Journal of Plant Biochemistry & Physiology
Open Access

Brief Note on Stereoisomers and Chirality in Plant Biochemistry

Aransh Tedwop^{* *}Correspondence: Aransh Tedwop, Department of Biochemistry and Forensic Science, Gujarat University, Gujarat, India, Email:

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Description

Stereoisomers in plants are molecules with the same molecular formula and connection between atoms but differing in their spatial arrangement. They play a vital role in plant biology due to their impact on biological activity and ecological interactions. Considering secondary metabolites, stereoisomers can have distinct biological effects, influencing plant defense mechanisms, herbivore interactions, and even human health when consumed. Understanding the stereochemistry of plant compounds is critical in fields like phytochemistry and pharmacology, as it can indicate their bioactivity and guide the development of pharmaceuticals, herbicides, and pesticides.

Types of stereoisomers

Stereoisomers, in particular, differ in the spatial orientation of their atoms. This results in characteristic three-dimensional structures, even though they have identical connectivity between atoms. The two main categories of stereoisomers are enantiomers and diastereoisomers.

Enantiomers: Enantiomers are mirror-image isomers, much like left and right hands. They cannot be superimposed onto each other, making them non-superimposable mirror images. Enantiomers share identical physical and chemical properties, except for their interaction with plane-polarized light. This property is called optical activity. It is a defining feature of enantiomers. One enantiomer will rotate plane-polarized light in one direction, while its mirror image will rotate it in the opposite direction. The presence of chiral centers, or stereocenters, is responsible for the formation of enantiomers. In relation to plant biochemistry, enantiomers are often found in molecules such as amino acids and sugars. For example, the amino acid alanine exists as two enantiomers: L-alanine and Dalanine. In plants, L-alanine plays an important role in the synthesis of proteins, while D-alanine is found in the cell wall of certain species of bacteria, influencing plant-microbe interactions.

Diastereoisomers: The mirror-image relationship observed in enantiomers is absent in diastereoisomers. They have distinct physical and chemical properties, making them more chemically diverse compared to enantiomers. The presence of multiple chiral centers in a molecule often results in the formation of diastereoisomers. This complexity offers a wide range of functional diversity in plant biochemistry.

Significance of stereoisomers in plant biochemistry

Plant growth and development: Stereoisomers play a vital role in plant growth and development. One example is the plant hormone auxin. There are several naturally occurring auxin compounds, including Indole-3-Acetic Acid (IAA) and 4- Chloroindole-3-Acetic Acid (4-Cl-IAA). These compounds are diastereoisomers, and they exhibit different biological activities in plants. While IAA functions as a growth-promoting hormone, 4-Cl-IAA serves as an inhibitor, inhibiting plant growth. The stereochemistry of these compounds considerably effects their interactions with plant receptors, ultimately impacting plant development.

Defense mechanisms: A variety of secondary metabolites are used by plants as defense mechanisms against herbivores, pathogens, and stresses that are in the environment. Stereoisomers are frequently involved in the biosynthesis of these compounds. For example, some alkaloids found in plants, such as nicotine and anabasine, are made up of enantiomers. These enantiomers can have different levels of toxicity and resistance to herbivores, effectively increasing plant defense strategies.

Bioactive compound synthesis: The synthesis of bioactive compounds in plants often involves the interaction between stereoisomers. One example is the production of cannabinoids in Cannabis plants. Cannabidiol (CBD) and Δ-9- Tetrahydrocannabinol (THC) are two popular cannabinoids with different physiological effects. These compounds are diastereoisomers, with THC being psychoactive and CBD having non-psychoactive properties. Understanding the stereochemistry of these compounds is important in the development of medical and therapeutic applications of cannabis.

Plant-microbe interactions: Plant-microbe interactions are central to plant biology, influencing nutrient uptake, defense mechanisms, and overall health. The role of stereoisomers in these interactions were demonstrated by mycorrhizal fungi. These fungi form mutualistic relationships with plants and facilitate nutrient absorption. Mycorrhizal associations can be selective, and thes fungi that form symbiotic associations with the plant can be influenced by the secretions from the roots.

Stereochemistry in medicinal plants

Medicinal plants have been used for centuries in traditional medicine and are a rich source of bioactive compounds. The study of stereochemistry in medicinal plants is important for understanding the pharmacological properties and therapeutic potential of these plants.

Ginkgo biloba: Ginkgo biloba, known for its cognitiveenhancing properties, contains terpene lactones and flavonol glycosides. These compounds have multiple chiral centers, leading to the formation of diastereoisomers. The stereochemistry of these compounds influences their ability to absorb free radicals and improve mental performance.

Artemisia annua: Artemisinin, a compound found in Artemisia annua, is an important component in the treatment of malaria. This compound contains chiral centers, resulting in the formation of enantiomers. While both enantiomers exhibit antimalarial activity, one is has more strength than the other. Understanding the stereochemistry of artemisinin is vital for optimizing its medicinal use.

Conclusion

In conclusion, the importance of stereoisomers in plants is important, having wide effects for various aspects of plant biology, ecology, and human well-being. Their role in influencing bioactivity of secondary metabolites indicates the complexity of plant defense mechanisms, microbe interactions, the development of medicinal plants, and various other aspects of plant biology and herbivore interactions. Also, the influence of stereochemistry on the development of pharmaceuticals and agrochemicals highlights the practical importance of identifying these isomers. As we learn more about the stereoisomers that exist in plants, we not only gain perspectives on various aspects of plant-environment interactions but also identify chances to use this information for increasing agriculture, medicine, and environmental sustainability.