Alkaloids Lecture Notes

Flashcards on Steroidal, Diterpene and Imidazole Alkaloids

Steroidal Alkaloids

Alkaloids containing the perhydrocyclopentano-phenanthrene skeleton characteristic of sterols, often in glycosidal combination with sugars.

Solanum Alkaloids

Glycosidal alkaloids found in Solanum species (e.g., potato plants) with solanidine as the aglycone and solanose as the sugar part.

Solanine

A glycosidal alkaloid found in Solanum species, composed of solanidine as the aglycone and solanose as the sugar.

Properties of Solanine

White needles soluble in hot ethanol and dilute acids, insoluble in water, chloroform, and ether; yields solanidine, rhamnose, galactose, and glucose upon acid hydrolysis.

Tests for Identification of Solanine

Marquis' reagent produces a yellow to violet color; Mandalin's reagent gives an orange to violet-blue color.

Uses of Solanidine (aglycone of Solanine)

Used as a starting material for the synthesis of steroidal drugs.

Diterpene Alkaloids

Alkaloids derived from a diterpene structure.

Taxol (Paclitaxel)

Found in the bark of Taxus species (Yew tree), used in cancer treatment.

Uses of Taxol

Treatment of ovarian, lung, and breast cancers; induces tubulin polymerization leading to non-functional microtubules and apoptosis in cancer cells.

Mechanism of Action of Taxol

Induces the polymerization of tubulin, creating stable non-functional microtubules and inducing apoptosis in cancer cells.

Alkaloids of the Imidazole Group

Alkaloids containing an imidazole ring structure.

Pilocarpus Alkaloids

Pilocarpine and isopilocarpine, found in Pilocarpus jaborandi leaves.

Properties of Pilocarpine

Oily, non-volatile liquid, dextrorotatory, soluble in water; lactone ring opened by caustic alkalis, imidazole ring destroyed by oxidation.

Helch's Test

Aqueous solution of pilocarpine salt + H2O2 + K2Cr2O7 yields a violet color.

Uses of Pilocarpine

Used as a miotic drug (cholinergic properties) to reduce intra-ocular pressure in glaucoma; also used in veterinary medicine to stimulate gastric secretion.