Evaluation of Antioxidant and Cytotoxic Capacity of <i>Croton bonplandianum</i>. Baill

doi:10.4236/ajps.2013.49208

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American Journal of Plant Sciences, 2013, 4, 1709-1712

http://dx.doi.org/10.4236/ajps.2013.49208 Published Online September 2013 (http://www.scirp.org/journal/ajps)

Evaluation of Antioxidant and Cy totoxic Capacity of

Croton bonplandianum. Baill

Muhammad Naeem Qaisar*, Bashir Ahmad Chaudary, Muhammad Uzair, Sajid Nawaz Hussain

Faculty of Pharmacy, Bahauddun Zakariya University, Multan, Pakistan.

Email: *[email protected]

Received June 3rd, 2013; revised July 3rd, 2013; accepted July 31st, 2013

tion License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly

cited.

ABSTRACT

The antioxidant and cytotoxic activities of Methanolic and Dichloromethane extracts of Croton bonplandianum Baill

were evaluated in a bid to provide better scientific basis for the isolation of bioactive compounds from the plant. The

DPPH and hydroxyl radical scavenging activities o f the Methanolic extract were 59.62%, and Dichloromethane extract

was not toxic. Gallic acid used as reference compounds sho wed higher antioxidant activities to the plant ex tracts. Both

methanolic and dichloromethane extracts were evaluated for their brine shrimp lethality. Methanolic extract showed

cytotoxic activity in vitro with a LD50 value of 115.76 (0.0048 - 13.76) µg/ml. Etoposide was used as standard drug. Put

together, these results confirm that Croton bonplandianum extracts possess appreciable natural antioxidant and cyto-

toxic potentials, thereby providing good justification for the isolation of pure bioactive compounds.

Keywords: Antioxidant Activity; Scavenging Activity; Cytotoxic Activity; Brine Shrimp; Croton bonplandianum

1. Introduction

Plants are serving human needs in the forms of foods and

fruits. Plants also provide the important components of

medicines, cosmetics and beverages. The most recent

study by the World Health Organization (WHO) approxi-

mated that for the primary health care needs, four fifths

of the total population still put confidence on the plant

medicine [1], and most of these plant extracts or their

bioactive comp onents. Still tod ay, a huge public is taking

interest to use the herbal remedies.

Croton bonplan dianum Baill (syn. Croton sparsiflorus

Morong ) is a monoecious wood y shrub, which is 1 - 5 m

in height, but more usually c. 30 - 40 cm, with whorled

branches. The plant grows in sandy clay soil along road-

side, irrigation canal banks, in plantations and on waste

ground [2]. It has been reported that this plant grows in S.

Balivia, Paraguay, S. W. Brazil, N. Argentina, Bangla-

desh, South America, South India and Pakistan [3,4]. In

Pakistan, this plant is found near Khyber, Attock, Wah,

Rawalpindi, Sargodha, Gujarat, Sialkot, Lahore and Ka-

rachi.

Among the medicinal benefits of plants, antioxidant

properties have received increasing attention due to their

role in preventing or down-regulating myriads of oxida-

tive damages caused by free radicals in the body [5].

Oxidative stress is initiated by free radicals, which seek

stability through electron pairing with biological macro-

molecules such as proteins, lipids and DNA in healthy

human cells and cause protein and DNA damage along

with lipid peroxid ation. These changes contribute to can-

cer, atherosclerosis, cardiovascular diseases, ageing and

inflammatory diseases [6,7].

The antioxidant capacities of Croton bonplandianum

Baill consumed locally in Pakistan have not been clearly

presented. Such information, if provided, will not only

possibly introduce the plants as cost effective and acces-

sible sources of natural antioxidants but also justify the

need for renewed domestication effor ts on them. Against

this back-drop, th is study is aimed at evaluating the anti-

oxidant activities of Croton bonplandianum Baill in se-

lected in vitro assay systems.

Apart from already documented traditional uses, tradi-

tional healers claim to be using the leave extracts for

treating cancer, although it was difficult to establish the

type of cancer being treated. This indicated that the plant

might contain potentially useful anticancer compounds.

However, up to now there is little phyto chemical or phar-

macological work done on this. Therefore in this study

*Corresponding a uthor.

Evaluation of Antioxidant and Cytotoxic Capacity of Croton bonplandianum. Baill

1710

we present results of the brine sh rimp lethality test (BST)

of Methanolic and Dichloromethane extracts of Croton

bonplandianum.

2. Materials and Methods

2.1. Collection and Extraction of Plant Material

The plant material was collected from surroundings of

Sargodha district. The plant was identified as Croton

bonplandianum by Professor Dr. Altaf Hussain Dasti,

Institute of pure and applied Biology, Bahauddin Zaka-

riya University, Multan. For the purpose of effective ex-

traction, whole plant material was shade dried for 15

days. Then dried plant material was ground in blender

and weighed. The extraction of this finely ground mate-

rial was affected by simple maceration. The weighed

amount of plant material was taken in extraction bottle

and measured volume of dichloromethane was added to

it. Ultrasonication of this mixture was carried out occa-

sionally in order to achieve maximum possible extraction.

Filtration was carried out after 24 hours of addition of

solvent. The process was repeated three times with di-

chloromethane. The extraction of the marc was done by

methanol in the same manner. The Dichloromethane and

methanol extracts were concentrated separately under re-

duced pressure by using rotary evaporator. The dichloro-

methane (20.2 g) and methanol (48.9 g) extracts were

collected in separate sample bottles and designated with

codes as CBD and CBM respectively.

2.2. Chemicals

DPPH (1,1-diphenyl-2-picryl hydrazyl) radical and Rutin

were purchased from Sigma Aldrich Chemical Company,

USA; Folin and Ciocalteau’s Phenol reagent and Tri-

chloroacetic acid (TCA) from Qualikems Fine Chemical

Pvt. Ltd., New Delhi, India; Gallic acid monohydrate

from Kem Light Laboratories Pvt. Ltd., Mumbai, India.

Solvents and other chemicals used for this study were of

analytical grade, while water was glass distilled.

2.3. DPPH (1,1-Diphenyl-2-Picryl-Hydrazyl)

Radical Scavenging Assay

Antioxidant activity of the extracts of Croton bonplan-

dianum were measured in this assay as ability to scav-

enge stable DPPH radicals according to [8]. A con centr a-

tions (0.5 µg/ml) of the test extracts were prepared in

methanol. To 2.5 ml solution of each extract concentra-

tion was added 1 ml of 0.3 mM of freshly prepared

DPPH solution in methanol and allowed to react in the

dark at room temperature for 30 min. Absorbance of the

resulting solution was measured at 518 nm. Methanol (1

ml) added to 2.5 ml of each extract concentration was

used as blank, while 1 ml of 0.3 mM DPPH solution

added to 2.5 ml of methanol served as a negative control.

Gallic acid, prepared in the same concentrations as the

test extracts, were used as reference standards (positive

controls) for comparison.

Percentage DPPH scavenging activities of the extracts

and reference standards were determined using the formula.



sbc

% scavenging activity 100AAA100



 



where As = Absorbance of sample (extract or reference

standard), Ab = Absorbance of blank and Ac = Absorb-

ance of negative control [8].

2.4. Brine Shrimp Lethality Test (BST)

The brine shrimp lethality test (BST) was used to predict

the presence, in the extracts, of cytotoxic activity [9].

Both the crude extracts were tested for brine shrimp le-

thality. Solutions of the extract were made in DMSO and

incubated in duplicate vials with the brine shrimp larvae.

Ten brine shrimp larvae were placed in each of the du-

plicate vials. Control brine shrimp larvae were placed in

a third vial which contained sea water and DMSO only.

After 24 h the nauplii were examined against a lighted

background, and the average number of survived larvae

in each triplicate was determined. The mean percentage

mortality was plotted against the logarithm of concentra-

tions and the concentration killing fifty percent of the

larvae (LC50) was determined from the graph by taking

the antilogarithm of the concentration corresponding to

50% mortality rate of the test organisms. Etoposide was

used as a standard test drug.

3. Results

3.1. DPPH Radical Scavenging Assay

In this assay, the ability of the investigated extracts to act

as donors of hydrogen atoms or electrons in transforma-

tion of DPPH radical into its reduced form was investi-

gated. The results indicated that methanolic extract

(CBM) had IC50 396.205 and % radical scaven ging activ-

ity (%RSA) of 59.62% and while the dicholoromethane

extract (CBD) is inactive (Table 1). The scavenging ac-

tivities of the extracts were, however, lower than those

tested of gallic acid (93.13%).

Table 1. Antioxident activity of extracts.

Extract code Conc. mg/ml IC50 ± SEM.

µg/ml % RSA

CBM 0.5 396.205 ± 4.6 59.629

CBD 0.5 inactive 39.37

STD Gallic acid 0.094 4.3 ± 0.43 93.13

Evaluation of Antioxidant and Cytotoxic Capacity of Croton bonplandianum. Baill 1711

3.2. Brine Shrimp Lethality Test

In the brine shrimp lethality test methanolic extracts was

toxic with an with a LD50 value of 115.76 (0.0048 - 13.76)

µg/ml. Dichloromethane extract was not toxic (Table 2).

4. Discussion

Plants have been mentioned as one of the most important

targets to search for natural antioxidants from the point

of view of safety [10,11]. The activities of antioxidants

have been attributed to various mechanisms including

prevention of chain initiation, decomposition of perox-

ides, radical scavenging and reducing capacity [12]. Con-

sequently, these activities vary with assay methods and a

single assay may be inadequate. It is for this reason that

antioxidant activities of the extracts in this study were

evaluated Phenols and flavonoids represent two phyto-

chemicals whose relative abundance in plant extracts has

been profusely linked to antioxidant activities. Phenols

and flavonoids in extracts may explain their high anti-

oxidant activities [12]. DPPH radical scavenging assay

provides an easy, rapid, and convenient method to evalu-

ate antioxidants and radical scavengers [13]. It is based

on the ability of 1,1-diphenyl-2-picryl-hydrazyl (DPPH),

a stable free radical, to decolorize in the presence of an-

tioxidants. The DPPH radical contains an odd electron,

which is responsible for the absorbance at 515 nm and

also for the visible deep purple colour. When DPPH ac-

cepts an electron donated by an antioxidant compound,

the DPPH is decolorized, and this effect can be quantita-

tively measured from the changes in absorbance [14].

The extracts tested in this study showed DPPH radical

scavenging activities.

Bioactive compounds are often toxic to shrimp larvae.

Hence, in vivo lethality to shrimp larvae can be used as a

rapid and simple preliminary monitor for bioactive com-

pounds during the isolation of natural products. The eggs

of the brine shrimp Artemia salina (Leach) are readily

available as fish food in pet shops. When placed in artifi-

cial sea water, the eggs hatch within 48 hours, providing

large numbers of larvae. These tiny shrimp larvae have

Table 2. Brine shrimp lethality test of extracts.

Extract

code Dose

µg/ml No. of

shrimp No. of

survivors LD 50

µg/ml STD.

Drug LD 50

µg/ml

1000 30 04

100 30 20

CBM

10 30 23

115.76 Etoposide 7.4625

1000 30 16

100 30 19 CBD

10 30 24

1327.85 Etoposide 7.4625

been extensively used as a tool to monitor the cytotoxic-

ity of samples under study. This is a rapid, inexpensive,

in-house, general bioassay which has been developed for

screening, fractionation and monitoring of physiologi-

cally active natural products[9].The methanolic extract

was toxic with LD50 value of 115.76 (0.0048 - 13.76)

µg/ml against Artemia salina when tested in vitro, indi-

cated a possibility that the extract may contain a toxic

compounds.

5. Conclusion

The results of the present study indicate that the extracts

showed significantly different but appreciably potent

antioxidant and cytotoxic activity that cannot be neglec-

ted. These results support the traditional healers claim,

but it could also mean that methanolic extract is poten-

tially toxic, since brine shrimp lethality activity can also

be used as an indicator for toxicity. There is need to test

this compound on cancer cell lines and other tests in or-

der to establish its safety and the possibility of develop-

ing an anticancer agent. The study therefore not only

reveals these as accessible reservoirs of natural antioxi-

dants and cytotoxic compounds, but very importantly,

provides good scientific justification for the isolation of

pure bioactive compounds.

6. Acknowledgements

The authors are grateful to the Pharmacy Department,

Bahauddin Zakariya University Multan, Pakistan. Inter-

national Center of Chemical And Biological Sciences,

University of Karachi is also acknowledged for antioxi-

dant activity and brine shrimp lethality tests.

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