Ethnobotanical Leaflets 12: 461-468. 2008.
Studies on some Pharmacognostic Profiles of Bauhinia purpurea Linn.
M. Sugumaran* and T. Vetrichelvan
Department of Pharmaceutical chemistry, Adhiparasakthi College of Pharmacy,
Melmaruvathur 603 319, Tamil Nadu.
The leaves of Bauhinia purpurea Linn. were studied with the aim of determining the following pharmacognostical parameters for this species: Macroscopical characters; Leaf constants; Physico-chemical constants; Extractive values; Colour; Consistency; Extractive values with different solvents; Micro chemical tests; Fluorescence characters of liquid extracts and leaf powder after treatment with different chemical reagents under visible and UV light at 254nm&366 nm; Measurement of cells and tissues; Bulk density angle of repose; and, Powder microscopy. Hopefully, the determination of these characteristics will aid future investigators in their pharmacological analyses of this species. Preliminary pytochemical studies on different extracts of the leaves were also performed.
purpurea Linn. (Caesalpinaceae
) is an ornamental plant found throughout subtropical,
Numerous types of biological activities are attributed to bauhinia species. B. purpurea is the most important species used to treat many ailments in traditional system of medicine. (Table 1 ).4-7 It is also reported for its antidiarrhoeal , anticancer and thyroid gland stimulating properties.8-10 Hence, country traders often subject it to adulteration/ substitution .
Table 1. Ethnomedical information for bauhinia purpurea Linn.
But, no pharmacognostical work has been done on a drug plant of such potential until the present time. Therefore, the aim of the present investigation has been to study the important pharmacognostical characteristics of the leaves of bauhinia purpurea in both whole and powdered form.
Materials and Methods
The plant material was
collected from the
The macroscopical characters (size, shape, colour, odour, taste, surface, texture, venation, margin, base, and petiole ) of the leaves were observed11. Then, for powder microscopical study, the powder was stained with phloroglucinol and concentrated HCl to study the lignified cells, lignified parenchyma, trichomes, fibres, xylem vessels, mesophyll, palisade cells and stomata, etc. The powder was also stained with N/50 iodine solution to detect the presence of starch. A small portion of powder was mounted in water to identify calcium oxalate crystals11. Quantitative microscopy was determined by methods prescribed by Trease and Evans12.
Analysis and Discussion
Colour: Green; Odour: Odourless; Size:8-15 cm in diameter&10-20cm long; Shape: Shallowly cordate; Taste: Slightly bitter; Surface: Glabrous; Texture: Coriaceous; Apex: marginate ; Margin: Sinuate; Venation: Parallel ; Petiole : Size: 4-4.5 cm ; Base: Stipulate.
The physical constant values of total ash (7.05%), acid insoluble ash (2.72%), water insoluble ash (2.98%), sulphated ash (7.91%), loss on drying (12.87%), crude fiber content (27.76%) of leaves which are specific to the plant identification. The methanol and water soluble extractive values were 35.52% and 24.4% respectively, which indicated the nature of constituents present. Quantitative microscopical study also give valuable information regarding specific leaf constants such as vein islet no (15) , vein termination no (65), palisade ratio (78), stomatal no (3), and stomatal index (20), etc. Fluorescence studies on extracts revealed different shades of green fluorescence under UV light at 254 nm. The size of the cell elements like trichomes (66.5 -117.04 -159.6 ´ 13.3 -14.3 -26.3m), starch grains (6.65-14.63-26.6m), fibers (399 -687.8-997.5 ´ 26.3-41.2-99.3) and xylem vessels (93.1 -133.4 -226.1´ 26.3 - 46.7 - 67.5 70.8m) were recorded.
Powder of P. dulce is pale green, fine and tasteless but with a characteristic odour. Other features of the powder were the presence of covering trichomes, xylem vessels, paracytic stomata, calcium oxalate crystals in the form of sheeth and starch grains, etc. The behaviour of leaf powder (Table 2) upon treatment with different chemical reagents was also studied.
Table 2. Behavior of powdered leaves on treatment with different chemical reagents.
Reagents Colour developed in day light
Powder as such Green
1N NaOH Greenish brown
Picric acid Yellowish green
Glacial acetic acid Yellowish green
1N Hcl Pale yellowish green
1N HNO3 Pale yellowish green
5%Iodine Yellowish green
40% NaOH +few drops of 10% lead acetate Yellowish green
HNO3+ Ammonia solution Yellow
Con H2SO4 Brown
5% Fecl3 Reddish brown
10% sodium hydroxide +copper sulphate Green
Acetic acid +Con H2SO4 Green
Acetic acid +Ferric chloride +Con H2SO4 Dark blackish brown
Antimony tri chloride Green
Ammonia solution Pale green
Table 3. Fluorescence characters of the powdered leaves of bauhinia purpurea under UV light .
Treatments Colour Developed Under UV Light
Short (254nm) Long (366 nm)
Powder as such Buff Pale green
1N HNO3 Dark green Pale green
5N NaOH in water Pale green Pale green
1N Hcl Pale brown Pale green
50% HNO3 Green Green
Acetic acid Grey Pale green
Picric acid Dark green Pale green
Fecl3 (5%w/v aqueous solution) Black Bluish black
N/20 Iodine Black Greenish black
50% H2SO4 Dark green Yellowish green
Ethanol Green Green
1N NaOH in ethanol Reddish yellow Yellow
Methanol Green Dark green
Powder mounted with nitro cellulose Grayish white Greenish brown
Powder treated with NaOH in methanol, dried and
mounted with nitro cellulose Yellowish green Dark green
Powder treated with HCl, dried and mounted with
nitro cellulose Greenish yellow Yellowish green
Powder treated with NaOH in water and mounted
with nitro cellulose Brown Reddish brown
Powder treated with Antimony tri chloride Green Brown
Table 4. Fluorescence analysis of different extracts of bauhinia purpurea.
Colour Developed Under UV light
Extract Long ( 366 nm) Short ( 254 nm)
Petroleum ether Light green Greenish yellow
Chloroform Greenish brown Dark greenish brown
Acetone Dark green Light green
Ethyl acetate Blackish green Black
Methanol Yellowish green Green
Table 5 . The colour and consistency of leaf extracts of bauhinia purpurea.
S.No. Extracts Colour Consistency
1 Petroleum ether (60 80oc) Greenish black Semisolid
2 Chloroform Greenish black Semisolid
3 Acetone Greenish brown Semisolid
4 Ethyl acetate Yellow Semisolid
5 Methanol Dark brown Semisolid
6 Water Dark brown Sticky
The various qualitative chemical tests (Table 6) have shown the presence of phytosterols, flavonoids, fixed oils, phenolic, tannins, glycosides and saponins in huge amount; whereas, alkaloids, aromatic acids, carbohydrate, proteins and aminoacid, triterpenoids, gums, mucilage and volatile oils were totally absent in the leaf extract of this plant.
Table 6. Preliminary phytochemical screening of various extracts of bauhinia purpurea.
Macroscopic as well as microscopical studies of any phytodrug are the primary steps to establish its botanical quality control before going to other studies. As per WHO norms , botanical standards are to be proposed as a protocol for the diagnosis of the herbal drug. The above mentioned parameters are helpful for the future identification and authentification of the plant in the herbal industry and in factories. The physico-chemical standards, such as ash values, extractive values, crude fiber content and fluorescence analysis, will be useful to identify the authenticity of the drug even from the crushed or powdered plant materials. It will serve as a standard data for the quality control of the preparations containing this plant in future. The leaf constants can be included as microscopical standards in Indian herbal pharmacopoeia. Phytochemical study is also useful to isolate the pharmacologically active principles present in the drug. The information obtained from the ash values and extractive values are useful during the time of collection and also during extraction process. Using these standards, the plant can be differentiated from other related species.
The authors are grateful
to the Director, NISCAIR,
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