Hepatoprotective action of various partitions of methanol extract of Bauhinia purpurea leaves against paracetamol-induced liver toxicity: involvement of the antioxidant mechanisms.
BACKGROUND
Methanol extract of Bauhinia purpurea L. (family Fabaceae) (MEBP) possesses high antioxidant and anti-inflammatory activities and recently reported to exert hepatoprotection against paracetamol (PCM)-induced liver injury in rats. In an attempt to identify the hepatoprotective bioactive compounds in MEBP, the extract was prepared in different partitions and subjected to the PCM-induced liver injury model in rats.


METHODS
Dried MEBP was partitioned successively to obtain petroleum ether (PEBP), ethylacetate (EABP) and aqueous (AQBP) partitions, respectively. All partitions were subjected to in vitro antioxidant (i.e. total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH)- and superoxide-radicals scavenging assay, and oxygen radical absorbance capacity (ORAC) assay) and anti-inflammatory (i.e. lipooxygenase (LOX) and xanthine oxidase (XO) assay) analysis. The partitions, prepared in the dose range of 50, 250 and 500 mg/kg, together with a vehicle (10 % DMSO) and standard drug (200 mg/kg silymarin) were administered orally for 7 consecutive days prior to subjection to the 3 mg/kg PCM-induced liver injury model in rats. Following the hepatic injury induction, blood samples and liver were collected for the respective biochemical parameter and histopathological studies. Body weight changes and liver weight were also recorded. The partitions were also subjected to the phytochemical screening and HPLC analysis.


RESULTS
Of all partitions, EABP possessed high TPC value and demonstrated remarkable antioxidant activity when assessed using the DPPH- and superoxide-radical scavenging assay, as well as ORAC assay, which was followed by AQBP and PEBP. All partitions also showed low anti-inflammatory activity via the LOX and XO pathways. In the hepatoprotective study, the effectiveness of the partitions is in the order of EABP>AQBP>PEBP, which is supported by the microscopic analysis and histopathological scoring. In the biochemical analysis, EABP also exerted the most effective effect by reducing the serum level of alanine transaminase (ALT) and aspartate transaminase (AST) at all doses tested in comparison to the other partitions. Phytochemical screening and HPLC analysis suggested the presence of: flavonoids, condensed tannins and triterpenes in EABP; flavonoids, condensed tannins and saponins in PEBP and; only saponins in AQBP.


CONCLUSIONS
EABP demonstrates the most effective hepatoprotection against PCM-induced liver injury in rats. This observation could be attributed to its remarkable antioxidant activity and the presence of flavonoids that might probably act synergistically with other biocompounds to cause the hepatoprotection.
Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia. dr_zaz@yahoo.com.|Pharmacogenomics Centre (PROMISE), Faculty of Pharmacy, Universiti TeknologiMARA, 42300, Puncak Alam, Selangor, Malaysia. dr_zaz@yahoo.com.
Zainul Amiruddin
ZA
Zakaria
Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
Farhana
F
Yahya
Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
Siti Syariah
SS
Mamat
Department of Biomedical Science, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
Nur Diyana
ND
Mahmood
Department of Pathology, Faculty of Medicine & Health Sciences, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
Nurhafizah
N
Mohtarrudin
Department of Pharmaceutical Technology, Kulliyyah of Pharmacy, International Islamic University Malaysia, Jalan Istana, Bandar Indera Mahkota, 25200, Kuantan, Pahang, Malaysia.
Muhammad
M
Taher
Medical Technology Division, Malaysian Nuclear Agency, Bangi, 43000, Kajang, Selangor, Malaysia.
Siti Selina Abdul
SS
Hamid
Pharmacogenomics Centre (PROMISE), Faculty of Pharmacy, Universiti TeknologiMARA, 42300, Puncak Alam, Selangor, Malaysia.
Lay Kek
LK
Teh
Pharmacogenomics Centre (PROMISE), Faculty of Pharmacy, Universiti TeknologiMARA, 42300, Puncak Alam, Selangor, Malaysia.
Mohd Zaki
MZ
Salleh
D000082:Acetaminophen / Q000037:antagonists & inhibitors / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D036481:Bauhinia / Q000737:chemistry*; D056486:Chemical and Drug Induced Liver Injury / Q000517:prevention & control; D008099:Liver / Q000187:drug effects*; D008297:Male; D000432:Methanol; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley
D000975:Antioxidants; D010936:Plant Extracts; D000082:Acetaminophen; D000432:Methanol
Antioxidant; Bauhinia purpurea; Fabaceae; Flavonoids; Hepatoprotection; Synergistic action