PHARMACOGNOSTIC EVALUATION OF AN AROMATIC PLANT OF BASMATI FLAVOR: PANDANUS AMARYLLIFOLIUS ROXB.

Abstract

Many herbs are incorporated into food for their aromatic flavor like Lemon grass, Ocimum etc. One among them is Pandanus amaryllifolius Roxb. from the family Pandanaceae, cultivated in Southern India which is used for imparting aroma to rice preparations. Basmati rice is considered best due to its unique flavor. It is consumed by many as principal food, but is very expensive and unaffordable to the common man. Leaves of Pandanus amaryllifolius are widely used to flavor ordinary rice with the characteristic Basmati aroma. 2-acetyl-1-pyrroline is said to be the compound which gives this characteristic aroma. Besides its flavoring property, it also possesses therapeutic utilities and is used to treat Rheumatism and Diabetes. The whole plant is considered diuretic, sedative and having wound healing properties. Though with such wide range of uses, the plant has been least explored pharmacognostically. This study was undertaken to fulfill this aspect of the plant by throwing light upon the Microscopic, Powder microscopic & macroscopic characters. [PUBLICATION ABSTRACT]

Headnote

ABSTRACT

Many herbs are incorporated into food for their aromatic flavor like Lemon grass, Ocimum etc. One among them is Pandanus amaryllifolius Roxb. from the family Pandanaceae, cultivated in Southern India which is used for imparting aroma to rice preparations. Basmati rice is considered best due to its unique flavor. It is consumed by many as principal food, but is very expensive and unaffordable to the common man. Leaves of Pandanus amaryllifolius are widely used to flavor ordinary rice with the characteristic Basmati aroma. 2-acetyl-1-pyrroline is said to be the compound which gives this characteristic aroma.

Besides its flavoring property, it also possesses therapeutic utilities and is used to treat Rheumatism and Diabetes. The whole plant is considered diuretic, sedative and having wound healing properties. Though with such wide range of uses, the plant has been least explored pharmacognostically. This study was undertaken to fulfill this aspect of the plant by throwing light upon the Microscopic, Powder microscopic & macroscopic characters.

Key Words: Pandanus amaryllifolius, morphology, microscopic studies, powder microscopy

INTRODUCTION

Pandanus amaryllifolius Roxb. (Pandanaceae) is a shrub, native to Malaysia (West Indonesia, Malaysia, Philippines and Ceylon)1 growing in marshy lands and also cultivated in Southern India especially in the states of Kerala and Karnataka. It shows perpetuated sucker roots, aerial stem 0.5-1m in height, 2-5 cm in diameter, bearing long aerial descending roots often penetrating in the soil like prop roots. Leaves are simple.2

In South India, people prefer to grow this plant in home garden to procure its leaves in fresh condition, whenever required, to use as a flavoring agent especially to impart its pleasant Basmati flavor to the ordinary rice during cooking process. 2-acetyl-1-pyrroline is said to be the compound which gives this characteristic aroma3. Besides the flavoring property the leaves of the plant are also known to possess number of therapeutic properties like anti-rheumatism, anti-diabetic, diuretic, sedative and wound healing4, 5. In spite of all these reputed uses, the leaves have not yet been investigated fully which led us worth to evaluate them systematically with an objective to study the leaves of P. amaryllifolius for its macroscopic and microscopic characteristics including powder microscopy.

MATERIALS AND METHODS

Fresh plants of P. amaryllifolius were collected from the site of cultivation i.e. North Malabar area of Kerala and herbal garden of Institute for Post Graduate Teaching And Research in Ayurveda, Gujarat Ayurved University, Jamnagar. Correct authentification of the plant was done6 and with the help of experts of the institute. Leaves were separated from the plant, cleaned by washing in fresh water and dried in shade. Macroscopic and microscopic characters of the leaf were studied using fresh leaves.

Macroscopic study:

Macroscopic characters such as size, shape, margin, apex, surface, colour, odour, taste, nature and texture were studied.

Microscopic study:

Free hand transverse sections of leaves were used for microscopic evaluation. Surface preparation was done by placing wet leaf on the glass slide and tissues were scrapped offwith the sharp edge of razor blade with utmost care. Water was slowly and continuously added and scrapping was done till transparent and colorless epidermis was exposed7. The powder microscopy of dried leaves was carried out with and without staining8, 9. The photomicrographs were taken by Carl Zeiss binocular microscope.

Histochemical test:

Free hand sections of leaves were taken, cleared with chloral hydrate and then stained with phloroglucinol and hydrochloric acid to observe the lignified elements. Other reagents were also used separately to stain fixed oil globules (Sudan III), Tannin (ferric chloride), starch grains (IKI) 10 etc. Glycerin was used for slide mounting.

RESULTS

Macroscopic Characteristics:

Leaf simple, alternate, linear, lanceolate, 30-40 cm long, 2-4 cm wide, apex acute, base symmetrical, margin entire except at the apex where it becomes minutely spiny upto 1-1.3 cm of its length. Venation is parallel; midrib is prominent located in the channel formed by two longitudinally running veins each on its either side, other veinlets are obscure and run in parallel direction. Leaf surface is glabrous and smooth. (Fig No. 1, 2). Upper surface is dark green, lower surface is pale green in color. Taste bland. Odor is pleasant especially after crushing.

Microscopic characteristics of the leaves:

Diagrammatic representation of transverse section (Fig. No. 3) of the leaf blade passing through the midrib, shows protrusion conically at the lower side and narrowly grooved on the upper side, also shows discontinued patches of sclerenchymatous cells under the upper epidermis and rows of meristele of various sizes and shapes above the lower epidermis, the one located in the midrib being biggest in size. The meristeles located in lamina extensions is distantly placed and a few connect both the epidermis. Collenchyma cells are present in midrib just above the lower epidermis.

Detailed T.S (Fig. No.4) passing through midrib shows two layers of upper and lower epidermis covered with thin cuticle, embedded at places with stomata. The cells of the outer layer of the upper epidermis are small and uniform in size, unlike the cells lying underneath it, which are tangentially elongated and tubular in shape (Fig No. 5.1). The cells of lower epidermis are identical with those of upper epidermis but are highly papillose (Fig.No. 5.2). The cells lying underneath upper epidermis are not uniform throughout and show 5-7 small cells alternating with big sized cells (bulliform motor cells) (Fig.No. 5.1); underneath them lies groups of 2-8 thick walled non lignified sclerenchymatous cells (Fig. No. 5.4). The meristele located in the midrib is bigger in size than the other meristeles of the leaf blade and is composed of 2-3 centrally located metaxylem and radially running 3-4 protoxylem (Fig. No. 5.5 and 5.6), protected dorsiventrally by sclerenchymatous fibers embedded at places with tracheids and parenchyma. Occasionally a layer of ill developed endodermis is also seen encircling the meristele. Two to three rows of Collenchyma cell bands are also located underneath the cells of lower epidermis (Fig No. 5.7). Remaining cells of the ground tissue of the midrib runs radially; and is of different sizes and shapes. The cells of the mesophyll consist of spongy parenchyma; but at places they also run radially; prismatic and acicular crystals of calcium oxalate and oil globules are embedded throughout the parenchymatous cells of the section (Fig. No. 5.8, 5.9 and 5.10).

Histochemical tests:

The histochemical tests (Table No.1) revealed the presence of lignified tissue, oil globules and calcium oxalate crystals. Tannins and starch were absent.

Organoleptic characters:

The dried leaf powder was dark green in color without any characteristic taste, odor pleasent.

Powder Microscopy:

The diagnostic characters of the powder showed overlapping fragments of outer and inner epidermis in surface view the cells of the outer epidermis being hexagonal, thick walled unlike those lying underneath it, which are narrow and runs tangentially; fragments of annular and spiral vessels; sclerenchymatous cells in surface view, fibers with thick walled and narrow lumen. Lower epidermis showing papillae in surface view and in sectional view, transversely cut fragments of lamina, prismatic crystals of calcium oxalate and oil globules scattered as such or embedded in the cells of the epidermis and mesophyll. Stomata embedded in the upper and lower epidermis in surface view.

CONCLUSION

Present study defines the identity of Pandanus amaryllifolius Roxb. in terms of macroscopic, microscopic, histochemical parameters which were lacking till date. It is already known that 2-acetyl-1-pyrroline compound is the flavoring principle. Other chemical constituents and therapeutic/ toxicological evaluations are to be carried out in order to fulfill the complete scientific profile of the plant.

References

REFERENCES

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8. Wallis, T.E., 1985. Text book of Pharmacognosy, 5th Ed, CBS Publishers, New Delhi, 571-578

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10. Khandelwal K R, (2008), Practical Pharmacognosy Techniques & Experimental, Pune, Nirali Prakashan. p. 183-4

Source of Support: Nil

Conflict of Interest: None Declared