Indole Alkaloids

Causes contraction of pupil of the eye.

Natural Source and Uses of Vinca Alkaloids

Definition

Vinca alkaloids are oncolytic indoline alkaloids obtained from dried whole plant of Catharanthus roseus, family Apocynaceae

Constituents

1. Leurocristine (vincristine)
2. Vincaleukoblastine (vinblastine)

Vinblastine is converted into vincristine by chemical reactions or by microbial N-demethylation using Streptomyces albogriseolus

Uses

Vinblastine treatment of generalized Hodgkins disease, lymphocytic lymphoma, histiocytic lymphoma, advanced testicular carcinoma, kaposis sarcoma, choriocarcinoma and breast cancer unresponsive to therapy

Vincristine treatment of acute lymphocytic leukemia in combination therapy in Hodgkins disease, ymphosarcoma, reticulum cell sarcoma, neuroblastoma and Wilms tumour

Natural Sources and Uses of Ergot Alkaloids Definition Ergot is the dried sclerotium of a fungus Claviceps purpurea, arising in the ovary of the rye, Secale cereal, family Hypocreaceae The sclerotium arises in the ovary of the rye secale cereale Constituents Contains water soluble and water insoluble alkaloids Water soluble: Ergometrine Ergonovine Ergometrinine Water insoluble: Ergotamine Ergotaminine Ergotoxine Derivatives of lysergic acid Lysergic acid diethylamide (LSD) Uses of ergot alkaloids 1. Ergometrine is used to control postpartum haemorrhage 2. Ergometrine produces oxytocic effects Ergotamine and semi-synthetic dihydrohydroxy ergotamine are employed as specific analgesic for treatment of migraine (caffeine enhances absorption) Lysergic acid derivative, LSD is a psychomimetic (a potent hallucinogen) controlled under narcotics Natural Sources and Uses of Nux vomica Definition Nux vomica are dried, ripe seeds of Strychnous nux-vomica, family Loganiaceae Constituents The Main indole alkaloids are; Strychnine Brucine Strychnine is more physiologically active than brucine Strychnine is present in the inner part of the endosperm while brucine is in the outer layers Other alkaloids are: α-colubrine, β-colubrine, vomicine, pseudostrychnine and isostrychnine The drug also contains 3% fixed oils, glycoside - loganin Uses 1. It stimulates peristalsis in chronic constipation and is often combined with cascara and other laxatives 2. Bitter stomachich and tonic (increases gastric juice to improve appetite and digestion) 3. Improves the pulse and raises blood pressure 4. At higher doses it is a lethal poison Brucine is used commercially as an alcohol denaturant (as it is extremely bitter) Natural Sources and Uses of Calabar Beans Definition Calabar beans are dried seeds of Physostigma venonosum, family Leguminosae The seeds are extremely hard Constituents Physostigmine, Isophysostigmine, Physovenine Eserinmine Geneserine Uses 1.A reversible inhibitor of cholinesterase thus enhancing the effect of endogenous Acetylcholine 2. It is used systematically as an antidote for atropine poisoning and other anticholinergic drugs 3. Used in ophthalmology to contract the pupil, to combat mydriasis 3. It is used in the treatment of glaucoma 4. It decreases intra-ocular pressure caused by increased outflow of the aqueous humour Natural Sources and Uses of Rauwolfia

Definition Rauwolfia consist of dried rhizome and roots of Rauwolfia serpentine, family Apocynaceae The drug is commonly known as Indian snake root The African rauwolfia consists of dried roots of Rauwolfia vomitoria widely distributed in tropical Africa Constituents Major alkaloids are: 1. Reserpine 2. Resinnamine Other Alkaloids include: Rauwolfine (Ajmaline) Ajamalicine Serpentine Serpentinine Yohimbine Other constituents: Unsaturated fatty acids, phytosterols, esters, alcohols and sugars African rauwolfia contains mainly Reserpine and Rescinnamine Uses 1. It is used as a centrally acting anti-hypertensive agent (reserpine) 2. Used in very small concentration in combination with other antihypertensive agents due to its major side effect suicidal depression Natural Sources and Uses of Yohimbe Bark Definition Consists of dried bark of Pausinystalia yohimbe (family Rubiaceae) Grows in Cameroon Constituents Chief constituent is Yohimbine Use 1. As an aphrodisiac agent 2. Symptomatic treatment of erectly dysfunction