Adsorption/Desorption Characteristics and Simultaneous Enrichment of Orientin, Isoorientin, Vitexin and Isovitexin from Hydrolyzed Oil Palm Leaf Extract Using Macroporous Resins

Mohamad Shazeli Che Zain,Chian Ying Teo,Khozirah Shaari,Soo Yee Lee

doi:10.3390/pr9040659

Mohamad Shazeli Che Zain, Chian Ying Teo + Show 2 more

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https://doi.org/10.3390/pr9040659

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Abstract

Oil palm leaves (OPL) containing flavonoid C-glycosides are abundantly generated as oil palm byproducts. The performances of three macroporous resins with different physical and chemical properties for the enrichment of isoorientin, orientin, vitexin, and isovitexin from acid-hydrolyzed OPL (OPLAH) extract were screened. The XAD7HP resin exhibited the best sorption capacities for the targeted flavonoid C-glycosides and was thus selected for further evaluation. Static adsorption using the XAD7HP resin under optimal conditions (extract adjusted to pH 5, shaken at 298 K for 24 h) gave adsorption kinetics that fit well with a pseudo-second-order kinetic model. The adsorption of isoorientin and orientin was well described by Langmuir isotherms, while vitexin and isovitexin fit well with the Freundlich isotherms. Dynamic sorption trials using the column-packed XAD7HP resin produced 55–60-fold enrichment of isovitexin and between 11 and 25-fold enrichment of isoorientin, vitexin, and orientin using aqueous ethanol. The total flavonoid C-glycoside-enriched fractions (enriched OPLAH) with isoorientin (247.28–284.18 µg/mg), orientin (104.88–136.19 µg/mg), vitexin (1197.61–1726.11 µg/mg), and isovitexin (13.03–14.61 µg/mg) showed excellent antioxidant free radical scavenging activities compared with their crude extracts, with IC50 values of 6.90–70.63 µg/mL and 44.58–200.00 µg/mL, respectively. Hence, this rapid and efficient procedure for the preliminary enrichment of flavonoid C-glycosides by using macroporous resin may have practical value in OPL biomass waste utilization programs to produce high value-added products, particularly in the nutraceuticals, cosmeceuticals, pharmaceuticals, and fine chemicals industries.

Highlights

The optimum conditions for the adsorption of flavonoid C-glycosides from OPLAH were performed using batch adsorption tests, where the 15 mL OPLAH solution was mixed with a selected adsorbent
The 1/n values of the flavonoid C-glycosides were all above 2, suggesting that the XAD7HP resin was a suitable resin to use for absorbC-glycosides were all above 2, suggesting that the XAD7HP resin was a suitable resin to ing the flavonoid C-glycosides from OPLAH
The enrichment of the flavonoid C-glycosides content of Oil palm leaves (OPL) extract was conducted at optimal conditions, where the leaf extract, prehydrolyzed with acid and adjusted to a pH of 5, was shaken at 298 K for a period of 24 h for static adsorption

Summary

Introduction

The oil palm (Elaeis guineensis Jacq.) tree was introduced into Malaysia in 1875, with the first oil palm tree plantation established at Tennamaran Estate in Kuala Selangor [1]. Fueled by full support from Malaysian government agricultural diversification initiatives, palm oil plantations expanded tremendously and cover a large acreage of agricultural land areas [2]. Malaysia is the second-largest oil palm producer in the world after. The latest statistics show that Malaysia was reaching 20 million tons of crude palm oil production in 2020 [4]. In the wake of this massive cultivation, a huge amount of oil palm biomass is generated as agricultural waste. Apart from mesocarp fibers (MF), empty fruit bunches (EFB), and palm kernel shells (PKS) from downstream

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