and ipecac. The major alkaloids of opium may be put into two groups on the basis of their chemical structure, one group includes morphine, codeine and thebaine, and other group includes papaverine and narcotine.
Although the alkaloids of the first group exhibit a phenanthrene nucleus and second group exhibit a isoquinoline nucleus, but the alkaloids of both the groups have the same biosynthetic intermediate, i.e., benzylisoquinoline. e.g., Papaver somniferum (opium alkaloids ‑ papaverine, narcotine, narceine); Argemone mexicana.
Indole alkaloids
These alkaloids have indole nucleus as a part of their chemical structure. Alkaloids of such important crude poisonous plants,
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e.g., rauwolfia, vinca, physostigma and ergot belong to indole type.
Nux vomica alkaloids strychnine and brucine also have indole ring. Reserpine is the main alkaloids of the rauwolfia plant. It has two nitrogen atoms and a complex structure. The alkaloid is used as antihypertensive and tranquillizer.
Imidazole alkaloids
Imidazole ring containing alkaloid is represented by pilocarpine, which is the principle alkaloid of pilocarpus. e.g., Pilocarpus.
Steroidal alkaloids (Phenanthrene alkaloids)
The alkaloids, which have steroid (cyclopentano perhydro phenanthrene) nucleus with nitrogen attached to it are called steroidal alkaloids. Kurchi contains these types of alkaloids, conessine being the major one.
Alkaloidal amines (Phenylethylamine group)
The alkaloids of this class do not possess nitrogen in a ring system. Most of them are simple derivatives of phenylethylamine. The important poison plants of this group are Ephedra and Colchicum corn.
Purine bases
A group of nitrogenous compounds with purine nucleus chemical structure consists of caffeine, theophylline and theobromine. These are called as purine bases. Tea leaves and coffee seeds are the sources of these bases. e.g., Tea leaves, and coffee seeds.
Senecio alkaloids (Pyrrolizidine group)
Alkaloids are containing pyrrolizidine heterocyclic ring in their structure, e.g., seneciphylline Senecio spp. The genus Senecio comprises more than a thousand species of plants. They are noted to be serious cattle poisons. The name ‘Senecio bases’ was given to this group of alkaloids.
Quinolizidine alkaloids (Lupin alkaloids)
This group of alkaloids has been found to occur in a wide variety of plants. Many of them belong to the family Leguminosae though a few also belong to other families, e.g., Chenopodiaceae, Berberidaceae and Papaveraceaes. The alkaloids belonging to this group have the basic nucleus quinolizidine structure hence they are known as ‘quinolozidine alkaloids’.
Glycosides
Glycosides in general, are defined as the condensation products of sugars (including polysaccharides) with a host of different varieties of organic hydroxy (occasionally thiol) compounds (invariably monohydrate in character), in such a manner that the hemiacetal entity of the carbohydrate must essentially take
part in the condensation. Glycosides are colorless, crystalline carbon, hydrogen and oxygen‑containing (some contain nitrogen and sulfur) water‑soluble phyto constituents, found in the cell sap [10]. The sugar component of glycosides is called glycone, and the non‑sugar part is called aglycone.
On the basis of the chemical structure of the aglycone, the glycosides are divided as:
Steroidal glycosides
These glycosides contain a sterol as an aglycone. The sugar portion of the glycoside helps in its absorption and distribution in the body. Oxygen substitution on the steroid nucleus also affects the distribution and metabolism of the glycosides. Larger number of hydroxyl groups causes more rapid action of the glycoside in the body.
Cardiac glycosides
These are steroidal glycosides, and here the aglycone part is a steroidal nucleus. The sugar part is attached at C‑3 position of the steroidal nucleus, Strophanthus, Oleander, Calotropis and Convallaria.
Flavonoid glycosides
The flavonol glycosides and their aglycones are generally termed flavonoids occur in nature, and these yellow pigments are widely distributed throughout the higher plants. e.g. Rutin, quercitrin and the citrus bioflavonoids are among the best‑known flavonoid glycosides.
Anthraquinone glycosides
These glycosides are the ones whose aglycone component is a polyhydroxyanthraquinone derivative. The anthraquinone derivatives are often orange‑red colored. The common polynhydroxy anthraquinone derivatives present in these drugs are chrysophanic acid, aloe emodin, frangula emodin and rhein.
Cyanophoric glycosides
The aglycone part is Cyanogens. They yield hydrocyanic acid on hydrolysis.
Cyanogenetic glycosides: In these cases, the aglycone contains a cyanide group. These glycosides, yield most toxic acid, hydrocyanic acid compounds, are toxic to unadapted farm animals and humans. Glycosides, which may be said to have direct toxic action on animals are digitoxin found in Digitalis, cerbering found in Cerbera, strophanthin found in Antiaris, and so on. e.g., Brasica alba (white mustard).
Isothiocyanate glycosides: These glycosides contain sulfur and represent in many Cruciferous plants. On hydrolysis, they produce isothiocyanate aglycones, which may be aliphatic or
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aromatic. These glycosides are employed as counte‑irritant. e.g., Sinigrin from Black mustard (Brasica nigra koch), sinalbin from White mustard.
Alcohol glycosides
Salicin is an alcoholic glycoside obtained from several species of Salix and Populus. The active ingredients of alcohol glycosides are salicylate, (aglycone is Saligenin, which breaks down into salicin, which hydrolyzed and breaks down into Salicylates by emulsion). Its actions are similar to that of salicylic acid. e.g., Salicin in Salix purpurea species.
Lactone glycosides
These glycosides contain coumarin or hydroxylated coumarin derivatives aglycones. e.g., Scopoolin in belladonna and limettin Citrus trees.
Aldehyde glycosides
Green vanillin contains two glycosides, namely glucovanillin (vanilloside) and glucovanillic alcohol. Glucovanillic alcohol yields on hydrolysis glucose and vanillic alcohol; the latter compound is then by oxidation converted into vanillic aldehyde (vanillin).
Phenolic glycosides
The aglycone group of many of the naturally occurring glycosides is phenolic in character. Thus, arbutin, found in uva ursi, chimaphila and other ericaceous drugs, yields hydroquinone and glucose upon hydrolysis. e.g., Hesperidin in citrus fruits, phloridizine in root bark of rosaceous plants, baptisin and iridin in iris species.
Saponin glycosides
Saponins possess a bitter, acrid taste and in the form of a dry powder cause irritation to the nose. The more poisonous saponins are sometimes known as ‘sapotoxins.’ On hydrolysis, they yield different sugars, generally hexoses and pentoses.
According to the structure of the aglycone or sapogenin, two kinds of saponins are recognized, both of which have a glycosidal linkage at C‑3.
a) Steroidal saponin (TETRACYCLIC triterpenoid saponins): The saponin glycosides are broadly regarded as hemotoxic in nature by virtue of the fact that they afford the hemolysis of erythrocytes. A distinct subgroup of the steroidal saponins is that of the steroidal alkaloids, which characterize many members of the solanaceae. They possess a heterocyclic nitrogen‑containing ring, giving the compounds basic properties, e.g., solasodine.
b) Pentacyclic triterpenoid saponin: A triterpene molecule is condensed with a sugar component, e.g., glycyrrhizin.
Toxic proteins
All the proteins are composed of various amino‑acid units or their derivatives condensed together. The plants containing toxic proteins, also known as ‘toxalbumins’ belong to Leguminosae family, e.g., Croton, Ricinus, Jatropha and Hura. These toxalbumins are blood poison and agglutinating and precipitating the red blood cells.
e.g., Abrin from Abrus precatorius Linn.; Crotin from Croton tiglium Linn.; Ricin from Ricinus communis Linn.; and Crucin from Jatropha curcas linn.
The review on all toxic plants has been summarized in Table 1 and according to chemical structure, toxic plants constituents has been summarized in Table 2‑4 and 5, plant which provides a fundamental database for the forensic community. It has been reviewed with the available literature [4,7,12‑14]. It can be used during forensic crime scene search as well as by toxicologists as standard comparison during laboratory examination, for identification of plant poisons.
EXTRACTION AND ISOLATION
Purification or isolation of alkaloids from a plant is always a difficult process because an alkaloids bearing plant generally contains a complex mixture of several alkaloids with glycoside organic acid also complicate the process. Following steps are involved in the isolation process
Detection of presence of alkaloids: First of all confirm the presence of alkaloids in raw material or crud drugs by various reagents called alkaloids reagents, e.g., I. Mayer (Cream Color) Test II. Marquis (Conc. HCHO) Test III. Erdmann (Conc. HNO3) Test IV. Hager’s (Yellow Color) Test V. Frohdes (Molybdic acid) Test.
Extraction: The plants is dried, then finally powdered and extracted with boiling methanol. The solvent is distilled off, and the residue treated with inorganic acids, when the bases (alkaloids) are extracted as their soluble salts. The aqueous layer containing the salt of alkaloids and soluble plant impurities is made basic with NaOH. The insoluble alkaloids are set free precipitate out. The solid man (ppt.) so obtained is then extracted with ether when alkaloid pass into solution and impurity left behind. Flow Chart of extraction
Separation of alkaloids: After detection of next step is the separation of a relatively small percentage of alkaloids from a large amount of crude drugs. e.g., Opium contains 10% Morphine; Cinchona contains 5‑8% Quinine, Belladona‑0.2% of Hyoscyamine. The required alkaloid is separated from the mixture from fractional, crystallization, chromatography and ion exchange method.
PHYSICAL PROPERTY
They are colorless, crystalline solid. Exception ‑ Berberin (Yellow), Nicotine Coniine (liquid). They are insoluble in
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Table 1: Poisonous plants and their chemical constituentsClass. no. Name of the class Group no. Name of the group Examples of poisonous plants
1. Alkaloids A. Pyridine‑Piperidine alkaloids Nicotiana tabaccum Linn.; Cytissus scopariusB. Tropane alkaloids Atropa belladonna, Dhatura fastuosalinn, Erythroxylum cocalinn.C. Quinoline alkaloids Cinchona officinalis Linn.D. Isoquinoline alkaloids Papaver somniferum (Opium Alkaloids ‑ Papaverine, Narcotine,
Narceine); Argemone mexicanaE. Indole alkaloids Ergot, Strychnos nux‑vomicaF. Imidazole alkaloids PilocarpusG. Steroidal alkaloids
(Phenanthrene alkaloids)Papaver somniferum (opium alkaloids ‑ morphine, codeine, thebaine, oripavine)
H. Alkaloidal amines (Phenylethylamine group)
Colchicum corm, Gloriosa superb, Lophophora williamsii
I. Purine bases. Verbamate, Gurana berries, Guayusa, and the Vaupon holly. Tea bush and coffee plant (Caffeine)
J. Senecio alkaloids (Pyrrolidine group) Nicotiana tobaccum Linn.K. Lupin alkaloids (Quinolizidine group) Lupin polyphyllus
2. Glycosides A. Steroidal glycosides Cardiac glycosides
Thebatia peruviana; D. purpurea linn; Plumbago zeylanica; Cerbera thevetia; Calotropis gigentea; Nerium oleander
B. Flavonoid glycosides Semicarpus anacardiumC. Anthraquinone glycosides Aloe veraD. Cyanophoric glycosides
a) Cyanongenetic glycosidesb) Isothiocyanate glycoside
A. palmate; Dieffenbachia sp.; Manihot utilissima; Sorghum laurocerasus, Prunus amygdalusBrassica nigra; Brassica alba
E. Alcohol glycosides Salix purpureaF. Lactone glycosides Nerium oleanderG. Aldehyde glycosides VanillinH. Phenolic glycosides Arctostaphylos uva‑ursiI. Saponin glycosides
1. Steroidal saponin2. Pentacyclictriterpenoid saponin
Solanum nigrum linn. Glycyrrhiza glabra
3. Toxic protein Toxalbumines Abrus precatorius Linn; Croton tiglium Linn; Ricinus communis Linn; Jatropha curcas Linn
4. Resins Cannabis sativa
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Name of Plant/Family Common Name/Hindi Name
Toxic parts Toxic constituents Specific chemical constituents/group
Basic ring structure
Nicotiana tabaccum Linn.(Solanaceae)
Tobacco and tambaku
All parts except ripe seeds
Nicotine Pyridine‑piperidine alkaloids
Cytissus scoparius (Leguminosae)
Yellow broom Seed, leaves and Twigs
Cytisine and Sparteine Pyridine‑piperidine alkaloids
Atropa belladonna (Solanaceae)
Deadly nightshade All parts Atropine, Scopolamine, Hyoscyamine, and Belladonnine
Tropane alkaloid
Dhatura fastuosa linn (Solanaceae)
Thorn apple and dhatura
All parts especially seeds and fruit
Atropine, Hyoscyamine, Hyscine and Dutarin
Tropane alkaloid
Erythroxylum coca (Linaceae)
Coke, snow Leaves Cocaine Tropane alkaloid
Cinchona officinalislinn (Rubiaceae)
Cinchona Bark Quinine, Cinchonine and Cinchonidine
Quinoline alkaloids
Papaver somniferum (Papaveraceae)
Opium poppy and afim (Hindi)
Petals, stem and seeds
Papaverine, narcotine, narceine
Isoquinoline alkaloids.
Argemone mexicana (Papaveraceae)
Argemone and Sial‑kanta (Hindi)
All parts especially seeds
Sanguinarine Isoquinoline alkaloids
Clavicep purppurea is sclerotium (compact mycelium or spawn) of the parasitic fungus clavicep
Ergot Seeds of different plants
Ergotoxin, ergotamine Indole alkaloids.
Strychnos nux vomica (Loganiaceae)
Poison nut and Kuchila (Hindi)
All parts especially seeds of ripe fruits
Strychnine (C21H22O2N), Brucine (C23H26O4N2) and Vomicine
Indole alkaloids.
Table 2: Plant contains alkaloids
(Contd...)
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Name of Plant/Family Common Name/Hindi Name
Toxic parts Toxic constituents Specific chemical constituents/group
Basic ring structure
Pilocarpus jaborandi (Rutaceae)
Jaborandi Leaves Pilocarpine Imidazole alkaloids
Papaver somniferum (Papaveraceae)
Opium poppy and afim (Hindi)
Ripe and dried capsules, petals and seeds
morphine, codeine, thebaine
Steroidal alkaloids
Colchicum corm (Liliaceae)
Meadow saffron hiran‑tutiya
All parts Colchicine Alkaloidal amines
Gloriosa superb (Liliaceae)
Superb lily, Flame lily and Kalihari (Hindi)
Tubers and roots Superbine, Gloriosine and Glucosine
Alkaloidal amines
Lophophora williamsii Mescal buttons, peyotl, peyote
Stem Peyote, lophophorine, mescaline
Alkaloidal amines
Tea bush, a coffee plant and cocoa
Tea leaves and coffee seeds
Caffeine, crystalline xanthine
Purine bases.
Nicotiana tobaccum Linn (Solanaceae)
Tabacco, Tambaku Leaves Nicotine, Nicotianine Senecio alkaloids (Pyrrolidine group)
Lupin polyphyllus Lupin All parts (leaves, pods and seeds)
Sparteine (lupinidine), lupinine, lupanine
Lupin alkaloids (Quinolizidine group)
Tests of various plant chemical constituents
Table 2: (Continued...)
water (exception liquid alkaloids soluble in water), soluble in the organic solvent (CHCl3, ethyl alcohol ether) Taste: They are bitter in taste. Optically active, Most of levorotatory but few are ‑Dextro rotatory, e.g. Coniine, some inactive, e.g., Papaverine.
CHEMICAL TEST OF ALKALOIDS
1. Mayer’s test: (Potassiomercuric iodide solution): Specimen with Mayer’s reagent give Cream or pale yellow ppt.
2. Dragendorff reagent test: (Solution of potassium bismuth
iodide potassium chlorate, a drop of hydrochloric acid, evaporated to dryness and the resulting): Specimen with dragendorff reagent gives orange ppt.
3. Wagners test: (Iodine in potassium iodide): Specimen with Wagner’s Reagent gives brown or reddish brown ppt.
4. Hager’s test: (A saturated solution of picric acid): Specimen with Hager’s reagent gives yellow ppt (Special type).
5. Ammonium rinker test: Specimen with Ammonium Rinket solutions with HCl gives flocculent pink ppt.
6. Murexide test for caffeine: (residue is exposed to ammonia vapor): Purine alkaloids produce pink color.
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Name of Plant/family Common Name/Hindi Name
Toxic parts Toxic constituents Specific chemical constituents/group
Basic chemical structure of aglycone
Thebatia peruviana (Apocynaceae)
Tobacco and tambaku
Seeds and milky juice
Nicotine Steroidal glycosidesCardiac glycosides
Digitalis purpurea linn (Terophularaceae)
Yellow broom, Fox glove
Seed, leaves and Twigs
Digitoxin, DigitalinDigitalein and Digitonin
Steroidal glycosidesCardiac glycosides
Plumbago zeylanica (Plumbaginaceae)
Ceylon leadwort and chitra (Hindi)
Root Plumbagin Steroidal glycosidesCardiac glycosides
Cerbera thevetia (Apocynaceae)
Yellow oleander and Pila kaner
All parts especially leaves and fruits
Thevetin, Thevetoxin, Nerifolin, Peruvoside, Ruvoside and Cerberin
Steroidal glycosidesCardiac glycosides
Calotropis gigentea (Apocyanaceae)
Calotropis and madar, akdo (Hindi)
Juice and roots Uscharin, Calotoxin, Calactin and Calotropin
Steroidal glycosidesCardiac glycosides
Nerium oleander (Apocynaceae)
White oleander and Kaner (Hindi)
All parts Neriodorin, Neriodorein and Karabin
Steroidal glycosides Cardiac glycosides
Semecarpus anacardium (Anacardiaceae)
Marking nut And bhilawa (Hindi)
Juice Semecarpol and Bhilawanol
Flavonol glycosides
Aloe vera Indian aloe (Hindi) Stem Aloin Anthraquinone glycosides
Adenia palmate (Passifloraceae)
Fruit Toxalbumin (Cyanogenic glycoside) and Emulsin (enzyme)
Cyanophoric glycosidesa) Cyanogenetic glycosides
Dieffenbachia sp. (Araceae)
Dieffenbachia, dumbcane
All parts Cyanogenic Glycosides and Calcium oxalate
Cyanophoric glycosidesa) Cyanogenetic glycosides
Table 3: Plants contain glycosides
(Contd...)
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Name of Plant/family Common Name/Hindi Name
Toxic parts Toxic constituents Specific chemical constituents/group
Basic chemical structure of aglycone
Manihot utilissima (Euphorbiaceae);
Cassava, tapioca Root and leaves Linamarin‑ a
Manihotoxin Cyanophoric glycosidesa) Cyanogenetic glycosides
Sorghum laurocerasus (Gramineae)
Dhurrin Cyanophoric glycosidesa) Cyanogenetic glycosides
Prunus amygdalus (Rosaceae)
Almond, Baadam (Hindi)
Almond Amygdalin Cyanophoric glycosidesa) Cyanogenetic glycosides
Brassica nigra (brassicaceae)
Black mustard Seeds and pods Sinigrin Ally isothiocyanate
Brassica alba (Cruciferae)
White or yellow mustard
Oil, seeds Sinalbin Thioglycoside
Nerium oleander (Apocynaceae)
White Kaner flower All parts Nerine Lactone glycosides
Vanillin Aldehyde glycosides
Arctostaphylos uva‑ursi Bearberry Arbutin Phenolic glycosides
Solanum nigrum linn (Solanaceae)
Black nightshade Immature berries
Solanine and Steroids Saponin glycosidesa) Steroidal saponin
Glycyrrhiza glabra Glycyrrhizin b) Pentacyclic Triterpenic glycosides
Table 3: (Continued...)
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Table 4: Plant contain toxic proteinName of Plant/Family
Common Name/ Hindi Name
Toxic parts Toxic Constituents Specific chemical constituents/group
Basic chemical structure of toxic protein
Abrus precatorius linn (Leguminosae)
Jequirity, Indian Liquorice, Gunchi or Rati.
Seeds (mainly), Root and stem
Abrine Toxalbumines
Croton tiglium linn (Euphobiaceae)
Croton tiglium, Jamal‑gota or Naepala
Seeds Crotonoside Toxalbumines
Ricinus communislinn (Euphorbiaceae)
Castor bean, Erandi Entire plant especially seeds
Recine and Recinine Toxalbumines
Cerbera thevetia (Apocynaceae)
Yellow oleander and Pila kaner
All parts especially seeds and fruit
Thevetin, Thevetoxin, Cerberin
Toxalbumines
Test for Glycosides [15]
FeCl3 test cefor glycoside
5 ml of the concentration H2SO4 was added to 0.5 g of the plant extract and was boiled for 15 minutes. This was then cooled and neutralized with 20% KOH. The solution was divided into two portions. Few drops of FeCl3 (ferric chloride) solution was added to one of the portions, and a green to black precipitate indicate the presence of phenolic aglycone as a consequence of hydrolysis of glycoside.
Cardenolides
5 ml of the alcoholic extract were mixed with buljet reagent if an orange precipitate was formed; this indicates the presence of cardenolides.
Test for flavonoids
a) 1 ml of 10% ethanolic extract of the studied plant was mixed with 0.5 ml of hydrochloric acid (10%) and magnesium
metal. A reddish color was developed indicating the presence of flavonoids.
b) 5 ml of 1% hydrochloric acid extract were shaken with sodium hydroxide; a yellow color appeared indicating the presence of compind flavonoids.
Test for saponins
1 g of the plant under investigation was boiled with 10 ml water for few minutes and filtrated. The filtrate was vigorously shaken. The persistent froth (1 cm height) was observed for 1 h. indicates the presence of saponins.
Test for tannins
About 2 g of the air‑dried powder of the plant were extracted with ethanol (50%) and tested for the presence of tannins using the following tests.
a) One drop of ferric chloride was added to 2 ml of the extract, the appearance of bluish or greenish black coloration indicates the presence of pyrogallol or catechol tannins, respectively.
Table 5: Plant contain resinsName of Plant/Family
Common Name/Hindi Name
Toxic parts Toxic Constituents Specific chemical constituents/group
Basic chemical structure of resins
Cannabis sativa or Cannabis indica
Indian Hemp, Marijuana
Leaves fruiting tops of the female plant dried leaves fruiting shoots of both male and female plant flowering tops of the plant
Cannabinol, cannabidiol, cannabidiolic acid and tetrahydrocannabinol (THC)
Cannabidiolic acid
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b) 5 ml of the alcoholic extract of the studied plant were mixed with 2 ml vanillin hydrochloric acid solution if a precipitate was formed; this indicates the presence of gallic acid.
Test for unsaturated sterols and or/triterpenes
For testing the presence of unsaturated sterols and triterpenes, 1 g of the air‑dried powder of the studied plant was extracted with few ml of ethanol then filtrated, and the filtrate was evaporated till dryness. The residue was dissolved in 10 ml chloroform, filtered, and the filtrate was divided into two equal portions for preceding the following tests.
(a) Liebermann–Burchard test:
To the first portion of chloroform filtrate 1 ml of acetic acid anhydride was added, followed by 2 ml of sulfuric acid down the wall of the test tube. The appearance of a reddish violet color at the junction of the two layers and a bluish green color in the acetic acid layer indicates the presence of unsaturated sterols or triterpenes [16].
b) Salkowski’s test:
To the second portion of chloroform filtrate, an equal volume of sulfuric acid was added. The appearance of a red color indicated the presence of unsaturated sterol and/or triterpenes.
Anthraquinones
The alcoholic extract was adjusted to pH 3 with 1 N HCl, and then the solution was washed by diethyl ether. The (upper layer) ether solution was separated from the aqueous one. Ether solution was extracted with 5% sodium bicarbonate solution in separating the funnel. The alkaline aqueous solution was separated, and then acidified, shacked with ether in separating the funnel, and the two layers were separated. If ether layer gives a rose pink color with 10% ammonia, the carboxylic‑free anthraquinones are present.
Concentrated hydrochloric acid was added to the separated aqueous extract in ratio 1:2 and placed in boiling water bath for 15 min, cooled and then shacked with ether. The separated ether layer was tested for anthraquinones as before.
Cyanogenic glycosides
a) Plant material is subjected to steam distillation in acid medium for release of HCN gas. The distillate is collected in N/10 solution of sodium hydroxide. The distillate thus obtained may be subjected to tests for cyanides.
b) Test with Picrate paper: A portion of plant material is taken a test tube, and few drops of water and toluene are added.
The tube is then firmly corked with a moistened picrate paper suspended from the cork (paper is prepared by dipping in 0.05 M aqueous solution of picric acid neutralized with NaHCO3 and then filtering). The test tube is then incubator at 40°C for
2 h. A color change from yellow to reddish brown occurs due to enzymatic release of HCN gas.
Lactone glycosides
(a) Baljet Tests:
Plant material + Sodium picrate + alkaline = Orange color
(b) Legals Tests:
Plant material + Sodium nitroprusside + pyridine + alkali = Red color
(c) Raymond Tests:
Plant material + dinitrobenzene in ethanol + alkali = Violet blue color
TEST FOR RESINS
A total of 0.5 g of the pulverized plant was extracted with 15 ml petroleum ether and filtered. 5 ml of the filtrate was dispensed into a test tube and shaken vigorously with an equal volume of copper acetate solution TS. The mixture was allowed to stand for a few minutes. Formation of a green colored solution indicates the presence of resins [17].
CONCLUSION
More than 50 poisonous plant species belonging to different families are reported in the present review. The poisonous parts of the majority of plants species were seeds, latex and root or root bark. Besides these, poisonous parts of some plants were fruits, stem bark, tubers or bulbs and sometimes the whole plant also [18].
The listed plants in this study certainly contain active chemical constituents and their chemical test, which either cause physiological impairment in human beings as well as livestock population or poisoning to human beings only. This data regarding the family of the poisonous plant, its active chemical constituents and its poisonous part may be useful in developing poisonous plants classification according to their chemical constituents or toxic chemical group.
Significance of this review on such plants helps forensic investigators in searching the poisonous‑plant materials in autopsy material as well as on crime spot. On the basis of plant origin toxicity, Forensic expert can speculate about whether it is the case of suicide, homicide or accident. With the help of this study, it is hoped that the contents of this wok will so prepare the mind of all crime investigators and Forensic Scientists to greatly increase their chances of solving poisonous plants type of crime.
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