Quali–Quantitative Characterization of Volatile and Non-Volatile Compounds in Protium heptaphyllum (Aubl.) Marchand Resin by GC–MS Validated Method, GC–FID and HPLC–HRMS2

Protium heptaphyllum (Aubl.) Marchand (PH) trees are endemic to the tropical region of South America, mostly Brazil. Antibacterial, antinociceptive, anti-inflammatory, anxiolytic, antidepressant and anti-hyperlipidemic/anti-hypercholesterolemic effects were reported for its resinous exudate Protiumheptaphyllum resin (PHR). This work aims to provide a qualitative and quantitative consistent chemical profiling of the major constituents of this resin and two extracts enriched in acid (acidic triterpene concentrated extract, ATCE) and neutral triterpenes (α and β-amyrin concentrated extract, AMCE). GC–MS/GC–FID was used for volatile terpene fraction, a validated GC–MS method was developed for quantification of neutral α and β-amyrin and HPLC–APCI HRMS2 was used for acidic triterpenes analysis. The chemical investigation reported 29 molecules, including 14 volatile terpenes, 6 neutral triterpenes and 11 acid triterpenes. The most abundant compounds were α-amyrin (251.28 g kg−1, 123.98 g kg−1 and 556.82 g kg−1 in PHR, ATCE and AMCE, respectively), β-amyrin (172.66 g kg−1, 95.39 g kg−1 and 385.58 g kg−1 in PHR, ATCE and AMCE, respectively), 3-oxo-tirucalla-7,24-dien-21-oic acid (80.64 g kg−1, 157.10 g kg−1 and 15.31 g kg−1 in PHR, ATCE and AMCE, respectively) and 3α-hydroxy-tirucalla-8,24-dien-21-oic acid (77.71 g kg−1, 130.40 g kg−1 and 11.64 g kg−1 in PHR, ATCE and AMCE, respectively). Results showed specific enrichment of acidic and neutral triterpenoids in the two respective extracts.

β-Caryophyllene: A Single Volatile Component of n-Hexane Extract of Dracaena cinnabari Resin

The pure Soqotri resin of Dracaena cinnabari Balf.f. (Dracaenaceae) has no volatile smell due to its low content of volatile constituents. Although it is insoluble in n-Hexane, we found that the resin, when suspended in n-Hexane within five days at 5 °C, led to the extraction of a small portion of a single volatile liquid constituent, which was identified by GC-MS as sesquiterpene β-caryophyllene. This method of extracting the volatile constituents using hexane under cooling is very suitable for resins of the Dracaena species because these resins usually contain very few volatile terpenes and/or non-terpenes, and they may contain only one volatile terpene per resin as this study result. β-Caryophyllene was identified and separated for the first time from the Soqotri standard resin of Dracaena cinnabari. Therefore, β-caryophyllene, as a new chemical property, can support to evaluate the purity of the Soqotri resin. Moreover, a big mass of D. cinnabari resin can yield concentrated β-caryophyllene as a liquid extract for further pharmaceutical and nutraceutical applications.

Changes in the component composition of Thymus vulgaris L. essential oil depending on the method of distillation

The objective of the work was to identify changes in the amount and component composition of essential oil in the raw material of Thymus vulgaris L. (common thyme) when using different distillation methods. The object of the study was two samples of thyme-thymol and linalool chemotypes. Essential oil was obtained from freshly harvested raw materials (inflorescences in the mass flowering phase) by the following methods: hydrodistillation method on Clevenger apparatuses and steam extraction method on the installation for the production of essential oil and intermediates "Alpha-Ether Compact". The component composition of volatile substances was determined by gas chromatography-mass spectrometry. In the composition of volatile compounds of plant essential oil, 29 components for the thymol chemotype were identified, and 18 components for the linalool chemotype were identified. It was found that the use of the hydrodistillation method allows extracting 40-50% more essential oil. Significant differences were found between the mass fraction of extracted essential oil components using different methods and the content of the mass fraction of essential oil in the raw material of Th. vulgaris and found that depending on the method of obtaining essential oil, the proportion of volatile terpene hydrocarbons and oxygen-containing compounds changes. The method of steam distillation leads to a deterioration of the component composition of the essential oil, reducing the content of the dominant components of both chemotypes (thymol and linalool).

Isolation and Investigation of Potential Non-Saccharomyces Yeasts to Improve the Volatile Terpene Compounds in Korean Muscat Bailey A Wine

The Muscat Bailey A (MBA) grape, one of the most prominent grape cultivars in Korea, contains considerable amounts of monoterpene alcohols that have very low odor thresholds and significantly affect the perception of wine aroma. To develop a potential wine starter for Korean MBA wine, nine types of non-Saccharomyces yeasts were isolated from various Korean food materials, including nuruk, Sémillon grapes, persimmons, and Muscat Bailey A grapes, and their physiological, biochemical, and enzymatic properties were investigated and compared to the conventional wine fermentation strain, Saccharomyces cerevisiae W-3. Through API ZYM analysis, Wickerhamomyces anomalus JK04, Hanseniaspora vineae S7, Hanseniaspora uvarum S8, Candida railenensis S18, and Metschnikowia pulcherrima S36 were revealed to have β-glucosidase activity. Their activities were quantified by culturing in growth medium composed of different carbon sources: 2% glucose, 1% glucose + 1% cellobiose, and 2% cellobiose. W. anomalus JK04 and M. pulcherrima S36 showed the highest β-glucosidase activities in all growth media; thus, they were selected and utilized for MBA wine fermentation. MBA wines co-fermented with non-Saccharomyces yeasts (W. anomalus JK04 or M. pulcherrima S36) and S. cerevisiae W-3 showed significantly increased levels of linalool, citronellol, and geraniol compared to MBA wine fermented with S. cerevisiae W-3 (control). In a sensory evaluation, the flavor, taste, and overall preference scores of the co-fermented wines were higher than those for the control wine, suggesting that W. anomalus JK04 and M. pulcherrima S36 are favorable wine starters for improving Korean MBA wine quality.

Chemical entrapment and killing of insects by bacteria

Actinobacteria such as the filamentous streptomycetes are widely known for their ability to produce specialized metabolites that include antibacterial and antifungal compounds. In addition, a growing body of work demonstrates that many insects harbour actinobacteria on their bodies and in their nests. The result of these mutualistic relationships is the protection of their offspring or food sources by virtue of the bacterially encoded specialized metabolites. However, some actinobacteria produce molecules that are toxic to insects and the relevance of this toxicity in nature is unknown. We have explored interactions between streptomycetes and the fruit fly Drosophila. We find that many streptomycetes produce specialized metabolites that have potent larvicidal effects against the fly. Larvae that ingest spores of the species that produce these toxic molecules die as a result. Strikingly, the mechanism of toxicity is specific to the bacterium’s chemical arsenal: cosmomycin D producing cells induce a relatively slow-acting cell death-like response in the larval digestive tract and avermectin producing cells induce rapid onset, whole-body paralysis. We further show that fruit flies are attracted to the volatile terpene 2-methylisoborneol that is produced by most streptomycetes. This interaction can influence their food choice and egg-laying destination such that they preferentially deposit their eggs on contaminated food sources. As a result, the larvae that hatch in these toxic environments are subsequently killed. This phenomena of terpene-mediated attraction and specialized metabolite toxicity must pose a significant risk to insects in nature.

Diversity and function of terpene synthases in the production of carrot aroma and flavor compounds

Carrot (Daucus carota L.) is an important root vegetable crop with high nutritional value, characteristic flavor, and benefits to human health. D. carota tissues produce an essential oil that is rich in volatile terpenes and plays a major role in carrot aroma and flavor. Although terpene composition represents a critical quality attribute of carrots, little is known about the biosynthesis of terpenes in this crop. Here, we functionally characterized 19 terpene synthase (TPS) genes in an orange carrot (genotype DH1) and compared tissue-specific expression profiles and in vitro products of their recombinant proteins with volatile terpene profiles from DH1 and four other colored carrot genotypes. In addition to the previously reported (E)-β-caryophyllene synthase (DcTPS01), we biochemically characterized several TPS proteins with direct correlations to major compounds of carrot flavor and aroma including germacrene D (DcTPS7/11), γ-terpinene (DcTPS30) and α-terpinolene (DcTPS03). Random forest analysis of volatiles from colored carrot cultivars identified nine terpenes that were clearly distinct among the cultivars and likely contribute to differences in sensory quality. Correlation of TPS gene expression and terpene metabolite profiles supported the function of DcTPS01 and DcTPS03 in these cultivars. Our findings provide a roadmap for future breeding efforts to enhance carrot flavor and aroma.

Ethnobotany and Phytochemistry of the genus Eremostachys Bunge

In this review, the species from the genus Eremostachys Bunge are described and explored from different standpoints. In particular, the main attention is focused on phytochemistry also with reference to the biogenesis of the most important class of chemotaxonomic marker, the iridoids, and their co-occurrence with volatile terpene components of essential oils which own the same biogenetic precursors. The ethnopharmacological implications of the plants belonging to this genus are also reported in detail. Nevertheless, a few morphological and botanical details of Eremostachys are also presented, as well as some topics about its chemotaxonomy and pure pharmacology. Based on the data reported in the literature, different species of the genus Eremostachys show important and interesting peculiarities under all these aspects that are extensively discussed and commented.