Tamarillo (Solanum betaceum): Chemical composition, biological properties, and product innovation

A Review of Phototoxic Plants, Their Phototoxic Metabolites, and Possible Developments as Photosensitizers

This study provides a comprehensive overview of the current knowledge regarding phototoxic terrestrial plants and their phototoxic and photosensitizing metabolites. Within the 435,000 land plant species, only around 250 vascular plants have been documented as phototoxic or implicated in phototoxic occurrences in humans and animals. This work compiles a comprehensive catalog of these phototoxic plant species, organized alphabetically based on their taxonomic family. The dataset encompasses meticulous details including taxonomy, geographical distribution, vernacular names, and information on the nature and structure of their phototoxic and photosensitizing molecule(s). Subsequently, this study undertook an in-depth investigation into phototoxic molecules, resulting in the compilation of a comprehensive and up-to-date list of phytochemicals exhibiting phototoxic or photosensitizing activity synthesized by terrestrial plants. For each identified molecule, an extensive review was conducted, encompassing discussions on its phototoxic activity, chemical family, occurrence in plant families or species, distribution within different plant tissues and organs, as well as the biogeographical locations of the producer species worldwide. The analysis also includes a thorough discussion on the potential use of these molecules for the development of new photosensitizers that could be used in topical or injectable formulations for antimicrobial and anticancer phototherapy as well as manufacturing of photoactive devices.

Functional and Antioxidant Evaluation of Two Ecotypes of Control and Grafted Tree Tomato (Solanum betaceum) at Different Altitudes

Tree tomato (Solanum betaceum) is susceptible to nematode attack; for this reason, grafting is used as an alternative to reduce this impact. In this study, the bioactive compounds of the fruit (shell, pulp, and seed jelly) of two tree tomato ecotypes ('giant orange' and 'giant purple') were evaluated in both control and grafted plants grown at different altitudes (2010-2250, 2260-2500, 2510-2750 and 2760-3000 masl). Commercial quality, vitamin C, organic acids, phenolics, carotenoids and antioxidant activity were determined by microextraction and quantified by liquid chromatography (RRLC) or spectrophotometry (microplate reader). The results showed high concentrations of vitamin C, organic acids and antioxidant activity in the seed jelly, organic acids in the pulp and phenolic compounds, carotenoids, and antioxidant activity in the shell. The main phenolics were ferulic acid, caffeic acid and luteolin, while the main carotenoids were lutein, B-cryptoxanthin and B-carotene. Multivariate analysis showed that tree tomato quality was mainly influenced by altitude and fruit part and that grafting positively affected soluble solids for both ecotypes and all altitudes.

Primary Metabolite Screening Shows Significant Differences between Embryogenic and Non-Embryogenic Callus of Tamarillo (Solanum betaceum Cav.)

Tamarillo is a solanaceous tree that has been extensively studied in terms of in vitro clonal propagation, namely somatic embryogenesis. In this work, a protocol of indirect somatic embryogenesis was applied to obtain embryogenic and non-embryogenic callus from leaf segments. Nuclear magnetic resonance spectroscopy was used to analyze the primary metabolome of these distinct calli to elucidate possible differentiation mechanisms from the common genetic background callus. Standard multivariate analysis methods were then applied, and were complemented by univariate statistical methods to identify differentially expressed primary metabolites and related metabolic pathways. The results showed carbohydrate and lipid metabolism to be the most relevant in all the calli assayed, with most discriminant metabolites being fructose, glucose and to a lesser extent choline. The glycolytic rate was higher in embryogenic calli, which shows, overall, a higher rate of sugar catabolism and a different profile of phospholipids with a choline/ethanolamine analysis. In general, our results show that a distinct primary metabolome between embryogenic and non-embryogenic calli occurs and that intracellular levels of fructose and sucrose and the glucose to sucrose ratio seem to be good candidates as biochemical biomarkers of embryogenic competence.

Physicochemical, Antioxidant, Sensory, and Starch Digestibility Properties of Steamed Bread Fortified with Tamarillo Powder

The effects of lyophilized tamarillo powder (TP) on the physicochemical, antioxidant, sensory, and starch digestibility characteristics of steamed breads were studied. The TP was used to substitute 5-20% of wheat flour to make steamed breads, assigned as T5, T10, T15, and T20, respectively. The results showed that TP is rich in dietary fiber (36.45%). Its extract is rich in bioactive components, including phenolic compounds (28.90 mg GAE/g extract), ascorbic acid (3.25 mg/g extract), total anthocyanins (316.35 μg C3GE/g extract), and total carotenoids (12.68 μg βCE/g extract) and has good antioxidant capacity. As the level of TP increased, the color of steamed breads became darker, redder, and yellower; the texture became harder, and the overall consumption preference decreased. However, their bioactive components content and antioxidant activity increased. The starch hydrolysis percentage of T5 (43.82%), T10 (41.57%), T15 (37.41%), and T20 (35.63%) at 180 min was significantly lower than that of the control (49.80%) (p < 0.05). The in vitro predicted glycemic index (80.02) of T20 was categorized as a medium-GI food when bread was used as the reference. On a nine-point hedonic test, control and T5 had the highest overall preference scores (7.1-7.4). The T20 supplemented with extra 15-20% water improved its volume and specific volume, and the overall preference scores (7.4-7.5) were not significantly different from the control (p > 0.05). Overall, a partial replacement of wheat flour with TP in steamed bread making could be developed as a new type of medium-GI value food containing more bioactive components and effective antioxidant capacity.

Unearthing of the Antidiabetic Potential of Aqueous Extract of Solanum betaceum Cav. Leaves

Solanum betaceum Cav., commonly known as tamarillo or Brazilian tomato, belongs to the Solanaceae family. Its fruit is used in traditional medicine and food crops due to its health benefits. Despite the numerous studies involving the fruit, there is no scientific knowledge about the tamarillo tree leaves. In this work, the phenolic profile of aqueous extract obtained from S. betaceum leaves was unveiled for the first time. Five hydroxycinnamic phenolic acids were identified and quantified, including 3-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, chlorogenic acid, caffeic acid and rosmarinic acid. While the extract displayed no effect on α-amylase, the extract inhibited the activity of α-glucosidase (IC₅₀ = 1617 mg/mL), and it was particularly effective for human aldose reductase (IC₅₀ = 0.236 mg/mL): a key enzyme in glucose metabolism. Moreover, the extract exhibited interesting antioxidant properties, such as a potent capacity to intercept the in vitro-generated reactive species O₂^•- (IC₅₀ = 0.119 mg/mL) and ^•NO (IC₅₀ = 0.299 mg/mL), as well as to inhibit the first stages of lipid peroxidation (IC₅₀ = 0.080 mg/mL). This study highlights the biological potential of S. betaceum leaves. The scarcity of research on this natural resource underscores the need for additional studies in order to fully explore its antidiabetic properties and to promote the value of a species currently at risk of extinction.

An Efficient Agrobacterium-Mediated Genetic Transformation Method for Solanum betaceum Cav. Embryogenic Callus

Somatic embryogenesis in Solanum betaceum (tamarillo) has proven to be an effective model system for studying morphogenesis, since optimized plant regeneration protocols are available, and embryogenic competent cell lines can be induced from different explants. Nevertheless, an efficient genetic transformation system for embryogenic callus (EC) has not yet been implemented for this species. Here, an optimized faster protocol of genetic transformation using Agrobacterium tumefaciens is described for EC. The sensitivity of EC to three antibiotics was determined, and kanamycin proved to be the best selective agent for tamarillo callus. Two Agrobacterium strains, EHA105 and LBA4404, both harboring the p35SGUSINT plasmid, carrying the reporter gene for β-glucuronidase (gus) and the marker gene neomycin phosphotransferase (nptII), were used to test the efficiency of the process. To increase the success of the genetic transformation, a cold-shock treatment, coconut water, polyvinylpyrrolidone and an appropriate selection schedule based on antibiotic resistance were employed. The genetic transformation was evaluated by GUS assay and PCR-based techniques, and a 100% efficiency rate was confirmed in the kanamycin-resistant EC clumps. Genetic transformation with the EHA105 strain resulted in higher values for gus insertion in the genome. The protocol presented provides a useful tool for functional gene analysis and biotechnology approaches.

Antioxidant Potential of Tamarillo Fruits-Chemical and Infrared Spectroscopy Analysis

Native to South America, tamarillo (Solanum betaceum Cav.) is a small tree cultivated as a fruit crop in several regions of the world. Known for its sweet and sour taste, tamarillo fruits are very nutritious due to the presence of health-beneficial components such as fiber, vitamins, and antioxidants. Despite its nutritional value, tamarillo remains poorly known in global markets. The present work aims to study the antioxidant activity of four genotypes of tamarillo. Several chemical assays were performed to assess the antioxidant components and antioxidant activity of aqueous ethanolic extracts from each genotype. Overall, the Mealhada genotype (a red cultivar) showed the most interesting results, displaying the highest amount of total phenolic, flavonoids, and anthocyanin contents, as well as higher antioxidant activity. To evaluate the composition of the extract, Fourier-transform infrared spectroscopy (FTIR) was used to characterize important components in aqueous ethanolic extracts of the fruits, having revealed the presence of high amounts of phenols (the main compounds responsible for antioxidant activity), as well as triterpenoids and polysaccharides. The present results highlight the potential nutraceutical importance of tamarillo fruits.

Averrhoa carambola L., Cyphomandra betacea, Myrciaria dubia as a Source of Bioactive Compounds of Antioxidant Properties

Natural bioactive compounds play an important role in the prevention of various diseases. The exotic fruits Averrhoa carambola L. (star fruit), Cyphomandra betacea (tamarillo) and Myrciaria dubia (camu-camu) can be valuable sources of phytochemicals with antioxidant properties. The aim of this study has been to compare the antioxidant properties of these exotic fruits, the structure of polyphenolic compounds and the content of vitamin C and β-carotene. All the juices were analyzed for their antioxidant capacity (DPPH and ABTS assays) and the composition of phenolic compounds (TP and FBBB assays, total flavonoid content, total anthocyanins). In addition, HPLC assays were performed to analyse the content of phenolic acids, flavonoids, vitamin C and β-carotene. The results demonstrated that juice from the Myrciaria dubia fruit had the highest antioxidant capacity, which was 4.5-fold higher than that of juice from Averrhola carambola L., and nearly 7-fold higher than the antioxidant capacity of Cyphomandra betacea fruit juice. Additionally, juice from the camu-camu fruit had a 3- to 4-fold higher total polyphenol content (8290 ± 254 mg GAE L^-1) and a high level of vitamin C (8410.8 ± 16.9 mg AA kg^-1). In turn, tamarillo juice had a high content of total anthocyanins (5796 mg CGE L^-1) and phenolic acids (mostly chlorogenic acid and caffeic acid). Juice produced from carambola had a high content of total flavonoids (1345 mg CAE L^-1), and the composition of these compounds was dominated by flavanols (epicatechin). The research results justify the conclusion that fruits of Myrciaria dubia, Averrhoa carambola L., Cyphomandra betacea are rich sources of bioactive compounds with antioxidant properties, and in the near future may serve as healthful food ingredients.

Blood–Brain Barrier Permeability Study of Potential Neuroprotective Compounds Recovered From Plants and Agri-Food by-Products

Plants and agri-food by-products represent a wide and renewable source of bioactive compounds with neuroprotective properties. In this research, various green extraction techniques were employed to recover bioactive molecules from Kalanchoe daigremontiana (kalanchoe), epicarp of Cyphomandra betacea (tamarillo), and cooperage woods from Robinia pseudoacacia (acacia) and Nothofagus pumilio (lenga), as well as a reference extract (positive control) from Rosmarinus officinalis L. (rosemary). The neuroprotective capacity of these plant extracts was evaluated in a set of in vitro assays, including enzymatic [acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and lipoxygenase (LOX)] and antioxidant [ABTS, and reactive oxygen and nitrogen species (ROS and RNS)] bioactivity tests. Extracts were also submitted to a parallel artificial membrane permeability assay mimicking the blood–brain barrier (PAMPA-BBB) and to two cell viability assays in HK-2 and SH-SY5Y cell lines. Comprehensive phytochemical profiling based on liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (LC-Q-TOF-MS) analysis showed enriched content of phenolic and terpenoid compounds in the target extracts. Moreover, in vitro bioactivity tests showed promising neuroprotective capacity, particularly for supercritical-fluid extraction (SFE) extract from acacia (ABTS IC₅₀ = 0.11 μg ml⁻¹; ROS IC₅₀ = 1.56 μg ml⁻¹; AChE IC₅₀ = 4.23 μg ml⁻¹; BChE IC₅₀ = 1.20 μg ml⁻¹; and LOX IC₅₀ = 4.37 μg ml⁻¹), whereas PAMPA-BBB assays revealed high perfusion capacity of some representative compounds, such as phenolic acids or flavonoids. Regarding cytotoxic assays, tamarillo and rosemary SFE extracts can be considered as non-toxic, acacia SFE extract and lenga pressurized liquid extraction (PLE) extract as mild-cytotoxic, and kalanchoe as highly toxic extracts. The obtained results demonstrate the great potential of the studied biomass extracts to be transformed into valuable food additives, food supplements, or nutraceuticals with promising neuroprotective properties.

The powerful Solanaceae: Food and nutraceutical applications in a sustainable world

The Solanaceae family is considered one of the most important families among plant species because, on one hand encompasses many staple food crops of the human diet while, on the other hand, it includes species rich in powerful secondary metabolites that could be valorized in medicine or drug formulation as well as nutraceuticals and food supplements. The main genera are Solanum, Capsicum, Physalis, and Lycium which comprise several important cultivated crops (e.g., tomato, pepper, eggplant, tomatillo, and goji berry), as well as genera notable for species with several pharmaceutical properties (e.g., Datura, Nicotiana, Atropa, Mandragora, etc.). This chapter discusses the nutritional value of the most important Solanaceae species commonly used for their edible fruit, as well as those used in the development of functional foods, food supplements, and nutraceuticals due to their bioactive constituents. The toxic and poisonous effects are also discussed aiming to highlight possible detrimental consequences due to irrational use. Finally, considering the high amount of waste and by-products generated through the value chain of the main crops, the sustainable management practices implemented so far are presented with the aim to increase the added-value of these crops.

Simultaneous Quantification of Organic Acids in Tamarillo (Solanum betaceum) and Untargeted Chemotyping Using Methyl Chloroformate Derivatisation and GC-MS

Sixteen organic acids were quantified in peel and pulp of Amber, Laird’s Large and Mulligan cultivars of tamarillo using GC-MS. Fourteen of these compounds had not previously been quantified in tamarillo. An untargeted metabolomics approach was used in parallel to identify and quantify 64 more metabolites relative to the internal standard, indicating abundances of glutamic acid, pro-line, aspartic acid and γ-aminobutyric acid as well as lower concentrations of several other essential fatty acids and amino acids. The main findings were that total organic acid concentration was significantly higher (p < 0.05) in pulp than in peel, with the highest concentration seen in Mulligan pulp (219.7 mg/g DW). Remarkably, after citric acid, the potent bactericide itaconic acid was the second most abundant organic acid. At least 95% of organic acids in tamarillo were one of these two acids, as well as cis-aconitic, malic and 4-toluic acids. Differences between cultivar chemotypes were as substantial as differences between tissues. These results suggest that the bitter flavour of the peel does not result from organic acids. The combination of targeted and untargeted metabolomics techniques for simultaneous qualitative and quantitative investigation of nutrients and flavours is efficient and informative.

Phytochemical Characterization of a Tree Tomato (Solanum betaceum Cav.) Breeding Population Grown in the Inter-Andean Valley of Ecuador

Tree tomato (Solanum betaceum Cav.) is an Andean fruit crop that is grown in Ecuador. It is an exceptional source of minerals and vitamins, thus has nutraceutical properties. The objective of this research was to carry out a phytochemical characterization of a breeding population composed of 90 segregants. Pulp (including mesocarp, mucilage, seeds and placenta) was ground and sieved in order to obtain the liquid pulp to be lyophilized for the chemical analyzes. Antioxidants compounds were determined by spectrophotometry and vitamin C by reflectometry. Data were analyzed by principal components, grouping, and variance analyses; in addition, Z Score estimation was carried out to select elite individuals. There was a broad variability in the data obtained for the breeding population, polyphenol content varied from 5.11 to 16.59 mg GAE g^-1, flavonoids from 1.24 to 6.70 mg cat g^-1, carotenoids from 50.39 to 460.72 µg β-carotene g^-1, anthocyanins from 1.06 to 240.49 mg cy-3-glu 100 g^-1, antioxidant capacity from 49.51 to 312.30 µm Trolox g^-1, and vitamin C from 78.29 to 420.16 mg 100 g^-1. It can be concluded that tree tomato is a good source of beneficial biocompounds and has a high antioxidant capacity.

Neuroprotective Potential of Tamarillo (Cyphomandra betacea) Epicarp Extracts Obtained by Sustainable Extraction Process

Tamarillo (Cyphomandra betacea (Cav.) Sendt.), or tree tomato, is a tropical fruit from the Andean region of South America; it is highly rich in vitamins, minerals, and polyphenolic compounds. In this study, extracts from tamarillo epicarp (TE) were obtained by pressurized liquid extraction (PLE), and their in-vitro neuroprotective potential was assessed. A central composite design with response surface methodology was performed to optimize PLE as a function of solvent composition and temperature. Selected response variables were extraction yield, total phenolic content (TPC), total flavonoid content (TFC), total carotenoid content (TCC), antioxidant (ABTS), and anti-inflammatory (LOX) activities, and anti-acetylcholinesterase (AChE) inhibitory capacity. According to the desirability function, the optimal conditions were 100% ethanol and 180°C with a 0.87 desirability value. Next, the anti-butyrylcholinesterase enzyme (BChE), reactive oxygen species (ROS), and reactive nitrogen species (RNS) inhibition as well as cytotoxicity in HK-2, THP-1 monocytes, and SH-5YSY neuroblastoma cell lines were studied for the TE extract obtained under optimized conditions. The optimum TE extract provided the following results: extraction yield (36.25%), TPC (92.09 mg GAE/g extract), TFC (4.4 mg QE/g extract), TCC (107.15 mg CE/g extract), antioxidant capacity (ABTS, IC₅₀ = 6.33 mg/ml extract), LOX (IC₅₀ = 48.3 mg/ml extract), and AChE (IC₅₀ = 97.46 mg/ml extract), and showed no toxicity at concentration up to 120 μg/ml extract for all the tested cell lines. Finally, chemical characterization by liquid chromatography-tandem mass spectrometry (UHPLC-q-TOF-MS/MS) of the optimum TE extract exhibited an important presence of hydroxycinnamic acid derivatives and other phenolic acids as well as quercetin hexoside and rutin, as main metabolites responsible for the observed biological properties. All these results suggested that TE, which represents between 8 and 15% of the total fruit, could become a promising natural by-product with a potential "multitarget" activity against Alzheimer's disease.

Elucidation of Endogenous Aroma Compounds in Tamarillo (Solanum betaceum) Using a Molecular Sensory Approach

Glycosidically bound volatiles (GBVs) are flavorless compounds in fruits and may undergo hydrolysis during fruit maturation, storage, and processing, releasing free aglycones that are odor active. However, the contribution of glycosidic aglycones to the sensory attributes of fruits remains unclear. Herein, the key odor-active aglycones in tamarillo fruits were elucidated through the molecular sensory approach. We extracted GBVs from three cultivars of tamarillo fruits using solid-phase extraction and subsequently prepared aglycone isolates by enzymatic hydrolysis of GBVs. Gas chromatography-mass spectrometry-olfactometry (GC-MS-O) coupled with odor activity value (OAV) calculation, comparative aroma extract dilution analysis (cAEDA), and omission tests were used to identify key aromatic aglycones. A total of 42 odorants were determined by GC-MS-O analysis. Among them, trans-2,cis-6-nonadienal, 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF), linalool, 4-vinylguaiacol, geraniol, and α-terpineol showed high OAVs. The cultivar Amber had more aglycones with flavor dilution (FD) factors >16 than the Mulligan cultivar (27 vs 21, respectively), and the Laird's Large fruit showed the highest FD of 1024 for glycosidic DMHF. Omission tests indicated 14 aglycones as essential odorants related to GBVs in tamarillo fruits. Moreover, the enzymatic liberation of aglycones affected the sensory attributes of the tamarillo juice, resulting in an intensified odor profile with noticeable fruity and sweet notes. This study gives insights into the role of endogenous aroma during tamarillo-flavor perception, which lays the groundwork for developing tamarillo-based products with improved sensory properties.

Free and Glycosidic Volatiles in Tamarillo (Solanum betaceum Cav. syn. Cyphomandra betacea Sendt.) Juices Prepared from Three Cultivars Grown in New Zealand

This study investigated the free and glycosidic-bound volatiles in the juice samples of three tamarillo cultivars (i.e. Amber, Mulligan, and Laird's Large) that are widely grown in New Zealand. Juice samples were prepared from fruits at different ripening stages (green, middle, and ripe). Headspace solid-phase microextraction combined with gas chromatography-mass spectrometry was applied to analyze the free volatiles in the samples. A total of 20 free volatiles were detected. Among the samples, the ripe Mulligan juice gave the highest contents of free terpenoids (424 μg/L) and esters (691 μg/L). The glycosidic-bound volatiles were prepared by solid-phase extraction. The matrix effect was evaluated based on the recovery rate of analytes containing multiple aglycone classes. From the results, phenyl β-d-glucopyranoside was selected to compensate the matrix effect caused by insufficient acquisition of glycosidic volatiles during analyte preparation. In all the ripe-fruit juice samples, the aglycones 4-hydroxy-2,5-dimethyl-3(2H)-furanone and trans-2, cis-6-nonadienal were found to give high odor activity values. According to multivariate statistical analysis, 11 free volatiles and 22 glycosidic volatiles could be potentially applied as volatile makers to distinguish the juice samples. This study has provided a comprehensive understanding of the flavor chemistry of tamarillo juices, with a focus on the potential role of glycosidic aglycones as aroma contributors to tamarillo products.

Propriedades físico-químicas da polpa de tamarillo (Solanum betaceum) e sua aplicabilidade na elaboração de sorvetes

Resumo O tamarillo, também conhecido no Brasil como tomate de árvore, tem ganhado projeção devido à riqueza de nutrientes e compostos bioativos que apresenta, sendo um candidato promissor para aplicação pela indústria alimentícia. Ressalta-se que a adição de frutas tropicais na elaboração de sorvetes desempenha papel fundamental tanto nas características finais do produto como na aceitação dos consumidores. Os objetivos deste trabalho foram caracterizar físico-quimicamente as polpas de duas variedades de tamarillo e caracterizar físico-química e sensorialmente quatro formulações de sorvetes elaborados com a polpa do fruto. Para caracterização da polpa de fruta e do sorvete, foram realizadas análises de umidade, cinzas, carboidratos, proteína, gordura, acidez titulável, textura e overrun. Os sorvetes foram analisados sensorialmente para os atributos de cor, sabor, textura, impressão global e intenção de compra. Os parâmetros físico-químicos apresentaram diferenças tanto entre as variedades de tamarillo quanto entre as diferentes formulações de sorvete, exceto no teor proteico do fruto. Os valores de overrun dos sorvetes elaborados variaram de 66,41% a 92,30%. O sorvete adicionado de 20% de polpa de tamarillo roxo obteve a melhor nota no atributo sabor, 7,85. No geral, os produtos obtiveram boa aceitação. Conclui-se que a concentração e a variedade da polpa utilizada influenciam nas características do sorvete e que o tamarillo pode ser considerado uma fruta em potencial na fabricação do produto.

Electrochemical Methods and (Bio) Sensors for Rosmarinic Acid Investigation

Rosmarinic acid (RA) is an important bioactive phenolic acid with significant biochemical activities, including the antioxidant one. It is widely found in plants of the families Lamiaceae and Boraginaceae and has many uses in the food, pharmaceutical and cosmetics industries. RA is an electroactive species owing to the presence of the two catechol groups in its structure. Due to their inherent characteristics, such as sensitivity, selectivity, ease of operation and not too high costs, electrochemical methods of analysis are interesting tools for the assessment of redox-active compounds. Moreover, there is a good correlation between the redox potential of the analyte and its capability to donate electrons and, consequently, its antioxidant activity. Therefore, this paper presents a detailed overview of the electrochemical (bio)sensors and methods, in both stationary and dynamic systems, applied for RA investigation under different aspects. These comprise its antioxidant activity, its interaction with biological important molecules and the quantification of RA or total polyphenolic content in different samples.