ALKALOIDS

SEJARAH Derosne (Apt Perancis) mengisolasi senyawa yg sekarang dikenal sebagai narcotine th 1803 Sertürner (Apt Hanoveria) mengisolasi morphine dari opium th 1806 & 1816 Pelletier & Caventou : strychnine (1817), emetine (1817), brucine, piperine, caffeine (1819), quinine, colchicine (1820) & coniine (1826) Coniine alkaloid pertama yg ditentukan strukturnya (Schiff, 1870) & disintesis (Ladenburg, 1889)

PENAMAAN  akhiran -ine (Inggris) Nama genus tumbuhan penghasil ex : hydrastine, atropine Nama spesies tumbuhan penghasil ex : cocaine, belladonine Nama umum tumbuhan penghasil ex : ergotamine Aktivitas fisiologi yg ditimbulkan ex : emetine, morphine Nama penemunya ex : pelletierine

PENAMAAN Adakalanya di + awalan / akhiran untuk membedakan alkaloid utama dgn alkaloid lain dlm satu tumbuhan ex : quinine, quinidine, hydroquinine contoh lain cari sendiri!!

DEFINISI Alkaloid : senyawa basa nitrogen asal tumbuhan yg bersifat fisiologi aktif Secara umum sulit didefinisikan karena tidak mewakili sekelompok senyawa homogen dari sudut pandang kimia, biokimia atau fisiologi

DISTRIBUSI Fungi : deriv as lisergat (lysergic acid) & gliotoksin (gliotoxin) Pteridophyta : lycopodium Gymnospermae : Ephedra & Taxus sp. Kulit katak Phyllobates sp  alkaloid yg paling beracun  lainnya : 24 kelas alkaloid yg mencapai 300 Mamalia  indole & isoquinoline alkaloid  morfin mamalia Angiospermae : distribusi tidak merata

DISTRIBUSI : Angiospermae Alkaloid biasa terdapat pada ordo : Centrospermae (Chenopodiaceae) Magnoliales (Lauraceae, Magnoliaceae) Ranunculales (Berberidaceae, Menispermaceae, Ranunculaceae) Papaverales (Papaveraceae, Fumariaceae) Rosales (Leguminosae, sub Familia Papilionaceae)

DISTRIBUSI : Angiospermae Rutales (Rutaceae) Gentiales (Apocynaceae, Loganiaceae, Rubiaceae) Tubiflorae (Boraginaceae, Convolvulaceae, Solanoceae) Campanulales (Campanulaceae, sub famili Lobeioidoe, Compositae, sub famili Senecioceae)

FUNGSI BAGI TUMBUHAN : Beberapa kemungkinan : Senyawa racun yg melindungi tumbuhan dari serangga & herbivora Produk akhir rex detoksifikasi (metabolic lock up) senyawa2 yg berbahaya bagi tumbuhan Regulator faktor pertumbuhan Senyawa cadangan u/ sumber N / elemen lain yg berguna bagi tumbuhan

SIFAT-SIFAT : Dlm tumbuhan alkaloid di dlm bentuk bebas, garam atau dlm N-oksida Sebagian besar mrpkn kristal yang halus yang bereaksi dg asam membentuk garam, lainnya amorf. Bentuk kristal  identifikasi mikroskopis Kebanyakan mgd atom O, kecuali coniine (Hemlock) dan nicotine (tembakau) yg tdk punya O  cair Kebanyakan tdk barwarna kecuali berberine (kuning) dan garam sanguinarine (merah tembaga)

SIFAT-SIFAT : Kelarutannya sgt bervariasi tergantung struktur Dlm bentuk basa bebas, sedikit larut dlm air, larut dlm pelarut organik Dlm bentuk garam sebaliknya ex : Strychnine HCl lbh larut dlm air drpd bentuk basanya Perkecualian : Caffeine basa, terekstraksi o/ air Colchicine larut dlm air,dlm suasana asam, netral dan basa Quinine Sulfat kelarutan 1 bag dlm 1000 bag air Quinine HCl kelarutan 1 bag dlm < 1 bag air

STRUKTUR DAN KLASIFIKASI: Berdasarkan struktur kimia : Non heterosiklik atau Atipikal Alkaloid, sering disebut sebagai Protoalkaloid atau Amina Biologis Heterosiklik atau Tipikal Alkaloid

STRUKTUR DAN KLASIFIKASI: Berdasarkan kedudukan atom N : N 1’ yaitu mescaline N 2’ yaitu ephedrine N 3’ yaitu atropine N 4’ yaitu tubecurarine Pengaruh thd prosedur isolasi

Alkaloid-alkaloid N-Oksida Pada awal thn 1920 dilakukan uji farmakologi dan toksikologi terhadap alkaloid2 spt morphine, Strychnine dan Hyoscyamine dg senyawa N-oksidanya, senyawa N-oksida alkaloid2 tsb sifat lepas lambat, toksisitas rendah dan efek adiksinya lbh rendah N-oksida quinolizidine Boraginaceae, Compositae dan ex : Senecio sp

Alkaloid-alkaloid N-Oksida N-oksida indole bersifat halusinogenik ex : Amanita sp, reserpine, strychnine dan alkaloid Mitragyna Daun segar Atropa, Datura, Hyoscyamus, Scopolia & Mandrogara masing2 mempunyai 2 isomer n-oksida Hyoscyamine

UJI ALKALOID Sebagian besar alkaloid dalam larutan netral atau sedikit asam diendapkan oleh : Reagen Mayer (potassium mercuric iodide Sol.) Reagen Wagner (sol. of iodine in potassium iodide)  merah kecoklatan Sol.Tannic acid Reagen Hages (saturated sol of picric acid) kuning Reagen Dragendorff (sol of potassium bismuth iodide) merah kecoklatan  Endapan dlm bentuk amorf atau kristal

UJI ALKALOID Reagen2 diatas juga mengendapkan protein, dlm proses ekstraksi & penguapan , beberapa protein tidak terekstraksi, lainnya terdenaturasi pada proses penguapan atau penyaringan Jika ekstrak dipekatkan hingga volumenya berkurang dan alkaloid diekstraksi dengan pelarut organik suasana basa dan dicuci dg asam encer (ex: as.tatrat) maka larutan terakhir  bebas protein dan siap dilakukan uji alkaloid Kafein dan Alkaloid lain tidak memberikan endapan dg reagen Dragendorff

UJI ALKALOID TEST MUREXIDE Ditambah sedikit potassium chlorate + 1 tts HCl  uapkan ad kering, residu dialiri dg uap amonia  ungu Reaksi juga berlaku untuk turunan basa purin lainnya (Theophylline, Theobromine) Colchicine + As.mineral kuning Alkaloid Indole + H2SO4 ungu kebiruan-merah p-dimethylaminobenzaldehyde

PENGGOLONGAN Ornithine - derived alkaloids tropane alk, pyrrolizidine alk Lysine - derived alkaloids Phenylalanine-tyrosine-dihydroxyphenylalanine- derived alkaloids protoalk, benzylisoquinoline deriv, tetrahydoisoquinoline monoterpenoid alk & glycosides, Amaryllidaceae alk, phenetylisoquinoline alk Tryptophan- derived alkaloids Miscellaneous alkaloids indolizidine alk, imidazole alk, purine alk, reduced pyridine alk, terpenoid alk, steroidal alk

Occurrence, Distribution & Location of Alkaloids Occur in bacteria (Pseudomonas aeruginosa) and rarely in fungi (pscilocin from hallucinogenic mushrooms). Some alkaloids occur in several genera from different species (caffeine), but most occur in closely related species. Some occur in certain families (hyoscyamine), while others occur only in a specific species (morphine). Rarely do plants contain more than 1 type of alkaloid. All alkaloids of one plant will have a common biogenenetic origin

Alkaloids occur in all plant parts, but are usually localized in one organ (e.g. the bark or seeds). Within the plant, [alkaloid] can vary widely from part to part – some parts may contain no alkaloids. Occasionally, different alkaloids also form in different parts of the plant. Alkaloid concentrations occur in wide ranges – e.g. Madagascan periwinkle contains 3g per (anti-cancer) alkaloids per tonne of leaves.

The Nitrogen of Alkaloids The N2 atom can either be 1º, 2º, 3º or 4º (quaternary). This N2 feature affects the alkaloid derivatives which can be prepared and the isolation procedures.

Alkaloid Extraction Extraction method normally depends on the raw material, the purpose of extraction & the scale on which is to be performed. For research purposes: chromatography allows for quick and reliable results. If larger amounts of alkaloids need to be extracted, one of the following methods can be used. TLC plate

Extraction in an Alkaline Medium Step 1: Powdered, defatted herb is mixed with an alkaline aqueous solution. This displaced alkaloids from their salt combinations. Free bases are then extracted with organic solvents. Normally aqueous ammonia is used, but a carbonate solution is used when alkaloids contain fragile elements such as a ester or lactone. In some cases, e.g. Cinchona bark, a mixture of calcium hydroxide & sodium hydroxide should be used as the alkaloids are bound to tannins. Organic solvent: chloroform, dichloromethane or ethyl acetate – depends on the toxicity, safety, cost & ease of recovery and recycling of the solvent).

The Soxhlet Apparatus Industry: uses solid-liquid extractors based on the principle of counter-current extraction, such Soxhlet apparatus.

Extraction of Alkaloids: Step II Organic solvent containing alkaloids (bases) is separated from residue & concentrated by distillation under pressure if needed. Solvent is stirred with an acidic aqueous solution: alkaloids go into the solution as salts. Impurities remain in the organic phase. Repeated until the organic phase no longer contains alkaloids. Many acids can be used (HCL, Sulfuric, citric, tartaric), but always in very dilute concentrations (1-5%)

Alkaloid Extraction: Step III Aqueous solution of alkaloid salts is washed with an apolar solvent (hexane) Alkalinized with a base using an organic solvent not miscible with water. Alkaloids precipitate and dissolve in the organic phase. Extraction of aqueous phase continues till all alkaloids have moved into the organic phase (tested when Mayer’s reaction on the aqueous phase becomes negative). This purification step may be carried out in a separation funnel or in centrifugal extractors. Separation Funnel

Final Step Organic solvent containing alkaloid bases is decanted, freed from water traces (drying over anhydrous salt e.g. sodium sulphate) and evaporated under reduced pressure. A dry residue remains: total basic alkaloids. Kava Powder

Alkaloid Extraction in Acidic Medium 2 Methods possible Pulverized drug is extracted directly with acidified water Or Pulverized drug is extracted with acidified alcoholic or a hydroalcoholic solution. This is then followed by distillation under vacuum (eliminates that alcohol, leaving behind and acidic aqueous solution of alkaloid salts) Vacuum Distillation

Ion-Exchange Resin

Isolation of Alkaloids All methods of alkaloid extraction yield impure compounds, so alkaloids therefore have to be separated. TLC and HPLC are most commonly used. Under the best conditions, alkaloids can be obtained by direct crystallization: simply by neutralizing the acidic extraction medium. Crystals of Hydrastine

Isolation of Alkaloids Large-scale extractions may be sent to a factory for purification & separation (for cinchona and cocoa alkaloids). Separation and final purification may be done using fractional precipitation or fractional crystallization of salts. Chromatograpy is used for complex alkaloids and if only small amounts of alkaloids are needed. Volatile liquid alkaloids (nicotine) are isolated by distillation – alkaloid is distilled off in steam. Nicotine is an important insecticide, and large amounts are prepared from the parts of the tobacco plant which is not used for tobacco manufacture

Biogenesis of Alkaloids Alkaloids are produced in plants by basic substances and reactions well-known in organic chemistry. Biosynthetic origin cannot be discussed in general terms for all alkaloids, instead it has to be covered separately for each of the major groups of alkaloids

True alkaloids are based on an amino acid (pre-cursor). Only a few amino acids form the pre-cursors for all alkaloids: ornithine, lysine, phylalanine, tyrosine, tryptophan, histidine and anthranilic acid. Alkaloid formation may require the involvement of only one molecule of amino acid, or 2 molecules of the same AA, or less commonly, 2 molecules of different AA or else several molecules of the same AA. The formation starts with the formation of a Schiff base or a Mannich reaction. When the alkaloid has additional C-atoms, these play important roles in other metabolic pathways.

Main Pre-cursors for Alkaloids Group 1: Aliphatic AA’s – ornithine & lysine * Pre-cursors to pyrrolidien, piperridine & tropane alkaloids Aromatic AA – Phenylalanine, tyrosine, tryptophane c. Precursors of terpenes, steroids & polyketides – often together with the aliphatic or aromatic AA’s  result in alkaloids of mixed biosynthetic origin

Hetrocyclic Alkaloids Pyrrolidine Alkaloids Piperridine/pyridine Pyrrolizidine Tropane Alkaloids Quinoline Alkaloids Isoquinoline Alkaloids Opium Alkaloids Aporphine Norlupinane Ipecac Alkaloids Indole Alkaloids Indolizidine Imidazole Purine Alkaloids Protoalkaloids Steroidal Terpenoid

Tropane Alkaloids Derived from tropine and consist of mandelic, tropic or benzoic acid esters of tropine. Are very closely related to each other All have pronounced physiological actions. Natural alkaloids include Hyoscyamine Hyoscine Atropine Cocaine The above mentioned alkaloids occur within the Solanaceae family (except cocaine – from Erythroxylaceae family)

Atropine & Hyoscine Have the same structure – differ only in their optical activity. Also have different physiological actions Atropine – deadly nightshade, Atropa belladonna: dilates eye pupils, decreases sweating, produces stomach acid and saliva & relaxes smooth muscle (asthma and colic). Hyoscine – black henbane, Hyoscyamus niger: Limited influence on the CNS. Sedative Cocaine: Narcotic properties & local anaesthetic action (e.g. used in eye drops).

What makes plants medicinal or therapeutic? Primary metabolites: needed for the life of a plant; includes sugars, amino acids, proteins, fats and nucleic acids Secondary metabolites: chemicals that are needed for specific stages of development; have various metabolic activities 3 major classes of secondary metabolites: alkaloids, terpenoids and phenolics

Selected medicinal plants developed from Ethnobotanical sources

Cinchona sp. (Rubiaceae)

source of quinine bark used against malaria malaria is the world's greatest killer Cinchona was discovered by the Jesuits in South America used by the Indians

Filipendula ulmaria (Rosaceae)

Source of salicylic acid bark is boiled but very bitter and can cause stomach ache no. 1 used for aches and pains and resulted to aspirin

Rauvolfia sp. (Apocynaceae)

used by the Hindu people of Nepal and India originally used to treat snakebites because the root resembled a snake is now used to treat hypertension due to the chemical reserpine

Atropa belladonna (Solanaceae)

also called deadly nightshade because it is very poisonous women use drops from the leaves to make their pupils expand and produce wide-eyed, innocent look used to treat glaucoma

Erythroxylum coca (Erythroxylaceae)

coca leaves used by Peruvians to control hunger source of cocaine which act on the central nervous system so that the coca chewer feel invigorated and relatively immune to fatigue and hunger

Papaver somniferum (Papaveraceae)

Opium called “joy plant” b the Sumerians Arabs brought the plant to China no. 1 choice as an analgesic in the form of morphine and codeine(very potent alkaloids) heroin is the synthetic form

Digitalis purpurea (Scrophulariaceae)

contains digitoxin and digoxin used for atrial fibrillation or irregular heartbeats

Ephedra sinica (Ephedraceae)

part used are the stems contain ephedrine also called ma huang in China stimulates the central nervous system and may decrease appetite and elevate mood

Syzygium aromaticum (Myrtaceae)

contains eugenol which cures toothache very aromatic and can be used as spice

Physostigma venenosum (Fabaceae)

Pilocarpus jaborandi (Rutaceae)

source of physostigmine and pilocarpine respectively both used for glaucoma

Camellia sinensis (Theaceae)

active ingredient: caffeine stimulant contain theophylline which is a diuretic and used for asthma also contain essential oils that are good antibacterial and antifungal agents anti-oxidants ?

Catharanthus roseus (Apocynaceae)

important chemicals are vinblastine and vincristine used in the treatment of Hodgkin's disease and pediatric leukemia

Cannabis sativa (Cannabaceae)

active ingredient is THC (tetrahydrocannabinol) used as an anti-emetic

Philippine Medicinal Plants (DOH) Akapulko (Cassia alata)

Ampalaya( Momordica charantia)

Banaba (Lagerstroemia speciosa)

Bawang, Bauang / Garlic (Allium sativum)

Bayabas (Psidium guajava)

Ginger (Zingiber officinale)

Gumamela (Hibiscus rosa-sinensis Linn)

Lagundi (Vitex negundo)

Oregano (Origanum vulgare)

Pansit-Pansitan (Peperomia pellucida Linn.)

Sabila or Aloe Vera (Aloe barbadensis)

Sambong (Blumea balsamifera L.)

Milk Thistle (Silybum marianum)

Tsaang Gubat or Wild Tea (Ehretia microphylla Lam.)

Yerba Buena (Mentha spicata)

Classification of glycosides according to a glycone part. 1- phenolic group of glycosides:- Such as arbutin which isolated from bearberry leaves Uses: UTI as antiseptic and antibacterial & mild diuretic Drugs : -Esoterica :cream :age spots -hydroquinone solution : wet hands 2- saponin group of glycoside Important group of glycosides which widely distributed specially in the higher plants parts b. Most of them are neutral compounds, soluble in water insoluble in the organic solvents. d. Irritant compounds for mucous membranes e. They form with hydrolysis glycone part which usually β-D-glucose or it’s acids (glucuronic acid) + Sapogenin