Cytotoxic Properties of Some Herbal Plants in Oman

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Journal of Taibah University for Science 8 (2014) 71–74

Cytotoxic properties of some herbal plants in Oman

∗

Sadri A. Said , Sheikha Hamed Ali Al-Saadi, Ahlam R. Al-Abri,

Md. Sohail Akhtar, Afaf M. Weli, Qassim Al-Riyami

School of Pharmacy, College of Pharmacy and Nursing, University of Nizwa, Oman

Received 28 October 2013; received in revised form 23 December 2013; accepted 13 January 2014

Available online 23 January 2014

Abstract

Organic extracts from ﬁve medicinal plants collected in Oman were assayed for in vitro cytotoxic property. Dried samples from

latex, leaves, roots and stem bark of these species were macerated in ethanol to give crude extracts which were Kupchan’s partitioned

into hexane, chloroform and ethyl acetate fractions. Six different concentrations of each fraction were subjected to brine shrimp

test to determine their lethality values. Percent mortalities from each fraction were then converted to LC50 values by Finney probit

analysis. Chloroform and ethyl acetate extracts from Calotropis procera latex and aerial part of Rhazya stricta were the most active.

LC50 values for C. procera latex were 3.0 and 8.2 ␮g/ml, respectively, while that of R. stricta were 18.1 and 13.9 ␮g/ml, respectively.

C. procera and R. stricta growing in Oman are good sources of cytotoxic compounds.

Keywords: Brine shrimp test; Cytotoxicity; Medicinal plants; Oman

1. Introduction thereof [19]. The Arabian Gulf is considered the land

of traditional healing, and herbal remedies were the pri-

Natural products have been recognized since ancient mary form of health care in the region until recently

times as potential sources of human drugs. Still today, [6]. Oman has 1204 terrestrial plants, many of which are

over half of all pharmaceutical drugs are of natural origin reported to be used in traditional medicine [11]; however,

[15], and many new chemical entities enter the market less than 10% of terrestrial species in the Gulf region

or clinical trials annually. Thus, for example, since the have been screened for medicinal use [6]. Among the

1940s, 48.6% of the 175 small molecules approved for important herbal plants of Oman are Calotropis procera,

cancer chemotherapy are natural products or derivatives Echinops spinossissimus, Fagonia indica, Rhazya stricta

and Ziziphus jujube.

C. procera (Asclepiadaceae) is an erect glabrous

∗ shrub up to 4.5 m high, with milky juice and purple-

Corresponding author at: School of Pharmacy, University of

Nizwa, PB 33, PO 616, Nizwa, Oman. Tel.: +968 25446423. spotted pink ﬂowers [2]. The powdered root of this

E-mail addresses: [email protected], sadrinoﬂ[email protected] plant is used for dyspepsia, fevers, cough, cold, asthma

(S.A. Said).

and rheumatism, while the leaves are used to treat

Peer review under responsibility of Taibah University

paralysis, arthralgia and swelling [3,28]. F. indica Burm

F (Zygophyllaceae) is an annual to perennial, minutely

and densely glandular, branched herb up to 80 cm high,

which is found in the deserts of Asia and Africa [21]. It is

used against cancer and most disorders considered to be

due to poisons [5]. It is widespread in the Arabian Gulf,

http://dx.doi.org/10.1016/j.jtusci.2014.01.004 in shallow sands over gravel or limestone, on hillsides

72 S.A. Said et al. / Journal of Taibah University for Science 8 (2014) 71–74

and in wadis [10]. R. stricta Decne. (Apocynaceae), extract was suspended in 90% aqueous methanol and

known as harmal in Oman, is a small glabrous erect extracted twice with hexane, and the aqueous layer was

shrub with a smooth central stem and dense semi-erect concentrated in vacuo to remove methanol. The result-

branches, which grows commonly in the Arabian Penin- ing solution was diluted with water and then successively

sula and the Indian subcontinent [29]. R. stricta is an extracted with chloroform, ethyl acetate and butanol. All

important herbal drug for treating various diseases, such solvents were then removed in a rotary evaporator to give

as diabetes, fever, tumours, sore throat, skin diseases and the crude fractions.

inﬂammation [12]. Z. jujuba, a deciduous tree growing

up to 10 m, is native to many parts of Asia, as it requires 2.3. Cytotoxicity test

hot summers and sufﬁcient water for fruiting. The plant

both provides a delicious fruit and is an effective herbal Cytotoxicity was measured in second instar larvae

remedy for gaining weight, improving muscular strength of brine shrimp (Artemia salina Leach), as described

and increasing stamina. In Chinese medicine, it is pre- by McLaughlin et al. [18]. Shrimp larvae were exposed

␮

scribed as a tonic to strengthen liver function. It functions to 10, 250, 500, 750 and 1000 g/ml of each extract,

as an antidote, diuretic, emollient and expectorant; its and the percentage mortality was recorded after 24 h.

leaves are said to promote hair growth [13,17]. The median lethal concentrations (LC50) and 95% con-

We studied the in vitro cytotoxicity of organic extracts ﬁdence intervals (CIs) of each extract were generated by

of these species. Finney probit analysis of shrimp percentage mortality

with the Probit programme.

2. Materials and methods

3. Results and discussion

2.1. Collection of plant materials

Table 1 shows the LC50 values in shrimp larvae for

All plants were collected in March 2012. Z. jujube organic extracts of C. procera, E. spinossissimus, F.

leaves and stem bark were sampled from the University indica, R. stricta and Z. jujube.

of Nizwa campus. Leaves of R. stricta were collected

from Ibri, while aerial part of E. spinossissimus were col- 3.1. C. procera

lect from Nizwa. The roots and aerial parts of F. indica as

well as the leaves and latex of C. procera were collected Chloroform and ethyl acetate extracts of the latex of

from Jalan bani Bu Ali. At the time of collection, each C. procera had strong cytotoxic activity against shrimp

plant was photographed, and a voucher specimen was larvae, and an ethyl acetate extract of the leaves also

taken and deposited at the herbarium of the Department showed strong cytotoxic activity (Table 1). These results

of Biology, Sultan Qaboos University. All samples were are comparable to those reported in the literature. For

then dried under shade in the laboratory. instance, crude ethanolic extracts of the leaves and stem

of C. procera in Nigeria showed potential cytotoxic

2.2. Preparation of organic extracts activity against brine shrimp larvae [20]; however, the

C. procera extracts used in our study were more cyto-

Dried samples of each species were ground and toxic, as the LC50 values reported previously were 19.2

soaked in ethanol to obtain crude extracts. The ethanol and 18.2 ppm for ethanolic extracts of leaves and stem,

Table 1

Cytotoxic activities in vitro of some medicinal plants collected in Oman.

Plant Part LC50 (␮g/ml) (conﬁdence interval)

Hexane Chloroform Ethyl acetate

C. procera Latex 65.2 (55.9; 71.3) 3.0 (2.0; 5.7) 8.2 (5.0; 12.8)

C. procera Leaves >1000 74.5 (21.3; 153.9) 11.7 (5.3; 16.7)

E. spinosissimus Aerial 766.5 780.5 802.8

F. indica Root >1000 >1000 900.1

F. indica Aerial 17.4 (15.1; 22.7) >1000 >1000

R. stricta Aerial 30.1 (14.2; 57.0) 18.1 (14.4; 23.5) 13.9 (11.4; 18.6)

Z. jujube Leaves >1000 >1000 >1000

Z. jujube Stem bark >1000 93.6 (71.9; 123.2) 145.8 (108.0; 198.5)

S.A. Said et al. / Journal of Taibah University for Science 8 (2014) 71–74 73

respectively [20]. A methanolic extract of dried latex brine shrimp larvae, and all the leaf extracts were

induced extensive cell death in both Huh-7 and COS-1 inactive. The lowest LC50 value of Z. jujube was found

carcinoma cells in vitro [8,23], and an ethanolic extract of with the chloroform extract of stem bark (Table 1).

dried latex showed cytotoxic properties against MCF-7 Our results are similar to those of Ahmad et al. [4]

and HeLa tumour cells [23]. with chloroform and ethyl acetate extracts of aerial

parts of Z. jujube collected in Pakistan. Triterpenoids

3.2. E. spinosissimus isolated from Z. jujube fruits by Lee et al. [16] had

strong cytotoxic activity against a number of tumour

As can be seen from Table 1, all extracts of E. cell lines in vitro, and a water extract of dried fruits of

spinosissimus were not active against the brine shrimp Z. jujube was active against leukaemia cell lines [27].

larvae. E. spinosissimus from other geographic loca- The difference between these results and ours might be

tions is reported to possess a number of bioactivities. due to the geographical origin of the plants, the methods

Fokialakis et al. [9] reported strong insecticidal activ- of evaluation and preparation of the extracts, the purity

ity of organic extracts obtained from E. spinosissimus of the tested materials or the part of the plant used.

collected in Greece; and E. spinosissimus samples from

Egypt had antifungal activity [1]. 4. Conclusion

3.3. F. indica Organic extracts from C. procera and R. strica col-

lected in Oman have strong cytotoxic activity against

None of the extracts of the roots of F. indica was active brine shrimp larvae. We now plan to isolate the active

against the test organisms; however, hexane extracts of cytotoxic compounds from these species.

the aerial part of this plant showed strong cytotoxicity

(Table 1). These results are contrary to those reported Acknowledgement

previously, most of which found higher activities of polar

extracts of F. indica against test organisms. For exam-

We thank the University of Nizwa for material sup-

ple, Shehab et al. [24] reported that an ethanolic extract port.

of F. indica had marked activity against the carcinoma

cell lines MCF7 and HCT and that a chloroform extract

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