Phytochemistry: Introduction to Plant Chemistry

Explore how primary metabolism powers respiration and growth, while secondary metabolism uses primary metabolites to form nitrogen compounds, phenolic compounds, and terpenes for defense, pollination, and communication with the environment.

Investigate how secondary metabolites influence pollination by attracting pollinators through color and aroma. Flavonoids, anthocyanins, terpenes, and phenylpropanoids shape pigments and volatile signals guiding animals to flowers.

this lecture explains plant defenses against herbivores, focusing on physical structures and secondary metabolites like jeselnik acid that inhibit insect digestion, and tri-trophic interactions via volatile compounds that attract predators.

Explore how plants recognize pathogen-associated molecular patterns and activate innate and acquired defenses, producing defense metabolites such as nicotine and allicin, and free radicals such as H2O2.

Allelopathy describes plants releasing water-soluble chemicals from leaves or roots that hinder neighboring seed germination, creating an inhibition zone and a competitive advantage for light, water, and space.

Explore how photoperiod, temperature, drought stress, and soil salinity influence the content and composition of secondary metabolites in plants, with examples such as anthocyanins and alkaloids.

Explains flavonoids, a key class of plant secondary metabolites with a three-ring conjugated core and hydroxyl groups, responsible for coloration and exhibiting antioxidant and antiinflammatory activities.

Discover alkaloids, nitrogen-containing secondary metabolites that defend plants and influence humans, ranging from bitter toxins such as strychnine to stimulants like cocaine and psychedelic mescaline.

Explore terpenes, built from isoprene units, including monoterpenes, sesquiterpenes, and diterpenes, their roles in essential oils, fragrances, antimicrobial and anti-inflammatory activities, and plant defense.

Explore triterpenes, six isoprene units forming C30 H48, their biosynthesis from IPP and DMAPP to squalene and 2,3-oxidosqualene, and their anti-cancer, anti-inflammatory, and anti-protozoal activities, including lupeol and betulinic acid.

Saponins are amphiphilic plant compounds featuring a triterpene or sterol aglycone linked to sugar moieties, producing soaplike foaming and contributing to bitterness and toxicity by membrane disruption.

Tannins are phenol-based secondary metabolites with benzene rings and hydroxyl groups, including tannic and gallic acids, that are acidic, astringent, water-soluble, and exhibit antioxidant activity.

Learn how plant secondary metabolites are extracted with solvents, using maceration, decoction, infusion, and soxhlet methods, with attention to solvent type, plant parts, heat effects, and process speed.

Learn to isolate a single chemical constituent from a plant extract by fractionation guided by polarity, using silica gel and thin layer chromatography with solvents of varying polarity.

Explore silica gel chromatography in glass columns to separate plant extract fractions by polarity, then use thin layer chromatography to visualize and measure retention times and factors.

Combine silica gel column chromatography with thin-layer chromatography to fractionate a plant extract. Collect and re-fractionate fractions using progressively more polar solvents to isolate purified constituents.

Learn practical phytochemical screening of plant extracts using simple colorimetric tests to detect sterols, flavonoids, tannins, phenolics, and saponins, via Liberum Burchard, Shinoda, ferric chloride, and foam tests.

Explore how nuclear magnetic resonance (nmr) spectroscopy determines spectra and elucidates the structure of plant molecules using one-dimensional and two-dimensional approaches.

Learn how mass spectrometry analyzes plant compounds by ionizing samples and separating fragments in a magnetic field to determine mass and molecular weight from their relative abundances.

Explore gas chromatography, a technique that separates vaporized compounds with a carrier gas and a liquid stationary phase, producing a chromatograph by analyzing retention times and peaks.

Explore infrared spectroscopy, a vibrational technique identifying functional groups in plant compounds by measuring infrared absorption. Understand bond vibrations and how wave numbers reflect bond type and atomic weight.

Learn to search plant compounds in PubChem by name, CID, or drawn structure, view 2D/3D structures and smiles, and access properties, spectra, vendors, safety, and related compounds.

Explore strategies for selecting medicinal plants to investigate biological activity, from random biodiversity screening to empirical use by native populations, traditional medicine, and bioprospecting based on animal behavior.

Explore how natural products shape drug discovery by reviewing FDA approvals from 1981 to 2019 and the role of natural products and botanical extracts in drug development.

Discover how a botanical compound becomes a drug through in vitro and in vivo preclinical tests, pharmacokinetics, and three-phase clinical trials.

Explore how plant secondary metabolites offer pest control options with biodegradable ecological advantages, showing essential oils and monoterpenes reducing seed germination and fungal growth while offering alternatives to synthetic pesticides.

Explore how natural products can prevent microbial contamination in packaged foods through antimicrobial and antioxidant assays. Examine DPPH antioxidant testing and diffusion assays, with turmeric extracts illustrating antimicrobial activity.