zqc8-2026-02-21_09_17_42-fphar-16-1587215.pdf
zqc8-2026-02-21_09_17_42-fphar-16-1587215.pdf
Plant-based secondary metabolites as natural remedies: a comprehensive review on terpenes and their therapeutic applications
Terpenes are among the most diverse kinds of natural products because of their remarkable chemical variety. Numerous biological characteristics of terpenoids have been documented, including their antibacterial, antifungal, antiviral, antihyperglycemic, anti-inflammatory, and antiparasitic effects, as well as their cancer chemopreventive benefits. Additionally, terpenes are utilized in the manufacturing of organic solvents, varnishes, inks, adhesives, synthetic polymers, natural rubbers, cleaning supplies, biofuels, insecticides, and food and beverage items. Terpenes are therefore highly valued in modern medicine, pharmacy, nutraceuticals, cosmetics, and other fields. Plant oils, including terpenes, have been used to treat a variety of diseases without a full understanding of the roles or modes of action of particular bioactive substances. Many of these compounds are only present in nature in extremely small amounts; thus, methods such as metabolic engineering and synthetic biology are used to harvest them in large quantities in order to produce enough medicine. This comprehensive review aims to elucidate the biochemistry, phytochemical properties, and pharmacological activities of terpenes in metabolic disorders.
One. Terpene: biochemical and phytochemical properties
One. Terpene: biochemical and phytochemical properties
Terpenes are the largest and most functional class of secondary metabolites. Owing to their diverse characteristics, terpenes have been used in numerous applications because they perform specialized chemical functions to protect plants from abiotic and biotic stresses. The term "terpene" originates from the Latin word terebinthina, which denotes turpentine, a resinous material extracted from trees belonging to the genus, which are related to pine trees. Terpenes are an enormous class of naturally derived chemicals comprising over thirty thousand members and are common sources for a wide variety of purposes. Although they occur in all organisms, they are mostly found in higher plants. According to a study by Wallach in eighteen eighty-seven, these are simple hydrocarbons comprising isoprene units, often referred to as the backbone of the terpenes. Two precursor molecules are responsible for terpene biosynthesis: the isopentenyl diphosphate unit and its isomer, dimethylallyl diphosphate. Two autonomous pathways are involved in the production of these two molecules. The mevalonate and two-C-methyl-D-erythritol-four-phosphate pathways. Both isopentenyl diphosphate and dimethylallyl diphosphate undergo further rearrangement, repetition, and cyclization to yield different terpenes. With further modifications, they are converted into terpenoids, also known as oxygenated derivatives of terpenes, by changing the type of functional groups attached to them.
Terpenes have a variety of medical applications, but their antiplasmodial activity stands out because they work similarly to the widely used antimalarial drug chloroquine. Despite their widespread use, there is currently little scientific data on the effects of terpenes on the cardiovascular system, which restricts their prospective application as cardioprotective and/or cardiotherapeutic drugs. Certain terpenes are widely used in natural folk medicine. Terpenes constitute the largest group of constituents in essential oils. Approximately a quarter of the terpene fractions of essential oils are composed of monoterpenes and sesquiterpenes. Additionally, they bring helpful insects such as pollinators and dispersers, as well as natural enemies of pests. Additionally, a number of studies have shown that certain terpenes may lessen the symptoms of inflammation by reducing the release of pro-inflammatory cytokines such as interleukin one, tumor necrosis factor-alpha, and nuclear transcription factor-kappa B. It has been extensively researched how plants produce terpenes to combat biotic and abiotic stressors.
The biochemistry of terpenes can be easily understood through their oxygenation, hydrogenation, and dehydrogenation to form terpenoids. Large amounts of terpenes are released into the troposphere by vegetation, where they react easily with ozone, hydroxyl, and nitrate radicals to produce a variety of oxidation products. Thus, the biochemical reaction pathways of terpenes include reactions of hydroxyl, ozone, and nitrate with simple alkenes, cycloalkenes, and conjugated dienes under tropospheric conditions. The oxidation products of terpenes are mainly carbonyl, carboxylic acids, alcohols, epoxides, esters, nitrates, and peroxynitrates, which are minor products. Terpene epoxides are thought to be promising primary intermediates in the synthesis of several green polymers, such as epoxy resins, polycarbonates, nonisocyanate polyurethanes, and even certain polyamides. Terpenes were hydrogenated at temperatures as high as two hundred degrees Celsius and twenty-five bar. In high yields and purities, the terpenes were converted to two, six-dimethyloctane, farnesane, and squalane. The purpose of hydrogenating terpenols is to eliminate double bonds. Direct hydrogenation using pressurized hydrogen is possible. To eliminate the double bonds in terpenols, a safer method is to use perhydrogenated cyclic hydrocarbons for transfer hydrogenation. In this process, virtual hydrogen is held inside the hydrogen donor molecule. The presence of at least one double bond facilitates terpene dehydrogenation. The process of dehydrogenating terpenes and steroids to produce aromatic chemicals is reviewed, along with the current applications of some of the products. The underlying carbon structures of natural compounds, especially terpenoids and alkaloids, can be clarified using this technique before spectroscopic and crystallographic techniques take over.
Terpenes are phytochemically important for plant defense against invasive plants and herbivores, disease resistance, chemical signaling and communication, defense against photooxidation, plant-environment mediation, thermoprotection, and pollinator attraction. A type of resin that contains terpenes is secreted by capitate-stalked glandular hairs that are found on flower bracts, and to a lesser degree, by capitate sessile and bulbous trichomes that are also found in other vegetative organs. Additionally, yellowish and pungent essential oils have been extracted from the volatile terpenes of hemp glandular trichomes. Terpenes give plants their flavor, aroma, and pigmentation, which is why they are commercially used as food colors and fragrances. Natural terpenoids present new opportunities for the discovery of drugs with fewer side effects. Furthermore, terpenoids have been closely linked to a variety of biological activities, including anti-inflammatory, anti-allergic, antibacterial, antifungal, antioxidant, antiangiogenic, and antimetastatic properties. They usually comprise essential oils that are economically valuable in the form of scents and flavors. In the food sector, they are widely used as natural flavoring agents. They are utilized as natural food preservatives, natural flavorings, novel anticancer drugs, insecticides, and herbicides in agriculture and as raw materials for industrial chemical manufacturing.