Canna Indica Natural Indicator

Research Article

Use of Canna indica Flower Extract As A Natural Indicator In Acid Base Titration Mahajan Niranjan Shishir*1 , Jadhav Rahul Laxman1 , Pimpodkar Nayana Vinayak1 , Dias Remeth Jacky1, and Karande Prashant Pradip1 . 1 Department of Pharmaceutical Chemistry,Satara College of Pharmacy, Satara, Maharashtra, India 415 004. For correspondence: Mahajan Niranjan Shishir, Department of Pharmaceutical Chemistry, Satara College of Pharmacy,Plot No.1539, Behind Spicer India Ltd,Additional MIDC, Satara, Maharashtra, India - 415 004. E-mail: [email protected] Received on: 09-08-2008; Accepted on :15-08-2008 ABSTRACT: Canna indica is a species of the Canna genus, belonging to the family Cannaceae. The present work highlights the use of Canna indica flower extract as an acid base indicator in different types of acid base titrations. The equivalence points obtained by the flower extract coincide with the equivalence points obtained by standard indicators. In case of weak acid and weak base titration, the results obtained by the flower extract matched with the results obtained by mixed indicator. This natural indicator is found to be a very useful, economical, simple and accurate for the said titrations. Key words: Canna indica, Acid base indicator, Natural indicator, Flavonoids.

INTRODUCTION: Canna indica, also known as Saka siri, Indian shot, Canna, Bandera, Chancle, Coyol, or Platanillo, is a species of the Canna genus, belonging to the family Cannaceae. It is a native of the Caribbean and tropical America. It is a perennial growing from 0.5 m to 2.5 m, depending on the variety. Indian shot is a robust perennial herb up to three feet (1m) tall that grows from a thick, branching, and underground rhizome. The large green leaves taper into slender petioles that form a sheath around the main stem. Unlike the numerous cultivated varieties of domesticated cannas e.g.Canna x generalis, with showy yellow, orange, pink or red blossoms, the flowers of Canna indica are much smaller and typically only come in red. Cannas are popularly cultivated flowers in tropical and temperate gardens because they produce some of the worlds’ most beautiful and exotic blossoms [1-4]. Canna indica was found to contain terpenes, paraffin hydrocarbons and a toxic red oil termed can-

Journal of Pharmacy Research

nabinol as the major chemical constituents [5]. The flowers of Canna indica are brightly red. The appearance of red color is due to presence of flavonoids, phenols and anthocyanins [6]. The plant is used in the treatment of women’s complaints. A decoction of the root with fermented rice is used in the treatment of gonorrhea and amenorrhoea. The plant is also considered to be demulcent, diaphoretic and diuretic [7]. The biological activities of flavonoids have been extensively reviewed. Some of them have been found to possess anti-ischemic, anti-platelet, anti-inflammatory and anti-lipoperoxidant activities. Flavonoids have also been found to inhibit a wide range of enzymes involved in oxidation systems such as 5–lipoxygenase, cyclooxygenase, monooxygenase, or xanthine oxidase. These biological activities are related to their antioxidative effects.[8]. As flavonoids, anthocyanins are present in flowers of Canna indica and are pH sensitive [9]; it was

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hypothesized that the flower extract could be utilized as an indicator for different types of acid base titrations. Hence the flavonoids were extracted, isolated and identified for their potential use as an acid base indicator in various acid base titrations. MATERIAL AND METHODS: Analytical grade reagents were made available by Satara College of Pharmacy, Satara. Reagents and volumetric solutions were prepared as per standard books [10, 11]. Canna indica flowers were collected from plants growing wild in the hilly region of Satara and authenticated from Department of Botany Yashwantrao Chavan College of Science, Satara. The selected flowers were collected. The fresh petals of these selected flowers were cut into small pieces and were freeze dried by utilizing –20°C temperature to minimize oxidative loss before grinding into fine powder with a mechanical blender [8]. The resulting powder was extracted with methanolic hydrochloric acid, to convert the anthocyanins into their corresponding soluble chlorides. From this solution, anthocyanins were isolated by using ether [12]. Finally extract was

filtered and used as an indicator. The anthocyanins isolated by this method were confirmed by using various characteristic tests [12]. The experiment was carried by using the same set of glasswares for all types of titrations. As the same aliquots were used for both titrations i.e. titration by using standard indicators and flower extract, the reagents were not calibrated. The equimolar titrations were performed using 10 ml of titrant with three drops of indicator. All the parameters for experiment are given in Table 1. A set of five experiments were carried out and means and standard deviations were calculated from the results. RESULT AND DISCUSSION: The flower extract was screened for its use as an acid base indicator in various acid base titrations, and the results of this screening were compared with the results obtained by standard indicators methyl red, phenolphthalein and mixed indicator [methyl orange: bromocresol green (0.1:0.2) [13]. The titrations of strong acid with strong base (HCl & NaOH), strong acid with weak base (HCl & NH4 OH),

Table 1: Parameters Used For Analysis and the Comparison of Color Change Titrand

Titrant

HCl

NaOH

HCl

NH4OH

CH3COOH

NaOH

CH3COOH

NH4OH

Indicator Color Change Standard (pH range)

Flower Extract (pH range)

Red to Yellow (3.8 - 8.8) Colorless to Pink (3.5 - 8) Colorless to Pink (4.5 - 9) Orange to Blue-green (4 .5- 7.8)

Green to Colorless (4 - 9) Green to Colorless (4 - 8) Green to Colorless (5 - 9) Green to Colorless (5 - 8)

HCl: - Hydrochloric Acid, NaOH: - Sodium Hydroxide, NH4OH: - Ammonium Hydroxide.CH3COOH: - Acetic Acid.

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Table2: Results of Screening. Sr.No.

Titration (Titrant v/s Titrand)

Strength (Moles)

Indicator

Mean (ml) S.D. (±)

1

NaOH V/S HCl

0.1

Methyl red Flower extract Methyl red Flower extract Methyl red Flower extract

10.2 ± 0.13 10.1 ± 0.19 10.3 ± 0.13 10.2 ± 0.16 10.1± 0.15 10.1 ± 0.08

Phenolphthalein Flower extract Phenolphthalein Flower extract Phenolphthalein Flower extract

5.3 ± 0.16 5.3 ± 0.25 5.2 ± 0.15 5.1 ± 0.17 5.3 ± 0.08 5.2 ± 0.09

Methyl red Flower extract Methyl red Flower extract Methyl red Flower extract

10.6 ± 0.05 10.7 ± 0.22 10.7 ± 0.13 10.5 ± 0.18 10.6 ± 0.12 10.3 ± 0.13

Mixed indicator Flower extract Mixed indicator Flower extract Mixed indicator Flower extract

4.8 ± 0.23 4.9 ± 0.27 4.7 ± 0.20 4.9 ± 0.28 4.8 ± 0.12 4.8 ± 0.19

0.5 1

2

HCl V/S NH4OH

0.1 0.5 1

3

CH3COOH V/S NaOH

0.1 0.5 1

4

CH3COOH V/S NH4OH

0.1 0.5 1

HCl: - Hydrochloric Acid, NaOH: - Sodium Hydroxide, NH4 OH: - Ammonium Hydroxide.CH3 COOH: - Acetic Acid, S.D.: - Standard Deviation.

weak acid with strong base (CH3 COOH & NaOH), and weak acid with weak base (CH3 COOH and NH4 OH) were carried out using standard indicators and floral extract. The results of these titrations are given in Table 2. The floral extract of Canna indica was found to have flavonoids, anthocyanins and is PH sensitive. The results of PH changes in various acid base titrations of this floral indicator are shown in Table 1. It could be due to these flavonoids, the sharp end point appeared in the above mentioned titrimetric analyses. The end point determination of acid base titrations by the traditional indicators, compared with floral indicator, it was observed that traditional indicators gave incorrect results due to addition of excess of titrant (base) after the neutralization reaction was completed, Journal of Pharmacy Research

but floral indicator has given sharp end point because solutions became colorless at the equivalence points. If titrant (base) was added in more amount solution became greenish yellow colored. Thus natural indicator employed in the acid base titrations was found economic, safe and an efficient alternative for traditional indicators. In comparison to this, chemical indicators were found more expensive and hazardous, which proves that floral extract of Canna indica, as a natural indicator is more worthy. CONCLUSION: The results obtained in all the types of acid base titrations lead us to conclude that, it was due to the presence of flavonoids sharp color changes occurred at end point of the titrations. We can also conclude that, it is always beneficial to use Canna indica flower extract

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as an indicator in all types of acid base titrations because of its economy, simplicity and wild availability.

ACKNOWLEDGEMENTS: The authors are thankful to Prof. M. S. Jagtap, Chairman, Gourishankar Education Society and Satara College of Pharmacy, Satara, for providing the necessary facilities to carry out the research work. The authors are also grateful to Department of Botany, Yashwantrao Chavan College of Science, Satara, for their assistance. REFERENCES: [1] Swarup V, Garden Flowers, National Book Trust, India, pp.104-105. [2] Rendle AB, Gymnosperms and Monocotyledons: The Classification of Flowering Plants, 2nd Ed., Vol I, Vikas Publishing House, pp. 337-339. [3] Shulka P, Misra SP, An Introduction to Taxonomy of Angiosperms, Vikas Publishing House, pp. 497-499. [4] Subrahmanyam NS, Laboratory Manual of Plant Taxonomy, Vikas Publishing House, pp. 359,409,563,609. [5] Chopra RN, Chopra IC, Handa KL, Kapur LD, Indigenous Drugs of India, IInd Edition, A c a d e m i c

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Publishers, New Delhi, 1982, pp. 86. [6] Vankar PS, Srivastava J, Comparative Study of Total Phenol, Flavonoid Contents and Antioxidant Activity in Canna indica and Hibiscus rosa sinensis: Prospective Natural Food Dyes, International Journal of Food Engineering, 4(3), 2008, pp.1-17. [7] Duke JA, Ayensu ES, Medicinal Plants of China, Inc, ISBNO-917256-20-4, Reference1985, pp. 218. [8] Tinoi J, Rakariyatham N,Deming RL,Determination of Major Carotenoid Constituents in Petal Extracts of Eight Selected Flowering Plants in the North of Thailand,Chiang Mai J. Sci., 33(2), 2006, pp.327 – 334. [9] Chatwal GR, Organic Chemistry of NaturalProducts, IVth Ed., Vol II, Himalaya Publishing House, New Delhi, 2007, pp. 2.38-2.40. [10] Jaffrey GH, Bassett J, Denny RC, Mendham J, Vogel’s Textbook of Quantitative Chemical Analysis, Vth Ed. ELBS Publication, Longman Group, England, 1996, pp. 262. [11] Government of India, Ministry of Health Family Welfare, Indian Pharmacopoeia, Vol II, Controller of Publications, New Delhi, 1996, pp. A-208. [12] Finar IL, Organic Chemistry: Stereochemistry and the Chemistry of Natural Products, Vth Ed., Vol II, ELBS Publication, New Delhi, 1975, pp. 769-771. [13] http://en.wikipedia.org/wiki/ PH_indicator. Acessed - December 10, 2007.

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