Deciphering rubber particle destabilisation by Hevea bark extract

Sunderasan E., . and Ling S. K., . and Siti Arija M. A., . and Yeang H. Y., . Deciphering rubber particle destabilisation by Hevea bark extract. pp. 97-106. ISSN 1511-1768

Filtration of Hevea bark extract through Millipore spin cartridge (molecular weight cut-off at 100 kDa) yielded a brown slurry retentate and a clear liquid in the flow through fraction. The retentate was then separated by preparative reverse phase high performance liquid chromatography (HPLC) and the brown bark pigment was recovered in a broad peak. The whole bark extract the spin cartridge retentate and the brown HPLC fraction readily destabilised the high density rubber particles (Zone 2 and Zone 3) suspensions but only negligible destabilising activity was observed with the clear spin cartridge flow through fraction. Destabilisation of Zone 1 rubber particles bywhole bark extract spin cartridge retentate and the brown HPLC fraction occurred only when C-serum was substituted with Zone 3 rubber particles in the reaction mixture. Polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) which are known to bind phenolic compounds/tannins effectively precipitated the brown pigment of the bark extract. The clear supernatant recovered from the PVP and PEG treated bark extract also failed to induce rubber particle destabilisation. The presence of substantial levels of phenolics in the bark extract was confirmed by a modified Folin-Ciocalteau assay. Analyses on thin layer chromatography indicated that the brown pigment of the bark extract consists of highly polymeric condensed tannins. Analytical reverse phase HPLC revealed that three different peaks with UV spectra similar to those of tannins and one peak that resembles phenolics could be separated from the bark extract and its spin cartridge retentate.

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Abstract

Filtration of Hevea bark extract through Millipore spin cartridge (molecular weight cut-off at 100 kDa) yielded a brown slurry retentate and a clear liquid in the flow through fraction. The retentate was then separated by preparative reverse phase high performance liquid chromatography (HPLC) and the brown bark pigment was recovered in a broad peak. The whole bark extract the spin cartridge retentate and the brown HPLC fraction readily destabilised the high density rubber particles (Zone 2 and Zone 3) suspensions but only negligible destabilising activity was observed with the clear spin cartridge flow through fraction. Destabilisation of Zone 1 rubber particles bywhole bark extract spin cartridge retentate and the brown HPLC fraction occurred only when C-serum was substituted with Zone 3 rubber particles in the reaction mixture. Polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) which are known to bind phenolic compounds/tannins effectively precipitated the brown pigment of the bark extract. The clear supernatant recovered from the PVP and PEG treated bark extract also failed to induce rubber particle destabilisation. The presence of substantial levels of phenolics in the bark extract was confirmed by a modified Folin-Ciocalteau assay. Analyses on thin layer chromatography indicated that the brown pigment of the bark extract consists of highly polymeric condensed tannins. Analytical reverse phase HPLC revealed that three different peaks with UV spectra similar to those of tannins and one peak that resembles phenolics could be separated from the bark extract and its spin cartridge retentate.

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Item Type:	Article
AGROVOC Term:	Rubber
AGROVOC Term:	Chromatography
AGROVOC Term:	Bark extracts
AGROVOC Term:	Polymers
AGROVOC Term:	Hevea
AGROVOC Term:	Filtration
AGROVOC Term:	Electron microscopy
AGROVOC Term:	Phenolic content
AGROVOC Term:	Phytochemistry
Geographical Term:	Malaysia
Depositing User:	Ms. Suzila Mohamad Kasim
Last Modified:	28 Apr 2025 03:10
URI:	http://webagris.upm.edu.my/id/eprint/23076

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