Background Rumex nepalensis, a widely known traditional medicinal plant and is used as the source of medicines and human diet in various communities. Currently, the phytochemical investigation and pharmacological studies of R. nepalensis are of significant research interest. Therefore, the current review is mainly focused on the phytochemical investigation and pharmacological applications of R. nepalensis Main body Various secondary metabolites like emodin, endocrocin, chrysophanol, neopodin, physcion, torachrysone, aloesin, catechin, quercetin, resveratrol, and their derivatives were isolated from root and aerial parts of the plant. Both isolated compounds and extracts from R. nepalensis are reported to have pharmacological activities such as anti-inflammatory, antioxidant, antimicrobial, wound healing, and anti-plasmodial activities Conclusions Different parts of R. nepalensis have ethnomedicinal importance. R. nepalensis is one of the potential sources of pharmacologically active extracts and isolated compounds. In future R. nepalensis can play a vital role for the preparation of modern drugs. Graphical abstract

Cardiovascular diseases (CVDs) are the world’s leading killers, accounting for 30% deaths. According to the WHO report, CVDs kill 17.9 million people per year, and there will be 22.2 million deaths from CVD in 2030. The death rates rise as people get older. Regarding gender, the death rate of women by CVD (51%) is higher than that of men (42%). To decrease and prevent CVD, most people rely on traditional medicine originating from the plant (phytochemicals) in addition to or in preference to commercially available drugs to recover from their illness. The CVD therapy efficacy of 92 plants, including 15 terrestrial plants, is examined. Some medicinal plants well known to treat CVD are, Daucus carota, Nerium oleander, Amaranthus Viridis, Ginkgo biloba, Terminalia arjuna, Picrorhiza kurroa, Salvia miltiorrhiza, Tinospora cordifolia, Mucuna pruriens, Hydrocotyle asiatica, Bombax ceiba, and Andrographis paniculate. The active phytochemicals found in these plants are flavonoids, polyphenols, plant sterol, plant sulphur compounds, and terpenoids. A general flavonoid mechanism of action is to prevent low-density lipoprotein oxidation, which promotes vasodilatation. Plant sterols prevent CVD by decreasing cholesterol absorption in the blood. Plant sulphur compound also prevent CVD by activation of nuclear factor-erythroid factor 2-related factor 2 (Nrf2) and inhibition of cholesterol synthesis. Quinone decreases the risk of CVD by increasing ATP production in mitochondria while terpenoids by decreasing atherosclerotic lesion in the aortic valve. Although several physiologically active compounds with recognized biological effects have been found in various plants because of the increased prevalence of CVD, appropriate CVD prevention and treatment measures are required. More research is needed to understand the mechanism and specific plants’ phytochemicals responsible for treating CVD.

Background Dodonaea angustifolia is a known medicinal plant across East Arica. The flower of D. angustifolia is not well investigated in terms of phytochemistry and biological activities. This study aims to investigate the presence of flavonoids and phenolic acid in the flower of D. angustifolia and its antioxidant activity. Methods Preliminary phytochemical screening was carried out using standard protocols. Antioxidant activity evaluation using DPPH assay and total phenol content (TPC) and total flavonoid content (TFC) determinations in the flower extract was compared with the values of the leaf extract. UHPLC–DAD analysis was managed to develop the profile of the flower extract. Prediction of biological activity spectra for substances (PASS) was done using an online server for antioxidant and related activities. Results Preliminary phytochemical screening, TPC, and TFC values confirmed the presence of flavonoids and phenolic acids. From HPLC analysis of flavonoids: quercetin, myricetin, rutin, and phenolic acids: chlorogenic acid, gallic acid, and syringic acid were detected and quantified. The biological activity spectrum was predicted for the detected and quantified polyphenols. Conclusions D. angustifolia flower is a rich source of flavonoids and phenolic acids, which are extractable and can be checked for further biological activity. It was possible to identify and quantify phenolic compounds through HPLC analysis in the methanol extract of D. angustifolia flower. PASS biological activity prediction results showed that there were stronger antioxidant activities for the identified flavonoids. Future work will emphasize the isolation and characterization of active principles responsible for bioactivity.

Medicinal plants have been treating various ailments and diseases since ancient times. Aquatic and semiaquatic medicinal plants play an essential role in human welfare to fulfill their daily needs. They have shown biological, pharmacological, nutraceutical, and commercial applications. This review aims to collect and update all recent information on ethnomedicinal, phytochemistry, pharmacological activities, and nanoparticle synthesis and their uses in aquatic and semiaquatic medicinal plants. Original research papers, review papers, short communications, and book chapters on aquatic and semiaquatic plants have been retrieved from PubMed, Web of Science, Scopus, and Google Scholar. Keywords, ethnomedicinal studies, phytochemistry, pharmacological activities, and nanoparticle synthesis from aquatic and semiaquatic medicinal plants are used for the search. Different aquatic and semiaquatic medicinal plants belonging to the families Acanthaceae, Alismataceae, Amaranthaceae, Apiaceae, Araceae, Asteraceae, Boraginaceae, Ceratophyllaceae, Cyperaceae, Fabaceae, Hydrocharitaceae, Lythraceae, Marsileaceae, Menyanthaceae, Nelumbonaceae, Nymphaeaceae, Onagraceae, Plantaginaceae, Poaceae, Polygonaceae, Pontederiaceae, Primulaceae, Scrophulariaceae, and Zingiberaceae have been studied. They are rich in alkaloids, flavonoids, terpenoids, phenolics, saponins, tannins, dietary fiber, glycosidic derivatives, carbohydrates, and proteins. These phytochemicals have been used for their antimicrobial, antioxidant, hepatoprotective, sedative, anticonvulsant, cytotoxic, antiparasitic, and antidiabetic activities. Besides this, various parts of the plants are used as dietary supplements and green nanoparticle synthesis. These plants are also known for their commercial value and are used as an ingredient in some pharmaceutical industries.

Biological synthesis of silver nanoparticles (AgNPs) is a green, simple, cost-effective, time-efficient, and single-step method. This study mainly focused on the synthesis of silver nanoparticles (AgNPs) using essential oil of Laggera tomentosa (LTEO) and investigates their potential applications. Ultraviolet-Visible (UV-Vis) result showed the characteristic Surface Plasmon Resonance (SPR) peak of LTEO-AgNPs at 420 nm. Fourier transform infrared (FT-IR) spectroscopy indicated the functional groups present in LTEO and LTEO-AgNPs. Scanning electron microscope (SEM) image depicted the synthesized AgNPs mainly has spherical shapes with average nanoparticles size 89.59 ± 5.14 nm. Energy dispersive X-ray (EDX) peak at 3.0 keV showed the presence of Ag element in LTEO-AgNPs. The X-ray diffraction (XRD) peaks at 38°, 44° and 67° are assigned to (111), (200), and (220), respectively which displays the crystal nature of LTEO-AgNPs. The average particle size and zeta potential of LTEO-AgNPs were determined as 94.98 nm and −49.6 mV, respectively. LTEO-AgNPs were stable for six months against aggregation at room temperature. LTEO-AgNPs solutions exhibited potential activities for the treatment of some pathogenic bacteria species, agricultural productivity growth, determination of metallic ions, and catalytic reduction. This study is the first work to report nanoparticles synthesis using L. tomentosa extracts and evaluate their potential applications.

Cyclospermum leptophyllum is plant species known for its medicinal value and pleasant aroma. The aerial part and plant seeds are traditionally used as food additives as a spice. This study aims to isolate the chemical constituents of essential oil of the aerial part of the plant and study their potential antibacterial activities against some food contaminating bacteria. The essential oil of C. leptophyllum (CSEO) was isolated from aerial parts of the plant species and studied using GC-MS and FTIR techniques. The first four major chemical constituents determined from GC-MS analysis of CSEO (for peak area % ≥ 1.15%) were 2,5-dimethoxy-p-cymene (87.09%), 2-methoxy-1-methyl-4-(1-methylethyl) benzene (3.09%), 2-methoxy-4-methyl-1-(1-methylethyl) benzene (1.71%), and humulene (1.15%). 60%, 30%, 15%, 7.5%, and 3.75% of CSEO solutions were prepared and evaluated for their potential antibacterial activities against six food spoilage pathogenic bacterial strains. Three Gram-positive strains: Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 12228), Streptococcus agalactiae (ATCC 12386) and three Gram-negative strains: Escherichia coli (ATCC 25922), Proteus mirabilis (ATCC 35659), and Pseudomonas aeruginosa (ATCC 27853) were used as test microorganisms. Compared to ciprofloxacin, a positive control, the promising antibacterial activity was observed for CSEO against S. aureus at minimum and maximum test solutions as the values of the zone of inhibition diameter (ZID, mm) were recorded as 14.33 ± 0.58 for 3.75% CSEO solution and 30.67 ± 0.58 for 60% CSEO solution. Tests of CSEO solutions generally showed stronger antibacterial activities against Gram-positive than Gram-negative strains. Therefore, CSEO contains potent chemical constituents that might be applicable in treating pathogenic bacterial species.

Background. Dodonaea angustifolia is a known medicinal plant across East Arica. The flower of D. angustifolia is not well investigated in terms of phytochemistry and biological activities. This study aims to investigate the presence of flavonoids and phenolic acids in the flower of D. angustifolia and its antioxidant activity. Methods. Preliminary phytochemical screening was carried out using the standard protocols. Antioxidant activity evaluation using DPPH assay and total phenol content (TPC) and total flavonoid content (TFC) determinations in the flower extract were compared with the values of the leaf extract. UHPLC-DAD analysis was managed to develop the profile of the flower extract. Prediction of biological activity spectra for substances (PASS) was done using an online server for antioxidant and related activities. Results. Preliminary phytochemical screening and TPC and TFC values confirmed the presence of flavonoids and phenolic acids. From the HPLC analysis of flavonoids, quercetin, myricetin, rutin, and phenolic acids such as chlorogenic acid, gallic acid, and syringic acid were detected and quantified. The biological activity spectrum was predicted for the detected and quantified polyphenols. Conclusions. D. angustifolia flower is a rich source of flavonoids and phenolic acids, which are extractable and can be checked for further biological activity. It was possible to identify and quantify phenolic compounds through HPLC analysis in the methanol extract of D. angustifolia flower. The PASS biological activity prediction results showed that there were stronger antioxidant activities for the identified flavonoids. Future work will emphasize the isolation and characterization of active principles responsible for bioactivity.

Shigellosis is one of the major causes of death in children worldwide. Flavonoids and phenolic acids are expected to demonstrate anti-shigellosis activity and anti-diarrheal properties. The aerial part of A. integrifolia is commonly used against diarrhea. This study aimed to identify flavonoids and phenolic acids responsible for this therapeutic purpose. Antioxidant activity, total phenol content, and total flavonoid content were determined. The antibacterial activity of the aerial part against Shigella spp. was also tested using the agar well diffusion method. HPLC analysis was performed using UHPLC-DAD for different extracts of the aerial part. Autodock Vina in the PyRx platform was used to screen responsible components. Ciprofloxacin was used as a reference drug. An enzyme taking part in pyrimidine biosynthesis was used as a target protein. Molecular docking results were visualized using Discovery Studio and LigPlot1.4.5 software. Antioxidant activity, total phenol content, and total flavonoid content are more significant for the aerial part of A. integrifolia. From HPLC analysis, the presence of the flavonoids, quercetin, myricetin, and rutin and the phenolic acids gallic acid, chlorogenic acid, and syringic acid were identified from the aerial part of A. integrifolia. Regarding the antibacterial activity, the aerial part shows considerable activity against Shigella spp. Binding energies, RMSD and Ki values, interaction type, and distance are considered to identify the components most likely responsible for the therapeutic effects and observed activity. Antioxidant activity, total phenol content, and total flavonoid content of the aerial part are in line with anti-shigellosis activity. The top five components that are most likely potentially responsible for therapeutic purposes and anti-shigellosis activity are chlorogenic acid, rutin, dihydroquercetin, dihydromyricetin, and kaempferol.