Variation in Essential Oil Composition, Bioactive Compounds, Anatomical and Antioxidant Activity ofAchillea aucheri, an Endemic Species of Iran, at Different Phenological Stages

Evaluation of Chemical Composition and Anti-Staphylococcal Activity of Essential Oils from Leaves of Two Indigenous Plant Species, Litsea leytensis and Piper philippinum

Many indigenous plants of the Philippines, including essential oil-bearing species, remain phytochemically and pharmacologically unexplored. In this study, the chemical composition of leaf essential oils (EOs) hydrodistilled from Litsea leytensis (Lauraceae) and Piper philippinum (Piperaceae) was determined using dual-column (HP-5MS/DB-WAX)/dual-detector gas chromatography and mass spectrometry analysis. Caryophyllene oxide (15.751/16.018%) was identified as the main compound in L. leytensis EO, followed by β-caryophyllene (11.130/11.430%) and α-copaene (9.039/9.221%). Ishwarane (25.937/25.280%), nerolidol (9.372/10.519%) and 3-ishwarone (6.916/2.588%) were the most abundant constituents of P. philippinum EO. Additionally, the in vitro growth-inhibitory activity of the EOs in the liquid and vapour phases against Staphylococcus aureus was evaluated using the broth microdilution volatilisation assay. Although the results showed no anti-staphylococcal effect, the presence of various bioactive compounds in both EOs suggests their potential future use in industrial applications.

Evaluation of pharmaceutical compounds at vegetative and reproductive growth stages of Marrubium vulgare, a medicinal plant to cleanse the body

Marrubium vulgareis a plant with high bioactive potential. The rich bioactive compounds of medicinal horehound, as well as their antioxidant activity have led to its wider application in the pharmaceutical, cosmetic, and food industries. The present work aimed to determine the phenolic compounds, total phenols, flavonoids, and antioxidant activity at vegetative and reproductive growth stages of Marrubium vulgare. The experiments were performed in Eram Garden with five replications and using SPSS software (v. 13) and Mann-Whitney U-Test at p ≤ 0.01. The total content of flavonoids and main phenolic compounds increased when plants collected at vegetative stage. On the other hand, the highest vanillin content was observed in full flowering stage. Overall, this study can provide useful information about the best harvest period for horehound to produce the desired compounds for use in the food, pharmaceutical, and plant industries.

Harvest time optimization for medicinal and aromatic plant secondary metabolites

Plant secondary metabolites (SMs) play a crucial role in shielding plants from pathogens and environmental stressors. These natural products find widespread applications across various industries, including pharmaceutical, food, cosmetic, and healthcare. However, the quantity and quality of these compounds in plants can be influenced by factors such as genetics, morphology, plant age, and the seasonal and daily variations. The timing of harvest holds particular significance for medicinal and aromatic plants (MAPs) as their active compounds peak at a specific moment during the plant growth cycle. Determining the optimal harvest time is essential to ensure the plants meet their intended cultivation goal. In this review, we analyzed how developmental and external factors impact the qualitative and quantitative effectiveness of SMs in MAPs. We examined recent studies on the effects of environmental and developmental factors on SMs of MAPs, compiling relevant data for analysis. The results of this review demonstrate how these factors influence the quantity and quality of plant SMs, underscoring the importance of determining the optimal harvest time (known as the balsamic time) to maximize the utilization of these compounds. Our findings offer crucial insights into the factors affecting SMs, serving as a tool for quality control in MAPs production. Moreover, this review can be a valuable resource for researchers, farmers, and industrial users aiming to optimize plant growth and harvest timing for maximum yield. Overall, our review provides valuable information for devising effective strategies to produce high-quality MAPs products.

Essential oil composition and antioxidant activity of citron fruit (Citrus medica var. macrocarpa Risso.) peel as relation to ripening stages

Stages of maturity have decisive roles in determining the quality and quantity of essential oil (EO). In this regard, EO yield and composition and their antioxidant activity of citron fruit at four fruit maturity stages, i.e. the green mature (GM), intermediate (INT), yellow ripe (MAT) and overripe stage (OR) were studied. Obtained results showed significant effect of fruit maturity on most measured properties. The concentration of EO varied between 0.60 and 0.77% (v/w). The highest amount of limonene was 89.39% related to GM stage. The limonene decreased significantly during maturity. The highest antioxidant activity (76.08%) was measured at the OR stage, which is probably due to the presence of specific compounds in the EO and their synergistic effects. The phytochemical behaviors of this citron variety were different as relation to stages of fruit maturity. We can determine the ideal harvest period for maximum bioactive substances by recognizing these actions.

Herb and Flowers of Achillea millefolium subsp. millefolium L.: Structure and Histochemistry of Secretory Tissues and Phytochemistry of Essential Oils

Achillea millefolium L. herb and flowers have high biological activity; hence, they are used in medicine and cosmetics. The aim of this study was to perform morpho-anatomical analyses of the raw material, including secretory tissues, histochemical assays of the location of lipophilic compounds, and quantitative and qualitative analysis of essential oil (EO). Light and scanning electron microscopy techniques were used to analyse plant structures. The qualitative analyses of EO were carried out using gas chromatography-mass spectrometry (GC/MS). The results of this study showed the presence of exogenous secretory structures in the raw material, i.e., conical cells (papillae) on the adaxial surface of petal teeth and biseriate glandular trichomes on the surface flowers, bracts, stems, and leaves. Canal-shaped endogenous secretory tissue was observed in the stems and leaves. The histochemical assays revealed the presence of total, acidic, and neutral lipids as well as EO in the glandular trichome cells. Additionally, papillae located at the petal teeth contained neutral lipids. Sesquiterpenes were detected in the glandular trichomes and petal epidermis cells. The secretory canals in the stems were found to contain total and neutral lipids. The phytochemical assays demonstrated that the A. millefolium subsp. millefolium flowers contained over 2.5-fold higher amounts of EO (6.1 mL/kg) than the herb (2.4 mL/kg). The EO extracted from the flowers and herb had a similar dominant compounds: β-pinene, bornyl acetate, (E)-nerolidol, 1,8-cineole, borneol, sabinene, camphor, and α-pinene. Both EO samples had greater amounts of monoterpenes than sesquiterpenes. Higher amounts of oxygenated monoterpenes and oxygenated sesquiterpenoids were detected in the EO from the herb than from the flowers.

Phytochemical, Morphological, and Physiological Variation in Different Ajowan (Trachyspermum ammi L.) Populations as Affected by Salt Stress, Genotype × Year Interaction and Pollination System

In the present research, 28 populations of ajowan (Trachyspermum ammi L.) were evaluated for agro-morphological traits and essential oil yield in two consecutive years. Then, selected ajowan populations from these two years were used for further morphophysiological and biochemical studies under different salinity levels (control, 60, 90, and 120 mM NaCl). The main components of the oil were thymol (32.7-54.29%), γ-terpinene (21.71-32.81%), and p-cymene (18.74-26.16%). Salt stress caused an increase in essential oil content in the Esfahfo and Qazvin populations. The highest total phenolic and flavonoid contents were found in the Arak population grown in 60 mM NaCl (183.83 mg TAE g^-1 DW) and the Yazd population grown in 90 mM NaCl (5.94 mg QE g^-1 DW). Moreover, the Yazd population exhibited the strongest antioxidant activity based on DPPH (IC₅₀ = 1566 µg/mL) under 60 mM NaCl and the highest reducing power (0.69 nm) under 120 mM NaCl. The results revealed that low and moderate salt stress improves the phytochemicals of ajowan seeds, which are useful for pharmaceutical and food applications. In this research, some morphological traits, as well as essential oil yield, were evaluated in open pollinated versus self-pollinated plants. As a result, plant height, number of flowering branches, and crown diameter significantly decreased in some populations, while a significant increase was obtained for number of flowers per umbel and seed numbers per umbel. Finally, self-pollination of ajowan might provide new insights for further breeding programs to increase oil or thymol content in ajowan.

Chemometrics of the Composition and Antioxidant Capacity of Hyptis crenata Essential Oils from Brazil

Hyptis crenata (Pohl) ex Benth is used in traditional medicine as an analgesic to treat general pain. Six Hyptis crenata samples (Hc-1 to Hc-6) were collected in Pará state, Brazil. The leaf essential oils were obtained by hydrodistillation, and GC-MS and GC-FID were used to analyze their chemical compositions. The antioxidant capacity was measured in vitro using DPPH and carotene/linoleic acid assays. Chemometrics analysis (PCA, HCA, and clustered heat map) were used to identify the sample relationships between those collected in this study and those from the literature (Hc-7 to Hc-16) samples. According to the main chemical constituents identified in the samples described in this work and the literature, the sixteen samples were classified into ten groups. Group I was characterized by 1,8-cineole (31.0%), α-pinene (13.6%), (E)-caryophyllene (7.8%), and β-pinene (7.6%); and Group IV was characterized by 1,8-cineole (17.4-23.5%), α-pinene (15.7-23.5%), β-pinene (10.5-13.4%), and limonene (8.5-9.7%). Both groups are described for the first time. The total antioxidant capacity was expressed in Trolox Equivalent Antioxidant Capacity values (TEAC): TEAC of Hc-5 (551.9 mg.TE/g) and Hc-6 (475.1 mg.TE/g). In the β-carotene/linoleic acid assay, the highest inhibition was from Hc-2 (40.0%), Hc-6 (39.0%), and Hc-3 (29.4%).

Achillea moschata Wulfen: From Ethnobotany to Phytochemistry, Morphology, and Biological Activity

A multidisciplinary investigation on Achillea moschata Wulfen (Asteraceae) is outlined herein. This work, part of the European Interreg Italy-Switzerland B-ICE project, originated from an ethnobotanical survey performed in Chiesa in Valmalenco (Sondrio, Lombardy, Northern Italy) in 2019-2021 which highlighted this species' relevance of use in folk medicine to treat gastrointestinal diseases. In addition, this contribution included analyses of the: (a) phytochemical profile of the aqueous and methanolic extracts of the dried flower heads using LC-MS/MS; (b) morpho-anatomy and histochemistry of the vegetative and reproductive organs through Light, Fluorescence, and Scanning Electron Microscopy; (c) biological activity of the aqueous extract concerning the antioxidant and anti-inflammatory potential through cell-based in vitro models. A total of 31 compounds (5 phenolic acids, 13 flavonols, and 13 flavones) were detected, 28 of which included in both extracts. Covering and secreting trichomes were observed: the biseriate 10-celled glandular trichomes prevailing on the inflorescences represented the main sites of synthesis of the polyphenols and flavonoids detected in the extracts, along with volatile terpenoids. Finally, significant antioxidant and anti-inflammatory activities of the aqueous extract were documented, even at very low concentrations; for the first time, the in vitro tests allowed us to formulate hypotheses about the mechanism of action. This work brings an element of novelty due to the faithful reproduction of the traditional aqueous preparation and the combination of phytochemical and micromorphological research approaches.

Diversity and Distribution Patterns of Endemic Medicinal and Aromatic Plants of Iran: Implications for Conservation and Habitat Management

Iran, with its unique climatic and topographic conditions, is home to about 8200 species of vascular plants. Approximately 2300 of the 8200 species are popularly characterized as medicinal or aromatic. Here, we compile information about the endemic medicinal and aromatic plants (MAPs) of Iran and map their distributions. Our survey found 180 endemic species of MAPs, belonging to 10 families and 30 genera. The majority of species are found in Lamiaceae, Fabaceae, and Apiaceae, with 86, 30, and 18 species, respectively. Approximately 70% of these plants have been recorded in the 10 provinces of Esfahan, Kerman, Fars, Tehran, Chaharmahal va Bakhtiari, East Azarbaijan, Lorestan, West Azarbaijan, Hamadan, and Mazandaran. These provinces are located in the Iran-o-Turanian region, one of the three major phytogeographic regions in Iran, which covers five areas of endemism (i.e., Azarbaijan, Zagros, Kopet Dagh-Khorassan, Alborz, and Central Alborz). So, Iran-o-Turanian region is the main center of diversity for the Iranian endemic MAPs. The north, center and western parts of Iran are rich in MAPs and could be considered as the dominant biodiversity hotspots of Iran more seemingly due to the diverse climatic and geographic assortment which generates the highest frequency and distribution of MAPs. Many of these MAPs are at the edge of extinction due to the unwise, unscientific harvesting and/or global climate change. Therefore, there is an urgent need to conserve and propagate some of these important MAPs to save them from extinction and also to ensure the availability of raw materials for their use and future research into their efficacy. Furthermore, identifying the areas of endemism (AEs) is an essential part of ongoing regional conservation management programs in Iran and worldwide.

Profiles of Essential Oils and Correlations with Phenolic Acids and Primary Metabolites in Flower Buds of Magnolia heptapeta and Magnolia denudata var. purpurascens

Magnolia flower buds are a source of herbal medicines with various active compounds. In this study, differences in the distribution and abundance of major essential oils, phenolic acids, and primary metabolites between white flower buds of Magnolia heptapeta and violet flower buds of Magnolia denudata var. purpurascens were characterised. A multivariate analysis revealed clear separation between the white and violet flower buds with respect to primary and secondary metabolites closely related to metabolic systems. White flower buds contained large amounts of monoterpene hydrocarbons (MH), phenolic acids, aromatic amino acids, and monosaccharides, related to the production of isoprenes, as MH precursors, and the activity of MH synthase. However, concentrations of β-myrcene, a major MH compound, were higher in violet flower buds than in white flower buds, possibly due to higher threonine levels and low acidic conditions induced by comparatively low levels of some organic acids. Moreover, levels of stress-related metabolites, such as oxygenated monoterpenes, proline, and glutamic acid, were higher in violet flower buds than in white flower buds. Our results support the feasibility of metabolic profiling for the identification of phytochemical differences and improve our understanding of the correlated biological pathways for primary and secondary metabolites.

The Mastic Tree (Pistacia lentiscus L.) Leaves as Source of BACs: Effect of Growing Location, Phenological Stage and Extraction Solvent on Phenolic Content

RESEARCH BACKGROUND

Mastic tree (Pistacia lentiscus L.) of the Anacardiaceae family is an evergreen shrub from Mediterranean countries where it is used in traditional medicine. Analysis of P. lentiscus leaf, stem, fruit and root extracts showed high concentrations of principal groups of secondary metabolites (flavonoids, phenolic acids and tannins), suggesting the plant possesses great biological potential. Therefore, the aim of this research is to evaluate the impact of environmental parameters and the extraction solvent type on the concentration of phenols in mastic tree leaf extracts grown at four different locations along the Adriatic coast (Barbariga, Lun, Hvar and Vela Luka) during three phenological stages (early flowering, early fruiting and late fruiting).

EXPERIMENTAL APPROACH

Since mastic tree plant has phenolic compounds with different structures and chemical properties, ethanolic and methanolic leaf extracts were analysed using high-performance liquid chromatography (HPLC) coupled with UV/Vis PDA detector. Phenolic compounds were identified by comparing the retention times and spectral data with those of standards at 280 and 340 nm.

RESULTS AND CONCLUSIONS

In all samples, phenolic acids and flavonol glycosides were quantified, while catechin was quantified only in methanolic extracts. The 5-O-galloylquinic acid was determined as a predominant phenolic compound in all samples followed by monogalloyl glucose, 3,5-di-O-galloylquinic acid, 3,4,5-tri-O-galloylquinic acid and gallic acid, respectively. Myricetin-3-O-rhamnoside was found to be the predominant flavonol glycoside followed by myricetin-3-O-glucoside, myricetin-3-O-glucuronide, quercetin-3-O-rhamnoside and derivative of flavonol glycoside. The mass concentration of these compounds significantly varied during different phenological stages, at different growing locations and used extraction solvents. The highest phenolic mass concentration was determined in the samples harvested at Hvar growing location and extracted in 80% methanol. The highest total phenolic acid mass concentration was obtained in the samples harvested during the flowering phenological stage and the highest total flavonoid mass concentration in the samples harvested during the early fruiting stage.

NOVELTY AND SCIENTIFIC CONTRIBUTION

The obtained data provide a better understanding of the P. lentiscus species phenolic concentration, which can lead to further investigations regarding the valorisation of mastic tree leaves as pharmaceutical products or as food products with added value.

The effect of drought stress on polyphenolic compounds and expression of flavonoid biosynthesis related genes in Achillea pachycephala Rech.f

This study investigated the effect of drought stress on the amount of phenolic and flavonoid compounds as well as H₂O₂ and malondialdehyde (MDA) in Achillea pachycephala. The expression patterns of the key genes and their molecular mechanisms in the phenylpropanoid pathway (PAL, CHS, CHI, F3H, F3'H, F3'5'H, FLS) were also assessed during drought stress using quantitative real-time polymerase chain reaction (qRT-PCR). The samples were harvested at 0, 7, 14, 21 and 28 days after exposure to drought stress. High-performance liquid chromatography (HPLC) analysis was performed to determine the changes of phenolic and flavonoid compounds - chlorogenic acid, caffeic acid, rutin, luteolin-7-O-glycoside, 1,3-dicaffeoylquinic acid, apigenin-7-O-glycoside, luteolin, apigenin and kaempferol - during stress conditions. Concentrations of most of the compounds increased with increasing drought stress duration. Most of the phenolic acids continued to accumulate with increasing duration of stress, while flavonoids dramatically decreased at day 28 of stress. Chlorogenic acid was the most abundant phenolic acid (4.97 mg/100 g dry weight [DW]) at the beginning of the experiment, while it decreased at day 7 and increased again at day 21. However, different trends were observed for some flavonoids, such as luteolin and apigenin. At the beginning of stress treatment, high accumulation of free radicals (H₂O₂) and lipid peroxidation (MDA) led to elevated expression of most of the flavonoid genes. MDA increased from 22.66 to 43.28 μmol g^-1 DW at day 28. CHS gene expression was elevated at day 7, while chi gene expression remained unchanged. At the end of the stress period, most of the flavonoid concentrations and expression of the relevant genes also increased. The results can facilitate selection of appropriate drought conditions to obtain the highest levels of flavonoids such as luteolin and apigenin and phenolic compounds such as chlorogenic acid for improved health benefits.