Objective: The aim of this work was to characterize the antioxidant properties and to evaluate the total phenol content of leaves, bark, pericarp, and pulp extracts of Lebanese Annona squamosa Linn. (A. squamosa),, as well as a total screening of secondary metabolites present in the various plant parts studied. Methods: Two solvent systems were used for extraction: ethanol 80 % and methanol 80 %. The antioxidant activity of different extracts was investigated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The Total Phenol Content (TPC) of the different plant parts are determined and compared via Folin-Ciocalteu method. The results were presented as the mean of three separate experiments and error bars were used to illustrate standard deviation. Results: The phenolic content was found to be highest in the A. squamosa leaves methanolic and ethanolic extracts (117.2 mg and 112.92 gallic acid extract/g, respectively). The results showed that A. squamosa leaves methanolic and ethanolic extracts display the highest antioxidant activities than the bark, pulp and pericarp extracts, with half-maximal inhibitory concentration values 13.61 and 15.97 μg. ml-1 respectively. Ethanol 80 % and methanol 80 % were found to be efficient for the extraction of phenolic compounds. Conclusion: Results of this study indicate the presence of promising compounds in Lebanese A. squamosa that are able to act as antioxidants and free radical scavengers.

Diabetes mellitus has long been seen as a substantial economic burden on patients, their families, and society. Impairment in blood sugar regulation has major health repercussions. Furthermore, untreated diabetes causes major chronic complications like blindness, renal failure, and heart failure, as well as an increase in associated mortality. New anti-diabetic medicines are being researched to help alleviate this issue. Conventional Anti-diabetic medications are beneficial, several synthetic drugs are available in the market to treat diabetes, but they are costly and come with inevitable adverse effects. Medicinal plants, on the other hand, may serve as an alternate source of anti-diabetic agents. According to the World Health Organization, 80 % of the population in underdeveloped nations still relies on traditional medicines or folk medicines, which are largely made from plants, for disease prevention or treatment. For instance, anti- proliferative, anti-viral, anti-inflammatory and anti-hyperglycemic effects. In order to find a natural anti-diabetic source that comes with less side effects, several studies have been conducted. The aim of this work is to review these studies and highlight the potential of plants when it comes to their anti-diabetic effect.

Background: Screening of medicinal plants for their biological activities and phytochemicals is important for finding safe and potent new compounds for therapeutic use. The current investigation was conducted in extracts of Lebanese A. squamosa (leaves and bark) to evaluate the antioxidant, anticancer, and anti-inflammatory activities. Methods: Seven extracts were prepared by ultrasound-assisted extraction (UAE) or microwave-assisted extraction (MAE), and using various solvents. The evaluation of antioxidant activity was done using DPPH assay, the anticancer activity assessed on the colon cancer HCT116 cell line was determined by WST-1 viability assay, and finally the anti-inflammatory activity was investigated by measuring the secreted amounts of PGE2 and IL-6 using. Results: The TPC were in the range between 27.3 to 179.5 mg GAE/g of plant extract, while TFC were between 8.3 to 150.8 mg RE/g of plant extract. DPPH assay showed high antioxidant activity for the methanolic extracts obtained by UAE in both natural dried leaves and bark with IC50 values of 9.3 and 12.6 μg.mL-1, respectively. For WST-1 assay, methanolic extracts obtained by UAE showed a potent anti-proliferative effect against HCT116 cell line with IC50 values ranged from 0.18 to 0.88 μg.mL-1. Also, the western blot assay suggested that these extracts may inhibit the proliferation of HCT 116 cell line by causing cell cycle arrest through activation of p21 pathway. Significant anti-inflammatory activity was observed due to the decrease in the secretion of IL-6 in LPS-stimulated THP-1 cells. Conclusion: Therefore, the present study revealed that the dried leaves and bark of Lebanese A. squamosa methanolic extracts obtained by UAE possess effective bioactivities, thus hold potential application in the pharmacological field.

Propolis samples were collected from four different regions of Lebanon characterized by high biodiversity and high honey production. The samples were analyzed for their total phenolic contents (TPC), total flavonoid contents (TFC), chemical profiles, and antioxidant activity. The TPC was determined using Folin-Ciocalteu method while the TFC using the AlCl3 method. The antioxidant activity of propolis was examined by two different methods, namely free radical scavenging assay and reducing ability. The chemical profiles of the samples were assessed by thin-layer chromatography (TLC), UV-Vis, and gas chromatography/mass spectrometry GC-MS analysis. Total phenolic content ranged from 53.35 ± 7.09 to 148.27 ± 15.08 mg GAE/g, total flavonoid content ranged from 45.73 ± 2.8 to 134.5 ± 8.46 mg RUE/g. GC/MS analysis revealed the presence of 9-octadecene and tetradecene as major compounds that have been previously reported to demonstrate antioxidant activity. In addition, Berqayel propolis sample showed high content of phenolic compounds and high antioxidant activity and contained mainly hydrocarbons, while samples from Wadi Faara recorded poor chromatograms with the absence of most of the compounds present in Berqayel samples. The majority of propolis samples showed relatively interesting antioxidant activity, which was also correlated with TPC and TFC. Our results provide additional evidence on the importance of the chemical composition of propolis and its usefulness in the pharmaceutical industry.