An Evaluation Of Oil Palm Empty Fruit Bunch Lignin On Selected Phase Ii Drug Metabolizing Enzymes
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Date
2016-09
Authors
Mohd Salleh, Norliyana
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Abstract
In order to develop oil palm empty fruit bunch (EFB) lignin as a nutraceutical and health supplement, the investigation of its potential in interacting with other drugs via inhibition or induction of drug metabolizing enzymes (DME) would contribute towards product safety. Therefore, this study was carried out to investigate the effect of oil palm EFB lignin and its main oxidative compounds on phase II DME, UDP-glucuronosyltranferases (UGT) in rat liver microsomes (RLM) and rat kidney microsomes (RKM) as well as glutathione-S-transferases (GST) in rat liver cytosolic fraction (RLC) and rat kidney cytosolic fraction (RKC) by in vitro and in vivo treatment. The characterization of oil palm EFB lignin showed that all three types of oil palm EFB lignin extracts (soda, kraft and organosolv) consist of syringyl and guaiacyl. The total flavonoids content of oil palm EFB lignin was increased in the order of organosolv < kraft < soda. The high performance liquid chromatography (HPLC) analysis revealed that syringaldehyde was the main oxidation compound in oil palm EFB lignin followed by vanillin and p-hydroxybenzaldehyde. The oil palm EFB lignin evaluated as potential DPPH-radical scavenging activity. Results indicated that the lignin with more phenolic group (ArOH) content, low molecular weight (Mw) and narrow polydispersity (Mw/Mn) showed high DPPH-radical scavenging activity. p-nitrophenol (p-NP) and 4-methylumbelliferone (4-MU) were employed as probe substrates in UGT assays, respectively, while 1-chloro-2,4-dinitrobenzene (CDNB) was employed as probe substrate in GST assay. For in vitro treatment, the inhibitory potency of oil palm EFB lignin for both p-NP and 4-MU
glucuronidation in RLM and RKM were encouraged by its flavonoids content (soda > kraft > organosolv). The inhibitory potency was also encouraged by the presence of vanillin in the lignin extracts. For GST activity, the inhibitory potency of oil palm EFB lignin in RLC and RKC also encouraged by its flavonoids content (soda > kraft > organosolv). However, the inhibitory potency of oil palm EFB lignin on GST activity in both RLC and RKC was not encouraged by its main oxidation compounds. For in vivo treatment, the lower dosage (40 mg kg-1) of oil palm EFB lignin decreased the p-NP and 4-MU glucuronidation in both RLM and RKM. However, higher dosage (400 mg kg-1) of oil palm EFB lignin increased the p-NP and 4-MU glucuronidation in both RLM and RKM. For GST activity in RLC and RKC, both dosages increased the enzyme activity. Result also indicated that flavonoids content of oil palm EFB lignin might be responsible for the observed induction in GST activity. In conclusion, the findings suggest that oil palm EFB lignin may affect the conjugation of substrates by phase II enzymes which involved UGT1A6 and GST class μ- particularly in rat liver.
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The effect of oil palm EFB lignin and its main oxidative compounds , in vitro and in vivo treatment.