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The prevalent life-threatening microbial and cancer diseases and lack of effective pharmaceutical therapies created the need for new molecules with antimicrobial and anticancer potential. Bee venom (BV) was collected from honeybee workers, and melittin (NM) was extracted from BV and analyzed by urea-polyacrylamide gel electrophoresis (urea-PAGE). The isolated melittin was hydrolyzed with alcalase into new bioactive peptides and evaluated for their antimicrobial and anticancer activity. Gel filtration chromatography fractionated melittin hydrolysate (HM) into three significant fractions (F1, F2, and F3), that were characterized by electrospray ionization mass spectrometry (ESI-MS) and evaluated for their antimicrobial, anti-biofilm, antitumor, and anti-migration activities. All the tested peptides showed antimicrobial and anti-biofilm activities against Gram-positive and Gram-negative bacteria. Melittin and its fractions significantly inhibited the proliferation of two types of cancer cells (Huh-7 and HCT 116). Yet, melittin and its fractions did not affect the viability of normal human lung Wi-38 cells. The IC50 and selectivity index data evidenced the superiority of melittin peptide fractions over intact melittin. Melittin enzymatic hydrolysate is a promising novel product with high potential as an antibacterial and anticancer agent. [ABSTRACT FROM AUTHOR]

In Egypt, the most common mosquito-borne diseases transmitted to human beings are exacerbated by water contamination caused by the unregulated discharge of chemical contaminants. Population growth and urbanization have expanded possible habitats, resulting in an increase in the abundance of Culex pipiens. In the present study, the fifth generation was reared at 27± 2°C, 75% RH, and a photoperiod of 12:12h (light-dark) in clean, moderately, and contaminated water to determine the impact of water contaminants on the population dynamics of Culex pipiens. Our results showed that C. pipiens had a finite growth rate (λ) of 1.3116 d-1, an intrinsic growth rate (r) of 0.3145 d-1, a net reproductive rate (R0) of 100.06 offspring, and a mean fertility (F) of 262.53 eggs in highly contaminated water. These values are much higher than those found in the offspring of water with minimal contamination. While there was no significant difference in male adult lifetime across treatments, female adult lifespan was significantly reduced in clean water (9.91 days) and moderately polluted (10.54 days) water compared to contaminated water (13.63 days). In moderately and clean water, the parameters were as follows: λ = 1. 2311 d1, 198.02 eggs, r = 0.2105 d-1 and R0 = 68.45 offspring, λ = 1.169 d-1, 186.92 eggs, r = 0. 2047 d-1, and R0 = 64.09 offspring, respectively. This research suggests that Culex pipiens may undergo the degree of adaptation to severely contaminated water, which might do enough to increase the diversity of the mosquito-borne disease. [ABSTRACT FROM AUTHOR]

Simple Summary: Mosquito-borne diseases lead to serious public health concerns in tropical and sub-tropical countries worldwide. Due to the developed resistance to synthetic chemical insecticides, their effects on the surrounding environment, and economic concerns, natural products are considered promising agents to be used in vector control programs, due to their safety, low cost, and high activity. Therefore, the aim of this study is to evaluate the larvicidal, developmental, and repellent activities of the methanolic extract of Annickia chlorantha and its isolated compounds against the mosquito vector, Culex pipiens, besides their toxicity to the non-target aquatic organism, the zebrafish (Danio rerio). The results highlight the potential of A. chlorantha extract and its isolated compounds as effective mosquitocidal agents with a very low toxic effect on non-target organisms. In this study, the crude extract and its isolated compounds from the stem bark of Annickiachlorantha were tested for their larvicidal, developmental, and repellent activity against the mosquito vector, Culex pipiens, besides their toxicity to the non-target aquatic organism, the zebrafish (Danio rerio). The acute larvicidal activity of isolated compounds; namely, palmatine, jatrorrhizine, columbamine, β-sitosterol, and Annickiachlorantha methanolic extract (AC), was observed. Developmentally, the larval duration was significantly prolonged when palmatine and β-sitosterol were applied, whereas the pupal duration was significantly prolonged for almost all treatments except palmatine and jatrorrhizine, where it shortened from those in the control. Acetylcholinesterase (AChE) enzyme showed different activity patterns, where it significantly increased in columbamine and β-sitosterol, and decreased in (AC), palmatine, and jatrorrhizine treatments, whereas glutathione S-transferase (GST) enzyme was significantly increased when AC methanolic extract/isolated compounds were applied, compared to the control. The adult emergence percentages were significantly decreased in all treatments, whereas tested compounds revealed non-significant (p > 0.05) changes in the sex ratio percentages, with a slight female-to-male preference presented in the AC-treated group. Additionally, the tested materials revealed repellence action; interestingly, palmatine and jatrorrhizine recorded higher levels of protection, followed by AC, columbamine, and β-sitosterol for 7 consecutive hours compared to the negative and positive control groups. The non-target assay confirms that the tested materials have very low toxic activity compared to the reported toxicity against mosquito larvae. A docking simulation was employed to better understand the interaction of the isolated compounds with the enzymes, AChE and GST. Additionally, DFT calculations revealed that the reported larvicidal activity may be due to the differing electron distributions among tested compounds. Overall, this study highlights the potential of A. chlorantha extract and its isolated compounds as effective mosquitocidal agents with a very low toxic effect on non-target organisms. [ABSTRACT FROM AUTHOR]