Plant steroids, also known as phytosterols, are steroid compounds found in plants. They have a similar structure to cholesterol but differ in having additional double bonds and side chains. Phytosterols are classified into sterols and stanols, and over 200 types have been identified in plants. They help plants adapt to temperature changes and are important components of cell membranes. When consumed, phytosterols can lower LDL cholesterol in humans. They are extracted from vegetable oils and used commercially to lower cholesterol. Saponins are steroidal or triterpenoid glycosides found in some plants. Diosgenin, a steroidal sapogenin, is commonly used in industry as a starting material for synthesizing hormones

1. Plant steroids
Introduction to steroids:
Steroidscomprise agroupof cyclicorganiccompoundswhose basisischaracteristicarrangementof
seventeencarbonatomsina four ringstructure linkedtogetherfromthree 6-carbonringsfollowedbya
5 carbon ringand an eightcarbonside chainon carbon 17.
These are classifiedinto5categoriesdependingupontype of substituentgroup(grouR) onC-17.
Sterols:where R isan aliphaticside chain.Theycontainusually1or more hydroxyl groupsattachedin
alicycliclinkage.
Sexhormones: where Rbearsketonicor hydroxyl groupandmostlypossessatwocarbon side chain.
Cardiac glycosides:where Risa lactone ring.The glycosidesalsocontainsugarslinkedthroughoxygenin
otherparts of the molecule.Normallyonhydrolysisityieldsthissugartogetherwithcardiacaglycone.
Bile acids: where R isessentiallya5 carbon side chainendingwithacarboxylicacidmoiety.
Sapogenins:where Rcontainsan oxacyclic(ethereal) ringsystem.
Sterols:theyare furthersubdividedinto3categories
Zoosterols:suchsterolsthatare obtainedfromanimal kingdomonly. E.g.cholesterol
Phytosterols:thosewhichare derivedfromplantsources. E.g.stigmasterol
Mycosterols:those whichare obtainedfromeitheryeastorfungi.E.g.ergosterol
Phytosterols:
Phytosterolsare alsotermedasphytosteroids,occurinplants,have similaritytocholesterolanddivided
intotwo subcategoriesnamely:
Sterols:havingdouble bondinsterol ringstructure.E.g.sitosterolsandcampesterol
Stanols: are saturated sterols, having no double bonds in the sterol ring structure. E.g. sitostanol and
campestanol.
More than 200 sterols and related compounds have been identified. Free phytosterols extracted
from oils are insoluble in water, relatively insoluble in oil, and soluble in alcohols.
These are the hormones produced by the plants to help in adaptation to different temperatures. In
1950 it was recognized that plant sterols lower serum concentration of cholesterol.

2. Chemical structure:
They consist of steroid skeleton wih a hydroxyl group attached to the C-3 atom of the A ring and an
aliphatic side chain attached to the C-17 atom of the D-ring. Sterols have double bonds typically
between C-5 and C-6 of the sterol moiety, whereas this bond is saturated in phytostanols.
Fig: steroidal structure
Difference betweenphytosterol andcholesterol
Phytosterol Cholesterol
synthesizedbyplantsonly Synthesizedbyliverfromacetyl CoA anditis also
an essential componentof cell membrane
Helpsplantstomaintainthe temperature Helpsinmaintainingmembrane permeabilityand
fluidity.
Helpsto lowerthe lowdensitylipo-proteinsLDLby
10%
Servesasa precursorforthe biosynthesisof
steroidhormones,bile acidsandvitaminD
Dailyintake should be 1-2gmfor beneficial effects. Lessthan 200mg throughdietsince bodyalso
synthesize it.

3. Dietary phytosterols:the richestnaturallyoccurringsourcesof phytosterols are vegetableoilsand
productsmade from them.
Theycan be presentinthe free formandas estersof fattyacids/cinnamicacidsoras glycosides
respectively.The boundisusuallyhydrolyzedinsmall intestine bypancreaticenzymes.
Extraction of phytosterols:
It isa processforthe preparationof highpurityphytosterolsfromdeodourizerdistillatefromvegetable
oils.
step 1
•deodrization leads in removalof volatiles and gives a
distillate that is rich in free fatty acids but also significant
levels of tocopherols (5-15%) and phytosterols (8-20%)
step 2
•transesterification is carried out to give fatty acid methyl
esters and we get free tocopherols and free phytosterols
which are seperated by distillation.
step 3
•the freetocopherols areseperated from free phytosterols
by solventcrystallization and filteration.

4. the yieldof phytosterolsobtainedisinthe range of 80-90% of free sterolsavailable with95-99% purity.
Nomenclature ofsterols:
Fig: basic ring structure of steroid
Steroidsare widelydistributedinplantsaswell asanimalsandtheirname isderivedfrom“sterol”.They
are characterizedbythe presence of 1,2-cyclopentophenanthrenering.
1. If an alcoholicgroupisattachedat C-3 positionanda side chainof 8-10 carbon atomsat C-17
than the structure formedwill be termedassterol.
2. The substituentsattachedfromthe above are designatedasβ andshownas thickened.
3. The substituentsattachedfrombelow are designatedasα and shownas dottedor broken
preferably.
step 4
•addition of MeOH:H2SO4 (at50-80 degreeC)
•Vigorous stirring for 2-6 hours
step 5
•vaccum distillation of methanol
•seperation of H2SO4 by hotwater washing
step 6
•crystallization at0-25 degreeC for 1-10 hours
•filteration and than washing with hexane at 10 degre C
•purecrystals of sterolobtained.

5. 4. If the configurationof the substituentisunknownthanitsbondto the nucleusisrepresentedas
wavyline.
5. If the side chaindoesnotcontaina methyl ene group.Thanit will be indicatedbyprefix NOR
preceded bynumberof carbonatoms that hasdisappeared.
6. Naturallyoccurringsteroidscontainone ormore additional heterocyclicringfusedorattached
to ringD formedbymodificationof side chain.
Usesof plant sterols:
 Inheritedtendencytowardshighcholesterol(familial hypercholesterolemia): Whentakenin
people whoarealsofollowingalow-fatorcholesterol-loweringdiet,plantsterolscanreducetotal
and"bad"low-densitylipoprotein(LDL)cholesterolmorethanthedietalone.Plantsterolsdon't
decreasebloodfatscalledtriglyceridesorincrease"good"high-densitylipoprotein(HDL) cholesterol
levels.
 Highcholesterol.Takingplantsterolslowerstotalandlow-densitylipoprotein(LDLor"bad")
cholesterol levelsbyabout3%to15% inpeoplewithhighcholesterol whoarefollowinga
cholesterol-loweringdiet.Whenaddedtoacholesterol-loweringprescriptionmedication,suchas
certain"statins",plantsterols reducetotalcholesterolbyan additional12-22mg/dLandLDL
cholesterol byanother11-16mg/dL.Plantsterolscanbe incorporatedinmargarines,dairyproducts,
andbreadsandcereals,ortakeninpillform.Researchsuggestsadoseof about2-3gramsdaily
lowerscholesterolthemost.Butplantsterolsmaystopworkingaswell whentakenfor morethan2-
3 months.Plantsterolsdon'traise"good"high-densitylipoprotein(HDL)cholesterollevels.
 PossiblyeffectivetopreventheartdiseasesuchasCVDandCHDand29% lowerchancesofheart
attack.
 Usefulforobese toloosefatandeffectivein prediabetics.
Sourcesofphytosterols:
The richestnaturallyoccurring sourcesof phytosterol arevegetable oilsandproductsmadefromthem.

6. Fig: natural sources of phytosterols
Steroidalsapogenins:-
Sapogeninsare aglyconesornon-sacchrideportionsof thefamilyof naturalproduct knownassaponins
obtainedbyhydrolysis.Ithaseitheracomplex terpenoidora steroidal structure,andinthe lattercase
formsa practicable startingpointinthe synthesisof steroidhormones.
Sapogenins whencombinedwith“genin”orsaccharide partare termedas“Saponins”whichare actually
Glycosides.
Two typesof saponinsare recognized:PentacyclictriterpenoidandSteroidal types. Bothtypesof
saponinshave acommon biogenicorigin.
Nomenclature of sapogenins:
Chemicallytheyare steroidalcompoundscharacterizedbythepresenceof spiro-skeletalsidechain.
A spirocompoundisbicyclicorganiccompoundwithringsconnectedthroughjustoneatom.Theringscanbe
differentoridenticalinnature.The connectedatomisalsocalledasspiro-atomwhichismostoftenly a
quaternarycarbon.
WhensapogeninisattachedtoachainofsugaroruronicacidunitsorbothoftenatC-3positionthanthiswill
be termedaspentacyclictriterpenoidsaponins.

7. Sourcesandusesofsapogenin
MostcommonlyusedsapogenininindustryisDiosgenin.Naturalproductsserveasstartingpointsforthe
partial synthesisof commercialproducts.E.g.cortisone_synhesizedfromHecogenin.Sexhormones(oral
contraceptives)synthesizedfromdiosgenin.
Theyare foundinmonocotyledonssuchaswildyam(Dioscoreavilosa)andfewdicotyledonssuchas
Fenugreek.StrophanthusandDigitalis containbotthsteroidalsaponins(glycosides)andcardiacglycosides.
Examples
Dioscoreavillosa:undergroundrootsandtubersare usedandcommonlyknownaswildyambelongingto
familyDioscoreacea.
Traditionallyusedintheovarian,menstrualandlabourpain.
Mainconstituentsare steroidalsaponinssuchasDioscin,phytosterols,alkaloids,tannins,starchandusedas
anti-spasmodic, anti-inflammatory,anti-rheumatic,diuretics.Inzulutraditions,itisusedtotreat
convulsions,epilepsy,hysteria.Topicallyassalveforeczema,poulticeforbruisesandscabies.
Siberianginseng:driedrootsandrhizomesof Eleutherococcussenticosus are usedbelongingtofamily
aralaiceae.Unlikeotherherbsthisisbetteratmaintaininggoodhealthratherthantreatingillness.Chemical
constituentsare triterpenoidsaponins,glycones,polysaccharides, coumarins,lignins.Usedtotreatinsomnia,
stress,chemotherapypatients,cardiovasculardiseases.Itshouldnotbe usedinhypertensivepatients.
Trigonellafoenum:fenugreekconsistsof thedriedseedshavingchemicalconstituentssuchassteroidal
saponins(diosgenin,yamogenin),vitaminB,alkaloids,glycosides,flavonoids,coumarin,mucilage.Itisusedas
anti-inflammatory,carminative,anti-septic,emollient,hypoglycemic.
Glycyrrizaglabra:driendrootsof liquoriceare used,whichhavedemulcent,expectorant,anti-microbial,
anti-viralandanti-ulcerogenicactions.Itisusedasflavouringagent,Addison’sdisease,inflammatory
conditions,pepticulcer.
References:
https://www.slideshare.net/HARISHANKARSAHU/steroids-52790313
https://en.wikipedia.org/wiki/Phytosterol
https://www.slideshare.net/ammarbabar18/phytosterols
http://www.plantcell.org/content/24/3/842#:~:text=Abstract,various%20abiotic%20and%20biotic%20st
resses.

8. Plant Steroids: Occurrence, Biological Significance, and Their Analysis G. M. Kamal B.
Gunaherath1 and A. A. Leslie Gunatilaka2 1The Open University of Sri Lanka, Nugegoda, Sri
Lanka and 2The University of Arizona, Tucson, AZ, USA