Chemical characterization of essential oils from Drimys angustifolia miers (Winteraceae) and antibacterial activity of their major compounds

Cytotoxic Activity, Topoisomerase I Inhibition and In Silico Studies of New Sesquiterpene-aryl Ester Derivatives of (-) Drimenol

In this study, we aimed to evaluate two sets of sesquiterpene-aryl derivatives linked by an ester bond, their cytotoxic activities, and their capacity to activate caspases 3/7 and inhibit human topoisomerase I (TOP1). A total of 13 compounds were synthesized from the natural sesquiterpene (-)-drimenol and their cytotoxic activity was evaluated in vitro against three cancer cell lines: PC-3 (prostate cancer), HT-29 (colon cancer), MCF-7 (breast cancer), and an immortalized non-tumoral cell line (MCF-10). From the results, it was observed that 6a was the most promising compound due to its cytotoxic effect on three cancer cell lines and its selectivity, 6a was 100-fold more selective than 5-FU in MCF-7 and 20-fold in PC-3. It was observed that 6a also induced apoptosis by caspases 3/7 activity using a Capsase-Glo-3/7 assay kit and inhibited TOP1. A possible binding mode of 6a in a complex with TOP1-DNA was proposed by docking and molecular dynamics studies. In addition, 6a was predicted to have a good pharmacokinetic profile for oral administration. Therefore, through this study, it was demonstrated that the drimane scaffold should be considered in the search of new antitumoral agents.

Phytochemical composition, bioactive properties, and toxicological profile of Tetrapleura tetraptera

The use of medicinal plants has gained renewed wide popularity in Africa, Asia, and most parts of the world because of the decreasing efficacy of synthetic drugs. Thus, natural products serve as a potent source of alternative remedy. Tetrapleura tetraptera is a medicinal plant with cultural and traditional significance in West Africa. In addition to the plant being commonly used as a spice in the preparation of traditional spicy food for postpartum care it is also widely used to constitute herbal concoctions and decoctions for treatment of diseases. This review aimed to provide an up-to-date information on the ethnomedicinal uses, pharmacological activities and phytoconstituents of T. tetraptera. Preclinical studies regarding the plant's toxicity profile were also reviewed. For this updated review, literature search was done on PubMed, Science Direct, Wiley, and Google Scholar databases using the relevant keywords. The review used a total of 106 papers that met the inclusion criteria from January 1989 - February 2022 and summarised the bioactivities that have been reported for the rich phytoconstituents of T. tetraptera studied using various chemical methods. Considering the huge report, the review focused on the antimicrobial and antiinflammatory activities of the plant extracts and isolated compounds. Aridan, aridanin and several bioactive compounds of T. tetraptera have shown pharmacological activities though their mechanisms of action are yet to be fully understood. This study also highlighted the influence of plant parts and extraction solvents on its biological activities. It also presented data on the toxicological profile of the plant extracts using different models. From cultural uses to modern pharmacological research the bioactive compounds of T. tetraptera have proved effective in infectious disease management. We hope that this paper provided a robust summary of the biological activities and toxicological profile of T. tetraptera, thus calling for more research into the pharmacological and pharmacokinetic activities of natural products to help combat the growing threat of drug resistance and provide guidelines for their ethnomedicinal uses.

Essential oils from leaves of Vernonanthura montevidensis (Spreng.) H. Rob.: chemical profile and antimollicute potential

Aiming to valorise the Atlantic Rainforest biodiversity in Santa Catarina, the chemical characterisation of the essential oils (EOs) from leaves of Vernonanthura montevidensis (Spreng.) H. Rob. is described for the first time. Fresh leaves collected in the year 2014 and 2015, were submitted to hydrodistillation to give pale blue EOs in yields of 0.21 and 0.19%, respectively. The EOs were characterised by GC-MS and GC-FID semi- and quantitative methods. The monoterpene β-pinene was the major constituent in both samples reaching a maximum of 26.3%. The monoterpene α-pinene and the sesquiterpene β-caryophyllene, were also among the major constituents in both samples. By means of the extracted ion chromatogram procedure, it was possible to detect chamazulene, which was associated with the pale blue colour of the essential oils. In the in vitro antimollicute assays, the essential oil was moderately active against Mycoplasma genitalium and M. pneumoniae with MIC values of 250 µg mL^-1.

New Insights into the Chemical Composition, Pro-Inflammatory Cytokine Inhibition Profile of Davana (Artemisia pallens Wall. ex DC.) Essential Oil and cis-Davanone in Primary Macrophage Cells

Artemisia pallens Wall. ex DC., popularly known as davana, has gained considerable attention because of its unique fragrance, high economic value, and pharmacological properties. The compositional complexity of davana essential oil (DO) has been a challenge for quality control. In this study, the chemical profile of DO was developed using polarity-based fractionation and a combination of gas chromatographic (GC-FID), hyphenated chromatographic (GC/MS), and spectroscopic (Fourier-Transform Infra-Red, 1D, 2D-Nuclear Magnetic Resonance) techniques. The analysis led to the identification of ninety-nine compounds. Major components of the DO were cis-davanone (D3, 53.0 %), bicyclogermacrene (6.9 %), trans-ethyl cinnamate (4.9 %), davana ether isomer (3.4 %), spathulenol (2.8 %), cis-hydroxy davanone (2.4 %), and trans-davanone (2.1 %). The study led to identifying several co-eluting novel minor components, which could help determine the authenticity of DO. The rigorous column-chromatography led to the isolation of five compounds. Among these, bicyclogermacrene, trans-ethyl cinnamate, and spathulenol were isolated and characterized by spectroscopic methods for the first time from DO. Pharmacological profile revealed that the treatment of DO and D3 inhibited the production of pro-inflammatory cytokines (TNF-α, IL-6) induced by lipopolysaccharide (LPS) in primary macrophages without any cytotoxic effect after administration of their effective concentrations. The result of this study indicates the suitability of DO and D3 for further investigation for the treatment of chronic skin inflammatory conditions.

Ambrafuran (AmbroxTM) Synthesis from Natural Plant Product Precursors

Ambergris, an excretion product of sperm whales, has been a valued agent in the formulation of perfumes. The composition of ambergris consists of two major components: 40–46% cholestanol type steroids and approximately 25–45% of a triterpenoid known as ambrein. Ambergris undergoes oxidative decomposition in the environment to result in odorous compounds, such as ambraoxide, methylambraoxide, and ambracetal. Its oxidized form, ambrafuran (IUPAC name: 3a,6,6,9a-tetramethyl-2,4,5,5a,7,8,9,9b-octahydro-1H-benzo[e][1]benzofuran), is a terpene furan with a pleasant odor and unique olfactive and fixative properties. The current state of the fragrance industry uses ambrafuran materials entirely from synthetic or semisynthetic sources. However, natural compounds with the potential to be converted to ambergris-like odorants have been extracted from several different types of plants. Here we review plant terpenoids suitable as starting materials for the semisyntheses of ambrafuran or intermediates, such as ambradiol, that can be used in biocatalytic transformations to yield ambrafuran.

Antimicrobial Potential of Essential Oils from Cerrado Plants against Multidrug-Resistant Foodborne Microorganisms

Foodborne pathogens are a real public health concern in an escalating antimicrobial resistance scenario. Natural products represent a promising source of bioactive molecules, and essential oils have attracted much attention due to their myriad of biological properties, including antibacterial activities. In this context, essential oils obtained from the leaves of Chromolaena squalida, Campomanesia sessiliflora, Myrsine guianensis, Matayba guianensis, Siparuna guianensis, Ocotea minarum and Endlicheria paniculata—species from the Cerrado biome of Midwest Brazil—were extracted and evaluated for their antibacterial activity against a panel of four standard and three clinical multidrug−resistant bacterial strains. All tested oils showed moderate to good activity against at least four bacterial strains, including Salmonella Typhi and oxacillin−resistant Staphylococcus. The essential oils from C. squalida, C. sessiliflora, My. guianensis and Ma. guianensis showed strong inhibition of clinical Staphylococcus strains, which cause bovine mastitis and are related to milk−borne diseases. Their chemical profiles were investigated by gas chromatography coupled to mass spectrometry (GC/MS), which revealed a predominance of mono− and sesquiterpene hydrocarbons, some of which with well−known antimicrobial properties. The essential oil from Cerrado plants proved active against resistant Gram−positive and Gram−negative bacteria, revealing their potentialities for the development of new alternative agents to prevent the spreading of resistant bacterial contamination.

Chemical Compositions, Mosquito Larvicidal and Antimicrobial Activities of Leaf Essential Oils of Eleven Species of Lauraceae from Vietnam

The Lauraceae is a family rich in aromatic and medicinal plants. Likewise, essential oils derived from members of this family have demonstrated a myriad of biological activities. It is hypothesized that members of the Lauraceae from Vietnam will yield essential oils that may be useful in controlling mosquito populations and treating microbial infections. In this work, the leaf essential oils of eleven species of Lauraceae (Beilschmiedia erythrophloia, B. robusta, B. yunnanensis, Cryptocarya concinna, C. impressa, C. infectoria, Litsea viridis, Machilus balansa, M. grandifolia, Neolitsea ellipsoidea, and Phoebe angustifolia) have been obtained by hydrodistillation and the chemical compositions analyzed by gas chromatography – mass spectrometry (GC-MS) and gas chromatography with flame ionization detection (GC-FID). The essential oils were screened for larvicidal activity against Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus, and for antimicrobial activity against Enterococcus faecalis, Staphylococcus aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica, and Candida albicans. The leaf essential oil of N. ellipsoidea, rich in (E)-β-ocimene (87.6%), showed excellent larvicidal activity against Ae. aegypti with a 24 h LC₅₀ of 6.59 μg/mL. The leaf essential oil of C. infectoria, dominated by germacrene D (55.5%) and bicyclogermacrene (11.4%), exhibited remarkable larvicidal activity against Cx. quinquefasciatus (48 h LC₅₀ = 0.40 μg/mL). N. ellipsoidea leaf essential oil also demonstrated notable antibacterial activity against E. faecalis and B. cereus with minimum inhibitory concentration (MIC) values of 16 μg/mL, while the leaf essential oil of C. impressa showed excellent anticandidal with an MIC of 16 μg/mL. Leaf essential oils from the Lauraceae should be considered for utilization as alternative agents for controlling mosquito populations and as antimicrobial agents.

Kazakh Ziziphora Species as Sources of Bioactive Substances

Ziziphora species represent the prototypical example of the Lamiaceae family. The phytochemicals present in Ziziphora include monoterpenic essential oils, triterpenes and phenolic substances belonging to the flavonoids. In Kazakh traditional medicine, Ziziphora species possess several medicinal uses. In particular, Z. bungeana Lam. and Z. clinopodioides Lam. are used for the treatment of illnesses related to the cardiovascular system or to combat different infections. Unfortunately, the majority of the information about the complex Ziziphora species is only available in Russian and Chinese language, therefore, we decided gather all available information on Kazakhstan Ziziphora, namely its content compounds, medicinal uses and published patents, to draw the attention of scientists to this very interesting plant with high medicinal potential.

Antifreeze proteins in naturally cold acclimated leaves of Drimys angustifolia, Senecio icoglossus, and Eucalyptus ssp

Summary Antifreeze proteins (AFPs) present in plants may inhibit ice recrystallization even at low concentrations, and show potential application to many frozen foods. This study evaluated the presence of antifreeze proteins in naturally cold acclimated and non-acclimated leaves of Drimys angustifolia, Senecio icoglossus and Eucalyptus ssp. No proteins were detected in apoplastic extracts of Eucalyptus ssp. Extracts of cold acclimated and non-acclimated S. icoglossus showed protein concentrations of 42.89 and 17.76 µg mL-1, both with bands between 25 and 37 kDa in the SDS-PAGE. However, they did not inhibit recrystallization. The extract of cold acclimated D. angustifolia contained a protein concentration of 95.17 µg mL-1, almost five times higher than the extract of non-acclimated D. angustifolia. In the extract of cold acclimated D. angustifolia, there was presence of ice recrystallization inhibitors. This extract showed a protein band just below 37 kDa and another more intense band between 20 and 25 kDa. It is the first time that the presence of antifreeze proteins in this species is being described.

Volatile Constituents of the Leaves of Aniba hostmanniana (Lauraceae) and their Antibacterial Activities

The essential oil of Aniba hostmanniana (Nees) Mez, family Lauraceae, was obtained from fresh leaves by hydrodistillation. The chemical composition of the oil was assessed using gas chromatography with mass spectrometric detection (GC-MS). The antimicrobial activity of the essential oil was tested against Gram-negative bacteria ( Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia) and the Gram-positive bacterium Staphylococcus aureus. GC-MS analysis revealed the presence of 35 compounds in the essential oil, the predominant ones being benzyl benzoate (29.3%), δ-cadinene (12%), β-caryophyllene (10.5%), bicyclogermacrene (5.9%), and α-copaene (3.9%). The oil showed activity against most of the bacterial strains studied.