Hibiscus sabdariffa (Roselle) calyx: a systematic and meta-analytic review of memory-enhancing, anti-neuroinflammatory and antioxidative activities

Formulation and characterization of nanocapsules loaded with roselle anthocyanins extract and enhancement of anthocyanins bioaccessibility

Hibiscus sabdariffa L. (roselle) is a medicinal and edible plant which rich in anthocyanins with potent antioxidant properties. To enhance the stability of roselle anthocyanins, they were encapsulated in nanocapsules composed of carboxymethyl chitosan (CMC), chitosan hydrochloride (CHC), and β-lactoglobulin (β-Lg). In vitro simulated digestion assays evaluated the impact of various core-to-wall ratios and β-Lg concentrations on the bioaccessibility of seven anthocyanins. Nanocapsules with a core-to-wall ratio of 1:2 and β-Lg at 10 mg/mL exhibited the highest encapsulation efficiency (EE). Cyanidin-3-glucoside had the highest EE, while cyanidin-3-sambubioside showed the outstanding retention rate. Furthermore, simulated digestion experiments combined with molecular docking revealed that peonidin-3-glucoside and petunidin-3-glucoside likely interact with and bind to the outer β-Lg layer of the nanocapsules, increasing their release during in vitro digestion. This study demonstrates that encapsulating roselle anthocyanins in CMC, CHC, and β-Lg nanocapsules significantly enhances their bioaccessibility.

An extract of Hibiscus sabdariffa improves short-term memory in rats with experimental diabetic hyperglycemia

BACKGROUND

Calyxes of Hibiscus sabdariffa (Hs) contain anthocyanins, that normalize blood glucose levels (BGL) in diabetic patients. Diabetes also causes memory alterations, which could hypothetically decrease with the consumption of Hs.

OBJECTIVES

To investigate the effect of dietary supplementation with a Hs extract on working memory and BGL in rats.

METHODS

Diabetic hyperglycemia (DHG) was induced with streptozotocin (STZ, 55 mg/kg i.p.) in Wistar rats. After 72 h DHG was confirmed, and the consumption of Hs extract began (50 mg/Kg/day). BGL and body weight (BW) were measured at 10, 20 and 30 days after DHG induction in controls and treated animals. Learning and short-term memory were evaluated after 30 days with Novel Object Recognition Test (NOR) and Barnes Maze (BM). The gross hippocampal structure was histologically analyzed.

RESULTS

STZ-treated animals presented low BW and persistent DHG (BGL <300 mg/dL). Diabetic animals consuming the Hs extract had a dual response: some showed BGL comparable to controls, while others had levels comparable to diabetic animals not consuming extract. Diabetic animals that consumed the Hs extract had a better performance in NOR and BM than the diabetic animals not consuming the extract. At the histological level, hippocampal morphological differences were observed between diabetic animals that consumed the extract and those that did not.

DISCUSSION

The Hs extract used here could be a good co-adjuvant in the treatment of DHG, aimed at mitigating memory deficits and high BGL. These beneficial effects could be attributed to the anthocyanin content in the extract.

Synergistic Antibacterial Proficiency of Green Bioformulated Zinc Oxide Nanoparticles with Potential Fosfomycin Synergism against Nosocomial Bacterial Pathogens

The drug resistance of bacterial pathogens causes considerable morbidity and death globally, hence there is a crucial necessity for the development of effective antibacterial medicines to address the antibacterial resistance issue. The bioprepared zinc oxide nanoparticles (ZnO-NPs) were prepared utilizing the flower extract of Hibiscus sabdariffa and then characterized using different physicochemical techniques. The antibacterial effectiveness of the bioprepared ZnO-NPs and their synergism with fosfomycin were evaluated using disk diffusion assay against the concerned pathogens. Transmission electron microscopy (TEM) investigation of the bioprepared ZnO-NPs showed that their average particle size was 18.93 ± 2.65 nm. Escherichia coli expressed the highest sensitivity to the bioinspired ZnO-NPs with a suppressive zone of 22.54 ± 1.26 nm at a concentration of 50 µg/disk, whereas the maximum synergistic effect of the bioinspired ZnO-NPs with fosfomycin was noticed against Klebsiella pneumoniae strain with synergism ratio of 100.29%. In conclusion, the bioinspired ZnO-NPs demonstrated significant antibacterial and synergistic efficacy with fosfomycin against the concerned nosocomial bacterial pathogens, highlighting the potential of using the ZnO NPs-fosfomycin combination for effective control of nosocomial infections in intensive care units (ICUs) and health care settings. Furthermore, the biogenic ZnO-NPs’ potential antibacterial action against food pathogens such as Salmonella typhimurium and E. coli indicates their potential usage in food packaging applications.