regions); now cultivated extensively through-
out the world. Parts used are the aerial parts.
The species has several distinct variants in-
cludingM. sativa(sensu stricto) and subsp.
falcata(L.) Arcangeli (syn.M. falcataL.).
The former is a purple-flowered form
with strongly coiled legumes, originating
from an arid continental climate in alkaline
soils, principally from Turkey. Wild and cul-
tivatedM. sativasubsp.sativaand their prog-
eny are relatively low in hemolytic saponins.
M.sativasubsp.falcatahasyellow flowersand
uncoiled fruits, originating from cool, upland,
humid climates in acidic soils and is compara-
tively higher in hemolytic saponins. Both taxa
are involved in the parentage of numerous
commercial alfalfa cultivars.^1 Modern western
European and North American cultivars have
intermediate levels of hemolytic alfalfa sapo-
nins due to hybridization and introgressions
involvingM. sativasubsp.falcata.^2
CHEMICAL COMPOSITION
Alfalfa has been one of the most studied
plants. Its chemical constituents include the
following.
Saponins (2–3%) that on hydrolysis yield
theaglyconesmedicagenicacid,soyasapogen-
ols A, B, C, D, and E, and hederagenin and the
glycones glucose, arabinose, xylose, rham-
nose,galactose,andglucuronicacid;3–8sterols
(b-sitosterol,a-spinasterol, stigmasterol, cy-
cloartenol, and campesterol, withb-sitosterol
as the major component);9–11high molecular
weight alcohols (octacosanol, triacontanol);
and paraffins (nonacosane, triacontane, hen-
triacontane).^12 b-Sitosterol also occurs as es-
ters with fatty acids (mainly palmitic, lauric,
and myristic). Triacontanol has been shown to
be a plant growth regulator that increases the
growth of rice, corn, and barley as well as the
yield of tomato, cucumber, and lettuce.^13
Flavones and isoflavones (tricin, genistein,
daidzein, biochanin A, formononetin, and
()-5^0 -methoxysativan); coumarin deriva-
tives (coumestrol,medicagol, sativol, trifoliol,
lucernol, and daphnoretin); and pectin methy-
lesterase (an enzyme present in significant
quantities believed to be one of the causes for
bloating in cattle by releasing pectic acids that
combine with calcium in the rumen to form a
resinous material, trapping gases produced
during digestion).4,14–16
Alkaloids (trigonelline, which is in seeds
only; stachydrine; and homostachydrine);
plant acids (malic, oxalic, malonic, maleic,
and quinic, etc.); vitamins and growth factors
(vitamins A, B 1 ,B 6 ,B 12 , C, E, and K 1 ; niacin;
pantothenic acid; biotin; folic acid; etc.);
amino acids (valine, lysine, arginine, leucine,
isoleucine, tryptophan, phenylalanine, methi-
onine, and threonine; asparagine in high
concentrations in seeds); sugars (sucrose,
fructose, arabinose, xylose, galactose, ribose,
mannoheptulose, andD-glycero-D-mannooc-
tulose); plant pigments (chlorophyll, xantho-
phyll,b-carotene, anthocyanins); crude fibers
(17–25%); proteins (15–25% in dehydrated
alfalfa meal); minerals; and trace elements
(Ca, P, K, Mn, Fe, Zn, Cu) (KARRER;LIST AND
HO€RHAMMER).
Medicarpin-b-D-glucoside (in roots); cere-
brosides (sphingosines); plastocyanins and
ferredoxins; benzoylmesotartaric acid, and
benzoyl-(S),()-malic acid;17–19three phy-
toalexins;^20 medicosides A, C, G, I, J, and L
(triterpene glycosides) in roots;^21 and a new
amino acid, medicanine, (S)-N-(3-hydroxy-
propyl)-azetidine-2-carboxylic acid from
seedlings.^22
In commercial solid extracts of alfalfa and
red clover, traces of cannabinol, caffeine,
scopolamine, isocoumarin, phenylpentadie-
nal, phenylhexadiene, and nepetalactone have
been reported.^23 Whether or not these com-
pounds were results of contamination or adul-
teration remains to be confirmed.PHARMACOLOGY AND BIOLOGICAL
ACTIVITIESCoumestrol, genistein, biochanin A, and daid-
zein have estrogenic activities on rumi-
nants.14,15Studies have also demonstrated
that coumestrol when fed to pullets increases
the age of maturity and depresses egg
production.^24Alfalfa 13