1. INTRODUCTION:

There are several species of genus Boerhaavia, which are distributed in the tropical, sub tropical and temperate regions throughout the world like Australia, Asia, U.S.A., and Africa. Boerhaavia diffusa (Family: Nyctaginaceae) is indigenous to India and found throughout the warmer parts of the country up to an altitude of 2000m in the Himalayan region¹. Out of the 40 species of this genus, 6 species are found in India– B. diffusa, B. chinensis, B. erecta, B. repens, B.rependa, and B. rubicunda^{2, 3}.

B.diffusa is a wild perennial herb which may be encountered in different terrestrial habitats, ranging from managed grass lands, waste lands and agro eco systems to large forest gaps. The plant was named in honour of Hermann Boerhaave, a famous Dutch physician of the 18th century².

It is a very variable, diffusely branched, herb, abundantly occurring as a weed throughout India, up to an altitude of 2000m in the Himalayas. Root-stock stout, fusiform, woody; stems creeping, often purplish, swollen at the nodes, up to 1.2 m long; leaves long-petioled, ovate or oblong - cordate, entire or sinuate, usually whitish and smooth beneath and rough green on upper surface; flowers red, pink or white in small umbels arranged in axillary and terminal panicles; fruit ovate, oblong, pubescent, five-ribbed, viscid, glandular anthocarp³ (Fig.1A).

It has a long history of uses by indigenous and tribal people. It is known as Punarnava in Sanskrit and Mukkarattai in Tamil. The Siddha system of medicine is one of the oldest traditional systems of medicine, which has been originated from India for treating various diseases including chronic conditions. In Siddha system of medicine it is used as expectorant, diuretic, laxative, refrigerant, anthelmintic and emetic (in larger doses). The leaves are cooked in the form of a curry or chutney and taken daily to avoid constipation. This daily intake as part of diet also helps in maintaining a rejuvenated and glowing skin of the body⁴. The leaves are useful in dyspepsia, tumours, enlargement of the spleen, abdominal pains. The leaves have a sharp taste; appetizer, alexiteric, used in opthalmia. Roots and leaves are diuretic and anti-inflammatory than stems and whole plant activity is maximum in rainy season. It is also administered orally as a blood purifier and to relieve muscular pain. Leaves are used in dropsy and also in gonorrhorea; and hasten delivery. Dry and powdered leaves mixed with Brassica oil used for external application on itch and eczema. Boiled with rice, garlic and water rubbed on body to cure rheumatism. Plant-drug for oedema and ascites resulting from early cirrhosis of liver and chronic perintonitis³. The leaf extract of B. diffusa shows in vitro antifungal activity against Microsporon nanumi⁵.

This plant is also used by the tribes of Ambikapur district (Madhya Pradesh) for the treatment of
elephantiasis. In the Indo-Nepal Himalayan terrain region, the tribals harvest this plant for medicinal purposes mainly for flushing out the renal system, to treat seminal weakness and blood pressure⁶. In Purulia (West Bengal), tribals eat this plant as vegetable. The leaves are cooked and eaten in Assam, where it is commonly found in the markets. In Brazil the plant as a whole or its extracts is used for albuminaria, beri-beri, bile insufficiency, cystitis, edema, gallstones, gonorrhea, guinea worms, hepatitis, hypertension, jaundice, kidney disorders, kidney stones, liver disorders. The leaf extracts from B. diffusa has been shown to have hepatoprotective, antioxidant, antinociceptive, antibacterial and antidiabetic properties¹. The study carried out demonstrated that the leaves of Boerhaavia diffusa reduced the levels of glucose in the blood increasing the insulin release from the β cells of pancreas⁷. The plant is reported to be efficacious in abdominal tumours and cancer, it is also credited with cardio tonic properties. The analysis of leaves gave moisture, 84.5; protein 6.1; fat 0.9; carbohydrates, 7.2; minerals, 1.3g/100g; calcium 667.0; phosphorous 99.0; iron 18.4; vitamin C, 27mg/100g; and energy 61Kcal/100g³.

MATERIALS AND METHODS:

Fresh plants were collected from Siddha Central Research Institute, Chennai, Tamil Nadu. Botanical identification was carried out using Flora of Presidency of Madras⁸. The voucher herbarium specimens were deposited at the herbarium in Department of Pharmacognosy SCRI, Chennai and leaves were stored in FAA (5ml Formalin: 5ml Acetic acid: 90ml of 70% alcohol). Free – hand sections of the petiole and leaf were taken to study the anatomical structure. Staining was done by the methods described by Johansen⁹. Clearing of leaves for studying stomatal number and stomatal index was done by using chloral hydrate supplemented with gentle heat. Powder microscopy and quantitative values such as stomatal number, stomatal index, vein islet number, vein termination number and palisade ratio were determined¹⁰. Observations were photomicrographed at different magnifications with a Nikon Digital Camera fitted on a Nikon microscope.

RESULTS AND DISCUSSION:

Macroscopic characters of leaf:

Leaves opposite in unequal pairs, larger ones 2.5 - 3.8cm long and smaller ones 1.2 – 1.8 cm long, ovate, oblong or sub orbicular, apex rounded or slightly pointed, base subcordate or rounded, entire or sinuate, green and glabrous above, whitish below, dorsal side pinkish in certain cases, thick in texture; petiole long, nearly as long as the blade, slender (Fig.1A).

Microscopic characters

Petiole:

Transverse section of petiole is oval in shape with a deep groove on the dorsal side. Epidermal cells are rectangular and bear numerous clothing and glandular hairs. The hypodermal region is composed of 2 layers of collenchyma cells. Trichomes vary in their size, length, distribution and abundance. The walls of the trichomes are impregnated with numerous crystalline granules. The glandular hair consists of a row of cells, with enlarged terminal cell. The clothing hairs are simple, uniseriate with blunt terminal cells are not much larger than the others. (Fig.1B). The ground tissue is parenchymatous and some cells contain calcium oxalate crystals in the form of raphides. The vascular system is represented by an arc of collateral 6 or 7 vascular bundles. There are 2 small accessory bundles situated on either side of the adaxial face. (Fig.1C)

The powder is characterized by the fragements of epidermal cells with ranunculaceous stomata, numerous glandular hairs, parenchyma cells, raphides, fragments of vessels with annular, spiral in reticulate thickening. Vein islet and vein termination are clearly seen. Numerous raphides are present in the specific. (Fig.2L)

In T.S of lamina leaf is dorsiventral in structure (Fig.1D). The epidermal cells are large, irregular in shape and the walls are thickened and cuticularized. The outer wall is impregnated with crystalline granules of calcium oxalate which are more numerous on the abaxial surface than the adaxial surface. Tannin idioblasts are sometimes present in the epidermis or both surfaces. The ranunculaceous stomata are present on both leaf surfaces (amphiostomatic). The mesophyll consists of columnar one layered compactly arranged palisade tissue (Fig.2 G) and 2-4 layered spongy parenchyma cells arranged with small air spaces. Idioblasts containing raphides and occasionally cluster crystals of calcium oxalate and orange red resinous matter present in mesophyll. The lamina is traversed by minor veins are surrounded by atriplicoid Kranz anatomy (That is the veins surrounded by a layer of Kranz cells which in turn are surrounded by palisade cells (Fig.2 G) Stomatal index for adaxial epidermis 11-14, abaxial epidermis 10-13, vein islet number 9-15 and palisade ratio 3 to 6.

Epidermii on surface view:

The adaxial and abaxial epidermal cells on surface view are more or less polygonal in shape with slightly waxy walls. Ranunculaceous stomata are numerous on the abaxial side. Fig.2 J and K.

Transverse section of midrib shows a small depression on the adaxial side and convexity on the abaxial side. (Fig. 1D). Adaxial epidermal cells are slightly larger than the abaxial epidermal cells. Palisade cells are not continuous over the midrib region. The adaxial hypodermal region is provided with a zone of collenchyma of 2 to 4 layers of cells. Collateral vascular bundle is situated below the collenchymatous region. The ground tissue is parenchymatous. This bundle is not surrounded by atriplicoid kranz anatomy (Fig.1.F). Idioblast containing raphides are seen in the ground tissue.

The anatomy of leaves of Boerhaavia diffusa has Kranz anatomy around the minor veins; this corresponds to the finding of¹¹, Boerhaavia coccinea Mill. and Boerhaavia dominii Meikle and Hewson for the presence of Kranz anatomy in a study investigating the Kranz anatomy and biochemistry of C4 eudicots. Tannin idioblasts and raphides are recorded for the family by various authors^12,
13. The distribution of raphides is not in a specific pattern and of no taxonomic value.

The presence of Kranz anatomy, Tannin idioblasts, crystalline granules of Calcium oxalate, idioblasts containing raphides, ranunculaceous stomata on both the surface of the leaf are therefore diagnostic characters to identify Boerhaavia diffusa.

Fig.1

A: Plant D: T.S. of leaf

B: T.S of petiole E: T.S of lamina

C: T.S.of petiole –A portion enlarged F: T.S of midrib

Fig.2

G: T.S of lamina–enlarged J: Adaxial foliar epidermis–surface view

H: Unicellular trichome K: Abaxial foliar epidermis– surface view

I: Uniseriate, non glandular and glandular trichomes

L:Venation pattern

Abbreviations:

Ab - Accessory bundle;

Abe - Abaxial epidermis;

Ade - Adaxial epidermis;

Co – Collenchyma;

Cu - Cuticle;

Ep - Epidermis;

Gtr - Glandular trichome;

Kc - Kranz cell;

P - Parenchyma;

Pa - Palisade tissue;

Ra - Raphide;

Sp - Spongy tissue;

St - Stoma;

Utr - Uniseriate trichome;

Vb - Vascular bundle;

Vi - Vein islet;

Vt - Vein termination.

REFERENCES:

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7. Pari L, Amarnath Satheesh M. Antidiabetic activity of Boerhaavia diffusa L.: effect on hepatic key enzymes in experimental diabetes. Journal of Ethnopharmacology 91(1); 2004: 109-113.

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10. Wallis TE, Text Book of Pharmacognosy, J.A. Churchill Ltd., Gloucester plane, London, 1962.

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12. Kubitzki K, Rohwer JG, Bittrich V. The Families and Genera of Vascular Plants, Vol. II, Flowering Plants, Dicotyledons. Springer-Verlag, Berlin, Germany, 1993, 473-486.

13. Edeoga HO and Ikem CI. Tannins, saponins and calcium oxalate crystals from Nigerian species of Boerhavia L. (Nyctaginaceae). South African Journal of Botany. 68; 2002: 382-385.

Received on 21.07.2014 Modified on 25.08.2014

Res. J. Pharmacognosy & Phytochem. 6(4):Oct. - Dec.2014; Page 156-159