UPSI Digital Repository (UDRep)
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UPSI Digital Repository (UDRep)
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| Abstract : Perpustakaan Tuanku Bainun |
| The purpose of the study was to investigate phytochemicals, essential oils, and
antioxidant activity from Piper ornatum N.E.Br and Piper penangense C.DC
(Piperaceae). The essential oils were obtained by hydrodistillation technique and their
compositions were evaluated by gas chromatography (GC-FID) and gas
chromatography-mass spectrometry (GC-MS). Isolation of phytochemicals was
carried out through cold extraction of the leaves followed by separation using
chromatographic techniques. The isolated compounds were confirmed by
spectroscopic data and comparison with literature. The antioxidant activity of the
essential oils, crude extracts, and phytochemicals were evaluated using the total
phenolic content (TPC) and DPPH free radical scavenging assays. The study showed
that the essential oil of P. ornatum consists of caryophyllene oxide (31.5%),
sphatulenol (5.9%), aromadendrene (4.9%), and _-caryophyllene epoxide (4.5%). The
major components of P. penangense essential oil were humulene epoxide II (31.9%),
caryophyllene oxide (9.9%), muurola-4,10(14)-dien-1-ol (9.1%), and _-ionone (8.3%).
Isolation and purification of leaves extracts from P. ornatum yielded six compounds,
namely; 5,7-dimethoxyflavone (143), 4',7-dihydroxy-3',5',5- trimethoxyflavone (285),
piperine (47), _-sitosterol (286), 4'-hydroxy-3',5',5,7-tetramethoxyflavone (287), and
3',4',5,5',7-pentamethoxyflavone (288). Three compounds were isolated from P.
penangense which are 4-allyl resorcinol (289), chavibetol (63), and dillapiole (33).
The methanolic leaf extract of P. penangense showed good antioxidant activity with
high phenolic content (360.8 mg GAE/g) and percentage inhibition of DPPH radical
scavenging (67.3%). Furthermore, 4-allyl resorcinol (289) showed the highest activity
in the DPPH assay with percentage inhibition of 51.0%. In conclusion, the essential
oils of P. ornatum and P. penangense are composed of oxygenated sesquiterpenes as
their major components. Meanwhile, phytochemical studies of both Piper species
yielded flavones, amide, sterols, and phenylpropanoids with significant antioxidant
activity. Regarding the implication of the current study, the extracts and
phytochemicals of Piper species have therapeutic potential in the prevention of free
radical-related diseases such as atherosclerosis and diabetes. |
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