Table of Contents

    Topic review

    Saponin

    Subjects: Chemistry, Applied
    View times: 1082
    Submitted by: Ajaya Bhattarai

    Definition

    With increasing environmental concern, there is a trend of replacing synthetic products with their natural equivalents all across the globe. However, it is a grand challenge of the present generation, not merely due to the scarcity of their availability, but due to their high extraction and processing costs compared to the manufacturing of their synthetic equivalents. Along these lines are a group of synthetic chemical compounds known as surfactants. Surfactants are usually known as the major components of household detergents and cleaning products. It has the ability to reduce the surface tension of water, thereby enhancing its cleansing ability. Besides, they also find their application as emulsifiers, wetting agents, dispersants and foaming agents in cosmetics, personal care products, food, and paper processing, oilfield field chemicals, agricultural chemicals, pharmaceuticals, textiles, emulsion polymerization, and many other markets as well.  Owing to their widespread application in diverse fields, surfactants are among the most produced industrial chemicals. This far huge variety of surfactants have been synthesized to meet the demand of consumers. These synthetic surfactants are largely based on petrochemical raw materials. Because of their petrochemical origin, they are mainly toxic and non-biodegradable, causing many detrimental effects on the environment.

    Nevertheless, we have natural surfactants that stand out as eco-friendly and sustainable alternatives to their synthetic equivalents. However, at present, the choices are limited and the available product aesthetics do not offer good cleansing activities that the synthetic formulations do. Natural surfactants, as the name suggests, are of natural origin i.e. derived directly from nature either from plants or animal sources. Based on their origin, natural surfactants are broadly classified into two categories: (i) plant-derived natural surfactants and   (ii) natural surfactants produced by the fermentation of natural substrates like alkanes, oil, sugars, and wastes in the presence of microbes such as bacteria or yeast, usually termed bio-surfactants.  The production of biosurfactants, however, requires valuable carbon sources as raw materials, which are expensive and also a major food source for animals and humans. Providently, plants remain largely untapped sources of natural surfactants. Therefore, more research is to be carried out particularly in exploration, extraction, and isolation of natural surfactants from plants distributed widely in nature.

    1. Introduction

    Plants synthesize an unlimited number of bioactive chemical substances[10] that are less toxic and biodegradable than synthetic ones. Among the various bioactive chemical compounds derived from plants, saponins are the ones that exhibit surface-active properties[11]. In fact, they belong to a class of nonionic surfactants[8]. They got their name “saponin” derived from Latin word sapo, which means soap as they form soapy lather when agitated with water[12]. Structurally, they are composed of hydrophilic glycone moieties (sugars) glycosidically linked with hydrophobic aglycones moieties (steroids or triterpenoids[13]. This structural feature resembles that of a typical surfactant and hence attributes to their surface-active properties. Based on the aglycone counterpart of saponins, they are classified as (i) steroidal and (ii) triterpenoidal saponins[14]. Steroidal saponins are further classified as (i) spirostanols and (ii) furostanols glycosides[15]. Triterpenoidal saponins are most abundant in the plant kingdom[16]. Furthermore, phytochemical studies have reported the presence of saponins in more than 100 families of plants[17].

    2. Chemical Structure of Saponin

    Figure 1: Chemical Structure of a typical Saponin molecule.[18]

     

    Figure 2: Steroidal agyclones (a) Spirostanol (Diosgenin) (b) Furostanol (Protodiosgenin)[19]

     

    Figure 3: Terpenoidal agyclone[18]

    On the basis of the number of sugar units (glycone) attached to the agyclone saponins are classified as (i) monodesmosidic saponins: a single sugar unit attached to carbon-3. (ii) bidesmosidic saponins: two sugar unist , one attached to Carbon-3 and other attached to Carbon-26 or to Cabon-28.(iii) Tridesmosidic saponins:  three sugar units attached to the agyclone, but are rarely found [18][20]. The sugar units attached to the agyclone may be linear chains or branched chains, which are mainly D-glucose D-galactose, L-arabinose, L-rhamnose, D-xylose, D-fructose or D-glucuronic acid[20][21].

    Figure 4: (a) Monodesmosidic triterpenoid saponin and (b) Bidesomsidic triterpenoid saponin[16].

    Table 1: List of some saponin rich plants traditionally used as natural surfactants[19][23].

    Scientific Name

    Common Name

    Parts Used

    Saponaria officinalis

    Soapwort

    Roots and Leaves

    Chlorogalum pomeridia

    Soap root

    Root

    Quillaja saponaria

    Soap bark

    Innerbark

    Sapindus saponaria

    Soap berry

    Seed

    Sapindus mukurossi

    Soap nut  (Reetha)

    Fruit pericarp

    Table 2: List of some saponin rich plants that could be a potential source of natural surfactants.

    Scientific Name

    Common Name

    Parts Used

    References

    Acacia concinna

    Shikakai

    Pod and  bark

    [23]

    Acorus gramineus Aiton

     

    Leaf

    [23]

    Aesculus assamica

     

    Leaf

    [23]

    Aesculus indica

    Indian horse chestnut, Kanor, Bankhor

    Fruit

    [24]

    Agave americana L.

    Agave, Bara Kunwar, Kantala, Ran Ban

    Leaf

    [24]

    Agave offoyana

     

    Flower

    [18]

    Allium nigrum L

     

    Root and Leaf

    [18]

    Asparagus adscendens Roxb.

    Sansban, Saunspali

    Fruit and root

    [24]

    Asparagus racemosus Willd.

    Shatavari

    Root

    [24]

    Beaucarnea recurvata

     

    Leaf

    [18]

    Bupleurum chinense

     

    Root

    [18]

    Camellia sinensis

    Tea

    Seed

    [24]

    Caryocar villosum

     

    Stem

    [18]

    Chiococca alba

     

    Root

    [18]

    Cissus modeccoides

     

    Leaf and  stem

    [23]

    Cissus repen

     

    Stem

    [23]

    Chlorophytum borivilianum

    Safed musli

    Leaf

    [24]

    Dillenia parviflor

     

    Fruit

    [23]

    Harpullia austro-caledonica

     

    Bark

    [18]

    Garcinia sp.

     

    Fruit

    [23]

    Garuga pinnata Roxb

     

    Leaf

    [23]

    Lonicera japonica Thunb.

    Honeysuckle

    Leaf

    [24]

    Luffa cylindrica

     

    Fruit

    [23]

    Microcos tomentosa

     

    Leaf

    [23]

    Momordica charantia

     

    Fruit and stem

    [18]

    Oryza sativa L.

     

    Peel

    [23]

    Oxalis corniculata

     

    Leaf and  stem

    [23]

    Salix tetrasperma

     

    Pericarp

    [23]

    Sapindus rarak

     

    Fruit

    [23]

    Sesamun orientale

     

    Leaf

    [23]

    Silene inflata Sm.

    Bigru

    Root

    [24]

    Silphium asteriscus

     

    Leaf and stem

    [18]

    Solanum xanthocarpum

     

    Fruit

    [18]

    Tribulus terrestris

     

    Fruit

    [18]

    Yucca schidigera Roez

    Yucca

    Bark

    [1] [18]

    Besides their surfactant properties, they are also reported to exhibit a lot of useful biological activities such as antimicrobial, antioxidant, antifungal, anti-inflammatory, anti-cancer, and cholesterol-lowering properties[17].

    Because of their excellent surface activity, biological activities, and wide distribution in nature, saponin rich plants deserve deeper insight as a potential source of natural surfactants[23] as they possess the potential to replace toxic synthetic surfactants abundant today.

    References

    1. Javadzadeh, Y.; Hamedeyazdan, Y.J.A.S. Floating Drug Delivery Systems for Eradication of Helicobacter pylori in Treatment of Peptic Ulcer Disease. Trends in Helicobacter pylori Infection 2014, i, 13,, doi:10.5772/57353.
    2. Balakrishnan, S.; Varughese, S.; Deshpande, A.P. Micellar Characterisation of Saponin fromSapindus Mukorossi. Tenside Surfactants Deterg. 2006, 43, 262–268, doi:10.3139/113.100315.
    3. Tmáková, L.; Sekretár, S.; Schmidt, Štefan Plant-derived surfactants as an alternative to synthetic surfactants: surface and antioxidant activities. Chem. Pap. 2016, 70, 188–196,, doi:10.1515/chempap-2015-0200.
    4. Ribeiro, B.D.; Alviano, D.S.; Barreto, D.W.; Coelho, M.A.Z. Functional properties of saponins from sisal (Agave sisalana) and juá (Ziziphus joazeiro): Critical micellar concentration, antioxidant and antimicrobial activities. Colloids Surfaces A: Physicochem. Eng. Asp. 2013, 436, 736–743, doi:10.1016/j.colsurfa.2013.08.007.
    5. Sparg, S.; Light, M.; Van Staden, J. Biological activities and distribution of plant saponins. J. Ethnopharmacol. 2004, 94, 219–243, doi:10.1016/j.jep.2004.05.016.
    6. Weng, A.; Thakur; Melzig; Fuchs, C.A. Chemistry and pharmacology of saponins: special focus on cytotoxic properties. Bot. Targets Ther. 2011, 19, doi:10.2147/BTAT.S17261.
    7. Dinan, L.; Harmatha, J.; Lafont, R. Chromatographic procedures for the isolation of plant steroids. J. Chromatogr. A 2001, 935, 105–123, doi:10.1016/s0021-9673(01)00992-x.
    8. Ashour, A.S.; El Aziz, M.M.A.; Melad, A.S.G. A review on saponins from medicinal plants: chemistry, isolation, and determination. J. Nanomed. Res. 2019, 7, 282–288, doi:10.15406/jnmr.2019.07.00199.
    9. Güçlü-Üstündağ, Özlem; Mazza, G. Saponins: Properties, Applications and Processing. Crit. Rev. Food Sci. Nutr. 2007, 47, 231–258, doi:10.1080/10408390600698197.
    10. Oleszek, W.; Bialy, Z. Chromatographic determination of plant saponins—An update (2002–2005). J. Chromatogr. A 2006, 1112, 78–91, doi:10.1016/j.chroma.2006.01.037.
    11. Moghimipour, E.; Handali, S. Saponin: Properties, Methods of Evaluation and Applications. Annu. Res. Rev. Biol. 2015, 5, 207–220, doi:10.9734/arrb/2015/11674.
    12. Natural Products Isolation. Advanced Structural Safety Studies 2012.
    13. I. Chaieb, “Saponins as Insecticides : a Review,” vol. 5, no. 1, 2010.
    14. Wisetkomolmat, J.; Suppakittpaisarn, P.; Sommano, S.R. Detergent Plants of Northern Thailand: Potential Sources of Natural Saponins. Resour. 2019, 8, 10, doi:10.3390/resources8010010.
    15. Sharma, O.P.; Kumar, N.; Singh, B.; Bhat, T.K. An improved method for thin layer chromatographic analysis of saponins. Food Chem. 2012, 132, 671–674, doi:10.1016/j.foodchem.2011.10.069.
    16. Kregiel, D.; Berłowska, J.; Witonska, I.; Antolak, H.; Proestos, C.; Babic, M.; Babic, L.; Zhang, L.B.A.B. Saponin-Based, Biological-Active Surfactants from Plants. In Application and Characterization of Surfactants; IntechOpen, 2017.
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