Transthyretin Anti-Amyloidogenic and Fibril Disrupting Activities of Bacopa monnieri (L.) Wettst (Brahmi) Extract

Upcycling of Defatted Sesame Seed Meal via Protein Amyloid-Based Nanostructures: Preparation, Characterization, and Functional and Antioxidant Attributes

Herein, the possibility of valorizing defatted sesame seed meal (DSSM) as a viable source for valuable plant proteins and amyloid-based nanostructure was investigated. Sesame seed protein isolate (SSPI) and the major storage protein globulin (SSG) were prepared by alkaline extraction-isoelectric point precipitation as well as fractionation in the case of SSG. The protein samples were characterized for their physicochemical attributes. SSPI and SSG were also evaluated for their ability to form amyloid structures under heating (90 °C) at low pH (2.0). Additionally, the functional attributes, antioxidant activity, and biocompatibility of the proteins and amyloid nanostructures were also examined. SSPI and SSG were both successfully prepared from DSSM. The data showed that the physicochemical attributes of both protein samples were quite similar, except for the fact that SSG was mostly composed of 11S globulin, as evinced by Tricine-SDS-PAGE analysis. TEM micrographs revealed that SSG was able to form curly-shaped fibrillar amyloid structures, whereas those derived from SSPI were mostly amorphous. Thioflavin-T assay and Tricine-SDS-PAGE analysis indicated that acidic heating promoted protein hydrolysis and self-aggregation of the hydrolyzed peptides into a β-sheet rich amyloid structure. Importantly, the amyloid preparations displayed commendable solubility, superior water and oil holding capacities, and antioxidant activity against DPPH and ABTS. The protein amyloid nanostructures were found to be non-toxic against RAW264.7 cells, HaCaT cells, and red blood cells. These findings indicate that DSSM could be upcycled into valuable protein amyloid structures with good potentialities as novel food ingredients.

Antiproliferative Activities of the Lipophilic Fraction of Eucalyptus camaldulensis against MCF-7 Breast Cancer Cells, UPLC-ESI-QTOF-MS Metabolite Profile, and Antioxidative Functions

Although a number of pharmacological properties have been linked to Eucalyptus camaldulensis leaf essential oil and extracts, the biological attributes of the lipophilic fraction remain unknown. Moreover, only a limited number of active compounds have so far been identified. This work aimed to investigate the anti-oxidative, anti-aggregation, and cytotoxic properties as well as profile the secondary metabolites in the lipophilic fraction of E. camaldulensis leaf extract (Lipo-Eucam) using UHPLC-ESI-QTOF-MS and gas chromatography-mass spectrometry (GC-MS). It was found that Lipo-Eucam possessed potent antioxidant properties against DPPH, ABTS, and FRAP with IC₅₀ values of 31.46, 32.78, and 10.12 μg/mL, respectively. The fraction was able to attenuate metal-catalyzed oxidation of bovine serum albumin (BSA) in a dose-dependent manner (p < 0.05) and abrogated the aggregation of amyloidogenic BSA as revealed by the Congo red assay and transmission electron microscopy. Furthermore, Lipo-Eucam demonstrated potent cytotoxic effects against MCF-7 (IC₅₀ 7.34 μg/mL) but was noncytotoxic at used concentrations against HEK-293 cells (IC₅₀ > 80 μg/mL), suggestive of its selective anticancer properties. Spectrophotometric, UHPLC-MS, and GC-MS analysis revealed that Lipo-Eucam is rich in phenolics, flavonoids, terpenoids, volatile constituents, and a plethora of active metabolites, probably responsible for the observed activities. These findings indicate that Lipo-Eucam is endowed with pharmacologically relevant active principles with strong potential for use in the amelioration of disease conditions related to oxidative stress, protein aggregation, and breast cancer and therefore worthy of further investigations.

Peppermint extract inhibits protein aggregation

The extracts of 7 herbs were screened and compared for their functional ability to inhibit the aggregation of trypsin as an appropriate model protein for in vitro fibrillation in aqueous ethanol at pH 7.0. Turbidity measurements, total phenolic content determination, aggregation kinetics, Congo red binding assay as well as transmission electron microscopy were used to analyse the inhibition of amyloid fibril formation. This correlated with the total phenolic content of the herb extracts. The peppermint extract proved to be the most potent anti-amyloidogenic agent. Results showed that the peppermint extract exerted dose-dependent inhibitory effect on trypsin fibril formation.

Fabrication of intelligent pH-sensing films with antioxidant potential for monitoring shrimp freshness via the fortification of chitosan matrix with broken Riceberry phenolic extract

There is growing interest in chitosan-based intelligent packaging films for monitoring food quality. However, practical application of these biopolymeric films has been limited by their poor physical and mechanical attributes. Herein, a versatile colorimetric indicator film was developed based on chitosan (CHI) and broken Riceberry phenolic extract (RPE). The effects of RPE fortification on the microstructure, physical, and functional attributes of the CHI films were comprehensively evaluated. The results revealed that CHI-RPE films exhibited increased hydrophobicity, mechanical resistance, thermal stability, barrier properties, and antioxidant activity compared to plain CHI film. The CHI-RPE films were cytocompatible. Notably, CHI-RPE film also produced intense naked-eye detectable colorimetric response to pH (2-12) variation and volatile ammonia. When enclosed with fresh shrimp, CHI-RPE film changed from orange-red to yellow in response to shrimp spoilage. Thus, CHI-RPE film has high potential for fabricating pragmatic, smart packaging labels for on-site visual detection of freshness in seafood products.

Chromolaena odorata (Siam weed): A natural reservoir of bioactive compounds with potent anti-fibrillogenic, antioxidative, and cytocompatible properties

Protein fibrillation and oxidative damage are closely associated with the development of many chronic diseases such as Alzheimer's disease, Parkinson's disease and transthyretin amyloidoses. This work aimed at evaluating the fibrillogenic, antioxidant, anti-oxidative, hemolytic and cytotoxic activities of phenolic-rich extract from Chromolaena odorata (L) R.M. King & H. Rob aerial parts (COPE). As revealed by Thioflavin-T fluorescence, transmission electron microscopy, NBT redox cycling and ANS fluorescence analyses, COPE suppressed the fibril formation of hen egg-white lysozyme by directly binding to the protein and preventing surface exposure its of hydrophobic clusters. In addition, COPE demonstrated potent radical scavenging activities against DPPH˙ and ABTS˙⁺, chelated ferrous ions, and inhibited metal-catalyzed oxidation of bovine serum albumin. The observed effects could be explained by the high content of flavonoids (22.82 QE/g) and phenolics (190 mg GAE/g) present in COPE. UHPLC-ESI-QTOF-MS/MS analysis of COPE in negative ionization mode revealed that the predominant compounds were phenolics and terpenoids. Furthermore, COPE was found to exert very minimal cytotoxic effects against human red blood cells (≤ 5% hemolysis) and human embryonic kidney (HEK-293) cells (≥ 80% viability). These findings suggested that with further investigations, phenolic-rich extract from C odorata could be effectively valorized for pharmacological applications against protein fibrillogenic and oxidative damage related conditions.