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

Process optimization for gold nanoparticles biosynthesis by Streptomyces albogriseolus using artificial neural network, characterization and antitumor activities

Gold nanoparticles (GNPs) are highly promising in cancer therapy, wound healing, drug delivery, biosensing, and biomedical imaging. Furthermore, GNPs have anti-inflammatory, anti-angiogenic, antioxidants, anti-proliferative and anti-diabetic effects. The present study presents an eco-friendly approach for GNPs biosynthesis using the cell-free supernatant of Streptomyces albogriseolus as a reducing and stabilizing agent. The biosynthesized GNPs have a maximum absorption peak at 540 nm. The TEM images showed that GNPs ranged in size from 5.42 to 13.34 nm and had a spherical shape. GNPs have a negatively charged surface with a Zeta potential of - 24.8 mV. FTIR analysis identified several functional groups including C-H, -OH, C-N, amines and amide groups. The crystalline structure of GNPs was verified by X-ray diffraction and the well-defined and distinct diffraction rings observed by the selected area electron diffraction analysis. To optimize the biosynthesis of GNPs using the cell-free supernatant of S. albogriseolus, 30 experimental runs were conducted using central composite design (CCD). The artificial neural network (ANN) was employed to analyze, validate, and predict GNPs biosynthesis compared to CCD. The maximum experimental yield of GNPs (778.74 μg/mL) was obtained with a cell-free supernatant concentration of 70%, a HAuCl4 concentration of 800 μg/mL, an initial pH of 7, and a 96-h incubation time. The theoretically predicted yields of GNPs by CCD and ANN were 809.89 and 777.32 μg/mL, respectively, which indicates that ANN has stronger prediction potential compared to the CCD. The anticancer activity of GNPs was compared to that of doxorubicin (Dox) in vitro against the HeP-G2 human cancer cell line. The IC50 values of Dox and GNPs-based treatments were 7.26 ± 0.4 and 22.13 ± 1.3 µg/mL, respectively. Interestingly, treatments combining Dox and GNPs together showed an IC50 value of 3.52 ± 0.1 µg/mL, indicating that they targeted cancer cells more efficiently.

Antidiabetic potential of Gymnemic acid mediated gold nanoparticles (Gym@AuNPs) on Streptozotocin-induced diabetic rats-An implication on in vivo approach

Gymnemic acid is glycosides of triterpene with recognized and valuable applications for several chronic diseases, mainly diabetics. Despite this, it requires a delivery system in order to range its therapeutic target due to its limited solubility and bioavailability. Therefore, the Gymnemic acid mediated gold nanoparticles (Gym@AuNPs) was synthesised by eco-friendly approach. The synthesised Gym@AuNPs was confirmed by the colour change from light yellow to a deep ruby red. UV - visible spectroscopy results showed a strong narrow peak at 530 nm, confirming the controlled synthesis of monodispersed Gym@AuNPs. The reduction potential of standard Gymnemic acid (Gym) on synthesis of Gym@AuNPs was confirmed by using HPLC analysis. The spherical shaped Gym@AuNPs was observed by FESEM and HR-TEM studies with average size of 48.52 ± 5.53 nm. The XRD analysis exhibited a face-centered cubic (FCC) crystalline nature of Gym@AuNPs. The in vivo antidiabetic activity of Gym and Gym@AuNPs were validated using Streptozotocin induced diabetic Albino wistar rats. The Gym@AuNPs and Gym were regulates the glucose and lipid levels in experimental animals. The histopathology outcomes shown that the Gym@AuNPs were restoration of pancreatic islets cells in the animals. This investigation demonstrated that the Gym@AuNPs had the potential anti-diabetic properties.

Helichrysum Genus and Compound Activities in the Management of Diabetes Mellitus

The global management of diabetes mellitus (DM) involves the administration of recommended anti-diabetic drugs in addition to a non-sedentary lifestyle upon diagnosis. Despite the success recorded from these synthetic drugs, the traditional method of treatment using medicinal plants is increasingly accepted by the locals due to its low cost and the perceived no side effects. Helichrysum species are used in folk medicine and are documented for the treatment of DM in different regions of the world. This study reviews Helichrysum species and its compounds’ activities in the management of DM. An extensive literature search was carried out, utilizing several scientific databases, ethnobotanical books, theses, and dissertations. About twenty-two Helichrysum species were reported for the treatment of diabetes in different regions of the world. Among these Helichrysum species, only fifteen have been scientifically investigated for their antidiabetic activities, and twelve compounds were identified as bioactive constituents for diabetes. This present review study will be a useful tool for scientists and health professionals working in the field of pharmacology and therapeutics to develop potent antidiabetic drugs that are devoid of side effects.

Photonics of Viburnum opulus L. Extracts in Microemulsions with Oxygen and Gold Nanoparticles

In this paper, the optical properties of viburnum extract flavonoids in the visible region of the spectrum were investigated and their use as a potential photosensitizer of singlet oxygen for photodynamic therapy was evaluated. The presence of long-lived excited states in the extract molecules was established by spectral methods and time-resolved spectroscopy methods and the dependences of the absorption capacity and luminescence intensity of the extract molecules on the concentrations of oxygen and ablative nanoparticles of the gold in the reverse micelles of AOT (sodium dioctyl sulfosuccinate) were established. The plasmonic enhancement of the luminescence of the extract molecules and the processes of their complexation with oxygen were also established. Furthermore, the rate constants of the processes of conversion of exciting energy in complexes were determined.

Apium graveolens reduced phytofabricated gold nanoparticles and their impacts on the glucose utilization pattern of the isolated rat hemidiaphragm

The integration of nanotechnology with herbal medicines overcomes the limitations of herbal therapy and offers desirable bioactivity. Thus, this study was aimed at synthesizing Apium graveolens-gold nanoparticles (AG-AuNPs) and exploring their impact on the glucose utilization pattern of the isolated rat hemidiaphragm. The AG-AuNPs appeared in cherry red color and showed a plasmonic peak at 534nm. The bio-reduced AG-AuNPs appeared as spherical shapes with varying sizes of about 4–15 nm. It also depicted the zeta potential of -19.5 mV, face-centered cubic crystalline nature, stretching vibrations for different functionalities, and in vitro stability during various characterization studies. The AG-AuNPs showed non-cytotoxicity and promoted cellular glucose uptake on their exposure to the cell line and the diaphragm, respectively. Moreover, the identified flavonoids and polyphenols of AG depicted in silico interactions with the insulin signaling molecule. The observed results suggest that the interacting ability of AG-AuNPs with the insulin signaling molecule can promote the glucose uptake efficiency of the diaphragm.

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

The green chemistry approach has continuously been applied for the synthesis of functional nanomaterials to reduce waste, environmental hazards, and the use of toxic chemicals among other reasons. Bioactive natural compounds have been found great potential in this regard and are used to improve the stability, activity, and biodistribution of metal nanoparticles (MNPs). Aspalathin (ASP) from Aspalathus linearis (rooibos) has a well-defined pharmacological profile and functional groups capable of both reducing and capping agents in the synthesis of metallic nanoparticles (NP). This study provides the first report of the phytomediated synthesis of gold and silver nanoparticles (AuNPs/AgNPs) via ASP and the green rooibos (GR) extract. The study demonstrated a green chemistry approach to the biosynthesis of nanoparticles of GR-AuNPs, ASP-AuNPs, GR-AgNPs, and ASP-AgNPs. The results showed that GR and ASP could act both as reducing and stabilising agents in the formation of crystalline, with different shapes and dispersity of NPs in the ranges of 1.6-6.7 nm for AgNPs and 7.5-12.5 nm for the AuNPs. However, the ASP NPs were less stable in selected biogenic media compared to GR NPs and were later stabilised with polyethene glycol. The cytotoxicity studies showed that GR-AgNPs were the most cytotoxic against SH-SY5Y and HepG2 with IC₅₀ 108.8 and 183.4 μg/mL, respectively. The cellular uptake analysis showed a high uptake of AuNPs and indicated that AgNPs of rooibos at a lower dose (1.3-1.5 μg/mL) is favourable for its anticancer potential. This study is a contribution to plant-mediated metallic nanoparticles using a pure single compound that can be further developed for targeted drug delivery for cancer cells treatments in the coming years.