Ghazali, Siti Zulaiha
(2022)
Investigation of ethanol, acetone and aqueous azadirachta indica A. Juss (NEEM) extracts against plasmodium falciparum.
Masters thesis, Universiti Sains Malaysia.
Abstract
Malaria is a public health concern, causing significant morbidity and mortality
annually due to the emergence of drug-resistance parasites. Therefore, the need for
novel antimalarial agents with novel mechanisms of action and broad therapeutic
potential is critical. In this study, Azadirachta indica A. Juss (Neem), a long-used
herbal remedy has been chosen due to the scarcity of data on Malaysian Neem on its
antimalarial property. Thus, this study aimed to determine in vitro antimalarial activity
of Malaysian’s Neem leaves crude extracts against laboratory-adapted, sensitive (3D7)
and chloroquine-resistance (W2) P. falciparum strains. At first, all the collected leaves
were taxonomized by The Forest Research Institute Malaysia (FRIM) and further
authenticated molecularly before extraction with ethanol, acetone and aqueous
followed by a phytochemical screening of the extracts. DPPH radical scavenging is
used to determine antioxidant activity before GC-MS profiling. The brine shrimp
lethality test (BSLT) and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium
bromide (MTT) assay against the primary human umbilical vein endothelial cells
(HUVEC) were used for toxicity assay. The antimalarial activity was determined using
the malarial SYBR Green I fluorescence-based assay against both strains. The study
was extended with a green synthesis of Neem-silver nanoparticles (AgNPs) and further
evaluated on their antimalarial property. Our data showed that crude extract produced
by acetone (15.55 ± 0.04%) and ethanol (9.20 ± 0.05%) using the soxhlet method
produces more yield compared to aqueous extract (5.86 ± 0.06%). However, aqueous extract contained the highest total phenolic and flavonoid content. Meanwhile, the
brine shrimp lethality test and MTT assay showed all extracts are not toxic with LC50
> 1000 ppm and CC50 values > 30 g/mL, respectively. Whereas, all extracts showed
a moderate antimalarial effect against 3D7. However, acetone and aqueous extract
showed inactive antimalarial activity against W2 (IC50 > 50 ug/mL). On the other
hands, when Neem combined with nano silver (Neem-AgNO3), it showed a 4-folds
increment of antimalaria activity against 3D7 (IC50 = 8.815 ± 0.230) and W2 (IC50 =
23.110 ± 0.088). Thus, this study showed promising antimalarial activity of Malaysian
Neem when combining with nanoparticle and should be further evaluated of its
property to overcome the chloroquine resistance in malaria treatment.
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