In December 2019, an outbreak of coronavirus disease 2019 (COVID-19) commenced in Wuhan, China and affected around 210 countries and territories in a matter of weeks. It has a phylogenetic similarity to SARS-CoV and it was named coronavirus 2 (SARS-CoV-2) and caused severe acute respiratory syndrome that could lead to death. One of the promising therapeutic strategies for virus infection is the search for enzyme inhibitors among natural compounds using molecular docking in order to obtain products with minimal side effects. COVID-19 virus main protease plays a vital role in mediating viral transcription and replication, introducing it as an attractive antiviral agent target. Metabolic profiling of the aqueous extract of Salvadora persica L. (Salvadoraceae) aerial parts dereplicated eleven known flavonol glycosides using LC-HRESIMS. All the annotated flavonoids exhibited significant binding stability at the N3 binding site to different degrees, except isorhamnetin-3-O-β-D-glucopyranoside, when compared with the currently used COVID-19 main protease inhibitor, darunavir. Structural similarity between the identified flavonoids enabled the study of the relationship between their structure and interactions with the receptor in the N3 binding site of the COVID-19 main protease. The results indicate that the basic flavonol nucleus possesses activity itself. Moreover, the presence of a rutinose moiety at the 3 position of ring C and absence of an O-methyl group in ring B of the flavonol structure could increase the binding stability. This study provides a scientific basis for the health benefits of the regular use of S. persica as it leaches bioactive flavonoids in the aqueous saliva.

Dietary fruits and vegetables play a vital role as food and drugs and are the main sources of antioxidant defences against degenerative diseases, such as brain dysfunctions, cardiovascular diseases, immune system deteriorations, and cancers, brought on by oxidative damage. Phyllanthus emblica is a significant herbal remedy used in conventional medicine to recover lost strength and power. In this research, the potential value of Phyllanthus emblica as a food and drug is researched. The total phenolic, total flavonoid, and total tannin contents as well as the nutritional value, vitamin C, vitamin E, and mineral contents of different organs of P. emblica were evaluated. The antioxidant and antimicrobial activities of extracts and fractions of different organs of P. emblica were determined. A total of eleven flavonoids, simple phenolic, tannin-related phenolic, and tannin molecules were isolated from a hydroalcoholic extract of the leaves and fruits. The structures were identified by spectroscopic data and comparison with the literature values as gallic acid (1), naringenin 7-O-(6″-O-galloyl)-β-D-glucopyranoside (2), 3,3′-di-O-methyl ellagic acid-4′-O-β-d-glucopyranoside (3), 1-O-galloyl glycerol (4), 1,6-di-O-galloyl-β-d-glucopyranoside (5), flavogallonic acid bislactone (6), corilagin (7), ethyl gallate (8), urolithin M5 (9), (E)-p-coumaroyl-1-O-β-d-glucopyranoside (10), and 1,2,4,6-tetra-O-galloyl-β-d-glucopyranoside (11). Among them, compounds 3 and 10 are first isolated from the plant. Molecular docking was performed to investigate the comparative interactions between positive controls (galantamine and donepezil) and selected compounds utilizing acetylcholinesterase (4EY7) as a target receptor. Results exhibited the potency of these compounds against the target receptor. In summary, P. emblica has a wealth of minerals, vitamins C and E, and polyphenolic phytochemicals that may work together to treat infectious disease, prevent and/or treat oxidative-damage-related illnesses including Alzheimer’s disease.

Rose-scented geranium, Pelargonium graveolens L'Hérit. (Geraniaceae), is an economically important plant. GC-MS analysis of the essential oil, prepared by hydro-distillation from this plant species, showed the presence of iso-menthone (15.71%), epi-α-cadinol (15.49%), iso-menthol (6.46%), geranyl formate (6.22%), geraniol (6.16%) and citronellol (5.53%). The composition of the absolute prepared by solvent extraction was compared to that of the essential oil. Change in citronellol to geraniol ratio in the absolute was monitored during leaf development. Estimation of the ratio of the two compounds was carried out using ¹H NMR spectroscopy. Geraniol content was highest in young leaves and citronellol content increased with increase in leaf age. Meta-analysis of the essential oil constituents reported from different countries was carried out. Menthone and isomenthone as well as citronellol and geraniol were negatively correlated. A significantly positive correlation was found between geraniol and linalool.

Background: Three new series of coumarin derivatives 4a-e, 6a-d and 7a-d were synthesized and characterized by elemental analyses and spectral data including 2D NMR. All compounds 4a-e, 6a-d and 7a-d were evaluated for their in vitro antioxidant and anticancer activity against Hep-G2 hepatic cancer and MCF-7 breast cancer cell lines. Method: Compounds 4c, 4e, 6d and 7c showed higher antioxidant activity (IC50 = 78, 20, 90 and 46 μM, respectively) than the reference drug silymarin (IC50 = 76 μM). Results and Conclusion: However, the anticancer screening for the three series showed promising anticancer activity against hepatic Hep-G2 cancer cell line and compounds 4d, 4e, 6a and 6c (IC50 = 1890, 5327, 5715 and 10339 μM, respectively) have more potent cytotoxic activity than cisplatin (IC50 = 11898 μM). On the other hand, all compounds showed no anticancer activity against MCF-7 cell line except compound 6a with IC50 = 32441 μM in comparison with cisplatin (IC50 = 15030 μM).

Aims: Phytochemical study of the biflavonoid content of Dioon edule Lindl. leaves in addition to quantification of the phenolic content and evaluation of their antioxidant potential. Methodology: Chromatographic isolation of the total alcohol extract of the leaves followed by the spectroscopic identification of the isolated compounds was performed adopting 1D, 2D NMR techniques. The total phenolic content (TPC) was determined using the Folin-Ciocalteu method and the total flavonoids content (TFC) was measured by complexation with aluminum chloride and the antioxidant activity was evaluated with DPPH (2.2-diphenyl-1-picrylhydrazyl) assay. Results: Phytochemical investigation of Dioon edule Lindl. leaves afforded the isolation of 7,4′,7″,4″′-tetramethylamentoflavone (1), 4′,4″′-dimethylamentoflavone (isoginkgetin) (2) biolbetin (3) and amentoflavone (4) in addition to β-sitosterol (5). A more accurate assignment of ¹³C-NMR data of the methylated amentoflavone derivatives is performed using 2D NMR (HMQC and HMBC). Compounds 2 and 5 are reported for the first time in Dioon edule Lindl. leaves. Previous report on D. edule Lindl. leaves afforded the isolation of ginkgetin (6) as a dimethylamentoflavone but our investigation proved that it is isoginkgetin. The TPC was 0.27±0.01 gallic acid equivalents in mg/g plant material. The TFC was 1.8473±0.077 rutin equivalents in mg/g plant material. The plant exhibited a good antioxidant property as DPPH scavenging activity was 3.29±0.251 mg ascorbic acid equivalent antioxidant capacity in 1 g plant material. Conclusion: The phytochemical study of D. edule Lindl. leaves afforded isoginkgetin instead of the previously reported ginkgetin. The use of NMR provides the most powerful tool for a more accurate assignment of biflavonoids.