Natural curcuminoids encapsulated in layered double hydroxides: a novel antimicrobial nanohybrid

Abstract

Currently, there is an increased scientific interest to discover plant based drug formulations with improved therapeutic potential. Among the cornucopia of traditional medicinal plants, Curcuma longa rhizomes have been used as a powerful antibacterial and antifungal agent. However, its practical applications are limited due to its instability under thermal and UV radiation and its low bioavailability and the extensive procedures needed for isolation. This study focuses on exploring the potential of nanotechnology-based approaches to stabilize the natural curcuminoids, the major active components in turmeric without the need for its isolation, and to evaluate the release characteristics, stability and antimicrobial activity of the resulting nanohybrids. Natural curcuminoids were selectively encapsulated into nanolayers present in Mg–Al-layered double hydroxides (LDHs) using a method that avoids any isolation of the curcuminoids. The products were characterized using solid state techniques, while thermal and photo-stability were studied using thermogravimetric analysis (TGA) and UV exposure data. The morphological features were studied using scanning electron microscope (SEM) and transmission electron microscope (TEM). Drug release characteristics of the nanohybrid were quantitatively monitored under pH 3 and 5, and therapeutic potentials were assessed by using distinctive kinetic models. Finally, the antimicrobial activity of curcuminoids-LDH was tested against three bacterial and two fungal species. Powder X-ray diffraction, Fourier transform infra-red spectroscopy, SEM and TEM data confirmed the successful and selective encapsulation of curcuminoids in the LDH, while the TGA and UV exposure data suggested the stabilization of curcuminoids within the LDH matrix. The LDH demonstrated a slow and a sustained release of the curcuminoids in an acidic medium, while it was active against the three bacteria and two fungal species used in this study, suggesting its potential applications in pharmaceutical industry.Graphical abstractSynthesis of Curcuminoid-LDH by coprecipitation method and the slow release process of curcuminoids from LDH matrixElectronic supplementary materialThe online version of this article (doi:10.1186/s13065-016-0179-7) contains supplementary material, which is available to authorized users.

Effect of natural curcuminoids‐intercalated layered double hydroxide nanohybrid against Staphylococcus aureus, Pseudomonas aeruginosa, and Enterococcus faecalis: A bactericidal, antibiofilm, and mechanistic study

“…The presence of curcuminoids in acetone was confirmed by thin layer chromatography (TLC). The corresponding R f values for curcumin, DMC, and BDMC were 0.75, 0.55, and 0.27, respectively, which was in line with the R f values reported in a previous work (Megalathan et al., ).…”

“…The encapsulation was carried out by using the in situ selective encapsulation method described by Megalathan et al. (). A solution of 0.100 mol of Mg((NO 3 ) 2 .6H 2 O and 0.050 mol of Al(NO 3 ) 3 .9H 2 O in 250.00 ml of distilled water was added drop wise to 100 ml of a concentrated (0.4 g/ml) solution of crude turmeric in an acetone/water mixture (1:1) under a nitrogen atmosphere and with vigorous stirring, until a precipitate formed.…”

“…Layered double hydroxide (LDH) nanocomposites are a class of inorganic material with a unique structure of outer positively charged metal hydroxide sheets and inner interlayer anions, hydrated with water molecules aiding in its uptake and cellular penetration (Del, 2007;Indrasekara & Kottegoda, 2011;Karunaratne, Kottegoda, & De Alwis, 2012;Kovanda et al, 2009;Wang & O'Hare, 2012). A controllable anion exchange that is pH dependent is possible due to the fascinating structure of LDH (Del, 2007;Megalathan et al, 2016). Its controlled-release properties make it a valuable choice for biological and pharmaceutical applications.…”

“…Its controlled-release properties make it a valuable choice for biological and pharmaceutical applications. In the fields of biomedical applications, different types of LDH have been exploited for drug delivery, which have reached an advanced level of clinical trials and use because of their local sustained release and high intrinsic pharmacological activity compared with other conventional drugs (Ladewig, Niebert, Xu, Gray, & Lu, 2010;Ladewig, Xu, & Lu, 2009;Megalathan et al, 2016;Perera, Weerasekera, & Kottegoda, 2015). One such study is an encapsulation of natural curcuminoids to layered double hydroxides (Samindra & Kottegoda, 2014).…”

Evaluation of polymeric PLGA nanoparticles conjugated to curcumin for use in aPDT

“…One interesting result is the fact that the curcumin, which was initially verified to be unstable and very susceptible to the presence of light (Megalathan et al, 2016), was stabilized by interactions with PLGA particles that exhibited no in vitro toxicity. The suspension prepared for this study kept its biological activity for a storage period of more than 30 days at -20ºC.…”