Catharanthus Roseus Flower Extract as Natural Indicator in Acid Base Titration

CATHARANTHUS ROSEUS FLOWER EXTRACTThe experiment was carried by using the same
AS NATURAL INDICATOR IN ACID BASEset of glassware for all type of titrations. As the
TITRATIONsame aliquots were used for both titrations i.e.
Authors: Kokil S.U.*1., Joshi D.G.2., Jadhav R.L.3titration by using standard indicators and flower
1, 2 Department of Pharmaceuticalextract, the reagent were not calibrated. The
Chemistry,Tatyasaheb Kore College of Pharmacy,equimolar titrations were performed using 10 ml
Warananagar Tal-Panhala Dist-Kolhapur. 416113.of titrant with three drop of indicator. All the
3 Department of Pharmaceutical Chemistry,parameters for experiment are given in Table1. A
GES'S Satara College of pharmacy, Satara.set of five experiments was carried out and
415004.mean and standard deviation was calculated from
* Address for correspondence:results.
Kokil S.U.The flower extract was screened for its use as
Department of Pharmaceutical Chemistry,an acid base indicator in acid base titration7, and
Tatyasaheb Kore College of Pharmacy,the results of this screening were compared with
Warananagar,the result obtained by standard indicators (methyl
Tal-Panhala Dist-Kolhapur.red, phenolphthalein and mixed indicator) for
416113.strong acid strong base (HCl and NaOH), Strong
Ph- 9422600264., 9423867464.acid weak base (HCl and NH4OH), weak acid
E-mail- ABSTRACT:strong base (CH3COOH), weak acid weak base
Catharanthus roseus, family Apocynaceae is a(CH3COOH and NH4OH) titrations. The results of
large deciduous plant. The present work highlightsscreening were listed in Table1.
the use of vinca flower extract as acid baseRESULTS AND DISCUSSIONS:
indicator in different types of acid base titration.For all titrations the equivalence point obtained by
The equivalence points obtained by the fruitthe fruit extract coincident with the equivalence
extract coincident with the equivalence pointpoint obtain by standard indicator while in case of
obtain by standard indicator. In case of weak acidweak acid and weak base titration, the results
and weak base titration, the results obtained byobtained by the flower extract matched with the
the flower extract matched with the resultsresults obtained by standard indicator. But it is
obtained by mixed indicator. This natural indicatornoted that the flower extract is beneficial for
is found to be a very useful, economical, simpleweak acid and weak base titration because it
and accurate for said titration.involves use of mixed indicator, while the fruit
KEY WORDS: Catharanthus roseus, vinca, acidextract can be used alone in such titrations.
base titration, natural indicator.ACKNOWLEDGEMENT:
INTRODUCTION:The authors would like to thank Principal
Catharanthus roseus is known as MadagascarTatyasaheb Kore College of Pharmacy,
periwinkle. This plant was formerly classified asWarananagar Tal- Panhala Dist- Kolhapur for
the species Vinca rosea, Lochnera rosea andproviding laboratory facilities.
Ammocallis rosea1. This periwinkle is a perennialREFERENCES:
evergreen herb in the dogbane family1) Dobelis, Inge N. Magic and Medicine of Plants.
(Apocynaceae) that was originally native to thePleasantville, NY; 1989.
island of Madagascar. It has been widely cultivated2) Heywood VH, Flowering Plants of the World.
for hundreds of years and can now be foundNew York, NY, Oxford University
growing wild in most warm regions of the world,Press; 1993.
including the Southern U.S2-3. The plants grow one3) Simpson, Beryl B, Molly CO. Economic Botany:
or two feet high have glossy, dark green leavesPlants in Our World. New York,
(1-2 inches long) and flowers all summer long.NY: McGraw-Hill Publishing Co; 1986.
Horticulturists have developed varieties with colors4)
ranging from white to hot pink to purple. The5)
plant has historically been used to treat a wide6) Wagner H, Bladt S. Plant Drug Analysis A Thin
assortment of diseases. It was used as a folkLayer Chromatography. 2 nd ed. Springer-Verlag
remedy for diabetes in Europe for centuries. InBerlin Heidenberh, munchen: Atlas ;1996.
India, juice from the leaves was used to treat7) Untwal LS, Kondawar MS. Indian journal of
wasp stings. In Hawaii, the plant was boiled topharmaceutical sciences.2006; 68(3):399- 401.
make a poultice to stop bleeding. In China, it wasTable1: Parameters used for experiment and the
used as an astringent, diuretic and coughsresults of screening.
remedy. In Central and South America, it wasSr.no Titration
used as a homemade cold remedy to ease lung(Titrant v/s titrand) Strength in M Indicator S.D.
congestion and inflammation and sore throats.(+/-) pH Color change
Throughout the Caribbean, an extract from the1
flowers was used to make a solution to treat eyeHCl V/S NaOH
irritation and infections. The plant contains a0.1 Methyl red 11.0+/- 0.15 5.15 Yellow to orange
mother lode of useful alkaloids (70 in all at lastred
count). Some, such as catharanthine, leurosineFlower extract 11.1+/-0.15 4.99 Greenish-yellow to
sulphate, lochnerine, tetrahydroalstonine, vindolinecolorless
and vindolinine lower blood sugar levels (thus0.5 Methyl red 10.2+/- 0.12 4.38 Yellow to orange
easing the symptoms of diabetes). Others lowerred
blood pressure, others act as hemostatics (arrestFlower extract 10.3+/-0.17 4.94 Greenish yellow
bleeding) and two others, vincristine andto colorless
vinblastine, have anticancer properties. Periwinkles1 Methyl red 10.0+/-0.15 5.15 Yellow to orange red
also contain the alkaloids reserpine and serpentine,Flower extract 10.1+/-0.16 4.99 Greenish yellow
which are powerful tranquilizers.to colorless
In the 17thcentury chemist Robert Boyle,5 Methyl red 9.9+/-0.12 5.15 Yellow to orange red
described indicators extracted from roses andFlower extract 9.9+/-0.16 4.99 Greenish yellow to
other plant materials in his book "Thecolorless
Experimental History of Colors" published in 16644.2
Boyle included the ability to turn plant juices redHCl V/S NH4OH
among the properties of acids. The possibilities0.1 Phenolphthalein 4.2+/-0.11 8.47 Pink to colorless
listed were only a few of many. Almost anyFlower extract 4.2+/-0.10 6.54 Greenish yellow to
highly colored fruit or vegetable or flower petalcolorless
has the potential for use as an acid base indicator.0.5 Phenolphthalein 4.7+/-0.16 8.31 Pink to colorless
Acid-base indicators are commonly employed toFlower extract 4.7+/-0.11 5.70 Greenish yellow to
mark the end of an acid-base titration or tocolorless
measure the existing pH of a solution. These are1 Phenolphthalein 4.5+/-0.18 5.15 Yellow to orange
substances that reveal, through characteristicred
color changes, the degree of acidity or basicity ofFlower extract 4.6+/-0.09 4.99 Greenish yellow to
solutions. Indicators are weak organic acids orcolorless
bases that exist in more than one structural form5 Phenolphthalein 4.5+/-0.12 5.15 Yellow to orange
(tautomers) of which at least one form is colored.red
Intense color is desirable so that very littleFlower extract 4.5+/-0.14 4.99 Greenish yellow to
indicator is needed; the indicator itself will thus notcolorless
affect the acidity of the solution. Care must be3
used to compare colors only within the indicatorCH3COOH V/S NaOH
range. The indicator range is the pH interval of0.1 Methyl red 11.1+/-0.05 8.47 Pink to colorless
color change of the indicator. Some are mostFlower extract 11.1+/-0.12 6.54 Greenish yellow to
common indicators used for beginning chemistry,colorless
because its color change is very obvious which0.5 Methyl red 10.8+/-0.16 8.47 Pink to colorless
makes it easy to use.Flower extract 10.7+/-0.13 6.54 Greenish yellow
A pH indicator is a halochromic chemical compoundto colourless
that is added in small amounts to a solution so1 Methyl red 10.2+/-0.12 5.15 Yellow to orange red
that the pH (acidity or alkalinity) of the solutionFlower extract 10.2+/-0.13 4.99 Greenish yellow
can be determined easily. Hence a pH indicator is ato colorless
chemical detector for hydronium ions (H3O+) (or5 Methyl red 9.8+/-0.13 5.15 Yellow to orange red
Hydrogen ions (H+) in the Arrhenius model).Flower extract 9.9+/-0.02 4.99 Greenish yellow to
Normally, the indicator causes the color of thecolorless
solution to change depending on the pH5.In this4
study we observed the reaction of flowerCH3COOH V/S NH4OH
extract in different pH conditions and compared0.1 Mixed indicator 4.5+/-0.05 5.15 Blue green to
natural indicator to commercial indicators withorange
measurement of pH.Flower extract 4.5+/-0.05 4.99 Greenish yellow to
MATERIALS AND METHODS:colorless
Analytical grade reagents were procured from0.5 Mixed indicator 4.4+/-0.16 5.15 Blue green to
Tatyasaheb Kore College of Pharmacy,orange
Warananagar Tal-Panhala Dist-Kolhapur.ReagentsFlower extract 4.4+/-0.15 4.99 Greenish yellow to
and volumetric solutions were prepared as per I.P.colorless
The flowers of vinca were collected and1 Mixed indicator 4.4+/-0.12 5.15 Blue green to
authenticated. The petals were separated fromorange
whole flower and used for further study. Four gmFlower extract 4.4+/-0.18 4.99 Greenish yellow to
of petals were macerated for 15 min with 20 mlcolorless
methanol6. After pressing the mark, filtrate was5 Mixed indicator 4.4+/-0.06 5.15 Blue green to
collected. By repeating same procedure with sameorange
solvent the extract was concentrated. FinallyFlower extract 4.4+/-0.05 4.
extract was filtered and used as indicator.