Ethnobotanical Leaflets 12: 705-12. 2008.
Phytochemical Survey of Orchids in the Tirunelveli
M. Maridassa,� M.I. Zahir Hussainb and G. Rajuc
aAnimal Health Research Unit, St.Xavier�s College (Autonomous),
bDepartment of Advanced Zoology and Biotechnology
cDepartment of Advanced Zoology and Biotechnology
The conservation of plant biodiversity is one of the priorities for many nations to practice sustainable development. The knowledge of natural resources is necessary to carry out sustainable development. In this sense, the searching and finding medicinal properties in plants is a reason to conserve them and to favor of the ex situ culture. This result was greater control of plants whose improper use can have serious repercussions in natural and the well being of the population.
Plants have played a significant role in
maintaining human health and improving the quality of human life for
thousands of years and have served humans as well as valuable source of new
natural products. Despite the availability of different approaches for the
discovery of therapeutics, plant products still remain as one of the best reservoirs
of new structural types. About 25% of all prescriptions sold in the
Orchidaceae is a highly evolved and widely distributed monocotyledonous family with a large number of terrestrial, saprophytic and epiphytic species. It comprises more than 30, 000 species in approximately 750 genera (Kong et al., 2003), and new ones are being discovered by almost every botanical expedition in tropical areas.� Many orchids are used in traditional system of medicine as a remedy for a number of ailments.� The tubers and pseudobulbs of several orchids like Orchis latifolia, Orchis mascula, Cymbidium aloifolium, Zeuxine strateumatica, and some species of Dendrobium, Eulophia and Habenaria are used as a restorative and in the treatment of various diseases (Puri, 1970). The seeds of Cymbidium aloifolium used for healing of wounds. The powdered roots of Vanda tessellate is considered as antidote for poisoning. It is also used in rheumatic pains and abdominal complaints. Dendrobium fimbriatum has been used for liver upsets and nervous debility, while Dendrobium teretifolium for headache and pain reliever in other parts of body. Other orchid genera like Oberonia, Eria, Bulbophyllum, Eulophia, Geodorum, Grammatophylum, and Hetaeria are also reported to be used as medicine in different parts of the world to cure various diseases (Hawkes, 1944; Withner et al., 1974).
Phytochemical investigations of the orchid family were
performed for alkaloid constituents (Luning, 1974),
identification and inheritance of flower pigments in the species of
ornamental value (Arditti and Fischer, 1977). Apart
from the presence of chlorophyll in green flowered forms and carotenoids in some yellow flowers, anthocyanidins
are predominated. The cyaniding, pelargonidin and petunidin, and complex mixture of their glycosides and acylated derivatives are often present in a single
flower. William et al., (1978) has
made an extensive survey of the leaf flavonoids of Orchidaceae family. In the present investigation of the
preliminary phytochemical study of leaf flavanoids contents of Orchidiaceae
family members in the Tirunelveli hills of
Materials and Methods
All plant materials were collected from their natural habitats in the period of 1999-2006 in the Tirunelveli hills area.
Table 1. List of orchid and its collection locality in Tirunelveli hills.
The collected plant�s leaf materials (Table1) were air-dried and powdered. Ten grams of each dried plant material were separately extracted with 75% methanol (Plant materials and Solvent in the ratio of 1:4). The collected extracts were evaporated under reduced pressure to a volume of 25ml. The qualitative identification of the flavonoids were detected by the method of� Shinoda test (1ml of the methanol extracts were evaporated, diluted with 1 ml of water + 1 ml methanol + 3 - 4 mg magnesium + 3 - 4 drops of concentrated hydrochloric acid). The result of colouring of the solutions from pink to red was an indication for presence of flavonoids. Cyanogenic glycosides were identified by subjecting 1ml of extract in 10 ml sterile water and filtered. Sodium picrate paper was added to the filtrate and heated to boil. The extract was also tested for carbohydrates using resorcinol solution. Fehling's solution was added to the extract and heated to detect reducing sugar. Liebermann-Burchardt test is conducted for steroids and terpenoids - to 1 ml of methanolic extract of drug, 1 ml of chloroform, 2�3 ml of acetic anhydride and 1 to 2 drops of concentrated sulfuric acid were added. (Dark green colouration of the solution indicated the presence of Steroids and dark pink or red colouration of the solution indicated the presence of terpenoids). For alkaloids - a drop of methanolic extract was spotted on a small piece of precoated TLC plate and the plate was sprayed with modified Dragendorff�s reagent. (Orange coloration of the spot indicated the presence of alkaloids). Braemer�s test is used for identification of tannins: 10% alcoholic ferric chloride solution was added to 2�3 ml of methanolic extract (Dark blue or greenish grey coloration of the solution indicated the presence of tannins in the extract) (Maridas, 2006).
Results and Discussion
The results of qualitative phytochemical analysis of the leaf extracts of Orchidiaceae family members were shown in Tables 2. A total of 27 genus and sixty one species were qualitatively identified for the presence of flavonoids.� 37 orchid species are given positive results to reducing sugar and other 21 species were shown negative results to it.� In 48 orchid species, cyanogenic glycosides are found and other 13 species such as Anoectochilus elatus Lindl., Bulbophyllum neilgherrense Wight., Bulbophyllum tremulum Wight, Bulbophyllum xylophyllum Par & Reichb. f.,Calanthe masuca (D. Don) Lindl.,Cheirostylis flabellata Wight, Cymbidium ensifolium (L.)., Dendrobium macrostachyum Lindl., Epipogium roseum (D. Don), Eria reticosa Wight, Liparis atropurpurea� Lindl., Malleola gracilis (Lindl.), Papilionanthe subulata (Koen.), Vanda testacea (Lindl.) did not cyanogenic glycosides in their leaf extract. Therefore, further studies should be done on isolation of the individual components of Orchidiaceae family members and also analysis the phytochemicals properties for its pharmacological studies. 45 orchid species of Tirunelveli hills area contained tannin in its flowers and 14 species of orchids showed Terepenoids in its flowers. Only eight orchid species were contained all types of flavonoid contents.
Table-2: List of Leaf flavonoids found in the orchid species of Tirunelveli Hills
������������������ The authors gratefully
acknowledge the Principal, St.Xavier�s College
(Autonomous), Palyamkottai-627002, for providing laboratory facilities, and
sincere thanks to Dr. B.Victor and Mr. U. Manikandan for their valuable suggestions. We greatly
acknowledge the SERC-
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