Pharmacognostical Studies on Stem of Tribulus terrestris L.

 

Mamdouh N. Samy1*, Mokhtar M. Bishr2, Ahmed A. Ahmed3, Hanaa M. Sayed4 and Mohamed S. Kamel1

1Department of Pharmacognosy, Faculty of Pharmacy, Minia University, Minia 61519, Egypt.

2Research and Development Department, Mepaco Company, Cairo, 11361, Egypt.

3Department of Organic Chemistry, Faculty of Science, Minia University, Minia 61519, Egypt.

4Department of Pharmacognosy, Faculty of Pharmacy, Assuit University, Assuit 71526, Egypt.

 

 

ABSTRACT:

The present study was carried out to establish the pharmacognostical characters of stem of Tribulus terrestris L. No reports are available on the pharmacognostical studies of the stem; hence, the present study was carried out to help in identification of this plant for the future references. The microscopical studies of stem revealed the presence of cluster crystals, non-glandular hairs, starch granules, lignified fibers, pitted wood parenchyma, trachides and lignified spiral and pitted xylem vessels.

 

KEYWORDS: Tribulus terrestris, Zygophyllaceae, pharmacognostical study, stem.

 

INTRODUCTION:

The genus Tribulus belongs to family Zygophyllaceae comprises approximately 25 species which grow as prostrate hairy herbs in tropical and warm regions1,2. Tribulus terrestris L. (Zygophyllaceae) (Fig. 1) is commonly known as devil's thorn, cat head, puncture vine, goat head and caltrop3. It is a herbaceous, annual, prostrate or semierect, diffusely branched herb4; native in dry and sandy districts in South Europe to Central Asia and in tropical and South Africa 5, growing in India, other warm countries such as Ceylon6, desert plains, waste ground, weed of cultivation and Mediterranean region1. It is used in folk medicine in India, China, Bulgaria and other countries to increase spermatogenesis, for treatment of eye troubles, edema, abdominal distension, leucorrhea cardiovascular diseases and impotence, as aphrodisiac, galactagogue, anti-inflammatory, antidiarrheal and diuretic4,7,8.

 

Fig. 1: Photo of Tribulus terrestris

 

 

MATERIALS AND METHODS:

Plant material: The leaves of T. terrestris were collected during the flowering and fruiting stage in October 2004 from the green areas of Minia University Campus, Minia, Egypt. A voucher specimen of the plant is deposited in the Herbarium of Faculty of Pharmacy, Minia University, Egypt (Minia-04-Mar-TT).

 

Microscopic studies: T. S., Surface preparation and powder of the stem were used for observation of various microscopic features.

 

RESULTS AND DISCUSSION:

Macroscopical character:

The herb (Fig. 2 and 3) has a short woody stem base from which arise several slender hairy branches. The branch extends often to 30-70 cm long and has a diameter of 2 to 5 mm; the internodes vary from 1.5 cm to 2.5 cm long. The surface of the stem is smooth and of green to greenish-brown color. The stem is broken with short fracture and has bitter taste and faint odor.

 

Fig. 2: Photo of the stem

 

Fig. 3: Sketch of the stem

 

Microscopical character:

1- The basal part of the stem:

A transverse section in the basal part of the stem (Fig. 4and5) is circular in outline as shown in the figure. It shows an epidermis with a thick cuticle, followed by a comparatively wide cortex of several layers of ordinary parenchyma. The inner most layer of the cortex, the endodermis; is generally indistinguishable from the other layers of the cortex and show few starch granules. Within the cortex there are scattered groups of few layered pericyclic fibres interrupted by thin-walled parenchyma and surrounding a central cylinder formed of a complete ring of vascular elements enclosing the pith. The phloem region is very narrow, the xylem ring is continuous, radiating, comparatively wide and with the primary xylem projecting out into the medulla; being separated from the phloem by a narrow zone of cambial cells. Both the bast and wood are radially transversed by numerous medullary rays. In the center, there is parenchymatous pith. Scattered cluster crystals of calcium oxalate and abundant starch granules are present in the cortex and the pith.

 

The epidermis:

The epidermis is formed of one row of usually square to subrectangular cells as seen in transverse section. In surface view (Fig. 6 and 7) the epidermal cells are polygonal usually elongated, occasionally isodiametric with straight anticlinal walls; the walls varies from beaded walls to sometimes thin walls of the epidermal cells around the stomata, being about  10 to 50 µ in width, 40 to 100 µ in length and 10 to 20 µ in height. They are covered with smooth thick cuticle. Occasional stomata are present, being of anomocytic type, surrounded with 4-5 cells, oval in shape and measuring 25 to 30 µ in diameter and 30 to 35 µ in length. Stiff-like hairs with slightly lignified walls and wide lumen and long non-glandular, unicellular hairs have rounded base and acute apices are present being about 10 to 50 µ in width and 260 to 730 µ in length.

 

The cortex:

The cortex is formed of 4 to 5 rows of ordinary, thin-walled parenchyma with numerous, fairly wide intercellular spaces. The endodermis being indistinguishable from the other layers of the cortex and is formed of a single continuous layer of tangentially elongated cells, containing few starch granules. Scattered cluster crystals of calcium oxalate measuring from 50 to 60 µ in diameter and abundant starch granules are present in the parenchyma; the starch granules are mainly simple, muller-shaped to somewhat spherical with slightly eccentric, sometimes centric hilum measuring from 10 to 30 µ in diameter.

 

The pericycle:

The pericycle separates the central stele from the cortex and consists of groups of fibers interrupted by parenchymatous cells. The pericyclic fibers are long, having thick, lignified walls, wide lumen and tapering ends, being about 20 to 40 µ in width and 560 to 940 µ in length.

 

The vascular system:

The central stele of Tribulusterrestris Linn.stem shows a wide continuous ring formed mainly of secondary elements transversed by numerous medullary rays.

 

The phloem:

It is formed of a complete narrow ring of primary and secondary phloem surrounding the xylem; consisting of shining, thin-walled, soft, cellulosic elements; of sieve tubes, companion cells and phloem parenchyma.

 

The cambium:

Cambial zone is formed of few rows of thin-walled, cellulosic cells which are tangentially and radially arranged.

 

The xylem:

It is formed of a wide zone of lignified, thick-walled, radially arranged secondary elements. The vessels are wide; either isolated or in small scattered groups of 2 to 4; many vessels are spiral and pitted and measuring 20 to 60 µ in diameter. Tracheidsmostly possess lignified walls with usually rounded, oval and elongated simple pits. The wood fiber is elongated with thick, lignified wall being about 10 to 30 µ in width and 250 µ in length. The wood parenchyma is subrectangular, usually axially elongated cells with lignified pitted walls.

 

The medullary rays:

The medullary rays are uniseriate to biseriate, radially elongated cells with thick, pitted, lignified walls being about 60 to 90 µ in width and 80 to 120 µ in length.

 

The pith:

It is comparatively wide, parenchymatous, consisting of usually large, polygonal, isodiametric to rounded cells with intercellular spaces. Scattered cluster crystals of calcium oxalate measuring from 50 to 60 µ in diameter and abundant starch granules are present in the parenchyma; the starch granules are simple, muller-shaped to somewhat spherical with slightly eccentric, sometimes centric hilum measuring from 10 to 30 µ in diameter.

 

 

Fig. 4: Photo of T. S. of the basal part of the stem

 

Fig. 5: Sketch of T. S. of the stem

 

2- The upper part of the stem:

A transverse section in the upper part of the stem (Fig. 6) is similar to the basal part in structure, arrangement of tissues and outline of the section as well as in the characters of the elements except that the epidermis is more hairy, the vascular bundles are separated by a wide primary medullary rays being from 12 to 14 bundles in number and the pericycle is formed of separated collenhymatous groups with no fibers above each vascular bundle and absence of cambium, secondary phloem, secondary xylem and secondary medullary rays.

 

Fig. 6: Photo of T. S. of the upper part of the stem

 

 

3- The powder of the stem:

The powder of the stem (Fig. 7and8) is yellowish-green in color with faint characteristic odor and bitter taste. The main diagnostic microscopic elements are:

1.     Fragment of the epidermal cells consisting of polygonal usually elongated, occasionally isodiametric with straight anticlinal walls; the walls varies from beaded walls to sometimes thin walls of the epidermal cells around the stoma, covered with smooth cuticle and showing anomocytic stomata.

2.     Scattered cluster crystals of calcium oxalate.

3.     Abundant starch granules.

4.     Fragment of lignified pericyclic fibers. The fibers are long, having thick, lignified walls.

5.     Fragment of lignified xylem vessels with spiral thickening.

6.     Fragment of lignified tracheids with pitted thickening.

7.     Fragment of lignified wood fibers.

8.     Fragment of lignified pitted wood parenchyma.

9.     Fragment of lignified pitted medullary rays.

10.   Nonglandular, unicellular hair covered with smooth cuticle.

 

Fig. 7: Photos of the powdered stem

 

Fig. 8: Sketch of the powdered stem

 

 

CONCLUSION:

The pharmacognostical studies on the stem of Tribulus terrestris L. were carried out to identify the plant in the powder form and in the elimination of adulterants.

 

REFERENCES:

1.     Boulous L. Flora of Egypt. Al Hadara publishing, Cairo, Egypt. 2000; Vol. 2: 26‒31.

2.       Tackholm V. Students' Flora of Egypt. Cairo University Cooperating Printing Co., Beirut, 1974; 2nd Ed: 311‒313.

3.       Quattrocchi U. CRC world Dictionary of Plant Names. CRC press, Boca Raton, London, New York, Washington, D. C. 2000; Vol. IV: 2708.

4.       Ross IA. Medicinal plants of the world. Chemical Constituents, Traditional and Modern Uses. Humana Press Inc. 2001; Vol. II: 411‒426.

5.       Rendle AB. The Classification of Flowering plants. The University Press, Cambridge. 1959; Vol. II: 280.

6.       Chopra RN. Indigenous Drugs of India. The art press, 20 British Indian street, Calcutta. 1933; 408.

7.       De Combarieu E, Fuzzati N, Lovati M and Mercalli E. Furostanol saponins from Tribulus terrestris. Fitoterapia. 74(6); 2003: 583-591.

8.       Wang Y, Ohtani K, Kasai R, Yamasaki K. Steroidal saponins from fruits of Tribulus terrestris. Phytochemistry. 45(4); 1997: 811-817.

 

 

Received on 14.01.2013

Modified on 27.02.2013

Accepted on 20.03.2013

© A&V Publication all right reserved

Research Journal of Pharmacognosy and Phytochemistry. 5(4): July- August 2013, 171-177