Suppression of Inflammatory cytokine production by ar-Turmerone isolated from Curcuma phaeocaulis

Turmeric Essential Oil Constituents as Potential Drug Candidates: A Comprehensive Overview of Their Individual Bioactivities

The therapeutic properties of turmeric essential oil have been extensively documented in both preclinical and clinical studies. Research indicates that its primary active compounds are promising candidates for addressing a wide range of pathologies, exhibiting anticancer, anti-inflammation, antioxidant, cardiovascular, hypoglycemic, dermatological, hepatoprotective, neurological, antiparasitic, antiviral, insecticidal, antifungal, and antivenom activities. While numerous compounds possess similar potential applications, the isolated active constituents of turmeric essential oil stand out due to their unique pharmacological profiles and absence of toxicity. This literature review meticulously compiles and analyzes the bioactivities of these constituents, emphasizing their molecular mechanisms of action, reported pharmacological effects, and potential therapeutic applications. The aim of this review is to provide a comprehensive synthesis of currently available clinical and preclinical findings related to individual turmeric essential oil compounds, while also identifying critical knowledge gaps. By summarizing these findings, this work encourages further research into the isolated compounds from turmeric oil as viable drug candidates, ultimately contributing to the development of innovative therapeutic strategies.

Research Progress on Sesquiterpenoids of Curcumae Rhizoma and Their Pharmacological Effects

Curcumae Rhizoma, a traditional Chinese medicine with a wide range of pharmacological activities, is obtained from the dried rhizomes of Curcuma phaeocaulis VaL., Curcuma kwangsiensis S. G. Lee et C. F. Liang, and Curcuma wenyujin Y. H. Chen et C. Ling. Sesquiterpenoids and curcuminoids are found to be the main constituents of Curcumae Rhizoma. Sesquiterpenoids are composed of three isoprene units and are susceptible to complex transformations, such as cyclization, rearrangement, and oxidation. They are the most structurally diverse class of plant-based natural products with a wide range of biological activities and are widely found in nature. In recent years, scholars have conducted abundant studies on the structures and pharmacological properties of components of Curcumae Rhizoma. This article elucidates the chemical structures, medicinal properties, and biological properties of the sesquiterpenoids (a total of 274 compounds) isolated from Curcumae Rhizoma. We summarized extraction and isolation methods for sesquiterpenoids, established a chemical component library of sesquiterpenoids in Curcumae Rhizoma, and analyzed structural variances among sesquiterpenoids sourced from Curcumae Rhizoma of diverse botanical origins. Furthermore, our investigation reveals a diverse array of sesquiterpenoid types, encompassing guaiane-type, germacrane-type, eudesmane-type, elemane-type, cadinane-type, carane-type, bisabolane-type, humulane-type, and other types, emphasizing the relationship between structural diversity and activity. We hope to provide a valuable reference for further research and exploitation and pave the way for the development of new drugs derived from medicinal plants.

Germacrone: A Multi-targeting Sesquiterpene with Promising Anti-cancer and Chronic Disease Applications

BACKGROUND

Germacrone, a naturally occurring active compound found in essential oils extracted from medicinal plants within the Zingiberaceae family, has garnered attention for its potential therapeutic applications. Extensive research has highlighted its multi-targeting capabilities, positioning it as a promising treatment for various chronic diseases, including cancer, cardiovascular conditions, and neurodegenerative disorders like Alzheimer's disease.

OBJECTIVE

This review aims to provide a comprehensive overview of germacrone as a scaffold for developing multi-targeting drugs with therapeutic potential against a range of chronic disorders. The study delves into the molecular mechanisms that underlie the therapeutic effects of germacrone and explores its potential targets, including NF-κB, PI3K/AKT/mTOR, p53, JAK/STAT, caspase, apoptosis, and autophagy induction.

METHODS

A systematic review of literature databases was conducted to gather relevant studies on germacrone and its therapeutic applications. The molecular mechanisms and potential targets of germacrone were examined to elucidate its multi-targeting capabilities.

RESULTS

Germacrone exhibits significant potential in the management of chronic diseases, with demonstrated effects on various cellular pathways. The review highlights its impact on NF-κB, PI3K/AKT/mTOR, p53, JAK/STAT, caspase, apoptosis, and autophagy induction, showcasing its versatility in targeting multiple pathways associated with chronic conditions. Germacrone has emerged as a promising candidate for the treatment of diverse chronic diseases. The understanding of its multi-targeting capabilities, coupled with its natural origin, positions it as a valuable scaffold for developing therapeutics.

CONCLUSION

The exploration of germacrone as a structural framework for multi-targeting drugs offers a potential avenue to enhance efficacy while minimizing potential side effects. Further research and clinical trials are warranted to validate the therapeutic potential of germacrone in diverse medical contexts.

Antioxidation Abilities of Sesquiterpenoids from Curcuma aromatica in vitro

AIMS AND OBJECTIVES

In our previous study, 21 sesquiterpenoids with different skeleton types were isolated from the radix of Curcuma aromatica Salisb., a traditional Chinese medicine used for treating depression and qi and blood stasis. C. aromatica enhanced PC12 cell viability upon damage by H₂O₂. The aim of this study was to elucidate the antioxidation capability of these sesquiterpenoids using a model of H₂O₂-induced PC12 cells and analyze the correlation between their structure and bio-activity.

MATERIALS AND METHODS

PC12 cells were simultaneously treated with 400 μM H2O2 and sesquiterpenoid compounds or vitamin E (used as a positive control) for 24 h. The activities of GSH-Px, LDH, CAT, and SOD were detected by ELISA kits. The reactive oxygen species (ROS) level in the cells was determined by the fluorescence probe DCFH-DA. [Ca²⁺]i was detected based on the Fluo 2-AM fluorescence labeling assay. The structures of sesquiterpenoids were featured with 41 selected molecular descriptors, and the relationship between active parameters and structural features was determined by the partial least squares (PLS) analysis.

RESULTS

All twenty-one sesquiterpenoids from the radix of C. aromatica increased the activities of GSH-Px, CAT, and SOD, and decreased the LDH leakage, and levels of ROS level and [Ca²⁺]i to different degrees. Some relationships were observed between the molecular descriptors featured by the sesquiterpenoids and GSH-Px, CAT, SOD, LDH, ROS, and [Ca²⁺]i by PLS analysis.

CONCLUSIONS

Twenty-one sesquiterpenoids showed different antioxidation abilities as measured by a model of H₂O₂-induced PC12 cells. Five molecular descriptors were positively correlated with GSH-Px, CAT, SOD, and were negatively correlated with LDH and [Ca²⁺].

Sesquiterpenoids isolated from the rhizome of Curcuma phaeocaulis Valeton: antitumor activity, in silico molecular docking and molecular dynamics study

This work provides a deep insight into new sesquiterpenoids isolated from Curcumae Rhizoma acting as potential antitumor activity inhibitors.

Benefits of Cardamom (Elettaria cardamomum (L.) Maton) and Turmeric (Curcuma longa L.) Extracts for Their Applications as Natural Anti-Inflammatory Adjuvants

The genus Zingiberaceae has been widely used for phytotherapeutic purposes in traditional medicine throughout the world for its anti-inflammatory activity. Experimental studies have established that inflammation caused by chronic infections represents a risk factor for different forms of cancer. The objective of this study was focused on determining the anti-inflammatory capacity and cytotoxic activity of aqueous extracts of Elettaria cardamomum (cardamom) and Curcuma Longa (turmeric). The extracts were obtained by maceration and, through GC-MS/MS, a total of 11 different chemical components were determined in the aqueous extract of cardamom and 7 in the extract of turmeric. The main compounds found in cardamom and turmeric were α-terpinyl acetate (54.46%) and β-turmerone (33.45%), respectively. RT-qPCR results showed significantly lower gene expression levels of innate inflammatory cytokines (IL-6 and TNF-α) compared to the control (LPS). Also, it was observed that the extracts do not possess cytotoxic activity against different cell lines, where E. cardamomum showed EC₅₀ (µg/mL) of 473.84 (HeLa cells), 237.36 (J774A.1 cells), 257.51 (Vero E6 cells), and 431.16 (Balb/C peritoneal cells) and C. longa showed EC₅₀ (µg/mL) of 351.17 (HeLa cells), 430.96 (J774A.1 cells), 396.24 (Vero E6 cells), and 362.86 (Balb/C peritoneal cells). The results of this research suggest that natural extracts of E. cardamomum and C. longa possess anti-inflammatory effects and no cytotoxic activity against HeLa, J774A.1, Vero E6, and Balb/C peritoneal cell lines. Finally, it was observed that the extracts also decreased nitric oxide (NO) production in peritoneal macrophages.

Ar-Turmerone Exerts Anti-proliferative and Anti-inflammatory Activities in HaCaT Keratinocytes by Inactivating Hedgehog Pathway

Psoriasis, a common skin inflammatory disorder, is characterized by the aberrant growth and differentiation of keratinocytes. Ar-Turmerone, a main bioactive ingredient of Curcuma longa, has been found to alleviate skin inflammation in psoriasis-like mice. However, the effects and underlying mechanism of ar-turmerone on keratinocytes remain unknown. The effects of ar-turmerone alone or combined with recombinant human sonic hedgehog (rhShh) on cell proliferation, apoptosis, and inflammatory cytokine secretion were explored by MTT, flow cytometry analysis, and ELISA, respectively. The mRNA and protein levels of Shh, glioblastoma-1 (Gli1), and smoothened (SMO) were determined by RT-qPCR and western blot analysis, respectively. Results disclosed that ar-turmerone dose-dependently suppressed proliferation, facilitated apoptosis, and reduced TNF-α-mediated production of interleukin (IL)-1β, IL-6, and IL-8 in HaCaT cells. Ar-turmerone blocked Hedgehog pathway in HaCaT cells, as evidenced by the reduced expression of Shh, Gli1, and SMO. Moreover, activation of the Hedgehog pathway by rhShh abolished the effects of ar-turmerone on the proliferation, apoptosis, and TNF-α-mediated inflammatory cytokine expression in HaCaT cells. In conclusion, ar-turmerone suppressed cell proliferative ability and attenuated inflammatory cytokine expression by inactivating Hedgehog pathway in HaCaT cells, contributing to better understanding the potential anti-psoriasis effects of ar-turmerone on psoriasis.

Germacrone: A Potent Secondary Metabolite with Therapeutic Potential in Metabolic Diseases, Cancer and Viral Infections

Natural products, an infinite reserve of bioactive molecules, will continue to serve humans as an important source of therapeutic agents. Germacrone is a bioactive natural compound found in the traditional medicinal plants of family Zingiberaceae. This multifaceted chemical entity has become a point of focus during recent years due to its numerous pharmacological applications, e.g., anticancer, anti-inflammatory, antiviral, antioxidant, anti-adipogenic, anti-androgenic, antimicrobial, insecticidal, and neuroprotective. Germacrone is an effective inducer of cell cycle arrest and apoptosis in various cancers (breast, brain, liver, skin, prostate, gastric, and esophageal) via modulation of different cell signaling molecules and pathways involved in cancer proliferation. This is the first report highlighting the wide spectrum of pharmacological activities exhibited by germacrone. The reported data collected from various shreds of evidences recommend that this multifaceted compound could serve as a potential drug candidate in the near future.

Mechanistic study of attenuation of monosodium glutamate mixed high lipid diet induced systemic damage in rats by Coccinia grandis

In the context of failure of treatment for non alcoholic fatty liver disease (NAFLD)-mediated systemic damages, recognition of novel and successful characteristic drug to combat these anomalous situations is earnestly required. The present study is aimed to evaluate protective value of ethanol extract of Coccinia grandis leaves (EECGL), naturally occurring medicinal plant, on NAFLD-mediated systemic damage induced by high lipid diet along with monosodium glutamate (HM)-fed rats. Our study uncovered that EECGL significantly ameliorates HM-induced hyperlipidemia, increased lipogenesis and metabolic disturbances (via up regulation of PPAR-α and PPAR-γ), oxidative stress (via reducing the generation of reactive oxygen species and regulating the redox-homeostasis) and inflammatory response (via regulating the pro-inflammatory and anti-inflammatory factors with concomitant down regulation of NF-kB, iNOS, TNF-α and up regulation of eNOS). Furthermore, EECGL significantly inhibited HM-induced increased population of cells in sub G0/G1 phase, decreased Bcl2 expression and thereby loss of mitochondrial membrane potential with over expression of Bax, p53, p21, activation of caspase 3 and 9 indicated the apoptosis and suppression of cell survival. It is perhaps the first comprehensive study with a mechanistic approach which provides a strong unique strategy for the management of HM-induced systemic damage with effective dose of EECGL.

Anticonvulsant Essential Oils and Their Relationship with Oxidative Stress in Epilepsy

Epilepsy is a most disabling neurological disorder affecting all age groups. Among the various mechanisms that may result in epilepsy, neuronal hyperexcitability and oxidative injury produced by an excessive formation of free radicals may play a role in the development of this pathology. Therefore, new treatment approaches are needed to address resistant conditions that do not respond fully to current antiepileptic drugs. This paper reviews studies on the anticonvulsant activities of essential oils and their chemical constituents. Data from studies published from January 2011 to December 2018 was selected from the PubMed database for examination. The bioactivity of 19 essential oils and 16 constituents is described. Apiaceae and Lamiaceae were the most promising botanical families due to the largest number of reports about plant species from these families that produce anticonvulsant essential oils. Among the evaluated compounds, β-caryophyllene, borneol, eugenol and nerolidol were the constituents that presented antioxidant properties related to anticonvulsant action. These data show the potential of these natural products as health promoting agents and use against various types of seizure disorders. Their properties on oxidative stress may contribute to the control of this neurological condition. However, further studies on the toxicological profile and mechanism of action of essential oils are needed.

Chemical Composition and Biological Activities of Essential Oils of Curcuma Species

Members of the genus Curcuma L. have been used in traditional medicine for centuries for treating gastrointestinal disorders, pain, inflammatory conditions, wounds, and for cancer prevention and antiaging, among others. Many of the biological activities of Curcuma species can be attributed to nonvolatile curcuminoids, but these plants also produce volatile chemicals. Essential oils, in general, have shown numerous beneficial effects for health maintenance and treatment of diseases. Essential oils from Curcuma spp., particularly C. longa, have demonstrated various health-related biological activities and several essential oil companies have recently marketed Curcuma oils. This review summarizes the volatile components of various Curcuma species, the biological activities of Curcuma essential oils, and potential safety concerns of Curcuma essential oils and their components.

Sesqui- and Diterpenoids from the Radix of Curcuma aromatica

Eight new sesquiterpenoids (1-8), two new diterpenoids (9 and 10), and 17 known sesqui- and diterpenoids (11-27) were isolated from the radix of Curcuma aromatica. Among these compounds, 1 is an unprecedented guaiane with unique cyclopropane and furan functionalities, and 9 is the first atisane diterpenoid isolated from a Curcuma species. Their 2D and 3D structures were established using HRESIMS and spectroscopic methods, including ECD and IECD data. The antioxidant activities of compounds 1-27 were evaluated based on their ability to protect PC12 cells against H₂O₂-induced damage, with 1, 2, 5-8, 11, 12, 14, 16, 18, and 19 exhibiting notable antioxidant effects on oxidative injury induced by H₂O₂.

Traditional Chinese medicine formulas for the treatment of osteoporosis: Implication for antiosteoporotic drug discovery

ETHNOPHARMACOLOGICAL RELEVANCE

Osteoporosis is a chronic epidemic which can leads to enhanced bone fragility and consequent an increase in fracture risk. Traditional Chinese medicine (TCM) formulas have a long history of use in the prevention and treatment of osteoporosis. Antiosteoporotic TCM formulas have conspicuous advantage over single drugs. Systematic data mining of the existing antiosteoporotic TCM formulas database can certainly help the drug discovery processes and help the identification of safe candidates with synergistic formulations. In this review, the authors summarize the clinical use and animal experiments of TCM formulas and their mechanism of action, and discuss the potential antiosteoporotic activity and the active constituents of commonly used herbs in TCM formulas for the therapy of osteoporosis.

MATERIALS AND METHODS

The literature was searched from Medline, Pubmed, ScienceDirect, Spring Link, Web of Science, CNKI and VIP database from 1989 to 2015, and also collected from Chinese traditional books and Chinese Pharmacopoeia with key words such as osteoporosis, osteoblast, osteoclast, traditional Chinese medicine formulas to identify studies on the antiosteoporotic effects of TCM formulas, herbs and chemical constituents, and also their possible mechanisms.

RESULTS

Thirty-three TCM formulas were commonly used to treat osteoporosis, and showed significant antiosteoporotic effects in human and animal. The herb medicines and their chemical constituents in TCM formulas were summarized, the pharmacological effects and chemical constituents of commonly used herbs in TCM formulas were described in detail. The action mechanisms of TCM formulas and their chemical constituents were described. Finally, the implication for the discovery of antiosteoporotic leads and combinatory ingredients from TCM formulas were prospectively discussed.

CONCLUSIONS

Clinical practice and animal experiments indicate that TCM formulas provide a definite therapeutic effect on osteoporosis. The active constituents in TCM formulas are diverse in chemical structure, and include flavonoids, lignans, saponins and iridoid glycosides. Antiosteoporotic mechanism of TCM formulas and herbs involves multi regulatory pathways, such as Wnt/β-catenin, BMP/Smad, MAPK pathway and RANKL/OPG system. Phytochemicals from TCM formulas and their compositional herb medicines offer great potential for the development of novel antiosteoporotic drugs. The active ingredients in TCM formulas can be developed in combination as potent drugs, which may exhibit better antiosteoporotic effects compared to the individual compound.

Sesquiterpenoids from the Rhizomes of Curcuma phaeocaulis and Their Inhibitory Effects on LPS-Induced TLR4 Activation

Two new guaiane-type (2, 6) and one new furanogermacrane-type (11) sesquiterpenoids have been isolated along with twelve known compounds from an EtOAc-soluble extract of Curcuma phaeocaulis rhizomes. The structures of the isolated compounds were elucidated using a combination of NMR, MS, and circular dichroism (CD) spectra. The inhibitory effects of each compound on lipopolysaccharide (LPS)-induced Toll-like receptor 4 (TLR4) activation in THP-1-Blue cells were assessed, and compound 4 showed more potent inhibitory activity against LPS-stimulated TLR4 activation.

Natural nitric oxide (NO) inhibitors from the rhizomes of Curcuma phaeocaulis

An exploration we carried out for isolating nitric oxide (NO) inhibitors from the rhizomes of Curcuma phaeocaulis afforded one new salvialane-type sesquiterpene, phasalvione (1), two novel nor-sesquiterpenes, phaeocaudione (2) and phaeocauone (3), one aromatic acid 3-methyl-4-(3-oxo-butyl)-benzoic acid (4), two γ-elemene-type sesquiterpenes, 8β(H)-elema-1,3,7(11)-trien-8,12-lactam (5) and 8β-methoxy-isogermafurenolide (6), one eudesmane-type sesquiterpene, phaeusmane I (7), and one cyclic diarylheptanoid, phaeoheptanoxide (8). Their structures were established based on extensive spectroscopic analysis. The absolute configurations of compounds 1 and 2 were assigned using the circular dichroism data of the [Rh2(OCOCF3)4] complex, and the absolute configuration of 1 was further established by single crystal X-ray crystallography. It is noteworthy that compounds 5–7 were racemates analyzed by chiral HPLC. Furthermore, the inhibitory effects of the isolated compounds on nitric oxide production in LPS-activated macrophages were evaluated. Compounds 1, 3 and 4 showed strong inhibitory activities on NO production with IC50 values of 7.46 ± 0.69, 2.35 ± 0.17 and 3.49 ± 0.31 μM, respectively. A plausible biosynthetic pathway for 1–4 in C. phaeocaulis was also discussed.

Cadinane sesquiterpenes from Curcuma phaeocaulis with their inhibitory activities on nitric oxide production in RAW 264.7 cells

Four new cadinane-type sesquiterpenes named phacadinanes A-D (1-4) were isolated from the rhizomes of Curcuma phaeocaulis. Their structures were elucidated by 1D and 2D NMR, as well as accurate mass measurements. Compound 4 was the first example of a rare 4,5-seco-cadinane sesquiterpene isolated from the Zingiberaceae family. Furthermore, inhibitory effects of the isolated compounds on nitric oxide production in LPS-activated macrophages were evaluated. Compounds 1 and 2 showed strong inhibitory activities on NO production with IC50 values of 3.88±0.58 and 2.25±0.71 μM, respectively. A possible biogenetic pathway for 4,5-seco-cadinane sesquiterpene (4) was postulated.

Germacrane sesquiterpenes isolated from the rhizome of Curcuma xanthorrhiza Roxb. inhibit UVB-induced upregulation of MMP-1, -2, and -3 expression in human keratinocytes

Four sesquiterpenes were isolated from the rhizome of Curcuma xanthorrhiza Roxb.: furanodiene (1), germacrone (2), furanodienone (3), and 13-hydroxygermacrone (4). Importantly, this was the first time compounds 1 and 4 were isolated from this plant. The chemical structures of these compounds were determined using 1D- and 2D-nuclear magnetic resonance, infrared spectroscopy, and electron ionization mass spectrometry analyses. Among the isolated compounds, compounds 2 and 4 inhibited UVB-induced upregulation of the mRNA and protein expression levels of MMP-1, MMP-2, and MMP-3 in human keratinocytes (HaCaT). Moreover, this upregulation occurred in a dose-dependent manner over the range of 1-10 μM for each compound.