bioactivities

Bioactivity refers to the effects of a substance on living systems, including organisms, cells, tissues, or biomolecules. It encompasses molecular interactions such as enzyme inhibition or activation, receptor binding, ion channel modulation, and signaling pathway influence, as well as cellular responses like cytotoxicity, differentiation, or apoptosis. At the organism level, bioactivity covers antimicrobial, antiviral, antifungal, antiparasitic, anticancer, anti-inflammatory, immunomodulatory, and neuroactive effects, among others.

Bioactivities are typically evaluated using in vitro assays (cell-based or biochemical), ex vivo systems, and in vivo models. Common measures of potency and efficacy include the half-maximal inhibitory concentration (IC50), half-maximal effective concentration (EC50), minimum inhibitory concentration (MIC), and lethal dose (LD50). High-throughput screening and structure-activity relationships are used to discover and optimize bioactive compounds. Results depend on assay conditions, organism, metabolism, and bioavailability, so validation in multiple models is common.

Bioactive compounds originate from natural sources such as plants, microbes, and marine organisms, as well as from synthetic or semi-synthetic chemistry. In drug discovery and development, bioactivity screening helps identify lead compounds and informs optimization strategies. In addition to pharmacology, bioactivity assessments are important in toxicology, food safety, environmental monitoring, and agriculture. Interpreting bioactivity requires careful consideration of selectivity, potency, potential off-target effects, and context of use.