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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.

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.

The medicinal benefits of P. lanceolata L. have been acknowledged worldwide for hundreds of years. The plant is now distributed worldwide, especially in temperate zones. This review gives an overview of ethnomedicinal use, phytochemistry, pharmacological activities, and other potential application of P. lanceolate L. Several effective chemical constituents such as polyphenols, tannins, flavonoids, alkaloids, terpenoids, iridoid glycosides, fatty acids, and polysaccharides are found in P. lanceolata L., which contribute to its exerting specific therapeutic effects. Correspondingly, studies have found that P. lanceolata L. has different biological activities, including antioxidant, antibacterial, wound-healing, anti-inflammatory, cytotoxic, and antiulcerogenic activity. The plant also treats various diseases related to the skin, respiratory organs, digestive organs, reproduction, circulation, cancer, pain relief, and infections. The plant has many applications in cosmetics such as lotion and creams; it is also used as an excellent indicator to know the presence and absence of heavy metals and the accumulation in industrial and urban areas. The plant suppresses soil nitrogen mineralization in agriculture due to allelochemicals such as aucubin. The biological activities, medicinal properties, and industrial application of P. lanceolata mainly depend on the activities of the responsible, active chemical constituents. However, this field still needs more study to determine the exact mechanisms and the main bioactive compound activity accountable for these activities. Also, most of the studies have been performed in vitro, so further in vivo studies are recommended for the future.