Menthol Enhances an Antiproliferative Activity of 1alpha,25-Dihydroxyvitamin D(3) in LNCaP Cells

The powerful potential of amino acid menthyl esters for anti-inflammatory and anti-obesity therapies

Our newly developed menthyl esters of valine and isoleucine exhibit anti-inflammatory properties beyond those of the well-known menthol in macrophages stimulated by lipopolysaccharide (LPS) and in a mouse model of colitis induced by sodium dextran sulfate. Unlike menthol, which acts primarily through the cold-sensitive TRPM8 channel, these menthyl esters displayed unique mechanisms that operate independently of this receptor. They readily penetrated target cells and efficiently suppressed LPS-stimulated tumour necrosis factor-alpha (Tnf) expression mediated by liver X receptor (LXR), a key nuclear receptor that regulates intracellular cholesterol and lipid balance. The menthyl esters showed affinity for LXR and enhanced the transcriptional activity through their non-competitive and potentially synergistic agonistic effect. This effect can be attributed to the crucial involvement of SCD1, an enzyme regulated by LXR, which is central to lipid metabolism and plays a key role in the anti-inflammatory response. In addition, we discovered that the menthyl esters showed remarkable efficacy in suppressing adipogenesis in 3T3-L1 adipocytes at the mitotic clonal expansion stage in an LXR-independent manner as well as in mice subjected to diet-induced obesity. These multiple capabilities of our compounds establish them as formidable allies in the fight against inflammation and obesity, paving the way for a range of potential therapeutic applications.

The Emerging Role of Natural Products in Cancer Treatment

The exploration of natural products as potential agents for cancer treatment has garnered significant attention in recent years. In this comprehensive review, we delve into the diverse array of natural compounds, including alkaloids, carbohydrates, flavonoids, lignans, polyketides, saponins, tannins, and terpenoids, highlighting their emerging roles in cancer therapy. These compounds, derived from various botanical sources, exhibit a wide range of mechanisms of action, targeting critical pathways involved in cancer progression such as cell proliferation, apoptosis, angiogenesis, and metastasis. Through a meticulous examination of preclinical and clinical studies, we provide insights into the therapeutic potential of these natural products across different cancer types. Furthermore, we discuss the advantages and challenges associated with their use in cancer treatment, emphasizing the need for further research to optimize their efficacy, pharmacokinetics, and delivery methods. Overall, this review underscores the importance of natural products in advancing cancer therapeutics and paves the way for future investigations into their clinical applications.

Therapeutic Effects of Essential Oils and Their Bioactive Compounds on Prostate Cancer Treatment

Since prostate cancer (PCa) relies on limited therapies, more effective alternatives are required. Essential oils (EOs) and their bioactive compounds are natural products that have many properties including anticancer activity. This review covers studies published between 2000 and 2023 and discusses the anti-prostate cancer mechanisms of the EOs from several plant species and their main bioactive compounds. It also provides a critical perspective regarding the challenges to be overcome until they reach the market. EOs from chamomile, cinnamon, Citrus species, turmeric, Cymbopogon species, ginger, lavender, Mentha species, rosemary, Salvia species, thyme and other species have been tested in different PCa cell lines and have shown excellent results, including the inhibition of cell growth and migration, the induction of apoptosis, modulation in the expression of apoptotic and anti-apoptotic genes and the suppression of angiogenesis. The most challenging aspects of EOs, which limit their clinical uses, are their highly lipophilic nature, physicochemical instability, photosensitivity, high volatility and composition variability. The processing of EO-based products in the pharmaceutical field may be an interesting alternative to circumvent EOs' limitations, resulting in several benefits in their further clinical use. Identifying their bioactive compounds, therapeutic effects and chemical structures could open new perspectives for innovative developments in the field. Moreover, this could be helpful in obtaining versatile chemical synthesis routes and/or biotechnological drug production strategies, providing an accurate, safe and sustainable source of these bioactive compounds, while looking at their use as gold-standard therapy in the close future.

Changes in Physiological Traits, Gene Expression and Phytochemical Profile of Mentha piperita in Response to Elicitor

Peppermint (Mentha piperita) is a perennial medicinal plant containing active ingredients that can be used for treating liver and prostate cancers, acute respiratory infections, allergies, digestive problems, neuralgia, and migraines. The objective of this research is to investigate the expression of essential genes in the menthol pathway of Mentha piperita, including Pulegone reductase (Pr), Menthofuran synthase (Mfs), and limonene synthase (Ls) using qPCR, physiological analysis and essential oil composition in response to methyl jasmonate (MeJA) (0.5 mM) elicitation. Physiological analysis showed that 0.5 mM MeJA triggers defensive responsiveness in Mentha piperita by increasing superoxide dismutase (SOD) and Peroxidase (POD) enzymes activity. The highest transcript levels of Pr and Mfs genes were observed during 8 and 12 h after treatment respectively, but following 24 h, they were down-regulated. Essential oil analysis indicated that the percentage of constituents in the essential oil was changed using MeJA at 48 h and 96 h after post-treatment. Effective antimicrobial compounds, α-pinene, β-pinene, linalool and methyl acetate, were induced after 48 h. A non-significant positive relationship was detected between menthol content, and expression of the Pr and Mfs genes. Due to the significant change in the expression of Pr and Mfs genes in the menthol pathway, role of Pr gene in directing the pathway to the valuable compound menthol and deviation of the menthol pathway to the menthofuran as an undesirable component of essential oil by Mfs gene, it can be deduced that they are the most critical genes in response to MeJA treatment, which are appropriate candidates for metabolite engineering. In addition, MeJA improved defensive responsiveness and percentage of some constituents with antimicrobial properties in Mentha piperita.

Therapeutic Potential of Certain Terpenoids as Anticancer Agents: A Scoping Review

Cancer is a life-threatening disease and is considered to be among the leading causes of death worldwide. Chemoresistance, severe toxicity, relapse and metastasis are the major obstacles in cancer therapy. Therefore, introducing new therapeutic agents for cancer remains a priority to increase the range of effective treatments. Terpenoids, a large group of secondary metabolites, are derived from plant sources and are composed of several isoprene units. The high diversity of terpenoids has drawn attention to their potential anticancer and pharmacological activities. Some terpenoids exhibit an anticancer effect by triggering various stages of cancer progression, for example, suppressing the early stage of tumorigenesis via induction of cell cycle arrest, inhibiting cancer cell differentiation and activating apoptosis. At the late stage of cancer development, certain terpenoids are able to inhibit angiogenesis and metastasis via modulation of different intracellular signaling pathways. Significant progress in the identification of the mechanism of action and signaling pathways through which terpenoids exert their anticancer effects has been highlighted. Hence, in this review, the anticancer activities of twenty-five terpenoids are discussed in detail. In addition, this review provides insights on the current clinical trials and future directions towards the development of certain terpenoids as potential anticancer agents.

The Natural Product Eugenol Is an Inhibitor of the Ebola Virus In Vitro

PURPOSE

Since the 2014 Ebola virus (EBOV) outbreak in West Africa there has been considerable effort towards developing drugs to treat Ebola virus disease and yet to date there is no FDA approved treatment. This is important as at the time of writing this manuscript there is an ongoing outbreak in the Democratic Republic of the Congo which has killed over 1000.

METHODS

We have evaluated a small number of natural products, some of which had shown antiviral activity against other pathogens. This is exemplified with eugenol, which is found in high concentrations in multiple essential oils, and has shown antiviral activity against feline calicivirus, tomato yellow leaf curl virus, Influenza A virus, Herpes Simplex virus type 1 and 2, and four airborne phages.

RESULTS

Four compounds possessed EC₅₀ values less than or equal to 11 μM. Of these, eugenol, had an EC₅₀ of 1.3 μM against EBOV and is present in several plants including clove, cinnamon, basil and bay. Eugenol is much smaller and structurally unlike any compound that has been previously identified as an inhibitor of EBOV, therefore it may provide new mechanistic insights.

CONCLUSION

This compound is readily accessible in bulk quantities, is inexpensive, and has a long history of human consumption, which endorses the idea for further assessment as an antiviral therapeutic. This work also suggests that a more exhaustive assessment of natural product libraries against EBOV and other viruses is warranted to improve our ability to identify compounds that are so distinct from FDA approved drugs.

Phytochemical Screening and Biological Activity of Mentha × piperita L. and Lavandula angustifolia Mill. Extracts

The present study aimed to investigate the phytochemical composition of Mentha × piperita L. (MP) and Lavandula angustifolia Mill. (LA) extracts in terms of hydroxycinnamic acid (HCAs) content, in particular, caffeic (CA), p-cumaric (CU), ferulic (FE), and rosmarinic (RS) acids using LC-MS. Also, the in vitro antimicrobial effect against Staphylococcus aureus and the antiproliferative activity against two cancerous cell lines (A375 and MDA-MB-231) using the MTT assay were tested. The extracts were prepared using aromatic water which resulted from the extraction of oils from plants as extraction medium, with/without acid. The results showed that RS and FE represent the majority of HCAs compounds; the highest content of FE is found in LA (7.47 mg·g-1d.m.), and the maximum content of RS in MP (6.36 mg·g-1d.m.). Regarding the antimicrobial effect against Staphylococcus aureus, the two extracts showed a simulative role on the growth rate of Staphyloccocus aureus, but a slightly inhibitory effect (69.12%) can be attributed to the acidic environment. In terms of biological activity against MDA-MB-231 breast carcinoma cell line, and A375 human melanoma cell line, at the highest employed concentration, 150 μg·mL-1, the tested extracts present a weak antiproliferative effect.

Cycloartan-24-ene-1α,2α,3β-triol, a cycloartane-type triterpenoid from the resinous exudates of Commiphora myrrha, induces apoptosis in human prostatic cancer PC-3 cells

Plant-derived antitumor drugs are currently used in chemotherapy. Cycloartane triterpenoids have shown a cytotoxic effect on human prostate cancer cells. The aim of the present study was to isolate a cycloartane triterpenoid from Commiphora myrrha and evaluate its anticancer potential. Cycloartan-24-ene-1α,2α,3β-triol (MY-1) was isolated from Commiphora myrrha, and its structure was determined through 1H and 13C nuclear magnetic resonance spectroscopy. The cytotoxic and apoptotic effects of MY-1 on human prostatic cancer PC-3 cells were estimated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometric analysis and terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) staining assay, and the expression of apoptotic-related proteins were evaluated by western blotting. MY-1 showed cytotoxic activity on PC-3 cells in a concentration-dependent manner with an IC50 value of 9.6 µM at 24 h. MY-1 induced cell cycle arrest and apoptosis. Western blot analysis revealed that MY-1 regulated the expression levels of B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), p53 and caspase-3 in the PC-3 cells. These findings indicate that MY-1 exerts significantly pro-apoptotic activity against human hormone-independent prostatic cancer and support MY-1 as a potential anticancer drug.

Antitumor activity of monoterpenes found in essential oils

Cancer is a complex genetic disease that is a major public health problem worldwide, accounting for about 7 million deaths each year. Many anticancer drugs currently used clinically have been isolated from plant species or are based on such substances. Accumulating data has revealed anticancer activity in plant-derived monoterpenes. In this review the antitumor activity of 37 monoterpenes found in essential oils is discussed. Chemical structures, experimental models, and mechanisms of action for bioactive substances are presented.

Geraniol inhibits prostate cancer growth by targeting cell cycle and apoptosis pathways

The progression of prostate cancer is associated with escape from cell cycle arrest and apoptosis under androgen-depleted conditions. Here, we found that geraniol, a naturally occurring monoterpene, induces cell cycle arrest and apoptosis in cultured cells and tumor grafted mice using PC-3 prostate cancer cells. Geraniol modulated the expression of various cell cycle regulators and Bcl-2 family proteins in PC-3 cells in vitro and in vivo. Furthermore, we showed that the combination of sub-optimal doses of geraniol and docetaxel noticeably suppresses prostate cancer growth in cultured cells and tumor xenograft mice. Therefore, our findings provide insight into unraveling the mechanisms underlying escape from cell cycle arrest and apoptosis and developing therapeutic strategies against prostate cancer.