Review on essential oils, chemical composition, extraction, and utilization of some conifers in Northwestern Himalayas

Abstract

Essential oils (EOs) are regarded as alternative therapeutic agents for many diseases. In phytotherapy research areas, it is now well reported that conifers are the rich source of EOs. This review aims to update information on the biological sources and the best extraction processes of the significant constituents along with the traditional and therapeutic properties of the EOs from selected conifers of Himachal Pradesh, Northwestern Himalaya. In the present review, ten conifer species of high values have been selected. Results from several studies suggest that the conifers contain monoterpenes, sesquiterpenes, diterpenes, ketones, alcohols, and esters, which are used in medicines, food products, and cosmetics as well as other commercial and industrial products. Traditionally, the EOs from the conifers have been reported to be used against fever, cough, bronchitis, skin diseases, gastrointestinal disorders, and asthma. The pharmacological studies suggest that these EOs can be used as antirheumatic, antiseptic, antispasmodic, anticancer, anti-inflammatory, antitoxic, aphrodisiac, and astringent agents. It is, therefore, concluded that the EOs from the conifers might be one of the promising tools for the treatment of various diseases. Extensive research is required to ascertain the efficacy of the EOs from unstudied conifers.

Original Contributions to the Chemical Composition, Microbicidal, Virulence-Arresting and Antibiotic-Enhancing Activity of Essential Oils from Four Coniferous Species

“…The EOs main compounds of coniferous species are monoterpenes, monoterpenoides, sesquiterpenes, sesquiterpenoides and diterpenes [10,11]; however, the chemical composition of EOs could be variable, depending on the anatomical part of the tree, the genetic factors [12], the health condition of plant and also on the geographic and environmental conditions: soil and water composition, humidity and air pollution [13][14][15]. Research conducted in recent decades have highlighted the antibacterial [16,17], antifungal [17][18][19][20] and antioxidant [21,22] properties of EOs isolated from different coniferous species [15,19,[22][23][24][25][26][27][28][29][30] but there is scarce information concerning the biologically active principles isolated from populations of coniferous species on the Romanian territory.…”

Chemical Investigation and Dose-Response Phytotoxic Effect of Essential Oils from Two Gymnosperm Species (Juniperus communis var. saxatilis Pall. and Larix decidua Mill.)

“…saxatilis and L. decidua was determined by SPME-GC/MS analyses. Gymnosperms and, in particular, conifers produce EOs characterized by compounds belonging to the family of terpenes such as monoterpenes, sesquiterpenes, and their derivatives [ 18 ]. In agreement with previous works [ 19 , 20 , 21 , 22 ], our results showed monoterpenes prevail over sesquiterpenes.…”

Conifers Phytochemicals: A Valuable Forest with Therapeutic Potential

“…The following is a list in descending order of the key bioactive compounds responsible for antimicrobial effects: ketones > alcohols > esters > hydrocarbons > aldehydes > ketones > alcohols > esters > hydrocarbons [ 255 ]. Terpenoid compounds (α-terpineol, δ--3-carene, geranyl acetate, borneol, α and β-pinene, limonene, α-terpinene, ϒ-terpinene, β-ocimene, bornyl acetate, 1,8-cineole, α-phellandrene, p-cymene, linalool, ϒ-muurolene, α-humulene, and cadinene) have been found to be responsible for antimicrobial activity [ 8 , 33 ]. Alkaloids, especially 1,6-dehydropinidine obtained from P. abies needle and bark, have recently been discovered to have antimicrobial activity against Streptococcus equi (MIC = 55 g/mL) [ 13 ].…”

“…Coniferous plants, such as plants belonging to the Taxus, Cupressus, Picea, Pinus, Cedrus, Araucaria genera, are found worldwide and have shown several beneficial activities against diseases, highlighting the importance of conifers in drug development [ 7 ]. Conifers are woody, have needle-shaped single-veined leaves, and consist of male and female unisexual cones with bract scales [ 8 ]. They comprise eight families ( Pinaceae, Araucariaceae, Cupressaceae, Podocarpaceae, Cephalotaxaceae, Taxaceae, Phyllocladaceae, Sciadopityaceae ), 70 genera, and 630 species [ 9 ].…”