Planta Med 2014; 80 - P2N12
DOI: 10.1055/s-0034-1394832

Nanoencapsulation of a Withania somnifera extract with PCL and MPEG-PCL di-block copolymer

M Gregory 1, B Sarmento 2, 3, A Dias 1
  • 1Centre for the Research and Technology of Agro-Environment and Biological Sciences (CITAB-UM), AgroBioPlant Group, Department of Biology, University of Minho, Portugal
  • 2CESPU, IINFACTS – Instituto de Investigação e Formação Avançada em Ciências e Tecnologias da Saúde, Instituto Superior de Ciências da Saúde-Norte, Gandra-PRD, Portugal
  • 3INEB – Instituto de Engenharia Biomédica, University of Porto, Porto, Portugal

Withania sominifera (L) is a well-known Indian medicinal plant used to treat stress, arthritis insomnia and age related disorders including neurodegenerative disorders. It has several vernacular names including aswaganda and ginseng winter cherry [1 – 2]. Withanolides are the major and characteristic active compounds of this species [3]. The isolated fraction of withanolides have been studied for their anti-tumor, antiinflammatory, anti-stress, anti-oxidant, immuno-modulatory, cardio-protective and neuroprotective activity [4]. To enhance the solubility, bioavailability, protection from toxicity and increase the pharmacological activity of herbal extracts, several approaches has been proposed. Among them, plant extract based novel drug delivery system attracted much attention. In this investigation, we have developed and characterized a purified W. somnifera extract (WSE) encapsulated in PCL and MPEG-PCL nanoparticles and identified the entrapped compounds by reverse phase high performance liquid chromatography (RP-HPLC). WSE was obtained from leaf biomass extraction with aqueous MeOH and further purification with dichloromethane. MPEG-PCL di-block polymer was synthesised by ring opening polymerization of ε-Caprolactone on MPEG using Sn(Oct)2 as catalyst. Prepared WSE-nanoparticles were characterised by laser doppler anemometry and Transmission electron microscopy (TEM). The results from TEM and laser doppler anemometry confirmed that the size of PCL-WSE and MPEG-PCL-WSE nanoparticles ranged between 220 – 250nm and spherical in shape (Figure 1). The MPEG-PCL-WSE nanoformulation showed higher entrapment efficacy (54.4%) than PCL-WSE nanoparticles (31.2%). The RP-HPLC analysis revealed that Withanolide A, Withaferin-A, Withanolide-B were major compounds encapsulated in the nanoparticles.

Fig. 1: (a) Transmission electron microscopy image of MPEG-PCL-WSE nanoparticles; (b) Aqueous solubility of withania extract nanoparticles.

Acknowledgements: This work was supported by Fundação para a Ciência e Tecnologia (FCT), projects PTDC/AGR-ALI/105169/2008, PTDC/AGR-GPL/119211/2010, and project PEst-OE/AGR/UI4033/2014. Marslin Gregory is supported by a FCT PhD fellowship (SFRH/BD/72809/2010).

Keywords: Withania sominifera, nanoencapsulation

References:

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