A Review of Conifers in Iran: Chemistry, Biology and their Importance in Traditional and Modern Medicine

GC-MS analysis and the effect of topical application of essential oils of Pinus canariensis C.Sm., Cupressus lusitanica Mill. and Cupressus arizonica Greene aerial parts in Imiquimod-Induced Psoriasis in Mice

ETHNOPHARMACOLOGICAL RELEVANCE

Traditionally, Coniferous plants, in particular Pinus and Cupressus species, have been used in the treatment of burns, skin infections, and immune-mediated inflammatory diseases such as psoriasis.

AIM OF THE STUDY

A comparative study between essential oils (EOs) extracted from aerial parts of three coniferous plants: Pinus canariensis C.Sm. (PC), Cupressus lusitanica Mill. (CL) and Cupressus arizonica Greene (CA), cultivated in Egypt, was designed to investigate their composition and their anti-psoriasis mechanism.

MATERIALS AND METHODS

The phytochemical profiles were confirmed using Gas Chromatography-Mass Spectrometry (GC-MS) method. In-vivo Imiquimod (IMQ)-induced psoriasis model was performed and EOs were applied topically and compared to mometasone cream as a standard subsequently histopathological analysis and inflammatory biomarkers were measured.

RESULTS

In GC-MS analysis, Monoterpene hydrocarbons, sesquiterpene hydrocarbons and oxygenated monoterpenes were the major detected classes in the three plants, except in Pinus canariensis essential oil, oxygenated monoterpenes were absent. A significant attenuation of imiquimod-induced psoriasis symptoms after topical application of P. canariensis C.Sm., and C. lusitanica Mill. essential oils were observed by reducing the psoriasis area severity index (PASI) score, alleviating histopathological alteration, restoring the spleen index, and decreasing serum levels of interleukins 23 and 17A. Indeed, the results of Pinus canariensis essential oil is comparable to mometasone and showed no significant difference from standard treatment. On the other hand, the topical application of C. arizonica essential oil failed to alleviate imiquimod-induced psoriasis symptoms as observed in the PSAI score, the histopathological investigation, and the spleen index.

CONCLUSION

The essential oils of P. canariensis C.Sm., and C. lusitanica Mill aerial parts could be promising candidates for psoriasis treatment and for further studies on inflammation-related skin diseases.

Mediterranean Plants as Potential Source of Biopesticides: An Overview of Current Research and Future Trends

The development and implementation of safe natural alternatives to synthetic pesticides are urgent needs that will provide ecological solutions for the control of plant diseases, bacteria, viruses, nematodes, pests, and weeds to ensure the economic stability of farmers and food security, as well as protection of the environment and human health. Unambiguously, production of botanical pesticides will allow for the sustainable and efficient use of natural resources and finally decrease the use of chemical inputs and burden. This is further underlined by the strict regulations on pesticide residues in agricultural products and is in harmony with the Farm to Fork strategy, which aims to reduce pesticide use by 50% by 2030. Thus, the present work aims to compile the scientific knowledge of the last 5 years (2017-February 2023) regarding the Mediterranean plants that present biopesticidal effects. The literature review revealed 40 families of Mediterranean plants with at least one species that have been investigated as potential biopesticides. However, only six families had the highest number of species, and they were reviewed comprehensively in this study. Following a systematic approach, the extraction methods, chemical composition, biopesticidal activity, and commonly used assays for evaluating the antimicrobial, pesticidal, repellant, and herbicidal activity of plant extracts, as well as the toxicological and safety aspects of biopesticide formulation, are discussed in detail. Finally, the aspects that have not yet been investigated or are under-investigated and future perspectives are highlighted.

Cypress terpenes in sawfly larva of Susana cupressi (Hymenoptera: Symphyta: Tenthredinoidea)

Several sawfly species (Hymenoptera: Symphyta) possess larval stages with oesophageal diverticula in which plant compounds are sequestered and used for defence against predators. These organs are present in the larvae of Susana (Tenthredinidae) but remain poorly studied. Here, the aim was to analyse the diverticula extract of Susana cupressi by gas chromatography-mass spectrometry to better understand the ecology of this species. The foliage of the hostplant (Cupressus sempervirens), as well as the larval foregut, midgut, and haemolymph were also analysed. Complementary data were gathered by morphological observations, bioassays using ants, and genetic analyses to identify the studied Susana species. Altogether, 48 terpenes were identified, 30 being sesquiterpenes. The terpenes were generally detected in the foliage, but also in the diverticula, foregut, and midgut, whereas none of them in the haemolymph. The main compounds were alpha-cedrene, alpha-fenchene, alpha-pinene, alpha-terpinyl acetate, beta-myrcene, beta-pinene, cedrol, delta 3-carene, epi-bicyclosesquiphellandrene, germacrene D, limonene, sabinene, and terpinolene. The chemical profiles of these 13 compounds were significantly correlated between foliage-diverticula, diverticula-foregut and foregut-midgut, but not correlated for the three remaining possible comparisons. Alpha-pinene decreased and germacrene D increased from the foliage to the diverticula, which may reflect a specific sequestration of the latter terpene and its known deleterious effects on insects. We conclude that larvae of S. cupressi, similarly to those of diprionids, are well defended against predatory attacks by sequestering and regurgitating hostplant terpenes, including germacrene D.

Conifers Phytochemicals: A Valuable Forest with Therapeutic Potential

Conifers have long been recognized for their therapeutic potential in different disorders. Alkaloids, terpenes and polyphenols are the most abundant naturally occurring phytochemicals in these plants. Here, we provide an overview of the phytochemistry and related commercial products obtained from conifers. The pharmacological actions of different phytochemicals present in conifers against bacterial and fungal infections, cancer, diabetes and cardiovascular diseases are also reviewed. Data obtained from experimental and clinical studies performed to date clearly underline that such compounds exert promising antioxidant effects, being able to inhibit cell damage, cancer growth, inflammation and the onset of neurodegenerative diseases. Therefore, an attempt has been made with the intent to highlight the importance of conifer-derived extracts for pharmacological purposes, with the support of relevant in vitro and in vivo experimental data. In short, this review comprehends the information published to date related to conifers' phytochemicals and illustrates their potential role as drugs.

Identification of Polyphenols from Coniferous Shoots as Natural Antioxidants and Antimicrobial Compounds

Currently, coniferous shoots are almost absent as a food ingredient despite their wide availability in many parts of the world. The aim of the study was to assess and compare the composition of selected plant metabolites, evaluate the antioxidant and antimicrobial properties of selected shoots collected in 2019 from the arboretum in Zielonka (Poland), including individual samples from Picea abies L. (PA), Larix decidua Mill (LD), Pinus sylvestris L. (PS), Pseudotsuga menziesii (PM) and Juniperus communis L. (JC). The present work has shown that aqueous extracts obtained from tested shoots are a rich source of phenols such as caffeic acid, ferulic acid, chlorogenic acid, 4-hydroxybenzoic acid and many others. Obtained extracts exhibit antioxidant and antimicrobial properties in vitro. The highest sum of the studied phenolic compounds was found in the PA sample (13,947.80 µg/g dw), while the lowest in PS (6123.57 µg/g dw). The samples were particularly rich in ferulic acid, chlorogenic acid and 4-hydroxybenzoic acid. The highest values regarding the Folin-Ciocâlteu reagent (FCR) and ferric reducing ability of plasma (FRAP) reducing ability tests, as well as the total flavonoid content assay, were obtained for the LD sample, although the LD (14.83 mg GAE/g dw) and PM (14.53 mg GAE/g dw) samples did not differ statistically in the FCR assay. With respect to free radical quenching measurements (DPPH), the PA (404.18-μM Trolox/g dw) and JC (384.30-μM Trolox/g dw) samples had the highest radical quenching ability and did not differ statistically. Generally, extracts obtained from PA and PS showed the highest antimicrobial activity against tested Gram-negative bacteria, Gram-positive bacteria and fungi.