Cholesterol-lowering properties of defatted kenaf seed meal and its phenolics-saponins-rich extract in a rat model

Kenaf (Hibiscus cannabinus L.) is an important commercial fiber crop and defatted kenaf seed meal (DKSM) is a secondary by-product from the kenaf industry. The present study focused on the investigation of cholesterol-lowering properties of DKSM and its phenolics-saponins-rich extract (PSRE) in a ra...

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Main Author:	Chan, Kim Wei
Format:	Thesis
Language:	English
Published:	2019
Subjects:	Kenaf Phenols Antioxidants
Online Access:	http://psasir.upm.edu.my/id/eprint/78475/1/IB%202019%205%20ir.pdf
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spelling	my-upm-ir.784752022-01-17T07:15:44Z Cholesterol-lowering properties of defatted kenaf seed meal and its phenolics-saponins-rich extract in a rat model 2019-01 Chan, Kim Wei Kenaf (Hibiscus cannabinus L.) is an important commercial fiber crop and defatted kenaf seed meal (DKSM) is a secondary by-product from the kenaf industry. The present study focused on the investigation of cholesterol-lowering properties of DKSM and its phenolics-saponins-rich extract (PSRE) in a rat model. Proximate analysis revealed that DKSM was high in protein, carbohydrate and crude fibre; while magnesium, potassium and phosphorus were the major minerals found in DKSM. The absence of acute oral toxicity in DKSM was observed through brine shrimp and rat models. In addition, DKSM exhibited higher phenolic content and antioxidant activity as compared to the selected edible flours (p < 0.05). Next, PSRE was prepared from refluxed extraction of DKSM and then fractionated with n-butanol to obtain butanolic (BF) and aqueous (AqF) fractions, which were respectively rich and deficient in phenolic-saponin content. BF was confirmed to exhibit the highest phenolicsaponin content and antioxidant activity, followed by PSRE and AqF (p < 0.05). Antioxidant activity of PSRE and its fractions were strongly correlated to their phenolic-saponin content, suggesting that phenolics and saponins may be the key bioactives that contribute to the antioxidant properties of DKSM and PSRE. Cholesterol-lowering properties of DKSM and PSRE were evaluated through a hypercholesterolemic rat model and dietary interventions were conducted by incorporating DKSM (15% and 30% of total diet) or PSRE (at 2.3% and 4.6% of total diet, respectively equivalent to the total content of DKSM-phenolics and saponins in the DKSM groups) into the atherogenic diets. After 10 weeks of DKSM and PSRE supplementation, the hepatosomatic index, hepatosteatosis, serum lipid profile, Castelli risk indexes and toxicity biomarkers of hypercholesterolemic rats were significantly improved (p < 0.05). Besides, the levels of hepatic Hmgcr and serum Pcsk9 were lowered, along with transcriptional upregulations of hepatic Cyp7a1, Abca1, Lcat, ApoA2 and ApoE (p < 0.05). The gene expression of hepatic Ldlr was insignificantly enhanced by DKSM (p > 0.05), but significantly upregulated by PSRE (p < 0.05). The combined results showed that hypercholesterolemia and atherogenic risk in rats were effectively attenuated by DKSM and PSRE supplementation, possibly via modulations of multiple vital processes in hepatic cholesterol metabolism. In addition, serum total antioxidant capacity and hepatic expression of antioxidant genes of hypercholesterolemic rats were significantly enhanced by DKSM and PSRE supplementation, accompanied with marked suppression against the levels of circulating oxidized low-density lipoprotein and pro-inflammatory biomarkers (p < 0.05). Apart from the potential beneficiary effects of alleviated hypercholesterolemia, DKSM and PSRE may attenuate hypercholesterolemiaassociated oxidative stress and systemic inflammation in rats by enhancing the serum total antioxidant capacity as well as the endogenous antioxidant defense via activation of hepatic Nrf2-ARE pathway. In conclusion, DKSM and itsderived PSRE are effective functional food ingredients in ameliorating hypercholesterolemia and its-associated oxidative stress and systemic inflammation in the rat model. Phenolics and saponins may be the bioactives conferring DKSM and PSRE with their cholesterol-lowering, antioxidative and anti-inflammatory properties. Kenaf Phenols Antioxidants 2019-01 Thesis http://psasir.upm.edu.my/id/eprint/78475/ http://psasir.upm.edu.my/id/eprint/78475/1/IB%202019%205%20ir.pdf text en public doctoral Universiti Putra Malaysia Kenaf Phenols Antioxidants Ismail, Maznah
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English
advisor	Ismail, Maznah
topic	Kenaf Phenols Antioxidants
spellingShingle	Kenaf Phenols Antioxidants Chan, Kim Wei Cholesterol-lowering properties of defatted kenaf seed meal and its phenolics-saponins-rich extract in a rat model
description	Kenaf (Hibiscus cannabinus L.) is an important commercial fiber crop and defatted kenaf seed meal (DKSM) is a secondary by-product from the kenaf industry. The present study focused on the investigation of cholesterol-lowering properties of DKSM and its phenolics-saponins-rich extract (PSRE) in a rat model. Proximate analysis revealed that DKSM was high in protein, carbohydrate and crude fibre; while magnesium, potassium and phosphorus were the major minerals found in DKSM. The absence of acute oral toxicity in DKSM was observed through brine shrimp and rat models. In addition, DKSM exhibited higher phenolic content and antioxidant activity as compared to the selected edible flours (p < 0.05). Next, PSRE was prepared from refluxed extraction of DKSM and then fractionated with n-butanol to obtain butanolic (BF) and aqueous (AqF) fractions, which were respectively rich and deficient in phenolic-saponin content. BF was confirmed to exhibit the highest phenolicsaponin content and antioxidant activity, followed by PSRE and AqF (p < 0.05). Antioxidant activity of PSRE and its fractions were strongly correlated to their phenolic-saponin content, suggesting that phenolics and saponins may be the key bioactives that contribute to the antioxidant properties of DKSM and PSRE. Cholesterol-lowering properties of DKSM and PSRE were evaluated through a hypercholesterolemic rat model and dietary interventions were conducted by incorporating DKSM (15% and 30% of total diet) or PSRE (at 2.3% and 4.6% of total diet, respectively equivalent to the total content of DKSM-phenolics and saponins in the DKSM groups) into the atherogenic diets. After 10 weeks of DKSM and PSRE supplementation, the hepatosomatic index, hepatosteatosis, serum lipid profile, Castelli risk indexes and toxicity biomarkers of hypercholesterolemic rats were significantly improved (p < 0.05). Besides, the levels of hepatic Hmgcr and serum Pcsk9 were lowered, along with transcriptional upregulations of hepatic Cyp7a1, Abca1, Lcat, ApoA2 and ApoE (p < 0.05). The gene expression of hepatic Ldlr was insignificantly enhanced by DKSM (p > 0.05), but significantly upregulated by PSRE (p < 0.05). The combined results showed that hypercholesterolemia and atherogenic risk in rats were effectively attenuated by DKSM and PSRE supplementation, possibly via modulations of multiple vital processes in hepatic cholesterol metabolism. In addition, serum total antioxidant capacity and hepatic expression of antioxidant genes of hypercholesterolemic rats were significantly enhanced by DKSM and PSRE supplementation, accompanied with marked suppression against the levels of circulating oxidized low-density lipoprotein and pro-inflammatory biomarkers (p < 0.05). Apart from the potential beneficiary effects of alleviated hypercholesterolemia, DKSM and PSRE may attenuate hypercholesterolemiaassociated oxidative stress and systemic inflammation in rats by enhancing the serum total antioxidant capacity as well as the endogenous antioxidant defense via activation of hepatic Nrf2-ARE pathway. In conclusion, DKSM and itsderived PSRE are effective functional food ingredients in ameliorating hypercholesterolemia and its-associated oxidative stress and systemic inflammation in the rat model. Phenolics and saponins may be the bioactives conferring DKSM and PSRE with their cholesterol-lowering, antioxidative and anti-inflammatory properties.
format	Thesis
qualification_level	Doctorate
author	Chan, Kim Wei
author_facet	Chan, Kim Wei
author_sort	Chan, Kim Wei
title	Cholesterol-lowering properties of defatted kenaf seed meal and its phenolics-saponins-rich extract in a rat model
title_short	Cholesterol-lowering properties of defatted kenaf seed meal and its phenolics-saponins-rich extract in a rat model
title_full	Cholesterol-lowering properties of defatted kenaf seed meal and its phenolics-saponins-rich extract in a rat model
title_fullStr	Cholesterol-lowering properties of defatted kenaf seed meal and its phenolics-saponins-rich extract in a rat model
title_full_unstemmed	Cholesterol-lowering properties of defatted kenaf seed meal and its phenolics-saponins-rich extract in a rat model
title_sort	cholesterol-lowering properties of defatted kenaf seed meal and its phenolics-saponins-rich extract in a rat model
granting_institution	Universiti Putra Malaysia
publishDate	2019
url	http://psasir.upm.edu.my/id/eprint/78475/1/IB%202019%205%20ir.pdf
_version_	1747813299042385920

Cholesterol-lowering properties of defatted kenaf seed meal and its phenolics-saponins-rich extract in a rat model

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