Modern Chemistry & Applications

Significance of Transferring Diterpenes to Improve Antifungal Activities in Coffee Seeds

Yanbei Lui^* Department of Chemical Biology, Chinese Academy of Sciences, Mengla, China
^*Correspondence: Yanbei Lui, Department of Chemical Biology, Chinese Academy of Sciences, Mengla, China, Email:

Received: 27-Mar-2023, Manuscript No. MCA-23-21134; Editor assigned: 29-Mar-2023, Pre QC No. MCA-23-21134 (PQ); Reviewed: 14-Apr-2023, QC No. MCA-23-21134; Revised: 21-Apr-2023, Manuscript No. MCA-23-21134 (R); Published: 28-Apr-2023, DOI: 10.35248/2329-6798.23.11.410

Description

There are at least 130 species in the genus Coffea (Rubiaceae), the majority of which are found in tropical Africa and on islands in the western Indian Ocean. Nearly 90% of the coffee produced worldwide comes from Coffea arabica L. and Coffea canephora Pierre ex A. Froehner. Coffee seeds are albuminous and contain a small, spatulate embryo that is surrounded in a profusion of living cells that make up more than 98% of the dry mass of mature coffee seeds in C. arabica. As the main tissue for storing nutrients, the endosperm stores nutrient reserves, mostly in the form of cell wall polysaccharides, Tri Acyl Glycerols (TAGs), globulins, and sucrose. The apoplast, which gradually infiltrate and resorb the endosperm, transports nutrients from the endosperm to the seedling cotyledons during embryo germination and seedling growth.

The coffee endosperm stores a variety of peculiar secondary metabolites, including as phenolics (chlorogenic acids), alkaloids (such as caffeine and trigonelline), and others, in addition to storage compounds. The seedling can benefit from the remobilization of secondary metabolites. For example, the alkaloid trigonelline serves as a nicotinic acid reserve for quick NAD re-synthesis during coffee seed germination through trigonelline demethylase activity.

However, it is believed that secondary metabolites from coffee seeds play crucial roles in protecting seeds and seedlings from herbivores and diseases, which helps Coffea species reproduce successfully. Purine alkaloid caffeine serves as chemical defence against a variety of ailments and herbivores. It may also inhibit the growth of neighbouring plants. During seed germination and seedling development, caffeine is quickly transported from the endosperm to the cotyledons. A portion of this pool is then excreted into the soil by the radicle, where it has an allelopathic effect. Chlorogenic acids, which are esters formed when quinic and hydroxycinnamic acids combine, have a variety of biological effects, such as antibacterial and antifungal characteristics.

Additionally, they are swiftly remobilized for seedling lignin metabolism when they move from the endosperm to the cotyledons during germination, which contributes to plant defence because lignin makes tissues more resistant to microbial attack.

Less research has been done on the physiological significance of the diterpenoids of the ent-kaurane family, the most notable of which are cafestol and kahweol, which make up the third main class of secondary metabolites discovered in coffee seeds. Diterpenoids are a large group of polycyclic isoprenoids with 20 carbons that are generated from geranylgeranyl pyrophosphate. Cafestol and kahweol are ent-kaurene-structured diterpenes that are a part of the large class of labdane-related diterpenoids that includes over 7000 known organic compounds.

Several labdane-related diterpenoids have crucial roles in plant metabolism and growth, including gibberellin phytohormones, which are widespread in the plant kingdom. But since most of these substances are specialised secondary metabolites with narrow taxonomic distribution, it's possible that only certain cell types, tissues, or organs can accumulate them. Numerous diterpenoids, including the diterpene phytoalexins found in cereals and the diterpene resin acids found in conifer trees, have anti-microbial properties and act as a barrier against bacterial and fungal infections. Other diterpenoids suppress herbivory or facilitate allelopathic plant-plant interactions.

Particularly, numerous studies have shown the function of diterpenes of the kaurane class in plant defence. This is the case with phytoalexins called maize kauralexins, which also function as an antifeedant against the moth Ostrinia nubilalis while inhibiting the growth of the fungi Rhizopus microsporus and Colletotrichum graminicola. Although cafestol and kahweol have been shown in numerous studies to have pharmacological and anticancer characteristics, their biological function in coffee plants remains unknown.

Based on the material mentioned above, it is most likely assumed that they help seeds defend themselves against herbivores or dangerous fungi. It is unknown if they are transferred from the endosperm to the cotyledons to safeguard the seedling if they do provide defence. Every Coffea species so far researched has seeds that contain cafestol and kahweol, which can make up as much as 1.5% of the dry seed mass.

Diterpenes are mostly found in mature coffee seeds that have been esterified with different fatty acids, particularly palmitic and linoleic acids, suggesting that they may be stored in oil bodies with TAGs.