Citation
Yahya, Farhana
(2014)
Hepatoprotective effect of Bauhinia purpurea L. methanolic leaves extract.
Masters thesis, Universiti Putra Malaysia.
Abstract
The objective of this study was to determine the hepatoprotective activity of
methanolic extract of Bauhinia purpurea (Fabaceae) leaves (MEBP) and its
partitions using rat models, i.e., by evaluating the prophylactic effect of the plant
extracts administered prior to the induction of liver toxicity using a hepatotoxic
agent. The study was designed as a preventive method, as the hepatoprotective
potential of MEBP has never been reported. In an attempt to establish the
pharmacological properties of B. purpurea, the hepatoprotective potential of MEBP
was investigated using paracetamol (PCM)- and carbon tetrachloride (CCl4)-induced
hepatotoxicity in rats. Throughout this study, the animals were divided into 22
groups containing 6 rats per group. For the first stage of the in vivo study, rats were
divided into groups and administered orally once daily with 10% dimethyl sulfoxide
(DMSO) (negative control), 200 mg/kg silymarin (positive control), or MEBP (50,
250, 500 mg/kg) for 7 days, followed by hepatotoxicity induction using PCM or
CCl4. In the second stage of the in vivo study, MEBP was partitioned into 3 fractions:
petroleum ether extract (PEBP), ethyl acetate extract (EABP), and aqueous extract
(AQBP). PEBP, EABP, and AQBP activities were tested on PCM-induced
hepatotoxicity in rats. Blood samples underwent biochemical analysis to evaluate
alanine transaminase (ALT), aspartate aminotransferase (AST), alkaline phosphatase
(ALP), lactate dehydrogenase (LDH), and total protein (TP) levels; the livers were
subjected to microscopic analysis. All extracts (MEBP, PEBP, EABP, AQBP)
underwent antioxidant study using the 2, 2-diphenyl-1-picrylhydrazyl radical
scavenging assay (DPPH), superoxide dismutase scavenging assay (SOD), and
oxygen radical absorbance capacity assay (ORAC), and anti-inflammatory study
using lipoxygenase (LOX) and xanthine oxidase (XO) assays. Total phenolic content
(TPC), phytochemical screening, and high-performance liquid chromatography
(HPLC) analysis were also performed. From the histological observation,
lymphocyte infiltration and marked necrosis were observed in the DMSO-treated groups (negative control). MEBP showed encouraging activity for reducing the toxic
effect of CCl4 and PCM on the liver by reducing the weight of the liver in a dosedependent
manner; histological observation demonstrated normalization of the
histopathological changes, preserving hepatocyte structure, causing a significant
decline in ALT and AST levels (p < 0.05) and escalation of TP level. PEBP, which
contains non-polar compounds, reduced the liver enzyme levels in a dose-dependent
manner and increased the production of TP. EABP and AQBP, which contain
intermediate compounds and polar compounds, respectively, attenuated the liver
enzyme and LDH levels (concentration-independent). Among the extracts, EABP
had the best activity for attenuating the liver enzymes. MEBP had the highest TPC
value, followed by EABP, AQBP, and PEBP. EABP and MEBP demonstrated
potential free radical scavenging activity in the SOD assay. The trend for the ORAC
assay was slightly different from that of the DPPH and SOD assays. AQBP and
EABP had high ORAC value, which determines the capacity of an extract to act as
an antioxidant. All extracts in the present study had weak anti-inflammatory activity
in the inhibition of LOX and XO. Phytochemical screening of the extracts showed
that MEBP, PEBP, and EABP contained flavonoids, tannins, polyphenolic
compounds, and steroids. However, the phytochemical screening showed that AQBP
contained fewer compounds. HPLC analysis demonstrated several peaks detected at
different wavelengths of the chromatogram of MEBP, EABP and AQBP, which were
suggested to be flavonoid-based compounds. In conclusion, MEBP exerted potential
hepatoprotective activity that can be partly attributed to its antioxidant activity, and
EABP was considered to have the best activity among the fractions, which warrants
further investigation.
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