Citation
Duraivelu, Thirubuvanesvari
(2019)
Antioxidant and anticancer properties of crude extracts from dedalu (Helixanthera parasitica lour.).
Masters thesis, Universiti Putra Malaysia.
Abstract
Loranthaceae is a mystique plant that has been utilized ethnobotanically as medicinal
plant in Southeast Asia countries. Up to now and to the best of our knowledge very
scarce research has been conducted on this species to exploit its further medicinal
potential particularly on exploring its antioxidant capacity and towards one of the
leading non-communicable disease (NCD), that has remained difficult to treat but
preventable, the breast cancer. The present study was designed to prepare different
extracts from the leaves and stem of H. parasitica and to determine their total phenol,
flavonoids content, antioxidant activity as well as selecting the best extracts towards
anticancer assay by applying established methods. Different extracts were prepared by
maceration technique with powdered leaves and stem sample. Extraction of both plant
part were performed separately using solvents of different polarity, namely, distilled
water (dH2O), methanol (70% and 100), acetone (70% and 100%) and petroleum ether.
The parameters targeted on the plant extracts were determined using Total Phenolic
Content (TPC)/ Folin-Ciocalteu reagent (FCR), Total Flavonoid Content (TFC)/
aluminium chloride (AlCl3), 2, 2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing
antioxidant power (FRAP) and MTT (for anticancer assay) method. Highest extract
yield was obtained from leaf extracts (679.13 ± 9.60 mg/g DW) and the yields of
extraction by various solvents decreased in the following order: 70% acetone > 70%
methanol > 100% methanol > 100% acetone > dH2O > petroleum ether. Leaf extract
from pure acetone solvent was found to exhibit highest TPC (99.45 ± 12.87 mg GAE/g
DW), TFC (17.57 ± 0.63 mg QE/g DW) and DPPH (81.61 ± 1.22 %) with no
significant difference found between leaf and stem evaluated from TPC and DPPH.
This extract also showed slightly lower FRAP value (6.73 ± 0.36 mg TE/g DW), but
without significant difference compared to stem. In terms of 50% inhibition
concentration of DPPH (IC50), the lowest value was retrieved from 100% acetone stem
extract (42.66 ± 4.82 μg/mL), however this value is insignificant (p > 0.05) with the
top scoring extract, 100% acetone leaf (45.21±4.91 μg/mL) which are both almost
similar to the potent standard antioxidant Trolox (48.22 ± 0.79 μg/mL) with insignificant difference. A correlation study of the extracts demonstrated very strong
significant positive correlation between phenolic content (TPC) and antioxidant
potential especially with DPPH (r = 0.928) and followed by FRAP (r = 0.901). Crude
extracts of H. parasitica was found to be highly cytotoxic or antiproliferative to
Michigan Cancer Foundation-7 breast cancer cells (MCF-7) when tested for MTT IC50
particularly with selected 100% acetone stem extract at 97.47 ± 2.87 μg/mL, while 5-
fluorouracil used as positive standard revealed an IC50 of 3.31 ± 0.15 μg/mL.
Interestingly, all the 3 tested extracts (100% acetone, leaf; 100% acetone, stem and
100% methanol, leaf) had no cytotoxic effect up to the maximum extract concentration
tested on normal dermal fibroblast cells (IC50 > 500 μg/mL). Current study suggested
that extraction solvents and plant parts (for Objective 1 and 3) played significant effect
on extractability which depends to the preference of the research, either in terms of
targeting maximal extract yield or active phytocompounds. This study proposed the
presence of water with intermediate polar solvent (70% acetone) and leaf part could
provide increased extraction yield while 100% acetone is suitable for bioactive
compound recovery. Not forgotten, H. parasitica also revealed to be a potent source
exhibiting anticancer activities but further research need to be done to purify and
characterize the extract to identify the potent polar therapeutic compound or candidate
against breast cancer. Meanwhile, this report is the first in describing total phenols,
flavonoids content, extended assessment of antioxidant activity and anticancer property
against breast cancer cell line from extracts of H. parasitica especially on species from
Malaysia which may account for some of the medical claims attributed to this plant.
Hence, this research and outcome may become a follow up from previous discontinued
studies on the exploration of this potent source and lead for new nutraceutical and
pharmaceutical approach.
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