In vitro and in vivo inhibition of HCT116 cells by essential oils from bark and leaves of Virola surinamensis (Rol. ex Rottb.) Warb. (Myristicaceae)

In vitro evaluation of cytotoxic potential of essential oil extracted from leaves of Croton heliotropiifolius Kunth in human tumor cells

Croton heliotropiifolius Kunth, popularly known as "velame," is a shrub that resides in northeastern Brazil. The essential oil of C. heliotropiifolius contains high concentrations of volatile compounds in the leaves and is widely used in folk medicine for many purposes as an antiseptic, analgesic, sedative, and anti-inflammatory agent. Due to the apparent limited amount of information, the aim of this study was to determine the cytotoxic potential of essential oil extracted from leaves of C. heliotropiifolius, utilizing different human cancer cell lines (HL-60, leukemia; HCT-116, colon; MDA-MB435, melanoma; SF295, glioblastoma) and comparison to murine fibroblast L929 cell line. The chemical characterization of the essential oil revealed the presence of large amounts of monoterpenes and sesquiterpenes, the majority of which were aristolene (22.43%), germacrene D (11.38%), ɣ-terpinene (10.85%), and limonene (10.21%). The essential oil exerted significant cytotoxicity on all cancer cells, with low activity on murine L929 fibroblasts, independent of disruption of cell membranes evidenced by absence of hemolytic activity. The cytotoxicity identified was associated with oxidative stress, which culminated in mitochondrial respiration dysfunction and direct or indirect DNA damage (strand breaks and oxidative damage), triggering cell death via apoptosis. Our findings suggest that extracts of essential oil of C. Heliotropiifolius may be considered as agents to be used therapeutically in treatment of certain cancers.

Essential Oils: Chemistry and Pharmacological Activities

In this review, we provide an overview of the current understanding of the main mechanisms of pharmacological action of essential oils and their components in various biological systems. A brief introduction on essential oil chemistry is presented to better understand the relationship of chemical aspects with the bioactivity of these products. Next, the antioxidant, anti-inflammatory, antitumor, and antimicrobial activities are discussed. The mechanisms of action against various types of viruses are also addressed. The data show that the multiplicity of pharmacological properties of essential oils occurs due to the chemical diversity in their composition and their ability to interfere with biological processes at cellular and multicellular levels via interaction with various biological targets. Therefore, these natural products can be a promising source for the development of new drugs.

Production, Function, and Applications of the Sesquiterpenes Valencene and Nootkatone: a Comprehensive Review

Valencene and nootkatone, two sesquiterpenes, extracted from natural sources, have great market potential with diverse applications. This paper aims to comprehensively review the recent advances in valencene and nootkatone, including source, production, physicochemical and biological properties, safety and pharmacokinetics evaluation, potential uses, and their industrial applications as well as future research directions. Microbial biosynthesis offers a promising alternative approach for sustainable production of valencene and nootkatone. Both compounds exert various beneficial activities, including antimicrobial, insecticidal, antioxidant, anti-inflammatory, anticancer, cardioprotective, neuroprotective, hepatoprotective, and nephroprotective and other activities. However, most of the studies are performed in animals and in vitro, making it difficult to give a conclusive description about their health benefits and extend their application. Hence, more attention should be paid to in vivo and long-term clinical studies in the future. Moreover, valencene and nootkatone are considered safe for consumption and show great promise in the applications of food, cosmetic, pharmaceutical, chemical, and agricultural industries.

In Vitro Antibacterial Activity and in Silico Analysis of the Bioactivity of Major Compounds Obtained from the Essential Oil of Virola surinamensis Warb (Myristicaceae)

Essential oils are well known for their antimicrobial activity and they are used as an effective food preservative. Virola is one of the five genera of Myristicaceae and this genus is native to the American continent, especially in neotropical regions. The largest number of species of this genus is found in the Amazon region and the most important species include Virola surinamensis Warb. and Virola sebifera Aubl. In the present study, we describe the chemical composition of the essential oil of the V. surinamensis obtained at two different periods of the day in two seasons (rainy and dry), as well as their antimicrobial activity against pathogenic bacterial strains of Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus. In addition, we investigated, using in silico tools, the antimicrobial activity of the major chemical compounds present in the essential oil of V. surinamensis. The samples collected at different seasons and times showed a similar chemical profile, characterized by the major constituents α-pinene (>33%) and β-pinene (>13%). The essential oil of V. surinamensis showed an interesting antibacterial activity, exhibiting low inhibitory concentrations against the tested bacterial species. The computational investigation indicated that limonene, myrcene, and β-pinene could be related to the antibacterial activity against the tested pathogenic bacterial strains. Our results shed light on the possible constituents of essential oil that could be related to its activity against bacterial species and might be useful for further experimental tests that aim to discover new potential antibacterial agents for food preservation.

Essential Oil of the Plants Growing in the Brazilian Amazon: Chemical Composition, Antioxidants, and Biological Applications

Essential oils are biosynthesized in the secondary metabolism of plants, and in their chemical composition, they can be identified different classes of compounds with potential antioxidant and biological applications. Over the years in the Amazon, several species of aromatic plants were discovered and used in traditional medicine. The literature has shown that essential oils extracted from amazon species have several biological activities, such as antioxidant, antibacterial, antifungal, cytotoxic, and antiprotozoal activities. These activities are related to the diversified chemical composition found in essential oils that, by synergism, favors its pharmacological action. In light of this vital importance, this study aimed at performing a review of the literature with particular emphasis on the chemical composition and biological activities in studies conducted with species collected in the Amazon, taking into consideration in particular the last 10 years of collection and research.

Essential Oil from Bark of Aniba parviflora (Meisn.) Mez (Lauraceae) Reduces HepG2 Cell Proliferation and Inhibits Tumor Development in a Xenograft Model

Aniba parviflora (Meisn.) Mez (Lauraceae) is an aromatic plant of the Amazon rainforest, which has a tremendous commercial value in the perfumery industry; it is popularly used as flavoring sachets and aromatic baths. In Brazilian folk medicine, A. parviflora is used to treat victims of snakebites. Herein, we analyzed the chemical composition of A. parviflora bark essential oil (EO) and its effect on the growth of human hepatocellular carcinoma HepG2 cells in vitro and in vivo. EO was obtained by hydrodistillation and characterized by GC-MS and GC-FID. The main constituents of EO were linalool (16.3±3.15), α-humulene (14.5±2.41 %), δ-cadinene (10.2±1.09 %), α-copaene (9.51±1.12 %) and germacrene B (7.58±2.15 %). Initially, EO's cytotoxic effect was evaluated against five cancer cell lines (HepG2, MCF-7, HCT116, HL-60 and B16-F10) and one non-cancerous one (MRC-5), using the Alamar blue method after 72 h of treatment. The calculated IC₅₀ values were 9.05, 22.04, >50, 15.36, 17.57, and 30.46 μg/mL, respectively. The best selectivity was for HepG2 cells with a selective index of 3.4. DNA Fragmentation and cell cycle distribution were quantified in HepG2 cells by flow cytometry after a treatment period of 24 and 48 h. The effect of EO on tumor development in vivo was evaluated in a xenograft model using C.B-17 SCID mice engrafted with HepG2 cells. In vivo tumor growth inhibition of HepG2 xenograft at the doses of 40 and 80 mg/kg were 12.1 and 62.4 %, respectively.