Further knowledge on the phenolic profile of Colocasia esculenta (L.) Shott

Comparative Metabolome and Transcriptome Analyses Reveal the Regulatory Mechanism of Purple Leafstalk Production in Taro (Colocasia esculenta L. Schott)

Taro is a plant in the Araceae family, and its leafstalk possesses significant botanical and culinary value owing to its noteworthy medicinal and nutritional attributes. Leafstalk colour is an essential attribute that significantly influences its desirability and appeal to both breeders and consumers. However, limited information is available about the underlying mechanism responsible for the taro plant's colouration. Thus, the purpose of the current study was to elucidate the information on purple leafstalks in taro through comprehensive metabolome and transcriptome analysis. In total, 187 flavonoids, including 10 anthocyanins, were identified. Among the various compounds analysed, it was observed that the concentrations of five anthocyanins (keracyanin chloride (cyanidin 3-O-rutinoside chloride), cyanidin 3-O-glucoside, tulipanin (delphinidin 3-rutinoside chloride), idaein chloride (cyanidin 3-O-galactoside), and cyanidin chloride) were found to be higher in purple taro leafstalk compared to green taro leafstalk. Furthermore, a total of 3330 differentially expressed genes (DEGs) were identified by transcriptome analysis. Subsequently, the correlation network analysis was performed to investigate the relationship between the expression levels of these differentially expressed genes and the content of anthocyanin. There were 18 DEGs encoding nine enzymes detected as the fundamental structural genes contributing to anthocyanin biosynthesis, along with seven transcription factors (3 MYB and 4 bHLH) that may be promising candidate modulators of the anthocyanin biosynthesis process in purple taro leafstalk. The findings of the current investigation not only provide a comprehensive transcriptional code, but also give information on anthocyanin metabolites as well as beneficial insights into the colour mechanism of purple taro leafstalk.

Activity of Colocasia esculenta (Taro) Corms against Gastric Adenocarcinoma Cells: Chemical Study and Molecular Characterization

Colocasia esculenta (L.) Schott is a tuberous plant, also known as taro, employed as food worldwide for its renowned nutritional properties but also traditionally used in several countries for medical purposes. In this study, methanolic extracts were prepared from the corms and leaves of Colocasia, subsequently fractionated via molecular exclusion chromatography (RP-HPLC) and their anti-tumor activity assessed in an in vitro model of gastric adenocarcinoma (AGS cells). Vorm extract and isolated fractions II and III affected AGS cell vitality in a dose-dependent manner through the modulation of key proteins involved in cell proliferation, apoptosis, and cell cycle processes, such as caspase 3, cyclin A, cdk2, IkBα, and ERK. To identify bioactive molecules responsible for anti-tumoral activity fractions II and III were further purified via RP-HPLC and characterized via nuclear magnetic resonance (NMR) and electrospray mass spectrometry (ESI-MS) techniques. The procedure enabled the identification of ten compounds including lignans and neolignans, some isolated for the first time in taro, uncommon megastigmane derivatives, and a gallic acid derivative. However, none of the isolated constituents showed efficacy equivalent to that of the fractions and total extract. This suggests that the whole Colocasia phytocomplex has intriguing anti-tumor activity against gastric cancer.

Ultrasound-Assisted Extraction of Taro Leaf Antioxidants Using Natural Deep Eutectic Solvents: An Eco-Friendly Strategy for the Valorization of Crop Residues

Colocasia esculenta L. leaves are considered a by-product of taro cultivation and are discarded as environmental waste, despite their valuable phenolic composition. Their valorization to obtain value-added substances for medicinal, food, and cosmetic applications is the aim of the current work. An ultrasound-assisted extraction was developed for the environmentally friendly and sustainable isolation of taro leaf antioxidants using natural deep eutectic solvents (NaDESs). Among the utilized solvents, the NaDES based on betaine and ethylene glycol provided the best extraction efficiencies in terms of polyphenolic content and antioxidant activity. Multi-response optimization suggested a solvent-to-solid ratio of 10 mL g-1, a processing time of 60 min, an extraction temperature of 60 °C, and a water content of 33.8% (w/w) as optimal extraction parameters. Leaf extract obtained under these optimum operational parameters demonstrated a strong radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (65.80 ± 0.87%), a high ferric reducing antioxidant power (126.62 ± 1.92 μmol TE g-1 sample), and significant protection against oxidative stress-induced DNA damage. The chromatographic characterization of the optimum extract revealed its richness in flavonoids (flavones and flavonols). The outcomes of the present study suggest that the proposed method could serve as a highly efficient and green alternative for the recovery of polyphenols from agricultural wastes.

Phytochemical Profiling by UPLC-ESI-QTOF-MS of Kalaharia uncinata (Schinz) Moldenke, Widely Used in Traditional Medicine in DR Congo

Kalaharia uncinata (Schinz) Moldenke, is a tropical erect bushy shrub or subshrub of the Lamiaceae family. It is an endemic plant species of Southern Africa, widely used in the pharmacopoeia against upper respiratory tract infections. A previously conducted ethnobotanical survey revealed that it is believed to contain bioactive substances. However, no relevant phytochemical information was available. This study aimed to perform a phytochemical characterization of K. uncinata and also to discuss the potential bioactivity of the identified phytochemical constituents based on documented data. Ultra-performance liquid chromatography with electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOF-MS) was used for profiling and identification of the main phytochemical constituents from leaf extracts (MeOH 90 %, DCM, AcOEt, BuOH, hexane and residue) of K.uncinata. Twenty-four constituents, representing mainly flavonoids (14), followed by phenylethanoid glycosides (7), phenolic acids (2), and an iridoid glycoside (1) were tentatively identified. Most of the identified compounds are documented to have antiviral and anti-inflammatory properties, which could possibly be the rationale behind the use of K. uncinata against upper respiratory tract infections.

Metabolite Profiling of Alocasia gigantea Leaf Extract and Its Potential Anticancer Effect through Autophagy in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a poor-prognosis type of cancer with high resistance to chemotherapy, making the search for safe drugs a mandatory issue. Plant-derived products have potential to reduce negative side effects of cancer treatments. In this work, ability of a defatted methanolic extract of Alocasia gigantea leaves to fight HCC was evaluated in an animal model. Overall, treatment of HCC-induced mice with the methanolic extract at 150 mg/kg body weight for four consecutive weeks caused induction of autophagy through silencing of the relative expression of autophagy suppressor (mTOR) and inducement of autophagy markers (AMPK, Beclin-1, and LC-3). Moreover, it improved preservation of the hepatic histological architecture of the animals, with minor hepatocytic changes but scattered foci of hepatocytic apoptosis. Chemical profiling of the methanolic extract via ultra-high-performance liquid chromatography coupled to a diode array detector and an electrospray mass spectrometer (UHPLC-DAD-ESI-MS/MS) allowed identification of di-C-glycosyl flavones, mostly represented by 6-C-hexosyl-8-C-pentosyl apigenin isomers, which may possibly be associated with inducement of the autophagy pathway in HCC. Overall, these outcomes gave an initial visualization of the operative effect of some compounds in A. gigantea leaves that are potential treatment for HCC.

Nutritional, phytochemical composition and potential health benefits of taro (Colocasia esculenta L.) leaves: A review

Colocasia esculenta(L) or taro is a tropical crop largely produced for its tubers (corms) while leaves and stems remain underutilized and untapped by-products with promising potential applications.Colocasialeaves are low in calories, rich in proteins, dietary fiber, and micronutrients. However, its utilization as food remains limited owing to the lack of awareness vis-à-vis its nutritional profile and the presence of antinutrients such as tannins, phytates and oxalates. The antinutritional factors can be overcome by cooking and varied processing techniques thereby unveiling the nutritional benefits. The high content of bioactive compounds and antioxidative potential of colocasia leaves renders several health benefits such as anticancer, antidiabetic, anti-inflammatory activity. The paper reviews the available literature on the nutritional, antinutritional, phytochemical profile of taro leaves and the advanced analytical techniques for their identification and quantification. Further, its health benefits and food applications have been discussed.

Apoptosis Induction Associated with Enhanced ER Stress Response and Up-Regulation of c-Jun/p38 MAPK Proteins in Human Cervical Cancer Cells by Colocasia esculenta var. aquatilis Hassk Extract

Colocasia esculenta var. Aquatilis Hassk, elephant ear (CF-EE) has been widely used as traditional food and medicine. It also shows other therapeutic properties, such as antimicrobial and anti-cancer activity. In this study, we aim to investigate the effect of CF-EE extract on apoptosis induction associated with ER stress in cervical cancer HeLa cells. Cell viability was determined by MTT assay. Assessments of nuclear morphological changes, mitochondrial membrane potential, and intracellular reactive oxygen species (ROS) production were conducted by hoeshst33342, JC-1, and DCFH-DA fluorescence staining, respectively. Sub-G1 DNA content was analyzed by flow cytometry, and protein expression was determined by Western blotting. The results demonstrate that CF-EE extract suppressed HeLa cell growth and induced nuclear condensation and apoptotic bodies. There was also a loss of mitochondrial membrane potential and increased apoptosis marker protein expression, including Bax, cleaved-caspase-7, and cleaved-PARP. In addition, the results show that CF-EE extract induced ROS, increased ER stress proteins (GRP78 and CHOP), enhanced p38 and c-Jun phosphorylation, and inhibited Akt expression in HeLa cells. In summary, CF-EE extract induced apoptotic cell death-associated ROS-induced ER stress and the MAPK/AKT signaling pathway. Therefore, CF-EE extract has anticancer therapeutic potential for cervical cancer treatment in the future.

Vis-NIR Hyperspectral Imaging for Online Quality Evaluation during Food Processing: A Case Study of Hot Air Drying of Purple-Speckled Cocoyam (Colocasia esculenta (L.) Schott)

In this study, hyperspectral imaging (HSI) and chemometrics were implemented to develop prediction models for moisture, colour, chemical and structural attributes of purple-speckled cocoyam slices subjected to hot-air drying. Since HSI systems are costly and computationally demanding, the selection of a narrow band of wavelengths can enable the utilisation of simpler multispectral systems. In this study, 19 optimal wavelengths in the spectral range 400–1700 nm were selected using PLS-BETA and PLS-VIP feature selection methods. Prediction models for the studied quality attributes were developed from the 19 wavelengths. Excellent prediction performance (RMSEP < 2.0, r2P > 0.90, RPDP > 3.5) was obtained for MC, RR, VS and aw. Good prediction performance (RMSEP < 8.0, r2P = 0.70–0.90, RPDP > 2.0) was obtained for PC, BI, CIELAB b*, chroma, TFC, TAA and hue angle. Additionally, PPA and WI were also predicted successfully. An assessment of the agreement between predictions from the non-invasive hyperspectral imaging technique and experimental results from the routine laboratory methods established the potential of the HSI technique to replace or be used interchangeably with laboratory measurements. Additionally, a comparison of full-spectrum model results and the reduced models demonstrated the potential replacement of HSI with simpler imaging systems.

Anticancer and Immunomodulatory Benefits of Taro (Colocasia esculenta) Corms, an Underexploited Tuber Crop

Taro corms contain valuable bioactive molecules effective against cancer and cancer-related risk factors, such as carcinogens and biological agents, several pathophysiological conditions, including oxidative stress and inflammation, while controlling metabolic dysfunctions and boosting the immunological response. Such broad effects are achieved by the taro health-influencing compounds displaying antitumoral, antimutagenic, immunomodulatory, anti-inflammatory, antioxidant, anti-hyperglycemic, and anti-hyperlipidemic activities. Taro bioactivities are attributed to the combination of tarin, taro-4-I polysaccharide, taro polysaccharides 1 and 2 (TPS-1 and TPS-2), A-1/B-2 α-amylase inhibitors, monogalactosyldiacylglycerols (MGDGs), digalactosyldiacylglycerols (DGDGs), polyphenols, and nonphenolic antioxidants. Most of these compounds have been purified and successfully challenged in vitro and in vivo, proving their involvement in the aforementioned activities. Although these health-promoting effects have been recognized since ancient times, as well as other valuable features of taro for food profit, such as hypo-allergenicity, gluten-free, and carbohydrates with medium-glycemic index, taro crop remains underexploited. The popularization of taro intake should be considered a dietary intervention strategy to be applied to improve the overall health status of the organism and as supportive therapy to manage tumorigenesis.

Effects of estrogen-like plant compounds on the vaginal epithelium pituitary, adrenal glands, and uterus of rats

Plant species with recognized estrogenic activity and widely used by Brazil’s female population to prevent the unpleasant symptoms of menopause were investigated in this work to demonstrate if constituents of taro-inhame (Colocasia esculenta ), cumaru (Dipteryx odorata ), and camapu (Physalis angulata ) have the ability to mimic or interfere with the action of estrogens. Moreover, their potential use as natural sources of estrogen-like substances for hormone replacement therapy was evaluated. (a) In vivo pharmacological assays were conducted to determine the estrogenic effects of D. odorata isoflavone-rich extract, P. angulata physalin-rich extract, and C. esculenta flavonoid glycoside-rich fraction (FG) on endocrine glands and reproductive organs of female rats at three different stages of the life cycle. The protocols consisted of uterotrophic assays and cytological evaluation of vaginal smears to detect mucosa cell alterations correlated with changes in hormone levels in each phase of the estrous cycle of female rats. The results indicated that C. esculenta FG exhibited estrogenic activity in prepubescent, pubescent, and adult ovariectomized female rats, while D. odorata isoflavones only promoted a weight increase in the pituitary gland of prepubescent rats after prolonged treatment and P. angulata physalins induced a weight increment in the adrenal glands of ovariectomized rats. Additionally, C. esculenta exerted a significant effect on the opening of the vaginal canal in prepubescent rats and on vaginal epithelium. Prolonged treatment of ovariectomized rats with FG altered the proportion of different types of vaginal epithelial cells in these animals, suggesting an interference of FG with estrogen levels. Colocasia esculenta FG induced hypertrophy of the uterus and pituitary in ovariectomized rats similar to estradiol. To elucidate the mechanism of action of FG, its effects were compared to those of estradiol and of the selective estrogen receptor modulator raloxifene. The results suggest that the efficacy of C. esculenta FG is mediated by binding to selective estrogen receptors present in each organ and that raloxifene inhibits the mechanism of action of FG in the same way as it inhibits the effects of estradiol. The overall findings indicate that C. esculenta FG mimics the action of estrogens, with reduced harmful effects on specific tissues.

Tarin, a Potential Immunomodulator and COX-Inhibitor Lectin Found in Taro (Colocasia esculenta)

Taro (Colocasia esculenta) corm is a rustic staple food, rich in small starch granules, fibers, and bioactive phytoconstituents such as flavonoids, alkaloids, sterols, tannins, phytates, micronutrients, and proteins, including tarin, a GNA-related lectin. Tarin exhibits recognized biocide activities against viruses and insects, has antitumoral properties and is an immunomodulator molecule candidate. It has been isolated in highly purified form (>90%) from taro corms through low-cost and single-step affinity chromatography. It comprises 2-domain 27 to 28 kDa protomer, posttranslational cleaved into 2 nonidentical monomers, 11.9 and 12.6 kDa, held by noncovalent binding. At least 10 tarin isoforms sharing over 70% similarity have been described. The monomers assume the β-prism II fold, consisting of 3 antiparallel β-sheets formed by 4 β-strands each. Tarin exhibits an expanded-binding site for complex and high-mannose N-glycan chains 49, 212, 213, 358, 465, and 477 found on cell surface antigens of viruses, insects, cancer, and hematopoietic cells, explaining its broad biological activities. Tarin may stimulate innate and adaptive immune responses, enabling hosts to recover from infections or immunosuppressed status inherent to several pathological conditions. In a murine model, tarin stimulates the in vitro and in vivo proliferation of total spleen and bone marrow cells, especially B lymphocytes. Granulocyte repopulation has also been demonstrated in long-term mice bone marrow cell cultures. As a potential immunomodulator, tarin, administered to immunosuppressed mice, attenuated cyclophosphamide-induced leukopenia. We propose a molecular model that unites the potential prophylactic and therapeutic action of tarin on hematopoietic and cancer cells, as a potential immunomodulator.

Polyphenols from Root, Tubercles and Grains Cropped in Brazil: Chemical and Nutritional Characterization and Their Effects on Human Health and Diseases

Throughout evolution, plants have developed the ability to produce secondary phenolic metabolites, which are important for their interactions with the environment, reproductive strategies and defense mechanisms. These (poly)phenolic compounds are a heterogeneous group of natural antioxidants found in vegetables, cereals and leguminous that exert beneficial and protective actions on human health, playing roles such as enzymatic reaction inhibitors and cofactors, toxic chemicals scavengers and biochemical reaction substrates, increasing the absorption of essential nutrients and selectively inhibiting deleterious intestinal bacteria. Polyphenols present in some commodity grains, such as soy and cocoa beans, as well as in other vegetables considered security foods for developing countries, including cassava, taro and beetroot, all of them cropped in Brazil, have been identified and quantified in order to point out their bioavailability and the adequate dietary intake to promote health. The effects of the flavonoid and non-flavonoid compounds present in these vegetables, their metabolism and their effects on preventing chronic and degenerative disorders like cancers, diabetes, osteoporosis, cardiovascular and neurological diseases are herein discussed based on recent epidemiological studies.

The LC/ESI-MSMS Profiles and Biological Potentials of Vitex agnus castus Extracts

The chemical profile, cytotoxic and apoptotic effect, and antioxidant activity were determined of ethanolic extracts of Vitex agnus-castus L. (chaste tree). Ripened fruits and fruitless aerial parts were extracted with ethanol, and the chemical characterization of the extracts was determined by LC/ESI-MS-MS. Twelve compounds were tentatively identified in the extracts. The dose-dependent cytotoxic effects of the extracts were tested on C6, A549 and MCF-7 cells by using MTT assay; inhibition of DNA synthesis, and apoptotic and caspase-3 activation effects of the extracts were determined. The potential antioxidant activities of the extracts were evaluated by in vitro methods such as DPPH and ABTS scavenging activity, reducing power and β-carotene bleaching assays. The fruit extract showed noticeable cytotoxic activity against MCF-7 cells with an IC50 value of 88 μg/mL. Both extracts showed similar DPPH scavenging activity comparably with that of the standard.

Antiviral Action of Hydromethanolic Extract of Geopropolis from Scaptotrigona postica against Antiherpes Simplex Virus (HSV-1)

The studies on chemical composition and biological activity of propolis had focused mainly on species Apis mellifera L. (Hymenoptera: Apidae). There are few studies about the uncommon propolis collected by stingless bees of the Meliponini tribe known as geopropolis. The geopropolis from Scaptotrigona postica was collected in the region of Barra do Corda, Maranhão state, Brazil. The chemical analysis of hydromethanolic extract of this geopropolis (HMG) was carried out through HPLC-DAD-ESI-MS/MS and the main constituents found were pyrrolizidine alkaloids and C-glycosyl flavones. The presence of alkaloids in extracts of propolis is detected for the first time in this sample. The antiviral activity of HMG was evaluated through viral DNA quantification experiments and electron microscopy experiments. Quantification of viral DNA from herpes virus showed reduction of about 98% in all conditions and concentration tested of the HMG extract. The results obtained were corroborated by transmission electron microscopy, in which the images did not show particle or viral replication complex. The antiviral activity of C-glycosyl flavones was reported for a variety of viruses, being observed at different points in the viral replication. This work is the first report about the antiviral activity of geopropolis from Scaptotrigona postica, in vitro, against antiherpes simplex virus (HSV).

Development and validation of an UHPLC-LTQ-Orbitrap MS method for non-anthocyanin flavonoids quantification in Euterpe oleracea juice

Euterpe oleracea fruits have gained much attention because of their phenolic constituents that have shown potential health benefits. The aim of this work was to quantify the major non-anthocyanin flavonoids (NAF) in the fruit juice by an accurate method coupling ultra-high pressure liquid chromatography with a linear ion trap-high resolution Orbitrap mass spectrometry system (UHPLC-LTQ-Orbitrap MS). Fruits were processed to juice, and then the juice was lyophilized and defatted. The residue was then extracted in the presence of methanol by sonication. The extraction time was optimized and recovery rates of the extraction were >90%. The extracts were dried and solubilized again in 40% MeOH, which showed the best compromise for MS detection. For the UHPLC quantification, a HSS C18 column (1.8 μm) was used with a gradient elution of methanol and water both with 0.1% formic acid. Total error and accuracy profiles were used as validation criteria. Seven compounds and their isomers were successfully separated, including the major NAF. Calibration in the matrix was found to be more accurate than calibration without matrix. Trueness (<15% relative bias), repeatability, and intermediate precision (<13% RSD), selectivity, response function, linearity, LOD (ranged from 0.04 to 0.81 μg/mL) and LOQ (0.15-5.78 μg/mL) for 12 compounds were evaluated and the quantification method was validated. Its applicability was demonstrated on real samples from different suppliers. Their qualitative and quantitative profiles were similar and some compounds were for the first time quantified. In addition, eriodictyol was identified for the first time in this fruit along with five other flavonoids for which possible structures were proposed.

Influence of taro (Colocasia esculenta L. Shott) growth conditions on the phenolic composition and biological properties

Colocasia esculenta (L.) Shott, commonly known as taro, is an essential food for millions of people. The leaves are consumed in sauces, purees, stews, and soups, being also used in wound healing treatment. Nowadays, the consumers' demand for bioactive compounds from the diet led to the development of new agricultural strategies for the production of health-promoting constituents in vegetables. In this work, two strategies (variety choice and irrigation conditions) were considered in the cultivation of C. esculenta. The effect on the phenolic composition of the leaves was evaluated. Furthermore, a correlation between the biological activity of the different varieties and their chemical composition was established. Qualitative and quantitative differences in the phenolic composition were observed between varieties; furthermore, the irrigation conditions also influenced the composition. C. esculenta varieties were able to scavenge several oxidant species and to inhibit hyaluronidase, but data suggest that metabolites other than phenolics are involved. The results show that cultivation strategies can effectively modulate the accumulation of these types of bioactive compounds. Furthermore C. esculenta wound healing potential can be attributed, at least in part, to the protection of the wound site against oxidative/nitrosative damage and prevention of hyaluronic acid degradation.