Cerium nanoparticles synthesized using aqueous
extract of Centella asiatica: characterization,
determination of free radical scavenging activity
and evaluation of efficacy against cardiomyoblast
hypertrophy†
Vandana Sankar,‡ Palayyan SalinRaj, Raj Athira, Rema Sreenivasan Soumya
and Kozhiparambil Gopalan Raghu
*
Cerium nanoparticles (CeNPs) are used in biomedical applications due to their autocatalytic properties.
Even though their use in the management of neurodegenerative diseases, diabetes, etc. has been
reported, their role in cardiovascular disease management remains largely unexploited. Moreover,
conventional procedures for synthesizing metal nanoparticles are non- environmentally friendly and
require high-priced chemicals. Therefore, there is a need for eco friendly and cost effective “green
technologies” for CeNP synthesis. This study is the first of its kind to green synthesize, characterize, and
evaluate the efficacy of CeNPs against cardiomyoblast hypertrophy. CeNPs were synthesized using 1 : 5
volume ratios of Centella asiatica aqueous extract and an aqueous solution of cerium ammonium nitrate,
and were characterized by various methods such as UV-visible spectroscopy, DLS, SEM and HRTEM,
EDX, etc. The particles were demonstrated to be spherical and monodispersed with 8 nm diameter. Zeta
potential was found to be negative. Superoxide and hydroxyl radical scavenging activities of CeNPs were
found to be higher when compared to bulk cerium and the extract. H9c2 rat cardiomyoblasts were used
for cell line studies. Flow cytometry and fluorescence imaging were employed for the cell line
experiments. High cellular uptake and viability were revealed for CeNPs when compared to macro
counterparts. Intracellular superoxide anion generation was less on incubation with higher
concentrations of CeNPs. Moreover, preliminary results provided an insight into the potential of CeNPs
in attenuating isoproterenol-stimulated cardiomyoblast hypertrophy and has been linked to the inhibition
of intracellular calcium overload and reactive oxygen species.
1. Introduction
Cerium is the most abundant among the lanthanide series of
elements and is widely used for various applications such as in
catalytic converters, solid oxide fuel cells, and as excellent
oxygen buffers. Unlike the other elements of the lanthanide
series, which exhibit a trivalent state (+3), the cerium atom can
exist in either the +3 or +4 state. This is due to the requisite of
only small amounts of energy to change the relative occupancy
of the 4f and 5d orbitals. Cerium nanoparticles (CeNPs)
demonstrated strikingly different autocatalytic properties
compared to their macro counterparts, and the ability of
nanoceria to switch between oxidation states is comparable to
that of biological antioxidants. Cerium atom also exhibits
oxygen vacancies or defects in the lattice structure; these arise
through loss of oxygen and or its electrons, alternating between
CeO
2
and CeO
2x
during redox reactions. This property has
attracted lots of attention among researchers worldwide for
potential application in nanomedicine as a free radical scav-
enger.
1
Although cerium nanoparticles are perceived as
impressive antioxidants for therapeutic applications, very little
consideration has been given to the fact that one needs to
synthesize biocompatible cerium nanoparticles with better
stability and biocompatibility in physiological solutions.
2
The conventional methods that have been employed in the
synthesis of nanoparticles require several processing steps,
high-priced chemicals, expensive instruments and moreover,
may generate hazardous toxic chemicals to the ecosystem.
3,4
This has prompted the researchers to develop safe and eco-
Agroprocessing and Natural Products Division, Council of Scientic and Industrial
Research (CSIR) -National Institute for Interdisciplinary Science and Technology
(NIIST), Industrial Estate P.O, Pappanamcode, Thiruvananthapuram-695019,
Kerala, India. E-mail: raghukgopal2009@gmail.com; Fax: +91-471-
2491712/2490186; Tel: +91-9495902522
† Electronic supplementary information (ESI) available. See DOI:
10.1039/c4ra16893c
‡ These authors contributed equally to the work and deserve to have the status of
rst author.
Cite this: RSC Adv. , 2015, 5, 21074
Received 23rd December 2014
Accepted 16th February 2015
DOI: 10.1039/c4ra16893c
www.rsc.org/advances
21074 | RSC Adv. , 2015, 5, 21074–21083 This journal is © The Royal Society of Chemistry 2015
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