ABSTRACT: Spiders use their venom for defence and to capture prey. These venoms contain a cocktail of biologically active compounds that display several different biological activities, such as large molecules and small molecules including peptides, proteins/enzymes, and other components. Thus, venom constituents have attracted the attention of biochemists and pharmacologists over the years. The brown widow spider (Latrodectus geometricus) is a venomous spider found worldwide, including in Thailand. This spider causes human injuries, and the venom has many potential applications. In this study, we investigated the complexity and pharmacology of brown widow spider venom. Spider crude venom was investigated using partial proteome techniques and enzymatic activity, toxicity, and antibacterial activity assessments. We found that crude venom displayed a wide range of molecular masses from 19 to over 97 kDa, with molecular masses of 66 kDa intensely stained. Peptides and proteins were identified by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS), which showed that the crude venom contained a variety of substances, including latrotoxins, apolipophorins, hemocyanins, chitinases, arginine kinase, allergen antigen 5-like protein, astacin-like metalloproteases, and serine proteases. High hyaluronidase activity was observed based on the turbidimetric method. The venom presented toxicity in crickets (PD50 = 0.73 ± 0.10 ?g/g body weight), and substantial envenomation symptoms, such as slow-motion movement, paralysis, and even death, were noted. Moreover, this venom exhibited potential antibacterial activity against the gram-positive Bacillus subtilis but not the gram-negative Pseudomonas aeruginosa. Spider venom contains numerous molecules with biological activity, such as latrotoxins, which affect insects, and enzymes. In addition to latrotoxins, certain enzymes in venom are hypothesized to exhibit toxicity and antimicrobial activity. This study provides important information for the further development of natural compounds or insecticidal toxins.
