Pharmacognosy 2 Lecture 3

Academic Year: 2024/2025

• Course: Pharmacognosy 2 (Course Code PG203)
• Lecture No.: 3
• Topic: Non Official Seeds and Fruits Introduction

Lecture's Aim

• Provide comprehensive understanding of medicinal non-official seeds and fruits structure, identification, and pharmacognostic importance.
• Provide fundamental understanding of fruit structure and classification.
• Describe macroscopic and microscopic features of fruits, differentiate various types.
• Classify fruits based on development from floral structures (true, false, and composite fruits).

Lecture's Competencies

• Understand basic structure of fruits (epicarp, mesocarp, endocarp) and their functions in fruit anatomy.
• Recognize key macroscopic characteristics of fruits (shape, color, surface, and scars).
• Classify fruits into simple, aggregate, and composite fruits.
• Distinguish between true fruits (derived from gynoecium) and false fruits (involving other floral parts).

Lecture's Contents

• Non-official seeds: Castor Seeds, Nigella, Coffee beans Calabar beans.
• Introduction of fruits.

Nux Vomica Seeds

• Biological and Geographical Origin: Dried ripe seeds of Strychnos nux vomica (Loganiaceae).
• Contains: Not more than 1% foreign organic matter, not less than 2.5% alkaloids, and not less than 1.2% strychnine alkaloid.

Macroscopical Characters

• Very hard seed due to the hemicellulosic thick-walled endosperm.

Active Constituents

• Alkaloids (strychnine and brucine) 1.8–5.3%.
• Chlorogenic acid.
• Loganin (irrodoid glycoside).
• Fixed oil (3%).

Uses

• Bitter stomachic (improves appetite) and tonic.
• Stimulates muscular coat of the intestine, increasing peristalsis.
• Large dose causes violent convulsions involving respiratory muscles (asphyxia), and potentially death.

Castor Seeds

• Dried seeds of Ricinus communis (Euphorbiaceae).
• Castor oil is official in the E.P. as oleum Ricini.

Microscopical Characters

• Seeds are oval, 8–18 mm long, 4–12 mm broad.
• Testa is smooth, brittle, and grey, brown, or black in color.
• Small caruncle present at one end, from which the raphe terminates at the chalaza.

Active Constituents

• Fixed oil 46–63%.
• Protein 26%.
• Ricin (toxic protein).
• Ricinine alkaloid (toxic alkaloid).

Uses

• Castor oil is used as a purgative due to ricinoleic acid content.
• Used after food poisoning and before intestinal examination.
• Seeds are not used due to the presence of ricins.

Pumpkin Seeds

• Dried seeds of Cucurbita pepo (Cucurbitaceae).

Active Constituents

• Fixed oil (unsaturated fatty acids and phytosterols).

Uses

• Used for benign prostatic hyperplasia, atherosclerosis, and male infertility.

Evening Primrose

• Fixed oil obtained by extraction/expression from seeds of Oenothera spp. (O. biennis L., O. lamarkiana L.) (Onagraceae).
• Contains substantial amounts of esterified γ-linolenic acid (GLA).

Active Constituents

• Fixed oil
• γ-Linolenic acid (GLA)

Uses

• Psoriasis, eczema, premenstrual syndromes, breast cancer.

Nigella Seeds

• Dried ripe seeds of Nigella sativa (Ranunculaceae).

Active Constituents

• Volatile oil (thymoquinones).
• Fixed oil (saturated and unsaturated fatty acids).
• Triterpene and saponins.

Uses

• Immuno-stimulant, cough and chest disorders.
• Anticancer, antioxidant, and antiasthmatic.
• Lactagogue.

Coffee Beans

• Dried fermented seeds of Coffea Arabica (Rubiaceae).
• Grown in tropical countries such as Yemen and Brazil.

Active Constituents

• Alkaloids (caffeine 1–2%).
• Tannins.
• Chlorogenic acid.

Uses

• CNS stimulant.
• Diuretic.

Calabar Beans

• Dried ripe seeds of Physostigma venenosum (Leguminosae).

Active Constituents

• Alkaloids (e.g., physostigmine = eserine).
• Derived from tryptophan.
• Oxidizes into rubreserine on exposure to air and light.

Uses

• Antidote to strychnine poisoning.

The Fruit (Fructus)

• Developed or ripened ovary or ovaries as a result of fertilization.
• Whole product of the development of the gynoecium.

Macroscopical Characters of Fruits

• Type, shape, color, dimensions, surface characters, odor, taste.
• Scars (two distinct scars): at the base (attachment), apical & minute (remains of style & stigma).

Surface of Fruits

• Smooth and glaucous
• Glabrous
• Pubescent
• Rough or granular
• Spiny
• Striated
• Ridged
• Reticulated

Structure of Fruits

• Pericarp: swollen and modified ovary wall, enclosing seeds arranged on the placenta.
• Divided into 3 regions: Outer epicarp, inner endocarp, mesocarp between.
• Epicarp: Thin & membranous, Leathery, Thick & hard. Formed of outer epidermis only or epidermis with modified hypodermal layers.
• Endocarp: Inner epidermis only, or epidermis with hypodermal layers. Forms woody structure.
• Mesocarp: Parenchymatous, Vascular strands, Succulent or with several layers of different types.
• Placenta: structure differs from pericarp, may be knob-like, cord-like, membraneous, or enlarged.

Types of Fruits

• True fruit: Formed from gynoecium of a single flower.
• False fruit: Formed when other parts of the flower take part in the formation.
• Composite fruit: Formed from the whole inflorescence, with multiple ovaries.

Simple Fruit (Types)

• Simple, Dry, Dehiscent fruits: Pericarp dries, remains attached to plant, splits for seed release (e.g., legume, follicle, capsule).
• Simple, Dry, Indehiscent fruits: Pericarp dries, does not split (e.g., achene, grain/caryopsis, nut).
• Simple, Succulent fruits: Pericarp partially or entirely fleshy (e.g., drupe, berry).

Modified Berry (Types)

• Pepo
• Hesperidium

False Fruit

• Derived from the ovary and other parts of a flower.
• Parts of the flower enlarge to create the fleshy part of the fruit.
• e.g., apple, pear.

Composite Fruit (Types)

• Strobile
• Syconus
• Sorosis

Pomes

• Central seed core, many seeds or thick fibrous layer; e.g., apples, pears.

Additional details from the slides about specific fruit types are provided.