Variation in the Chemical Composition of Five Varieties of Curcuma longa Rhizome Essential Oils Cultivated in North Alabama

Turmeric-Black Cumin Essential Oils and Their Capacity to Attenuate Free Radicals, Protein Denaturation, and Cancer Proliferation

Turmeric rhizomes (Curcuma longa) and black cumin seeds (Nigella sativa) are polyherbal ingredients used for the management of cancer and other chronic inflammatory diseases in Nigerian ethnomedicine. Previous studies have shown the antioxidant, anti-inflammatory, and anticancer activities of the individual plant extracts. However, the two spices have not been biologically potentiated in their combined form. Therefore, this study obtained essential oils (EOs) from the combined spices and evaluated their inhibitory effects on free radicals, protein denaturation, and cancer proliferation. The EOs were extracted by hydro-distillation (HD) and characterized by gas chromatography-mass spectrometry (GC-MS). In vitro antioxidant assessment was conducted based on DPPH, hydrogen peroxide (H2O2), nitric oxide (NO), and ferric ion (Fe3+) radical scavenging assays. The cytotoxicity of the oil against non-tumorigenic (HEK293) and cancerous (HepG2 and HeLa) cell lines was determined following the MTT cell viability assay. An in silico molecular docking analysis of the oil constituents was also performed. Six batches of EOs I-VI were afforded, comprising twenty-two major constituents, with aromatic Ar-turmerone being the most prominent compound. There was a marked improvement in the bioactivity of the oils upon repeated HD and as a combination. The batch VI oil exhibited the best activity, with a cytotoxicity (CC50) of 10.16 ± 1.69 µg/100 µL against the HepG2 cell line, which was comparable to 5-fluorouracil (standard, CC50 = 8.59 ± 1.33 µg/100 µL). In silico molecular docking suggested δ-curcumene, Ar-curcumene, Ar-turmerol, and Ar-turmerone among the promising compounds based on their high binding energy scores with NOX2, NF-κB, and mdm2 proteins. In conclusion, the oils from the turmeric-black cumin combined possess a considerable inhibition ability against free radicals, protein denaturation, and cancer proliferation. This study's findings further underscore the effectiveness of turmeric-black cumin as a polyherbal medicinal ingredient.

Chromatographic analysis of the chemical composition and anticancer activities of Curcuma longa extract cultivated in Palestine

Curcuma longa (turmeric) is a plant that has been extensively utilized in traditional medicine for centuries. Turmeric has a long history of use in both food and traditional medicine for the treatment of ailments such as diarrhea, cancer, flatulence, and dyspepsia. In Palestine, this plant was cultivated for the first time. The objective of this study was to characterize the extract of C. longa and assess its antimutagenic activity against a variety of cancer cells. Gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) methods were employed to identify the constituents of turmeric. The cytotoxic effects of C. longa were evaluated on cancer and normal cell lines using the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay. The results revealed the presence of 10 components in turmeric extract as identified by GC-MS. The major constituents comprising 78% of the total constituents were α-zingiberene (27.51%), tumeron (19.44%), β-sesquiphellandrene (19.40%), and aromatic-tumeron (11.63%). HPLC analysis successfully separated the main constituent, curcumin (1.78%), along with two other curcumin derivatives. The cytotoxicity results demonstrated potent anticancer activity of the C. longa extract against HeLa and LX2 cell lines, with IC50 values of 46.84 ± 2.12 and 29.77 ± 1 µg/mL, respectively. Furthermore, the plant extract at a concentration of 250 µg/mL exhibited over 95% inhibition against all tested cancer cell lines. These findings highlight the promising potential of turmeric as a natural source with powerful anticancer activities. Moreover, the extract may possess other biological activities such as antioxidant and antimicrobial properties, which could be explored in future studies.

Cross-Compatibility in Interspecific Hybridization of Different Curcuma Accessions

Curcuma is extensively cultivated as a medicinal and ornamental plant in tropical and subtropical regions. Due to the bright bract color, distinctive inflorescence and long blooming period, it has become a new favorite in terms of the urban landscape, potted flowers and cut flowers. However, little research on breeding new cultivars using traditional plant breeding methods is available on the genus Curcuma. In the present study, pollen viability and stigma receptivity evaluation were performed, and the genetic relationship of 38 Curcuma accessions was evaluated, then 5 C. alismatifolia Gagnep. (Ca), 2 C. hybrid (Ch), 2 C. sparganiifolia Gagnep. cultivars and 4 Curcuma native species were selected as parents for subsequent interspecific cross-breeding. A total of 132 reciprocal crosses were carried out for interspecific hybridization, including 70 obverse and 62 inverse crosses. Obvious discrepancies among fruit-setting rates were manifested in different combinations and in reciprocal crosses. Results showed that the highest fruit-setting rate (87.5%) was observed in the Ca combinations. There were 87 combinations with a fruit-setting rate of 0%, which meant nearly 65.9% was incompatible. We concluded that C. alismatifolia 'Siam Shadow' (Ch34) was suitable as a male parent and C. petiolata Roxb. (Cpet) was suitable as a female parent to improve the fruit-setting rates. The maximum number of seeds per fruit (45.4) was obtained when C. alismatifolia 'Chiang Mai Pink' (Ca01) was used as a female parent followed by C. attenuata Wall. ex Baker (Catt) (42.8) and C. alismatifolia 'Splash' (Ca63) (39.6) as male parents. The highest germination rate was observed for the Ca group followed by Catt and C. sparganiifolia 'Maetang Sunrise' (Csms). The germination rates of Ca accessions ranged from 58.2% (C. alismatifolia 'Siam Scarlet' (Ca06) as a male parent) to 89.3% (C. alismatifolia 'Sitone' (Ca10) as a male parent) with an average value of 74.0%. Based on the results of hybrid identification, all the individuals from the four combinations exhibited paternal-specific bands, indicating that the true hybrid rates of crossings were 100%. Our results would facilitate the interspecific hybridization and introduction of genetic variation from wild species into the cultivars in Curcuma in the future, which could be helpful in realizing the sustainable application in urban green areas.

Natural Compounds in Plant-Based Food

Plant-based foods include a wide range of products, such as fruits, vegetables, herbs and spices, as well as food products based on them, such as sauces, soups, or beverages [...].

Insecticidal Activity of Essential Oils against Mealybug Pests (Hemiptera: Pseudococcidae): A Systematic Review and Meta-Analysis

Most mealybugs of the Pseudococcidae family are important pests of agriculture and ornamental gardens. Our aim was to perform a review and meta-analysis on 14 published scientific articles on the insecticidal activity of essential oils (EOs) against mealybug species of the Pseudococcidae family. Data on (1) species, genus, families, and plant parts from which the EO was extracted; (2) the main compounds of each EO; (3) the highest and lowest concentrations tested; and (4) the application method used for the toxicological studies was collected from each study. The metafor package (R software) was used to perform a three-level random effects meta-analysis. The families Lamiaceae, Rutaceae, Myrtaceae, Zingiberaceae and Euphorbiaceae and the genera Citrus, Cymbopogon, Syzygium, Cinnamomum and Jatropha were the most used among the studies. According to the results from the meta-analyses, 13 out of 24 genera analyzed were effective against mealybugs. All methods were effective, but fumigation and indirect contact were the most frequently used methodologies. The results obtained from the present review and meta-analysis could be used for the potential development of natural biopesticide formulations against mealybugs belonging to the Pseudococcidae family.

Untargeted Metabolomic Approach of Curcuma longa to Neurodegenerative Phytocarrier System Based on Silver Nanoparticles

Curcuma is one of the most famous medicinal and tropical aromatic plants. Its health benefits have been appreciated and exploited in traditional Asian medicine since ancient times. Various studies have investigated its complex chemical composition and demonstrated the remarkable therapeutic properties of curcuma's phytoconstituents. Oxidative stress is a decisive driving factor triggering numerous pathologies (neurodegenerative, psychiatric and cardiovascular diseases; diabetes; tumors, etc.). Numerous recent studies have focused on the use of natural compounds and nanomaterials as innovative molecular targeting agents as effective therapeutic strategies. In this study, we report, for the first time, the development of a simple target phytocarrier system that capitalizes on the bioactive properties of curcuma and AgNPs. The complete metabolic profile of curcuma was determined based on gas chromatography-mass spectrometry (GC-MS) and electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-QTOF-MS). A total of 80 metabolites were identified under mass spectra (MS)-positive mode from 10 secondary metabolite categories: terpenoids, amino acids, diarylheptanoids, flavonoids, phenolic acids, steroids, fatty acids, coumarins, alkaloids and miscellaneous. In addition, the biological activity of each class of metabolites was discussed. A comprehensive characterization (FT-IR, UV-Vis, DLS, SEM, TEM, EDS, zeta potential and XRD) was performed to study the morphostructural properties of this new phytocarrier system. Antioxidant activity of the new phytocarrier system was evaluated using a combination of in vitro methods (total phenolic assay, 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and cyclic voltammetric method (Trolox equivalent antioxidant capacity (TEAC) electrochemical assay)). Antioxidants assays showed that the phytocarrier system exhibits superior antioxidant properties to those of its components, i.e., curcuma or citrate-coated-AgNPs. These data confirm the potential to enhance relevant theoretical knowledge in the area of innovative antioxidant agents, with potential application in neurodegenerative therapeutic strategies.

Alpha-Phellandrene and Alpha-Phellandrene-Rich Essential Oils: A Systematic Review of Biological Activities, Pharmaceutical and Food Applications

Alpha-phellandrene is a very common cyclic monoterpene found in several EOs, which shows extensive biological activities. Therefore, the main focus of the present systematic review was to provide a comprehensive and critical analysis of the state of the art regarding its biological activities and pharmaceutical and food applications. In addition, the study identified essential oils rich in alpha-phellandrene and summarized their main biological activities as a preliminary screening to encourage subsequent studies on their single components. With this review, we selected and critically analyzed 99 papers, using the following bibliographic databases: PubMed, SciELO, Wiley and WOS, on 8 July 2022. Data were independently extracted by four authors of this work, selecting those studies which reported the keyword "alpha-phellandrene" in the title and/or the abstract, and avoiding those in which there was not a clear correlation between the molecule and its biological activities and/or a specific concentration from its source. Duplication data were removed in the final article. Many essential oils have significant amounts of alpha-phellandrene, and the species Anethum graveolens and Foeniculum vulgare are frequently cited. Some studies on the above-mentioned species show high alpha-phellandrene amounts up to 82.1%. There were 12 studies on alpha-phellandrene as a pure molecule showed promising biological functions, including antitumoral, antinociceptive, larvicidal and insecticidal activities. There were 87 research works on EOs rich in alpha-phellandrene, which were summarized with a focus on additional data concerning potential biological activities. We believe this data is a useful starting point to start new research on the pure molecule, and, in particular, to distinguish between the synergistic effects of the different components of the OEs and those due to alpha-phellandrene itself. Toxicological data are still lacking, requiring further investigation on the threshold values to distinguish the boundary between beneficial and toxic effects, i.e., mutagenic, carcinogenic and allergenic. All these findings offer inspiration for potential applications of alpha-phellandrene as a new biopesticide, antimicrobial and antitumoral agent. In particular, we believe our work is of interest as a starting point for further studies on the food application of alpha-phellandrene.

A bibliometric analysis of the 100 most-cited articles on curcumin

Background: Extensive studies related to curcumin were carried out over the preceding several decades. Citation frequencies represent the most prominent contributions in a specific field. This research aimed to identify and analyze the 100 most-cited articles on curcumin and to highlight the most important advances in this field.

Methods: Highly cited articles were identified in the Web of Science core collection database. “curcumin*” was used as the search string to retrieve in the “Title” field. VOSviewer was applied to perform bibliometric analysis of these papers.

Results: Totally 17,645 publications on the topic of curcumin were identified. The top most-cited 100 articles were published between 1973 and 2017. Most of these papers were original (n = 62). The total citation frequency in the top 100 article ranged from 355 to 3364, with a median of 560. The United States and India were the major countries researching curcumin. The University of Texas M.D. Anderson Cancer Center was the institution with the highest contribution rate of these articles. The most frequently nominated authors were Aggarwal B. B., Kunnumakkara A. B., Prasad S., and Priyadarsini K. I. The top 100 articles were published in 68 journals. The top four journals in terms of the number of our included articles were Cancer Research (n = 7), followed by Journal of Biological Chemistry, Biochemical Pharmacology, and Cancer Letters, with 4 articles each. NF-kappa B, cancer, gene expression, apoptosis, inflammation, chemopreventive agent, and nitric oxide synthase are presumed to be the current hot topics. Bioavailability, anticancer, anti-inflammatory, and antioxidant activities were the major research directions of curcumin.

Conclusion: This study analyzed the 100 most-cited articles on curcumin and provided insights into the characteristics and research hotspots of the articles on this topic.

Analysis of Volatile Constituents in Curcuma Species, viz. C. aeruginosa, C. zedoaria, and C. longa, from Nepal

The genus Curcuma, composed of 93 species mainly originating from Asia, Australia, and South America, has been used for medicinal purposes, aromatic, and nutritional values as well as cosmetic. It plays a vital role in flavoring and coloring as well as exhibiting therapeutic agents against different diseases. Nepalese farmers are unaware of the essential oil compositions of Curcuma species, viz. C. aeruginosa, C. zedoaria, and C. longa. The investigation of these three essential oils provides insight into their potential as cash crops and earns a reasonable return from their production. The essential oils were obtained from the rhizomes of each plant by hydrodistillation and subjected to Gas Chromatography/Mass Spectrometry (GC−MS) analysis to identify its volatile chemical constituents as well as chiral GC-MS to identify the enantiomeric distribution of chiral terpenoids. The order of extraction yields were C. longa (0.89%) > C. zedoaria (0.74%) > C. aeruginosa (0.37%). In total, the presence of 65, 98, and 84 compounds were identified in C. longa, C. zedoaria, and C. aeruginosa, representing 95.82%, 81.55%, and 92.59% of the total oil, respectively. The most abundant compounds in C. longa essential oils were ar-turmerone (25.5%), α-turmerone (24.4%), β-turmerone (14.0%), terpinolene (7.2%), β-sesquiphellandrene (5.1%), α-zingiberene (4.8%), β-caryophyllene (2.9%), ar-curcumene (1.6%) and 1,8-cineole (1.3%). The most dominant compounds in C. zedoaria were curzerenone (21.5%), 1,8-cineole (19.6%), curzerene (6.2%), trans-β-Elemene (5.1%), camphor (2.6%), and germacrone (2.3%). The major components in C. aeruginosa were curzerenone (59.6%), germacrone (5.3%), curzerene (4.7%), camphor (3.6%), trans-β-Elemene (2.6%), and β-eudesmol (1.6%). C. zedoaria, and C. aeruginosa essential oil from Nepal for the very first time. This study reports for the first time chiral terpenoids from C. aeruginosa, C. zedoaria, and C. longa essential oil. A chemical blueprint of these essential oils could also be used as a tool for identification and quality assessment.

Anthelmintic Efficacy of Palmarosa Oil and Curcuma Oil against the Fish Ectoparasite Gyrodactylus kobayashii (monogenean)

Monogeneans are a serious threat to the development of aquaculture due to the severe economic losses they cause. The prevention and treatment of this disease are increasingly difficult because of the environmental and health concerns caused by the use of chemical anthelmintics and the emergence of drug resistance. It is thus necessary to search for effective alternatives for the treatment of monogenean infections. In the current study, anthelmintic efficacy of 16 selected essential oils (EOs) was investigated using the goldfish (Carassius auratus)–Gyrodactylus kobayashii model. The screening experiment indicated that palmarosa oil and curcuma oil had satisfactory anthelmintic activity against G. kobayashii with EC100 values of 10 and 12 mg/L after 24-h exposure, respectively. The in vivo and in vitro assays indicated anthelmintic efficacy of palmarosa oil against G. kobayashii was in a time and dose-dependent manner. Interestingly, curcuma oil showed an anesthetic effect on G. kobayashii, and its anthelmintic activity was dose-dependent rather than time-dependent in the concentration range tested in this study. Additionally, the 24-h LC50 (50% lethal concentration) against goldfish of these two EOs was 8.19-fold and 5.54-fold higher than their corresponding EC50 (50% effective concentration) against G. kobayashii, respectively. Moreover, exposure to these two EOs at 100% effective concentration against G. kobayashii had no serious physiological and histopathological influence on goldfish. These results demonstrated a high safety for goldfish of these two EOs. Overall, palmarosa oil and curcuma oil could be potential candidates for the treatment of G. kobayashii infections in aquaculture.

Foliar Spraying of Salicylic Acid Enhances Growth, Yield, and Curcuminoid Biosynthesis Gene Expression as Well as Curcuminoid Accumulation in Curcuma longa

The application of exogenously applied salicylic acid plays important roles in improving the growth, yield, and bioactive compound compositions of different plant species. Curcuma longa is a medicinal plant that is commonly used as a spice and food additive, and has antioxidant potential. In this study, an innovative strategy for enhancing active compound production was investigated by applying a natural plant growth enhancer—namely, salicylic acid (SA)—to C. longa plants. The experiment was conducted using a complete randomized block design. The effects of SA on the growth, yield, and chemical compound contents of C. longa were recorded. Our findings demonstrated that SA significantly improved C. longa growth, yield, and curcuminoid content when compared to control treatment, with SA at 10−3 M having the greatest effect. The study also indicated that the increase in the curcuminoid content was accompanied by the overexpression of the curcumin synthase 1 (CURS1), 2 (CURS2), and 3 (CURS3) genes, as well as the diketide-CoA synthase (DCS) gene, which have been implicated in the synthesis of curcuminoids.

Essential Oil Chemotypes of Four Vietnamese Curcuma Species Cultivated in North Alabama

Curcuma (turmeric) species are important culinary and medicinal plants, and the essential oils of Curcuma rhizomes have demonstrated promising pharmacological properties. The essential oils (EOs) of Curcuma species possess a wide variety of pharmacological properties, including anti-inflammatory, anticancerous, antiproliferative, hypocholesterolemic, antidiabetic, antirheumatic, hypotensive, antioxidant, antimicrobial, antiviral, antithrombotic, antityrosinase, and cyclooxygenase-1 (COX-1) inhibitory activities, among others have been attributed to the essential components of Curcuma species. Curcuma oils are also known to enhance immune function, promote blood circulation, accelerate toxin elimination, and stimulate digestion. C. longa (turmeric) and C. zedoaria (zedoary) are the most extensively studied species of Curcuma due to their high commercial value. There is some interest in expanding the cultivation of Curcuma species to regions in North America where the climate is favorable. The purpose of this work was to examine the rhizome essential oil compositions of four species of Curcuma (C. aromatica, C. caesia, C. longa, C. zanthorrhiza) that were obtained from Vietnam and cultivated in North Alabama. The rhizome essential oils were obtained by hydrodistillation and analyzed by gas chromatographic techniques. The essential oils of C. aromatica were dominated by curzerenone (14.7–18.6%), germacrone (10.7–14.7%), 1,8-cineole (5.2–11.7%), and an unidentified component (8.7–11.0%). The major components in C. longa rhizome oil were ar-turmerone (8.3–36.1%), α-turmerone (12.7–15.2%), β-turmerone (5.0–15.4%), α-zingiberene (4.6–13.9%), and β-sesquiphellandrene (4.6–10.0%). The essential oils of C. caesia and C. zanthorrhiza were rich in curzerenone, curdione, and germacrone. These adapted turmeric varieties in North Alabama have potential use for medical purposes and medicinal plant oil market demands in the U.S.