Since December 2019, humanity has faced an important global threat. Many studies have been published on the origin, structure, and mechanism of action of the SARS-CoV-2 virus and the treatment of its disease. The priority of scientists all over the world has been to direct their time to research this subject. In this review, we highlight chemical studies and therapeutic approaches to overcome COVID-19 with seven different sections. These sections are the structure and mechanism of action of SARS-CoV-2, immunotherapy and vaccine, computer-aided drug design, repurposing therapeutics for COVID-19, synthesis of new molecular structures against COVID-19, food safety/security and functional food components, and potential natural products against COVID-19. In this work, we aimed to screen all the newly synthesized compounds, repurposing chemicals covering antiviral, anti-inflammatory, antibacterial, antiparasitic, anticancer, antipsychotic, and antihistamine compounds against COVID-19. We also highlight computer-aided approaches to develop an anti-COVID-19 molecule. We explain that some phytochemicals and dietary supplements have been identified as antiviral bioproducts, which have almost been successfully tested against COVID-19. In addition, we present immunotherapy types, targets, immunotherapy and inflammation/mutations of the virus, immune response, and vaccine issues.

Galanthus elwesii Hook. is an important plant species of the Amaryllidaceae family and is used for the medicinal purposes of its valuable bioactive compounds. The present study was conducted to investigate the effects of foliar salicylic acid (SA) and zinc (Zn) treatments on the proline, carotenoid, and chlorophyll content and the anti-oxidant enzyme activity in G. elwesii. The ascorbate peroxidase (APX) enzyme activity, catalase (CAT) enzyme activity, and protein contents were determined with ascorbate oxidation, hydrogen peroxide (H₂O₂), and Bradford experiments, respectively. The plants were treated with three different concentrations of SA (0.5, 1, and 2 mM) and Zn (40, 80, and 120 mM) and were compared with the control. Fresh leaves were harvested in the study. APX (3.99 ± 0.58 EU/mg protein) and CAT (154.64 ± 4.10 EU/mg protein) were obtained from Zn 80 and 120 mM treatments at the highest level, respectively. The proline, chlorophyll b, and carotenoid content increased 12.4, 1.54, and 3.95-fold, respectively, in 0.5 mM SA treatments, when matched with the control group. It was found that increasing doses of SA and Zn increased the content of malondialdehyde (MDA), but this was not at a significant level. The total chlorophyll content increased 2.27-fold in Zn 120 mM + SA 2 mM treatment and the chlorophyll content increased 2.41-fold in Zn 40 mM + SA 1 mM treatment.

Convection dryers are cost-effective and widely used, but they present challenges for fruit and vegetable powders. High temperatures or prolonged drying times can cause browning and nutrient degradation, leading to a loss in color vibrancy and nutritional value. These limitations reduce their suitability for functional applications that require high-quality powders with preserved bioactive integrity. This study examines the effects of freeze-drying and air-drying on the physicochemical properties, color attributes, and phenolic composition of strawberries. Both drying methods resulted in similar moisture (~ 6.5%) and ash (~ 3.5%) contents. However, freeze-dried samples retained higher potassium and magnesium levels, while air-dried strawberries exhibited higher iron content. Color analysis showed that freeze-drying better preserved redness (a* value: 29.14 vs. 24.04) and resulted in a lower total color difference (ΔE: 38.93 vs. 44.72), highlighting its superior ability to maintain visual quality. Polyphenolic composition analysis revealed a notable variation. Freeze-dried strawberries contained higher concentrations of catechin (18.720 ng/g vs. 3.463 ng/g) and syringic acid, while air-dried samples were richer in coumaric acid (12.755 ng/g vs. 653 ng/g) and ellagic acid (131.527 ng/g vs. 118.454 ng/g). These findings demonstrate that the choice of drying method significantly affects the nutritional and bioactive profiles of strawberries. Freeze-drying is advantageous for retaining antioxidant-related compounds and visual quality, whereas air-drying enhances specific bioactives like coumaric and ellagic acids. These insights provide a foundation for optimizing drying processes to enhance the functional and nutritional value of strawberries in food applications.

Elicitors play a crucial role in plant defense systems, often leading to an enhancement in secondary compounds across various species. The aim of this paper was to assess the effect of elicitors of salicylic acid (SA) and chitosan (CTS) applied to the leaves on essential oil (EO) composition of Achillea gypsicola and some terpenoids and biological activity. Treatments with SA at doses of 0, 0.5, 2, and 8 mM, and CTS at 0, 2, 4, and 8 g L⁻¹ were evaluated. Two harvests were conducted between 2021 and 2022. Elicitors SA at 8 mM and CTS at 2 g L⁻¹ led to an increase in EO productivity. The application of elicitors, particularly at doses of 2 mM SA and 4 g L⁻¹ CTS in A. gypsicola, has the potential to stimulate camphor production. Additionally, TPC and TFC were the highest in treatments of SA 2 mM and CTS 8 g L⁻¹. LC–MS/MS analysis indicated that the synthesis of camphor and 1,8‐cineole enhanced significantly compared to the control group, with enhancements of 213.2% at 8 g L⁻¹ CTS and 125.1% at 4 g L⁻¹ CTS, respectively. The EOs are especially effective against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Listeria monocytogenes.

Light is not only effective in photosynthesis, growth and development, but also play an important role in biosynthesis of primary and secondary metabolites. The present research was aimed to determine effect of light on biosynthesis of alkamide, caffeic acid derivatives and echinacoside in cell suspension cultures of Echinacea purpurea L. Stem explants derived from sterile plants were subjected to callus culture in a B5 media supplemented with 1.0 mg/L BAP and 2.0 mg/L NAA. Afterward, 8-day cell cultures were incubated in light and dark environments and cell harvesting, with a three-day interval, was carried out five times. The contents of alkamide, caffeic acid derivatives and echinacoside were determined using HPLC. Alkamide, caftaric acid and echinacoside content increased regularly with light application. Light application increased alkamide content by 57%, as an average, compared to darkness. The cell cultures exposed to 12 days of incubation in light produced the highest alkamide content, with a 2.11-fold increase, compared to dark. Subjecting the cell cultures to light for 12 days resulted in 70% and 63% increases in caftaric acid and echinacoside. This study showed that light application in Echinacea purpurea L. cell suspension culture had a great potential for increasing some important phytochemicals.