|Year : 2012 | Volume
| Issue : 4 | Page : 190-193
Botanical pharmacognosy of stem of Gmelina asiatica Linn
R Kannan, K Prasant, UV Babu
Research and Development Center, The Himalaya Drug Company, Bangalore, India
|Date of Web Publication||18-Feb-2013|
The Himalaya Drug Company, Makali, Tumkur Road, Bangalore
Source of Support: None, Conflict of Interest: None
Gmelina asiatica Linn (G. parvifolia Roxb.) is a large shrub or a small tree. Roots and aerial parts are used in Ayurvedic medicine and also have ethno-medical uses. Root is reported as adulterant to G. arborea roxb roots. Pharmacognostical characters of root were reported. Owing to the shortage of genuine drug and ever-increasing demands in market, it becomes necessary to search an alternative with equal efficacy without compromising the therapeutic value. Nowadays, it becomes a common practice of using stem. In case of roots phytochemical and pharmacological analysis of stem was reported. However, there is no report on the pharmacognostical characters of stem and to differentiate it from roots. The present report describes the botanical pharmacognostical characters of stem and a note to differentiate it from root. Hollow pith, faint annual rings in cut ends, alternatively arranged macrosclereids and bundle cap fibers, and presence of abundant starch grains and calcium oxalates in pith and in ray cells are the diagnostic microscopic characters of stem. Stem pieces can be differentiated from roots by absence of tylosis.
Keywords: Botanical pharmacognosy, ethnobotany, Gmelina arborea, Gmelina asiatica, pharmacognosy, root, stem
|How to cite this article:|
Kannan R, Prasant K, Babu U V. Botanical pharmacognosy of stem of Gmelina asiatica Linn. Ancient Sci Life 2012;31:190-3
| Introduction|| |
Gmelina asiatica Linn (Syn: G. parvifolia Roxb.) is called as 'Vikarini' in Sanskrit, 'Badhara' in Hindi, 'Nilakumil' or 'Kumil' in Tamil and Malayalam, 'Adavi Gummudu' or 'Challa Gummudu' in Telungu and Asian Bushbeech in English. It belongs to the family Verbenaceae, and after phylogenetic studies, it is now being classified under the family Lamiaceae. It is commonly found in peninsular India and parts of Maharashtra and Rajasthan. Especially found in dry lands, wastelands, as a live fence in agricultural lands and also on road sides. It is a much branched, deciduous or a semi-deciduous, large-sized bush, or rarely grows to a small tree. It has many irregular puberulous or slightly hairy branches, often much shortened and spinous at the ends, bears small simple opposite leaves. Leaves are ovate to elliptical, chartaceous, with cuneate base, entire or lobed margin, and obtuse apex. Petiole is up to 1 cm long. Flowers are large, nodding, in terminal densely pubescent racemes or panicles.
Roots are considered to be medicinal and useful in traditional medicine. Though the root bark and wood of the root are the official drugs,  leaves and young shoots are also useful in medicine.  Use of leaves and aerial parts in treatment of jaundice and other hepatic diseases by some tribes in Tamil Nadu  and another tribe for body heat  were reported. Roots, bark, fruit, leaves, and young shoots are used in various medicines in Sri Lanka.  Its roots are considered as a substitute for Gmelina arborea. It is also reported that this is one of the 'Anukta Dravya' drugs. 
Microscopical characters of root were described  and compared with G. arborea root.  Roots possess anti-oxidative properties,  and stem are also reported as a potential source of antioxidants.  Few major active constituents were identified from aerial parts by using GC-MS.  Stem bark showed hypoglycemic and anti-hyperglycemic effects.  Antioxidant and hepato-protective activity in chloroform and ethanol extracts of aerial parts was reported.  Nowadays, it becomes a common practice of using stem incase of root, and also, it was analyzed and found that the stem of the same plant can be used instead of roots. ,,
Reports on phytochemistry and pharmacology are available for aerial parts of the plant. There is no report on the pharmacognostical characters on aerial parts. In practical, with our experience, aerial parts of a shrubby plant that too has fever leaves, the market sample might be of stem pieces. Hence, the present study is on the macro-microscopical characters on stem of Gmelina asiatica. The characters were compared with the previously published characters of roots, to differentiate them in the market samples, in whole form or in powdered form.
| Materials and Methods|| |
Plants were collected from two different locations, outskirts of Bangalore (N13 05.555; E77 21.622) and Tirunelveli (N8 28.358 E77 54.835). They were identified with local floras, , and stem pieces were collected. Herbarium was prepared and archived in in-house archive in pharmacognosy lab. As per the general practice of raw material processing, in commercial scale, in India, collected raw material was reduced in size and sun-dried. Organoleptical, macroscopical, and microscopical characters were studied with the dried pieces as described in quality control methods, ,, which is being followed in herbal drug industries for standardization of herbal raw materials.
| Results|| |
Macroscopical and organoleptical characters
Stem pieces are up to 4 cm in thickness. In many of the pieces, bark was detached off and found separately. They are up to 2 mm in thickness on matured pieces and papery in young pieces. Outer bark is grayish-brown to yellowish-gray, and inner bark is mild reddish-brown to yellowish-brown in color. Numerous dots of pale gray or buff-colored lenticels are abundant on the bark's surface. Many of the matured and thicker pieces have grayish longitudinal streaks on the surface. Cut ends of the wood are white to yellowish in color. There was no difference of heart wood and sap wood. Cut ends on close observation shows faint circles of annual rings. Innermost region or the central portion, even in young and thin pieces, is hollow pith. In longitudinally split pieces, parenchyma cells are found as black-colored dried masses or streaks attached on the inner surface of the hollow pith. Thin and young stem pieces have decussately opposite spines of up to 5 mm long in the nodes. In general, the stem pieces are mild bitter in taste and do not reveal any typical, noticeable odor. Fracture is impossible, as they are very hard to break.
In TS, matured stem [Figure 1]a shows typical dicot structure with outer fissured or cracked cork cells made of suberized wall with lenticels, followed by secondary cortex, secondary phloem, wood and central pith. Secondary cortex is parenchymatous with starch grains as cell inclusions. However, it is completely collapsed in dried materials, and further details could not be observed. Even in many pieces, a thick, dark-colored band represents the cortex. Secondary phloem consists of patches of bundle cap fibers from primary vascular bundles, alternatively with groups of few macrosclereids, which has tiny lumen, and other phloem elements. Wood consists of vessel elements, fibers, and tracheids. Annual rings are clearly visible, demarked with thin tracheids with narrow lumen. Usually, rays are bi-seriate. Pith cells below the xylem elements are larger, and inner is hollow. Parenchyma cells of secondary phloem, ray cells, and pith cells are filled with starch grains and calcium oxalates. Starch grains are simple or compound without clear hilum, rounded or oval, and up to 16.5 μ in size. Calcium oxalates are prismatic, square or rectangular, especially abundant in the pith cells and ray cells, and are up to 12 μ in size. RLS and TLS of the stem also reveal the typical dicot structure. The pore size in matured stem is 90 μ and in young stem, it is 70 μ.
TS of spines [Figure 1]b are more or less similar as of stem. 3-4 layered suberized cork cells are followed by parenchymatous cortex, which is not collapsed as in stem. Secondary phloem has patches of fibers with narrow lumen. Xylem region has more fibers and tracheids and fewer vessel elements. Pith is large and filled with parenchyma cells.
|Figure 1: Microscopical characters of G. asiatica stem (a) TS of matured stem (a portion), (b) TS of spine, (c-l) stem powder shows the various cell elements, (c-e) powdered stem shows vessel elements, (f and g) Powdered stem shows cork cells, (h and i) powdered stem shows stone cells, (j and k) powdered stem shows patches of fibers, (l) powdered stem shows calcium oxalates|
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Powdered material is pale brown in color with streaks or pieces of mild reddish bark. Under microscope, xylem elements are abundant and commonly seen in all fields. Under close observation, it shows the fragments of vessel elements [Figure 1]c-e, lignified pith cells [Figure 1]f and g, macrosclereids from secondary phloem region [Figure 1]h and i, fragments of groups of tracheids [Figure 1]j or fibers [Figure 1]k, and calcium oxalates [Figure 1]l. Starch grains and cork cells are observed here and there.
| Discussion and Conclusion|| |
Following are the diagnostic characteristic features of stem of Gmelinia asiatica:
- Hollow pith, even in thinner stem
- Faint annual rings in cut ends
- Alternatively arranged macrosclereids and bundle cap fibers in secondary phloem
- Abundant starch grains and calcium oxalates in pith and ray cells.
In Sri Lanka, the plant has yellowish-white bark and blooms in September. In local floras, it was mentioned that the flowering season is from February to August or almost throughout the year. In our observation, bark was grayish-brown bark and blooms during March-April. This might be due to the general geographical variations.
It was reported that the rays are up to 3-seriate in roots. We observed bi-seriate rays in stem and uni-seriate in spines. This can be a diagnostic feature to identify the stem and roots in microscopical characters. However, it cannot be used as a diagnostic character if the material is powdered. Similarly, the pore size in root was reported as an important characteristic feature to differentiate between G. arborea and G. asiatica roots. In our observation, in matured stem, the average pore size is 90 μ and 70 μ. Thus, pore size cannot be a character to identify the roots and stem if they were powdered.
It was reported that numerous vessel elements of roots has tylosis. In our observation in stem, there was no tylosis, even in the much thicker and oldest stem pieces, and also there was no differentiation of heartwood and sapwood. This might be an important character to identify the stem and roots in commercial samples.
After a comparative analysis of phytoconstituents, of barks from stem and root, in case of Brihatpanchamoola, it is concluded that root bark can be effectively substituted by stem bark. It is also commented that, in practical, aerial portions are being used and sold instead of roots.  Modern researches substantiate that the whole plant or aerial parts are equally effective in case of Sida cordifolia, when compared with roots.  Likewise, when looking for sustainable collection methods, stem will be in use instead of root, and the present method of differentiation provides key to differentiate the stem and root in microscopical and powder characters.
The present pharmacognosy report reveals that the basic pharmacognostic details of stem of G. asiatica to Identify or authenticate them. Few pharmacological and phytochemical studies also reveal that stem can be used instead of roots. Further research is advised to substantiate the use of stem instead of root in case of G. asiatica or G. arborea has to be find out.
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