Standardization of the Corn silk (Zea mays Linn.)

Hayat M. Mukhtar*, Sandeep Singh, Harjas Kaur, Manwinder Singh

Natural Product Research Laboratory, Department of Pharmacognosy and Phytochemistry, Shaheed Bhagat Singh College of Pharmacy, Patti, Amritsar, Punjab. 143 416.

ABSTRACT:

Corn silk is collection of the stigmas of corn (Zea Mays). Zea Mays is a monotypic genus of short or tall, generally robust, monoecious, annual grasses belonging to family Poaceae. The plant is reported to possess antifungal, antiviral, diuretic, and antitumour activity. The plant material was collected from Punjab and authenticated by taxonomist of GNDU, Amritsar. In present study, various standardization parameters of corn silk like macroscopical, microscopical characters, physicochemical parameters like total ash (6.5% ), water soluble ash (3.6%), acid insoluble ash (1.65%), sulphated ash (1%), foreign organic matter, loss on drying (9.8%), swelling index (2.5%), foaming index (less than 100), successive extractive values in various solvents like petroleum ether (2.1%), benzene (2.4%), chloroform (2.9%), ethyl acetate (3.4%), methanol (28.5%). Cold Maceration values, petroleum ether (2% ), benzene (2.3%), chloroform (2%), ethyl acetate (3%), methanol (30%). Behaviour on treatment with different chemical reagents of the dried corn silk, fluorescence characters under visible and ultralviolet light at 254 nm and 366 nm were studied to fix some pharmacognostic parameters that vary from region to region. Preliminary phytochemical studies on different extracts were also reported.

KEYWORDS: Corn silk, solvent extracts, UV chamber, Poaceae

INTRODUCTION:

The drug consists of the stigmas of the female flowers harvested during the flowering period. The pale yellowish or brownish stigmas are filamentous, 0.1-0.2 mm thick, and upto 20 cm long. It is native to Central America, but now a days cultivated worldwide. The drug is imported from the former USSR, Bulgaria, Albania, and former Yugoslavia and it is also obtained from the USA. Corn have sweetish taste and its odour is faint, used in cystitis, rheumatism and arthritis¹. The plant is reported to possess antiviral², antifungal³, diuretic⁴ and antitumour⁵ activity. It contains fixed oil, essential oil (containing carvecrol and other terpenes), flavonoids, saponins, bitter substances, tannin-like polyphenols, reducing sugars, mucilage. Its utilization by the Peruvian Indians as an intoxicant is supposed to be based on the presence of alkaloids, which after being inhaled, cause psychic stimulation⁶.

MATERIAL AND METHODS:

Plant material:

The Corn silk was collected from Amritsar district of Punjab in the month of July. The plant was identified and authenticated by botanist, Dr. Adarash Pal Vig, Department of Botanical and Environmental Sciences, Guru Nanak Dev University, Amritsar. Its voucher number (1261) specimen was deposited in the same department for reference.

Processing of Plant material:

After authentication, Corn silk was dried at room temperature until they were free from the moisture and subjected to physical evaluation for different parameters.

Reagents:

All the reagents were of Analytical grade and purchased from S.D Fine- Chem. Ltd., Mumbai, India.

Methods:

The organoleptic characters including colour, odour, taste and external features of Corn silk were observed and the results were recorded in Table1. The extractive values were determined by successively starting from petroleum ether, benzene, chloroform, ethyl acetate and methanol by using soxhlet extraction apparatus. The extractive values were obtained after evaporation of solvent under reduced pressure using vaccum rotary evaporator. The behaviour of the powdered flower heads with different chemical reagents were studied and fluorescence characters were also observed under ultraviolet and visible light (compared with Nerolac Synthetic and Puja Satin Enamel Colour Reference Card). Preliminary phytochemical tests of different extracts were performed with specific reagents^7,8.

RESULTS AND DISCUSSION:

The dried Corn silk was subjected to standard procedures according to WHO Guidelines for the determination of various physicohemical parameters. The following parameters were determined:

Ash Values:

The determination of ash value is meant for detecting low-grade drugs, exhausted drugs, sandy or earthy matter. The results of ash values were recorded in Table 2.

Extractive Values:

This method determines the amount of active constituents extracted with solvents from a given amount of medicinal plant material. It is employed for materials for which as yet no suitable chemical or biological assay exists. The air dried, accurately weighed drug was treated with solvents: petroleum ether, benzene, chloroform, ethyl acetate and methanol. The values were recorded in Table 3.

Fluorescence analysis:

The powdered drug was examined under ordinary light, short UV (254 nm) and long UV (360 nm) light using different solvents and compared with Nerolac Synthetic and Puja Satin Enamel colour reference card. The results were recorded in Table 4.

Table 1: Organoleptic characters of the Corn silk

Organoleptic Characters	Observations
Type	Simple
Colour	Pale yellowish or Brownish
Odour	Characteristic
Taste	Sweet
Size	0.1-0.2 mm thick, upto 20 cm long
Shape	Filamentous

Table 2. Physicochemical parameters of Corn silk

Parameters	Values obtained (% w/w)
Total ash	6.5
Acid insoluble ash	1.65
Water soluble ash	3.6
Sulphated ash	1
Swelling index	2.5
Foaming index	Less than 100
Loss on drying	9.8

Table 3. Extractive values of Corn silk

Solvents	Successive extractive value (%w/w)	Cold maceration value (% w/w)
Petroleum ether	2.1	2
Benzene	2.4	2.3
Chloroform	2.9	2
Ethyl acetate	3.4	3
Methanol	28.5	30

Table 4. Fluoresence analysis of powder of Corn silk with various chemical reagents under visible light, short and long wave length*.

Solvents	Visible light	UV (254 nm)	UV(366 nm)
Drug Powder	Coppertone Tan 2083	Sugar Creek 2831	Espresso 2847
Picric acid	Gucci 2675	Cucumber Salad 2586	Brickred 6046
Ethyl acetate	Gingerspice 2161	Florida Everglade 2971	Espresso 2847
Conc. HCl	Cactus Pete 2551	Burnished Gold 2707	Espresso 2847
Conc. HCl + H2O	Pumpernickel 2824	Terracotta 6049	Espresso 2847
Conc. HNO3	Pebble 2787	Jamacian Sea 2481	Sugar creek 2831
Conc.HNO3 +H2O	Bumble Bee 2014	Green Genie 2546	Espresso 2847
Ammonia solution	Ra gold 2042	Wild lime 2594	Florida Everglade 2971
Methanol	Burnished Gold 2707	Burnt brick 2147	Espresso 2847
Ethanol	Sugar Creek 2831	Terracotta 6049	Espresso 2847
Chloroform	Burnt Brick 2147	Greatcanyon 2067	Espresso 2847
Pet. Ether	Coppertone Tan 2083	Terracotta 6094	Espresso 2847
Distilled water	Coppertone Tan 2083	Pumpernickel 2824	Espresso 2847
10% NaOH	Lime Peel 2629	Wild lime 2594	Espresso 2847
5% Iodine	Gingerspice 2161	Florida Everglade 2971	Espresso 2847

*Compared with Kansai Nerolac synthetic and Puja Satin enamel a subsidiary of kansai paint Co.Ltd., Japan, S-2011

Table 5. Preliminary Phytochemical screening of Corn silk

Phyto constituents	Petroleum ether extract	Benzene extract	Chloroform extract	Ethyl acetate extract	Methanol extract
Alkaloids	-	-	+	+	+
Glycosides	-	-	+	+	+
Proteins and Amino acids	++	++	++	++	++
Carbohydrates	-	-	-	-	+
Tannins	+++	+++	+++	+++	+++
Fats and Fixed oils	+	+	+	+	+
Saponins	-	+	+	+	+++
Gums and mucilages	+	+	+	++	+++

Phytochemical screening:

The plant material was subjected to preliminary phytochemical screening for the detection of various plant constituents. The extracts obtained from successive solvent extraction were subjected to qualitative test for the identification of various plant constituents like alkaloids, carbohydrates, glycosides, proteins and amino acids, saponins, mucilages, fixed oils and fats. The results were recorded in Table 5.

Powdered drug reaction with various chemical reagents:

The powdered drug was treated with various chemicals like concentrated hydrochloric acid, sulphuric acid, nitric acid, 10% NaoH, picric acid, iodine solution, methanol, ethanol, acetic acid, chloroform, petroleum ether, ferric chloride, ammonia solution. The behavioural change of the drug was determined⁹. The results were recorded in Table 6.

Table 6: Behavioural analysis of powdered Corn silk with various chemical reagents.

Procedure	Observations
Powder	Limepeel
Powder + conc. HCl	Limepeel
Powder + conc. H2SO4	Pumpernickel 2824
Powder + conc.HNO3	Montego Bay 2814
Powder + Acetic acid	Great canyon 2076
Powder + Picric acid	Ra Gold 2042
Powder + 5% iodine solution	Terracotta 6049
Powder + 5% NaOH	Limebright 2671
Powder + FeCl3	Burnished Gold 2707
Powder + Methanol	Golden fleece 2706
Powder + Ethanol	Cinnamon tea 2084
Powder + Ammonia solution	Burnished gold 2707
Powder + Chloroform	Terracotta 6049

CONCLUSION:

Generated data can be used for determining correct identity and purity of plant parts and for the detection of adulteration. Botanical authentication and physicochemical parameters will give an idea about the quality of drug. All these parameters which are being reported could be useful in identification of distinctive features of the drug. From the preliminary phytochemical study, it was concluded that only selected species of Zea mays Linn. contained the reported phytoconstituents. Hence, detailed screening may be done to isolate the active constituents so that it may be scientifically proved to access the pharmacological responses of the plant to ascertain its folklore uses.

ACKNOWLEDGEMENT:

The authors wish to thank SBS College of Pharmacy, Patti, providing necessary facilities for research.

REFERENCES:

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Received on 11.05.2012

Modified on 01.06.2012

Accepted on 07.06.2012

© A&V Publication all right reserved

Research Journal of Pharmacognosy and Phytochemistry. 4(4): July- August 2012, 226-228