INTRODUCTION:

Medicinal plants have been used for treatment of diseases and ailments since time immemorial in different traditional systems of medicine due to their well-tolerated effect, accessibility, low cost, and free from serious adverse effect¹. There has been a global interest in medicinal plants in recent years and concerns regarding usage of correct medicinal plant always remained in question due to lack of appropriate standardization and authentication parameters; which are otherwise necessary to ensure the quality and purity of the herbal drugs. Further, adulterations and substitution in herbal drugs have now become a major problem due to absence of standards relating to originality of drugs.

Tradescantia pallida (Rose) D. R. Hunt (Fig. 1), a member of Commelinaceae family is a herbaceous ornamental perennial plant, locally known as Setkrisia Ungu or Purple Queen is commonly distributed in tropical and subtropical regions². The plant is recognized for having a sharp acute apex, a deep royal violet with a dusty green undertone and a vivid violet shades underside of the leaves and with pink to purple flowers in a small densely cymose clusters³.

Traditionally, the plant is believed to improve blood circulation and act as an anti-inflammatory and anti-toxic supplement⁴, and as antioxidant⁵. In Malaysia, the Ayta communities from Porac Pampanga use this plant for the treatment of sore eyes⁶. Some reports also stated that the plant functioned to purify and clean volatile organic compound from the air⁷. T. pallida has been reported to exhibit a good alternative for in situ mutagenesis testing⁸. Methanol extract of the leaves showed promising antioxidant and antibacterial activities⁵. T. pallida-mediated zinc oxide nanoparticles are reported to possess activity against cervical cancer cell lines⁹. In the present paper, we report the pharmacognostic study of the leaves of T. pallida leaves using recommended procedures.

Figure 1: Tradescantia pallida leaves and flower

MATERIALS AND METHODS:

Plant material:

Fresh leaves of T. pallida was collected from Hock Loke Siew Nursery, Ipoh, Perak from the well grown and matured shrubs and authenticated. After confirmation, the leaves were collected in bulk and cleaned with water. The leaves were dried under shade and powdered using a mechanical grinder. The dried powder was sieved through 40 mesh and stored in an airtight container until further use.

Pharmacognostic study:

Fresh leaves were used for the macroscopical and anatomical studies. Dried coarse powder was used to study powder microscopy, physiochemical parameters and preliminary phytochemical analysis.

Macroscopy:

The morphological characters of the plant leaves such as shape, size, colour, odour, taste, texture, margin and phyllotaxis were studied.

Microscopy:

The microscopical studies of the leaves were performed as suggested by Vadivu and Lakshmi, 2008¹⁰.

Transverse section of the leaves:

Thinnest possible sections of fresh leaves stained with phloroglucinol and concentrated hydrochloric (1:1) were mounted on microscopic slides. The sample was covered with glycerine and cover slip and examined under a binocular compound optical microscope (Leica DM750, Germany) fitted with a digital camera. The images were then captured for further observation.

Powder microscopy:

The coarse powder was treated separately with different reagents such as phloroglucinol-hydrochloric acid (1:1), N/20 iodine solution and distilled water and the specimens were observed under the compound microscope to detect presence of lignified tissues, starch grains and calcium oxalate crystals respectively.

Physichochemical parameters:

The physicochemical characteristics of the dried leaf powder such as total ash, acid insoluble ash, water soluble ash, water soluble extractive and ethanol soluble extractive values were studied and reported as percentage with respect to dried plant material¹¹.

Preliminary phytochemical screening:

For preliminary phytochemical screening, about 2g of the dried powdered leaves were extracted successively with petroleum ether, chloroform, methanol and water. Ultrasonic extraction bath was used for 1 h at each stage of extraction. The liquid extracts were subjected to qualitative phytochemical screening^12,13 and fluorescence analysis under ultraviolet light at short wavelength (254nm) and long wavelength (365nm)¹⁴.

RESULTS AND DISCUSSION:

Macroscopy:

Macroscopic evaluation is a method used to determine the morphological aspects and sensory profiles of the plants which are observed by the naked eye or using a magnifying lens. It helps in distinguishing the characters and determining the correct identification of the crude drugs. The morphological observations of T. pallida is presented in Table 1 and Fig. 2.

Table 1. Macroscopic characteristics of T. pallida leaves

Macroscopic characteristics	Observation
Shape	Lanceolate-oblong to oblong-elliptic
Colour	Purplish violet
Phyllotaxis	Alternate
Margin	Entire
Leaf type	Simple
Leaf venation	Parallel
Texture	Fleshy
Length	7.6 - 12.7 cm
Width	2.5 cm
Taste	Characteristics
Odour	Odourless

Figure 2: Macroscopic characteristics of T. pallida leaves

Microscopy:

Transverse section of the leaves:

The transverse section of the leaf (Fig. 3) exhibits upper and lower epidermis and consists of thin walled cells without any inter cellular spaces in between them. The outer wall of epidermis is covered with thin cuticle. Chloroplasts cannot be seen in these cells. The stomata are surrounded by dumb-bell shaped guard cells. A few cells present in the upper epidermis are enlarged to form motor cells or bulliform cells. About 2-3 layers of closely packed parenchymatous cells are seenin the hypodermis just below the adaxial surface of leaf lamina. These cells are larger when compared to other epidermal cells. Presence of uniseriate multicellular covering trichomes were seen.

The ground tissue that is present between the upper and lower epidermis of the leaf is is not differentiated into palisade and spongy parenchyma. The tissue consists of small oval or spherical or irregular shaped palisade cells with chloroplasts and chlorophyll.

Many vascular bundles with different sizes are present within the mesophyll tissue. They are arranged in a parallel series. Most of the vascular bundles are smaller in size but large bundles occur at regular intervals. Vascular bundles are collateral and closed and surrounded by a parenchymatous bundle sheath. The xylem of the vascular bundle is located towards the upper epidermis and the phloem towards the lower epidermis.

Figure 3: Transverse section of the T. pallida leaf

Powder microscopy:

Diagnostic characteristics of T. pallida leaf powder (Fig. 4) showed presence of paracytic stomata, fragments of mesophyll, fragments of epidermal cells showing palisade cells beneath them, non-lignified phloem fibers, uniseriate multicellular covering trichomes and crystals of calcium oxalate.

Physicochemical parameters:

The results of the percentage of total ash, water soluble ash, acid soluble ash, water soluble extractive and ethanol soluble extractive values of the powdered leaves are presented in Table 2. Ash values and extractive values are important parameters in crude drug analysis especially in powder form. It provides information of the organic and inorganic matters or or impurities especially in herbal drug powders.

Figure 4: Powder microscopy of T. pallida leaves

Table 2. Physicochemical parameters of the powdered leaves of T. pallida

Parameters	%w/w
Total ash	20.63 ± 1.87
Water soluble ash	18.97 ± 1.05
Acid insoluble ash	1.66 ± 0.36
Water soluble extractive	21.3 ± 1.78
Ethanol soluble extractive	7.8 ± 0.83

Results expressed as Mean ± SD from three observations

Preliminary Phytochemical Screening:

The findings for the preliminary phytochemical tests of different extracts of the leaves is presented in Table 3. Based on the results, the leaves were found to contain tannins, flavonoids and sterols respectively.

Fluorescence analysis:

The results of fluorescence analysis of the extracts are presented in Table 4 and Fig.5. Certain phytoconstituents show fluorescence when examined under ultraviolet radiation. The shifting of colour from visible light to ultraviolet light can be served as an indicator for the presence or absence of chemical constituents.

Table 4. Fluorescence analysis of T. pallida leaf extracts

Extracts	Visible/ Daylight	Ultraviolet light
Extracts	Visible/ Daylight	Short (254 nm)	Long (365 nm)
Petroleum ether	Light green	Light green	Orange
Chloroform	Dark green	Dark green	Red
Methanol	Pale green	Pale green	Light orange
Distilled water	Dark brown	Dark green	Dark green

Figure 5: Fluorescence analysis of the different extracts of T. pallida (petroleum ether, chloroform, methanol, distilled water) under visible light and ultraviolet light (254 and 365 nm)

CONCLUSION:

Traditional medicinal plants have always retained their therapy in the literature for several health benefits but, unfortunately their quality and purity are yet to be guaranteed due to lack of standardization parameters. Thus, establishment of standards for a particular plant species becomes the initial steps prior to any further research. The present study on the pharmacognostic analysis could serve as a platform for proper identification of the plant species. Detailed study of the macroscopical, morphological and microscopical characters could be helpful in determining adulteration of the crude drug. It may also be helpful in building a suitable monograph of the species.

ACKNOWLEDGEMENTS:

The authors are thankful to Universiti Kuala Lumpur Royal College of Medicine Perak for providing necessary facilities to carry out this research work.

CONFLICTS OF INTEREST:

Nil.

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Received on 19.06.2019 Modified on 20.07.2019

Research J. Pharm. and Tech. 2020; 13(1):233-236.

DOI: 10.5958/0974-360X.2020.00047.5

Test	Chemical tests	Pet. ether extract	Chloroform extract	Methanol extract	Aqueous extract
Alkaloids	Dragendorff’s test	-	-	-	-
Saponins	Foam test	-	-	-	-
Tannins	Ferric chloride test	-	-	+	+
Flavanoids	Shinoda test	-	-	+	+
Steroids	Libermann Burchard test	+	+	-	-