Pharmacognostic study of Lepidium sativum Linn (Chandrashura).

Pharmacognosy is the study of naturally occurring biological substances, principally those derived from plants that find use in medicine. The word "Pharmacognosy" is derived from the Greek "Pharmacon," "a drug" and "gignosco," to acquire knowledge of. It is closely related to both botany and plant chemistry and both originated from the earlier scientific studies on medicinal plant. The plant kingdom still holds many species of plants containing substances of medicinal value which have yet to be discovered large number of plants constantly being screened for their possible pharmacological value. The plant Chandrashura is being used for the treatment of Amavata, Sandhivata, and Katishula successfully. Here, an attempt is made to study the plant pharmacognostically; the part taken for study is the seed. Diagnostic features of seed and seed powder were also worked out and the details were presented.

Introduction

In the beginning of the 20th century, the subject pharmacognosy had developed mainly on the botanical side, being particularly concerned with the description and identification of drugs, both in the whole state and in powder, and with their history, commerce, collection, preparation, and storage. Such branches of pharmacognosy are still of fundamental importance, but rapid development in other areas, particularly Phytochemistry and Pharmacology have enormously expanded the subject.[1] As a result, it is now possible to approach the study of medicinal plants from the botanical photochemical and pharmacological viewpoints[2] (Trease and Evams 14th ed.1997). The plant Chandrashura is being used for the treatment of Amavata, Sandhivata, and Katishula successfully.[3]

Aims and Objectives

To standardize the identification of the seeds of plant Lepidium sativum Linn; a pharmacognostic study including microscopic and macroscopic characters of the seed and seed powder was carried out.

Materials and Methods

Collection of sample

The plant material required for the present study was collected from the campus of Gujarat Ayurved University. The collection of plant was done in the month of April, 2004; the plant was uprooted without damaging the root system. The collected material was put into container and stored. The plant specimen was authenticated by expert of Botany from the department of Pharmacognosy GAU, Jamnagar.[4]

Processing and preservation

The seed of L. sativum was collected and preserved. Macroscopic and microscopic characters of seed and seed powder were studied systematically. Transverse and Longitudinal sections were prepared for microscopic examination. Standard stains and chemical reagents were used in all these studies.

Morphology of the plant

It is an erect branched, glabrous herb with 60 cm height. Leaves are entire or pinnately dissected, variously lobed often with linear segments; up to 6-5 cm long and lobes are 0.7-1.2 to 0.3-0.6 cm size, upper leaves usually entire, and 2-3 cm long, oblanceolate, sessile.

Racemes are 7 to 15 cm long axillary and terminal; flowers are white or pale pink; pedicels are 3 to 5 mm long. Pods are obovate or broadly elliptical, roundate, emarginated slightly but thickly winged above.

Seeds are small, oval-shaped pointed, and triangular at one end, smooth about 2 to 3 mm long and 1 to 1.5 mm wide, reddish brown, an arrow present on both surfaces, extending up to two-thirds downwards, a slight wing-like extension present on both the edges of seed when soaked in water seed coat swells and gets covered with a transparent, colorless mucilage.[5]

Taxonomic Classification Plant Chandrashura. (Lepidium sativum Linn)

Classification of Family Cruciferae (Brassicaceae) was mentioned by the various taxonomists. This family consists of 220 Genera and 1 900 species [Figures 1and 2]

Figure 1

Plate No. 1 Plant photographs

Figure 2

Plate No. 3 Seeds of Lepidium sativum (a) The larger size of Lepidium seeds; (b) Drawing of a mature Lepidium seed; the embryo is enclosed by the endosperm and the surrounding testa; (c) Initial testa rupture; (d) Advanced testa rupture; (e) Endosperm rupture; (f) Advanced tests rupture.

Family Feature

Cruciferae—Mustard family

These are herbaceous plants, often with stellate hairs, whose flowers have four distinct sepals and four petals. The stamens are six and are termed tetradynamous, because one pair is longer than the other two pairs.

There is a single pistil whose ovary is superior, two located, four carpelled, and has parietal placentation. The styles are short or absent and with two stigmas. The fruit is a modified capsule, usually dehiscing by two lateral valves (having a central septum) and when long and slender is termed a silique or when short and squat is termed a silicle. The arrangement of cotyledons and radical within the seed provide characters of taxonomic importance. The cotyledons may be acumbent, incumbent, conduplicate, or double acumbent.[7]

Distribution

This plant is a native of Mediterranean region. Now, it is being cultivated throughout India—very likely indigenous in West Asia. In India, it is mainly cultivated in U.P., Rajasthan, Gujarat, Maharashtra, and Madhya Pradesh.[8]

Macroscopic and microscopic characters of seed Lepidium sativum

Seed of Lepidium is very small, red colored, oval shape, and pointed at the end. Its size is 2 mm long and 1.5 mm broad. Seeds show micropyle and grove in between which can be easily seen in its lateral view and dorsal view. Here, its drawing is 10 times magnified due to its very small size.

In the Transverse section, seeds show testa, radical, and cotyledon.

In Longitudinal section, seeds show testa, radical, and cotyledon. Its embryo shows cotyledon, radical and on upper part lobes of cotyledon.

These structures are much clearly seen in enlarge embryo.

Transverse section of radical shows thin layer of epidermis on outer side than it shows cortex of parenchymatous cells. The other layer is of endodermis which covered the vascular bundle inside.

Study of seed powder of Lepidium sativum

Microscopic slides of the powder was prepared by using various mountains including

Distilled water,

Glycerin alcohol and water,

Phloroglucinol and hydrochloric acid for staining lignified tissues,

Iodine water for testing starch grain,

Hydrochloric acid,

Sulfuric acid,

Acetic acid for identification of crystals of calcium oxalate and carbonates, etc. [Figures 3–5]

Figure 3

Microscopic characters of seed powder of Lepidium sativum Linn. (a) Surface view Ep -Epidermis, Pal - Palisade cell; (b, c) Radical view; (d) Testa in surface view, Ep - Epidermis; (e) Epidermis in surface view; (f) Cotyledons, Ep - Epidermis, Par - Parenchyma, Olg - Oil globules; (g) Radical, Pa - Parenchyma; (h) Xylem; (i) Phloem, Ep - Epidermis, Pa - Parenchyma

Figure 5

Figure IA and IB - Dorsal view, Mi. - Micropyle, Gr. - Grove; Figure - II – Transverse section of seed IIA – Longitudinal section of seed, Ra - Radical, T - Testa, Co - Cotyledon; Figure - IIIA - Embryo IIIB - Enlarge Embryo, Co - Cotyledon, Lb, Co - Lobes of cotyledon, Ra - Radical; Figure - IV Transverse section of seed, Ep - Epidermis, Pal - Palisade cell, Pa - Parenchyma, En - Endosperma, Pa - Layer of parenchyma, Co - Cotyledons, Ep - Epidermis, Ol - Oil globules; Figure - V Transverse section of Radical, Ep - Epidermis, Cor - Cortex, End - Endodermis, Xy - Xylem vascular bundle, Ph - Phloem

(A) Entire seed, showing the mature and fully differentiated embryo, the endosperm, and the testa (seed coat); (B) Structure of the seed covering layers: Endosperm, a single cell layer; and testa (seed coat), composed of inner and outer integument. Note that the mucilage is generated from the outer testa upon imbibition; (C) Micropylar cap enclosing the radicle tip; (D) Chalazal seed region. Blue light filter (C, D) Differential contrast (D) Size bars are given for each panel

Discussion and Conclusion

Transverse section of seed shows uniformly thin-walled epidermis which has creamish yellow color with a number of reddish brown fragments of seed coats. Below the epidermis, there is a layer of palisade cells which are arranged symmetrically and filled with yellow coloring matter. After that, there is a layer of parenchyma cells which are colorless and thin walled. Just below it, there is a layer of endosperm. In between endosperm and epidermis, there are layer of parenchyma and cotyledons. Here, the parenchymatous cells show red coloring mater and other with uniformly thick walls endosperm oil globules.

Characters of seed powder in different view, i.e., surface view and radical view are presented. In surface view, it shows layer of epidermis and palisade cells.

Testa in surface view shows epidermis and parenchymatous cells filled with starch and coloring material. Some small oil globules are also seen.

Epidermis in surface view shows epidermis and oil globules. Under the microscope, it also shows xylem and phloem.