The potential of chalcone-capped gold nanoparticles for the management of diabetes mellitus

Abstract

Searching for new natural bioactive capping agents represent an urgent priority in the green synthesis of metal nanoparticles. Additionaly, the biosaftey of metal nanparticles is a major concern especially in medical applications. Recently, the use of pharmacollogicaly active natural products as capping agents has been deployed to avoid toxic effects during the nanoparticles preparation and to enhance their drugability compared with convential drugs. Helichrysum foetidum is a South African medicinal plant used in folk medicine for the treatment of different human pathologies, and it is known to contain a variety of bioactive compounds. Herein, the total extract and two pure chalcones, helichrysetin and helichrysin, isolated from the same plant were successfully used to synthesize quasi-monodispersed gold nanoparticles in the size range of 2-12 nm. The bio-evaluation of samples indicated that the AuNP/capping agent conjugates are biostable, and have different biological profiles from the total extract/pure compounds. The enzymatic inhibition assays showed significant inhibition by the total extract, helichrysetin and their gold nanoparticles. Interestingly, a similar activity was observed for glucose uptake in HEK293 treated cells. On the other hand, all the tested samples relatively demonstrated no cytotoxicity when tested against the HaCaT keratinocytes. In conclusion, the study demonstrated potential enhancement of glucose uptake in mammalian kidney cells, and inhibition of carbohydrate-hydrolysing enzymes by green synthesized gold nanoparticles of H. foetidum. It also provides a therapeutic appraisal of AuNPs/chalcones conjugate towards the development of antidiabetes drugs derived from H. foetidum and its gold nanoparticles.

Cytotoxic Effects of Phytomediated Silver and Gold Nanoparticles Synthesised from Rooibos (Aspalathus linearis), and Aspalathin

“…The effect of the reson and absorption of surface electrons of GR and ASP-synthesised Au-and AgNPs sh characteristic absorption peaks at 530 and 440 nm for AuNPs and AgNPs, respect The GR-mediated AuNPs and AgNPs (Figure 2a) agree with reports in the literatu these metals [9,21]. A similar result of AuNPs was obtained by a reduction of NaA with black tea [27] and by the green synthesis of chalcone-capped gold nanoparticles Helichrysum foetidum [17]. In Figure 2b, the AgNPs of ASP exhibited similar absor peaks at 540 nm (for AuNPs) and 444 nm (AgNPs).…”

“…It is interesting to note that the GR NPs showed smaller particle sizes by two to three-fold than their corresponding ASP in each of the AuNPs and AgNPs. This observation is complementary to the several reports of the synergistic effects of the other compounds in GR during synthesis despite ASP being the major compound [17][18][19]24]. Remarkably, smaller sizes of GR and ASP-AgNPs were formed relative to the AuNP counterparts, even though both Au and Ag belong to the same family of d-block in the periodic table.…”

“…In continuation of the previous studies to probe the involvement of isolated compounds from plant extracts in the phytomediated synthesis of metallic nanoparticles [17][18][19], green rooibos (GR) and ASP have been selected as reducing and stabilising agents in this study because of their wide spectrum of biological activities and antioxidant potential. The isolation procedures of pure ASP (Figure 1) and its spectroscopic data has been reported recently [20].…”

“…The spectra also showed higher intensities of the peaks for all the NPs before synthesis (Figures 4 and 5). These changes in the absorptions before and after synthesis were indicative of their involvement in the bio-reduction process [17].…”

“…Still, limited information exists in the literature on the application of ASP for the synthesis of gold (Au) and silver (Ag) nanoparticles and the toxicity of the synthesised NPs on cancer cell lines. Although, the use of natural pure compounds such as hypoxoside, the proanthocyanidin dimer, and chalcones from different plant species in the preparation of Au-and AgNPs have been reported [17][18][19]. The current study presents a complimentary report on the synthesis of metal NPs using a single natural compound with a well-defined pharmacological profile, such as ASP.…”