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Active ingredient/constituent
One or more molecules which have been isolated from the plant matrix and
scientifically established to have a specific physiological activity, both
in isolation and within the context of the whole herb or extract. This
concept comes from conventional pharmacy where an 'active ingredient' might
be part of a solution containing a number of other ingredients including
carriers or 'excipients.' Active ingredients generally exhibit a
'dose-dependent response' - in other words, the more one takes, the more
activity one gets. Many herbalists think that the entire herb or extract is
really the 'active ingredient/s' in which many constituents are acting
together - synergistically. Aglycone
Some molecules (such as anthocyanidins or isoflavones) can exist with or without a sugar
group attached to them. When they are without the sugar group, they are
known as aglycones ('a-' means 'without'). When they have the sugar group, they are known as
glycosides.
Allyl group
A functional group composed of H2C=CH-CH2-R, found in
many of the sulfur compounds of Garlic as well as in other organic
molecules; this group was actually named after the Latin for Garlic,
Allium, by a chemist researching Garlic oil in the 1840s.
Amino acid An organic
compound with an amine group (-NH2), a carboxylic acid group
(-COOH), a hydrogen atom, and a varying 'R' group bonded to the
central carbon atom (the 'alpha' carbon). There are 21 'standard'
amino acids from which proteins are composed, and many additional modified
types. Alliin, from Garlic, is an example of a modified amino acid.
Antioxidant A substance which
protects tissues from damage by stabilizing harmful free radicals.
Free radicals have an unpaired electron, which is very reactive;
antioxidants donate a companion electron to the free radical to 'calm it
down' so that it doesn't try to react with - and damage - other sensitive
molecules. The word 'antioxidant' arises from the chemical
definitions of 'oxidation' and 'reduction.' A free radical is an 'oxidant,'
'oxidizer' or 'oxidizing agent,' a chemical that wants to take an electron
away from another chemical and use that electron to stabilize itself. This
damages, or 'oxidizes' the other chemical. An antioxidant is a 'reducer' or
a 'reducing agent' that sacrifices one of its electrons to the free radical.
When a free radical and an antioxidant react, the free radical is 'reduced'
- it has gained an electron; and the antioxidant is 'oxidized' - it has lost
an electron. You'd think it would be the other way around...reduction
sounds like losing an electron rather than gaining one...but they did it
this way just to confuse chemistry students ;>) See also
Oxidation/Reduction and Lipid peroxidation.
Aromatic ring
A structure found in many kinds of phytochemicals, such as phenolic
compounds, alkaloids, and terpenes; it consists of six carbon atoms in a
flat, hexagonal pattern. It is represented like this: Each
angle in the drawing stands for a carbon; the double lines alternating with
single lines mean that the atoms are all sharing electrons. In many
chemicals, different functional groups (such
as -OH or -CH3) are attached to the ring, like this:
 (It looks like
there are double bonds alternating with single
bonds in this ring, but in this special case, there really aren't - all
atoms are sharing equally). The aromatic ring got its name from the fact
that early chemists discovered it in fragrant substances; but not all
phytochemicals containing this structure have an odor. (?
R)
Binding affinity A measure of the
strength of the attraction and 'sticking power' between a protein (i.e., an
estrogen receptor) and its ligand (the molecule which binds to it - i.e., an
isoflavone). For a technical explanation, see
this.
Biosynthesized A molecule is
biosynthesized if it is made by living systems (plants, animals, etc); as
opposed to laboratory synthesis.
Bond (covalent bond) When atoms in the molecules we discuss here
are bonded, they are sharing one or more pairs of electrons, and maintain a particular
relationship in space to one another. When only one pair is shared,
it's a single bond. When two pairs are shared, you have a
double bond. See also
Hydrogen bond.
Broad spectrum extract An herbal extract
designed to contain a wide range of the compounds found in the original
plant, as opposed to a narrow spectrum extract, which focuses on achieving
high levels of only one or a few compounds.
Carbonyl group An oxygen atom
double-bonded to a carbon atom.
Chromatography This word applies to various
different methods of chemical analysis that separate and detect compounds or
groups of compounds from a complex mixture. Types of chromatography include
TLC (thin layer chromatography), HPTLC (high performance thin layer
chromatography), HPLC (high performance liquid chromatography), GC (gas
chromatography - or GC/MS: gas chromatography/mass spectrometry), and GLC
(gas liquid chromatography). The word is made up of Greek roots
meaning 'color' and 'writing,' because early chromatographs separated
colored compounds into bands on a flat surface.
Compound A chemical composed of more than one type of atom. For
example, Sulfur (S) is an element, but allicin is a compound containing
sulfur, oxygen, carbon and hydrogen.
Deglycosylation The removal of a sugar
unit (i.e., glucose) from a larger molecule called a
glycoside. For example, an enzyme called beta-glycosidase removes the
sugar unit from the isoflavone glycoside daidzin, leaving the
aglycone, daidzein.
Demethylation The removal of a
methyl group (-CH3) from a molecule;
for example, when the methyl group is removed from the isoflavone biochanin
A, the resulting molecule is called genistein.
Derivative Chemicals which are made from their parent compounds
are known as derivatives of the parent compound.
Double bond Atoms are sharing two pairs
of electrons in a double bond. This kind of bond is therefore called
'electron rich.' A double bond can become the site of chemical reactions.
For example, this sulfide molecule from Garlic has a double bond at each
end, represented by the double lines. (Each angle in the drawing represents
a carbon atom; there is also a carbon atom at each end of the double lines).
Endogenous Biochemicals which are made by and within the
human body are called 'endogenous'; as opposed to exogenous, those which
come from outside. For example, estradiol is an endogenous estrogen, while
any phytoestrogen or pharmaceutical estrogen would be considered exogenous.
Exogenous estrogens are also known as xenoestrogens; this designation
includes both beneficial phytoestrogens and harmful estrogenic chemical
pollutants such as DDT.
Enteric coating A coating applied to tablets which prevents them
from dissolving in the stomach, but allows them to dissolve when they reach
the small intestine.
Enzyme A type of protein (almost always) that changes, constructs,
or decomposes other molecules without being changed itself. A biological
catalyst. Most biochemical
reactions are mediated by enzymes, which help otherwise slow reactions
proceed at a biologically useful pace. Enzymes are sensitive to high
temperatures and extremes of pH. For example, alliinase, the enzyme that
changes alliin to allicin in Garlic, is inactivated by heat (cooking) or low
pH (stomach acid).
Estrogen receptor A protein within
certain cells which can bind to endogenous estrogens, phytoestrogens, or
xenoestrogens. Once coupled with its estrogenic molecule, this protein
communicates with other molecules and starts a process that ultimately leads
to certain genes being switched on or off. The genes regulate many
hormone-influenced systems.
Free radical
A free radical is an 'oxidant,' 'oxidizer' or 'oxidizing agent,' a molecule
with one 'extra' electron that wants to take an electron away from another
molecule and use that electron to stabilize itself (electrons are happiest
in pairs). This process damages ('oxidizes') many biological chemicals
including the lipids in cell membranes.
Freeze drying Plant materials are frozen, then subject to high
vacuum. Water molecules sublimate (pass from solid to gas phase), and are
removed from the material. The drying is all done at low temperature.
Functional group In organic molecules, particular groups of atoms
where characteristic chemical reactions take place. There is a limited
number of functional groups, and they can be found in many different kinds
of molecules. Examples: Alcohol group, -OH; Amine group, -NH2;
Sulfide group, C-S-C.
Glucoside See glycoside, below.
Glycoside Any of
various kinds of molecules (including flavonoids) which have a sugar group
attached to the main part of the molecule. The molecule without the sugar is
known as the aglycone. A glycoside that has glucose
as its sugar unit is called a glucoside.
Gram One ounce contains 28.35 grams (g);
a milligram (mg) is 1/1000 of a gram, so one ounce contains 28,349.5
milligrams. A microgram (µg) is 1/1,000,000 of a gram; one ounce contains
28,349,523 micrograms. Here's a great
unit converter for translating one measurement into another.
Half-life The time it takes for half of a given quantity of a
particular compound to decompose or transform into other compounds.
Hydrogen bond A relatively weak kind of chemical bond where
there is an attraction between a hydrogen atom on one molecule and an oxygen
or nitrogen atom on another. Helps to stabilize the shape of molecules such
as proteins (including enzymes) and DNA; accounts for the 'surface tension'
of water.
Hydroxyl group
A hydroxyl group is a functional group
consisting of an oxygen atom bonded to a hydrogen atom (-OH). It is very
common in biomolecules.
In vitro Literally, 'in glass':
generally refers to scientific studies performed on cells cultured in Petri
dishes. The results of in vitro studies suggest, but cannot predict,
the effects a substance will have on a living organisms (such as a mouse or
human being). This is contrasted to in vivo, which means 'in the
living organism.'
Isomer Two compounds are isomers of each other
when they have the same number and kinds of atoms, but those atoms are
arranged in different ways.
Ligand A (usually smaller) molecule
which binds to a (usually larger) molecule such as an enzyme or protein, and
is either transformed into something else or initiates a metabolic process
(i.e., a phytoestrogen - the ligand - binds to an estrogen receptor - the
protein - and initiates a process such as transcription of a particular
gene).
Lipid Fatty or oily substance, insoluble
in water. Includes fatty acids and triglycerides. For more info, see
Lipid Library and
this
outline.
Lipid peroxidation
Lipids (such as the phospholipids in cell membranes and fatty acids in the
bloodstream) are subject to attack by free radicals, which damage them by
oxidation; this process is called lipid peroxidation. Lipid peroxidation has
been implicated in atherosclerosis and other diseases.
Antioxidants help protect against lipid
peroxidation.
Methoxy group A
functional group consisting of an oxygen
atom attached to a methyl group (-OCH3).
Methyl group
A functional group consisting of a carbon
atom with three hydrogen atoms attached (-CH3).
Microgram, see 'gram' above.
Milligram, see 'gram' above.
Moiety When referring to a molecule, a
'moiety' is a part or section of the whole.
Oligomeric 'Oligo' means short. It
refers to a type of polymer with only a few subunits,
as opposed to a 'monomer' - with one unit, or a 'polymer' - with many
subunits. For example, an oligomeric proanthocyanidin is a short-chain
polymer consisting of two to four or five flavanol subunits. Oligomers may
be further classified as 'dimers' - having two subunits, or 'trimers' -
having three subunits.
Organic In chemistry, any carbon-containing compound (with the
exception of molecules like carbon monoxide or carbon dioxide, and materials
like graphite and diamonds) is said to be 'organic.'
Organosulfur An organic compound containing sulfur.
Oxidation/Reduction
In phytochemistry, you can think of 'oxidation' as adding an atom of oxygen
or removing an atom of hydrogen from a molecule. You can think of
'reduction' as removing an oxygen atom or adding a hydrogen atom to a
molecule. For more detail, see this
Oxidation/Reduction
website.
Parent compound A compound from which other compounds are
derived. For example, alliin is the parent compound of allicin.
pH A measure of the acidity or alkalinity of a substance.
Neutral pH (pure water) is 7; acidic is less than 7 and basic, or alkaline,
is above 7. Examples: vinegar, 2.4-3.4; stomach acid, 1.0-3.0; blood, 7.4;
baking soda, 8.4.
Pharmacodynamics The study of the
physiological effects and mechanisms of action of a compound and how this
varies with concentration/dosage. In other words, the study of how the drug
acts upon the body.
Pharmacognosy The study of medicinal
plants and their extracts, constituents, and phytochemistry. Pharmacognosy
(from the Greek words for drug or medicine and knowledge) is currently
considered to be a branch of pharmacology and is studied in schools of
pharmacy.
Pharmacokinetics The study of how
compounds are absorbed, distributed, metabolized and eliminated by the body.
In other words, the study of how the body acts upon the drug.
Phenolic A molecule containing an
aromatic ring that bears one or more
hydroxyl
groups is referred to as 'phenolic.' Examples
include flavonoids, isoflavonoids, and lignans. The word comes from
'phenol,' the name for the structure below which has one hydroxyl group
attached to the ring:
Physiological concentrations
Concentrations of a substance likely to occur within the human body. Results
from research that uses significantly higher or lower concentrations of the
chemical being studied may not be applicable to the actual situation inside
the body.
Phytoalexin An antimicrobial, protective
compound synthesized by a plant in response to bacterial, viral, or fungal
infection. Many chemicals that are medicinal to humans are phytoalexins.
Phytochemistry The branch of chemistry
that focuses on the constituents of plants (phyto comes from the Greek word
for plant). Often, phytochemistry deals specifically with the chemistry of
medicinal plants. This discipline can also include studies of how to
extract, concentrate, analyze, standardize, & preserve herbal products.
Polyhydroxylated A molecule bearing more
than one hydroxyl group is called
polyhydroxylated.
Polymer A large molecule consisting of a
number of identical or similar subunits joined together. An example is the
starch molecule, which is made up of numerous glucose units. Proteins can be
thought of as polymers of amino acid units. Lignin, the polymer that gives
wood its rigidity, is a polymer of cinnamyl alcohol units (lignans are made
of two joined cinnamyl alcohols).
Precursor Plants make
phytochemicals by starting with one chemical, a 'parent compound,' and
changing it into another, called a 'derivative' -- meaning 'derived from the
parent compound.' There is a sometimes lengthy series of chemical
transformations where the original molecule changes shapes, splits up, or
joins with other molecules or atoms on the way to becoming the derivative.
Biochemists call this chain of transformative relationships a 'pathway.' A
pathway is organized by a specific group of enzymes that help change each
form of the molecule into the next form 'downstream.' A molecule that is
'upstream' in this process is called a precursor of the final
molecule.
Pro-oxidant Opposite of an antioxidant;
causes oxidation.
R In molecular structure, 'R' is a kind of shorthand
that stands for a variable group; for example, in a set of
related molecules that are mostly identical, you might find -CH3
attached to a particular spot in one molecule, -C3H5
in the corresponding place in the second molecule, and simply -H in that
spot in the third molecule. R is a way of saying, 'this could be any one of
a number of structures.'
Reactive oxygen species (ROS) Damaging
molecules, including oxygen radicals (i.e.
superoxide radical) and other highly reactive forms of oxygen (i.e. singlet
oxygen) that can harm biomolecules and contribute to disease states. Other
oxygen-containing radicals, such as the hydroxyl and peroxyl radicals, are
often classified as ROS too.
Significant In a scientific study, significant means that a
statistical analysis of the results has ruled out chance variation as the
cause of an observed effect.
Stable A stable compound remains unchanged for a relatively
long period of time.
Standardize To analyze a
concentrated botanical extract so that predetermined levels of certain compounds
(known as 'marker' compounds) are
guaranteed to be present in every batch. These levels are generally chosen
based on research results.
Steam distilling In order to extract
volatile or essential oils, plant material is either boiled in water or
steam is passed through it. The volatiles are carried off in the steam and
recovered in a condenser. Stereoisomer
Two molecules are 'stereoisomers' of each other when they contain the exact
same numbers and kinds of atoms, which are bonded to each other in the very
same order; the only difference between them is the way certain bonds are
oriented in space. Sulfide An
organic compound containing sulfur bonded to carbon; monosulfide: R-C-S-C-R;
disulfide: R-C-S-S-C-R;
Trisulfide: R-C-S-S-S-C-R
(mono=one, di=two, tri=3; R= R group, see above)
Sulfoxide An organic compound containing a
sulfur atom bonded to an oxygen atom.
Synergy In medicinal plants, constituents
that somehow work together are said to be working in 'synergy' or
'synergistically.' Two or more constituents may result in an increased
effect (potentiating synergy), or one constituent may modify the toxic
effects of another (attenuating synergy); protective synergy is when one
constituent stabilizes or protects another (i.e., an antioxidant may prevent
the breakdown of another constituent). Synergy is thought to occur in
addition to any additive effects the constituents of an herb may have
(simplified as 1 + 1 > 2). Another type of synergy occurs when one
constituent produces an effect upon an organism that allows a separate
constituent to have an enhanced effect on that organism. For example, some
herbs that produce the antimicrobial alkaloid berberine also produce a
chemical that inhibits bacteria from
pumping
the berberine out of their cells. Some herbs (i.e., Valerian) do not
have a prominent 'active ingredient' but instead achieve their effects
through synergy of multiple constituents. Synergy can be found operating in
formulas as well; for example, Nettle root & Pygeum bark work better
together for BPH (benign prostatic hyperplasia) than either herb alone.
Although the word synergy can have several definitions, there is a specific
mathematical test for true synergistic interactions between constituents,
known as the 'isobole method.'
Thiosulfinate An organic compound containing two sulfur atoms
bonded together, one of which is also double-bonded to an oxygen atom.
Example: allicin.
Transformation products Chemicals that are derived from a
particular compound when it undergoes chemical changes during extraction,
processing, or spontaneous decomposition.
Unstable An unstable compound is one which will spontaneously
decompose or transform into other compounds over a relatively short period
of time. Volatile A substance
which evaporates easily is said to be 'volatile.' Things with a strong aroma
are generally volatile, because the molecules easily pass into the
surrounding air. Wedges
Some bonds are represented by wedges instead of by straight lines. This is a
way of indicating the 3-dimensional structure of the molecule. The wedges
represent the way the bond is oriented in space: imagine that the part of
the molecule at the fat end of the dark wedge is coming out of the
page towards you. The part of the molecule at the fat end of the dotted
wedge is poking back into space behind the page:
In this particular molecule, the -OH group with the dark wedge is poking out
of the plane of the page towards the viewer; the ring on the end of the
dotted wedge is poking back behind the page. |
