Background: Star fruit (Averrhoa carambola) is a well-known plant in Malaysia which
bears a great significance in traditional medicine.
Objectives: This study aimed to evaluate the antihyperlipidemic effect, antioxidant potential and cytotoxicity
of aqueous and methanolic extracts of ripe and unripe fruits, leaves and stem of A. carambola.
Methods: Antihyperlipidemic activity was assessed in poloxamer-407 (P-407) induced acute hyperlipidemic
rat’s model. The antioxidant activity was assessed in vitro using 2, 2’-azino-bis (3-ethylbenzthiazoline-6-sulphonic
acid) (ABTS) radical scavenging, 1-diphenyl-2-dipicrylhydrazyl radical scavenging (DPPH) and ferric reducing antioxidant
power (FRAP) assays. In addition, cytotoxicity of A. carambola extracts was assessed using MTS assay on four leukemic
cell lines (human colon cancer, human promyeloid leukemia, erythroid leukemia, acute myeloid leukemia) and one
normal cell (human umbilical vein endothelial cells).
Results: Methanolic extract of leaves had the most potent antihyperlipidemic activity in P-407 model, whereby it significantly
reduced serum levels of total cholesterol (P<0.01), triglycerides (P<0.01), low-density lipoprotein (P<0.05), verylow-
density lipoprotein (P<0.01) and atherogenic index (P<0.01). On the other hand, methanolic extracts of A. carambola
stem and leaves showed the strongest antioxidant activity. Total phenolic and flavonoid contents of the extracts exhibited
significant correlations with antioxidant but not with antihyperlipidemic activities. All plant parts showed no cytotoxic
effect on the selected cancer or normal cell lines.
Conclusion: Antihyperlipidemic activity of different parts of A. carambola is greatly affected by extraction solvents used.
Methanolic extract of A. carambola leaves exhibited higher antihyperlipidemic and antioxidant potentials compared to
other parts of the plant.