Biosynthesis of essential oils in aromatic plants: A review

Abstract

In aromatic plants species, biosynthesis of essential oils oocurs through two complex natural biochemical pathways involving different enzymatic reactions. Isopentenyl diphosphate (IPP) and its isomer dimethylallyl diphosphate (DMAPP) are the universal precursors of essential oils biosynthesis and are produced by the cytosolic enzymatic MVA (mevalonic acid) pathway or by plastidic and enzymatic 1-deoxy-D-xylolose-5-phosphate (DXP), also called the 2-Cmethylerythritol 4-phosphate (MEP) pathway. In the particular plant cell part, prenyl diphosphate synthases condense isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) further to form prenyl diphosphates, which are used as substrates for geranyl diphosphate, C 10 (GPP) or for fernesyl diphosphate, C 15 (FPP). Essential oils are final terpenoid products and are formed by a huge group of enzymes known as terpene synthases (TPS). Essential oils are important secondary metabolites of plants and have been used not only in different industries but also in ethnobotanical medicines for centuries. Hence, considerable research has been undertaken to understand the essential oils biosynthetic pathways. This review will be a valuable source of information in the field of natural products as we give detailed insights about biosynthesis of essential oils in plants, and thus indicate also new unexplored horizons for further research.

Electrospinning of Essential Oils

“…Essential oils are complex mixtures of volatile compounds that are synthesised by plants for defence and signalling purposes [10][11][12][13]. EOs protect plants against herbivores and harmful insects by inhibiting their appetite and attracting their natural opponents.…”

“…The functionality and scent of EOs derive from their main chemical components that belong to the class of isoprenoids and phenylpropanoids [10,12,14,15]. Isoprenoids, also known as terpenoids, are the predominant constituents of EOs and derive from 5-carbon precursors (Figure 1a): isopentenyl pyrophosphate (IPP) and its isomer dimethylallyl pyrophosphate (DMAPP).…”

Characterisation and screening of antimicrobial essential oil components against clinically important antibiotic‐resistant bacteria using thin layer chromatography‐direct bioautography hyphenated with GC‐MS, LC‐MS and NMR

“…The resulting EO is a mixture of secondary metabolites, with around 20 to 100 different constituents. Most components are volatile, low molecular weight organic compounds including terpenes and terpenoids, the most abundant class of compound present in EOs . The complex composition of EOs means that isolation of each EO and determination of their bioactivity using fractional techniques can be time consuming.…”

“…Most components are volatile, low molecular weight organic compounds 11 including terpenes and terpenoids, the most abundant class of compound present in EOs. 12 The complex composition of EOs means that isolation of each EO and determination of their bioactivity using fractional techniques can be time consuming. Thin layer chromatography-bioautography (TLC-B) is an analytical technique used to identify antimicrobial compounds separated usingTLC; zones of inhibition (ZoIs) of bacterial growth corresponding to spots on eluted TLC plates are indicative of antimicrobial compounds.…”

A Practical Domino‐Claisen–Cope Sequence in the Synthesis of New Blooming Citrus and Potent Floral Rose Alcohols

“…) . Citronellol ( 1 ) and geraniol ( 2 ) are primary monoterpenoid products of the mevalonic acid pathway of aromatic plants and are, therefore, almost omnipresent constituents of natural scents, for instance of lily‐of‐the‐valley flowers, palmarosa, geranium, lemon and gardenia species . Apart from linalool, these alcohols represent the most elementary components of what is called a ‘floral accord’ in perfumery.…”