Chronic ozone exposure alters the secondary metabolite profile, antioxidant potential, anti-inflammatory property, and quality of red pepper fruit from Capsicum baccatum

Elevated tropospheric ozone and crop production: potential negative effects and plant defense mechanisms

Ozone (O3) levels on Earth are increasing because of anthropogenic activities and natural processes. Ozone enters plants through the leaves, leading to the overgeneration of reactive oxygen species (ROS) in the mesophyll and guard cell walls. ROS can damage chloroplast ultrastructure and block photosynthetic electron transport. Ozone can lead to stomatal closure and alter stomatal conductance, thereby hindering carbon dioxide (CO2) fixation. Ozone-induced leaf chlorosis is common. All of these factors lead to a reduction in photosynthesis under O3 stress. Long-term exposure to high concentrations of O3 disrupts plant physiological processes, including water and nutrient uptake, respiration, and translocation of assimilates and metabolites. As a result, plant growth and reproductive performance are negatively affected. Thus, reduction in crop yield and deterioration of crop quality are the greatest effects of O3 stress on plants. Increased rates of hydrogen peroxide accumulation, lipid peroxidation, and ion leakage are the common indicators of oxidative damage in plants exposed to O3 stress. Ozone disrupts the antioxidant defense system of plants by disturbing enzymatic activity and non-enzymatic antioxidant content. Improving photosynthetic pathways, various physiological processes, antioxidant defense, and phytohormone regulation, which can be achieved through various approaches, have been reported as vital strategies for improving O3 stress tolerance in plants. In plants, O3 stress can be mitigated in several ways. However, improvements in crop management practices, CO2 fertilization, using chemical elicitors, nutrient management, and the selection of tolerant crop varieties have been documented to mitigate O3 stress in different plant species. In this review, the responses of O3-exposed plants are summarized, and different mitigation strategies to decrease O3 stress-induced damage and crop losses are discussed. Further research should be conducted to determine methods to mitigate crop loss, enhance plant antioxidant defenses, modify physiological characteristics, and apply protectants.

Effect of ozone stress on crop productivity: A threat to food security

Tropospheric ozone (O3), the most important phytotoxic air pollutant, can deteriorate crop quality and productivity. Notably, satellite and ground-level observations-based multimodel simulations demonstrate that the present and future predicted O3 exposures could threaten food security. Hence, the present study aims at reviewing the phytotoxicity caused by O3 pollution, which threatens the food security. The present review encompasses three major aspects; wherein the past and prevailing O3 concentrations in various regions were compiled at first, followed by discussing the physiological, biochemical and yield responses of economically important crop species, and considering the potential of O3 protectants to alleviate O3-induced phytotoxicity. Finally, the empirical data reported in the literature were quantitatively analysed to show that O3 causes detrimental effect on physiological traits, photosynthetic pigments, growth and yield attributes. The review on prevailing O3 concentrations over various regions, where economically important crop are grown, and their negative impact would support policy makers to implement air pollution regulations and the scientific community to develop countermeasures against O3 phytotoxicity for maintaining food security.

Secondary metabolites responses of plants exposed to ozone: an update

Tropospheric ozone (O3) is a secondary pollutant that causes oxidative stress in plants due to the generation of excess reactive oxygen species (ROS). Phenylpropanoid metabolism is induced as a usual response to stress in plants, and induction of key enzyme activities and accumulation of secondary metabolites occur, upon O3 exposure to provide resistance or tolerance. The phenylpropanoid, isoprenoid, and alkaloid pathways are the major secondary metabolic pathways from which plant defense metabolites emerge. Chronic exposure to O3 significantly accelerates the direction of carbon flows toward secondary metabolic pathways, resulting in a resource shift in favor of the synthesis of secondary products. Furthermore, since different cellular compartments have different levels of ROS sensitivity and metabolite sets, intracellular compartmentation of secondary antioxidative metabolites may play a role in O3-induced ROS detoxification. Plants' responses to resource partitioning often result in a trade-off between growth and defense under O3 stress. These metabolic adjustments help the plants to cope with the stress as well as for achieving new homeostasis. In this review, we discuss secondary metabolic pathways in response to O3 in plant species including crops, trees, and medicinal plants; and how the presence of this stressor affects their role as ROS scavengers and structural defense. Furthermore, we discussed how O3 affects key physiological traits in plants, foliar chemistry, and volatile emission, which affects plant-plant competition (allelopathy), and plant-insect interactions, along with an emphasis on soil dynamics, which affect the composition of soil communities via changing root exudation, litter decomposition, and other related processes.

Antioxidant potential and factors influencing the content of antioxidant compounds of pepper: A review with current knowledge

The use of natural food items as antioxidants has gained increasing popularity and attention in recent times supported by scientific studies validating the antioxidant properties of natural food items. Peppers (Capsicum spp.) are also important sources of antioxidants and several studies published during the last few decades identified and quantified various groups of phytochemicals with antioxidant capacities as well as indicated the influence of several pre- and postharvest factors on the antioxidant capacity of pepper. Therefore, this review summarizes the research findings on the antioxidant activity of pepper published to date and discusses their potential health benefits as well as the factors influencing the antioxidant activity in pepper. The major antioxidant compounds in pepper include capsaicinoids, capsinoids, vitamins, carotenoids, phenols, and flavonoids, and these antioxidants potentially modulate oxidative stress related to aging and diseases by targeting reactive oxygen and nitrogen species, lipid peroxidation products, as well as genes for transcription factors that regulate antioxidant response elements genes. The review also provides a systematic understanding of the factors that maintain or improve the antioxidant capacity of peppers and the application of these strategies offers options to pepper growers and spices industries for maximizing the antioxidant activity of peppers and their health benefits to consumers. In addition, the efficacy of pepper antioxidants, safety aspects, and formulations of novel products with pepper antioxidants have also been covered with future perspectives on potential innovative uses of pepper antioxidants in the future.

Genetic Regulation, Environmental Cues, and Extraction Methods for Higher Yield of Secondary Metabolites in Capsicum

Capsicum (chili pepper) is a widely popular and highly consumed fruit crop with beneficial secondary metabolites such as capsaicinoids, carotenoids, flavonoids, and polyphenols, among others. Interestingly, the secondary metabolite profile is a dynamic function of biosynthetic enzymes, regulatory transcription factors, developmental stage, abiotic and biotic environment, and extraction methods. We propose active manipulable genetic, environmental, and extraction controls for the modulation of quality and quantity of desired secondary metabolites in Capsicum species. Specific biosynthetic genes such as Pun (AT3) and AMT in the capsaicinoids pathway and PSY, LCY, and CCS in the carotenoid pathway can be genetically engineered for enhanced production of capsaicinoids and carotenoids, respectively. Generally, secondary metabolites increase with the ripening of the fruit; however, transcriptional regulators such as MYB, bHLH, and ERF control the extent of accumulation in specific tissues. The precise tuning of biotic and abiotic factors such as light, temperature, and chemical elicitors can maximize the accumulation and retention of secondary metabolites in pre- and postharvest settings. Finally, optimized extraction methods such as ultrasonication and supercritical fluid method can lead to a higher yield of secondary metabolites. Together, the integrated understanding of the genetic regulation of biosynthesis, elicitation treatments, and optimization of extraction methods can maximize the industrial production of secondary metabolites in Capsicum.

Role of Elevated Ozone on Development and Metabolite Contents of Lemongrass [Cymbopogon flexuosus (Steud.) (Wats.)]

The present study was conducted to assess the effect of elevated ozone stress on the development and metabolite contents of lemongrass, a medicinal plant. The experimental plant was exposed to two elevated ozone concentrations (ambient + 15 ppb, and ambient + 30 ppb) using open-top chambers. Samplings were carried out at 45 and 90 days after transplantation (DAT), for the analysis of different characteristics, while the metabolite contents of leaves and essential oils were analyzed at 110 DAT. Both the doses of elevated ozone had notable negative effects on the carbon fixation efficiency of plants, resulting in a significant reduction in plant biomass. Enzymatic antioxidant activity increased during the second sampling, which suggests that the scavenging of reactive oxygen species was more prominent in lemongrass during the later developmental stage. The results of the present study showed a stimulated diversion of resources towards the phenylpropanoid pathway, which is made evident by the increase in the number and contents of metabolites in foliar extract and essential oils of plants grown at elevated ozone doses, as compared to ambient ozone. Elevated ozone not only upregulated the contents of medicinally important components of lemongrass, it also induced the formation of some pharmaceutically active bio compounds. On the basis of this study, it is expected that increasing ozone concentrations in near future will enhance the medicinal value of lemongrass. However, more experiments are required to validate these findings.

Influence of ozone treatment on functional and rheological characteristics of food products: an updated review

In this milieu, ozone technology has emerged as an avant-garde non-thermal mode of disinfection with potential applications in the food industry. This eco-friendly technology has a comprehendible adeptness in replacing alternative chemical sanitizers and is recognized as a generally safe disinfectant for fruits and vegetables. Several researchers have been focusing on the biochemical impacts of ozone on different quantitative and qualitative aspects of fruits and vegetables. A collection of those works is presented in this review highlighting the effect of ozone on the functional, antioxidant, and rheological properties of food. This can be a benevolent tool for discovering the processing states of ozone applications and ensuing influence on safety and quality attributes of previously studied foods and opening further research areas. It extends shelf life and never leaves any harmful residues on the product since it decomposes to form oxygen. It was seen that the impact on a specific property of food was dependent on the ozone concentration and treatment time, and the adverse effects of ozone exposure can be alleviated once the processing conditions are optimized. The present review can be used as a baseline for designing different food processing operations involving ozone.

Season-long exposure of bilberry plants to realistic and future ozone pollution improves the nutraceutical quality of fruits

Ozone (O₃) is a phytotoxic air pollutant capable of limiting plant yield and growth, and altering the quality of edible plant products. This study aimed to investigate the effects of long-term O₃ exposure at realistic and future concentrations (applied during fruit development) not only on morphological, physiological, and biochemical plant/leaf traits of Vaccinium myrtillus but also on its fruit yield and quality. Three-year-old saplings were grown from May to July under three levels of O₃ concentration [1.0, 1.5 and 2.0 times the ambient air concentrations, denoted as AA, 1.5_AA and 2.0_AA], using a new-generation O₃ Free Air Controlled Exposure system. Ozone induced oxidative pressure and membrane denaturation as confirmed by the accumulation of anion superoxide, hydrogen peroxide (^•O₂^-: +39 and + 29%; H₂O₂: +55 and + 59% in 1.5_AA and 2.0_AA, respectively, compared with AA), and malondialdehyde by-product (1.4- and 2.5-fold higher than AA, in 1.5_AA and 2.0_AA, respectively). The observed oxidative burst likely affected several cellular structures interested by photosynthetic processes (e.g., decrease of the maximum rate of carboxylation: -30%). This constraint likely induced a decline in plant vitality and a different partitioning of biomass allocation between above and below organs. An accelerated maturation of bilberries due to O₃ was reported, suggesting that plants grown under harsher environmental conditions suffered from metabolic changes associated with early ripening. Increasing O₃ concentrations might be responsible for an alteration of the ratio between oxidation and reduction processes mechanisms that was followed by a loss of integrity of membranes, so limiting the availability of energy/resources, triggering enzymatic oxidation of phenols to red/purple pigments, and promoting fruit maturation. To the best of our knowledge, this is the first research showing that long-term O₃ exposure during bilberry fruit development influenced not only several plant/leaf traits, but also fruit nutraceutical quality at the time of harvest.

Biostimulant Capacity of an Enzymatic Extract From Rice Bran Against Ozone-Induced Damage in Capsicum annum

Ozone is a destructive pollutant, damaging crops, and decreasing crop yield. Therefore, there is great interest in finding strategies to alleviate ozone-induced crop losses. In plants, ozone enters leaves through the stomata and is immediately degraded into reactive oxygen species (ROS), producing ROS stress in plants. ROS stress can be controlled by ROS-scavenging systems that include enzymatic or non-enzymatic mechanisms. Our research group has developed a product from rice bran, a by-product of rice milling which has bioactive molecules that act as an antioxidant compound. This product is a water-soluble rice bran enzymatic extract (RBEE) which preserves all the properties and improves the solubility of proteins and the antioxidant components of rice bran. In previous works, the beneficial properties of RBEE have been demonstrated in animals. However, to date, RBEE has not been used as a protective agent against oxidative damage in agricultural fields. The main goal of this study was to investigate the ability of RBEE to be used as a biostimulant by preventing oxidative damage in plants, after ozone exposure. To perform this investigation, pepper plants (Capsicum annuum) exposed to ozone were treated with RBEE. RBEE protected the ozone-induced damage, as revealed by net photosynthetic rate and the content of photosynthetic pigments. RBEE also decreased the induction of antioxidant enzyme activities in leaves (catalase, superoxide dismutase, and ascorbate peroxidase) due to ozone exposure. ROS generation is a common consequence of diverse cellular traumas that also activate the mitogen-activated protein kinase (MAPK) cascade. Thus, it is known that the ozone damages are triggered by the MAPK cascade. To examine the involvement of the MAPK cascade in the ozone damage CaMPK6-1, CaMPK6-2, and CaMKK5 genes were analyzed by qRT-PCR. The results showed the involvement of the MAPK pathway in both, not only in ozone damage but especially in its protection by RBEE. Taken together, these results support that RBEE protects plants against ozone exposure and its use as a new biostimulant could be proposed.

The Influence of Environmental Conditions on Secondary Metabolites in Medicinal Plants: A Literature Review

Medicinal plants, a source of different phytochemical compounds, are now subjected to a variety of environmental stresses during their growth and development. Different ecologically limiting factors including temperature, carbon dioxide, lighting, ozone, soil water, soil salinity and soil fertility has significant impact on medicinal plants' physiological and biochemical responses, as well as the secondary metabolic process. Secondary metabolites (SMs) are useful for assessing the quality of therapeutic ingredients and nowadays, these are used as important natural derived drugs such as immune suppressant, antibiotics, anti-diabetic, and anti-cancer. Plants have the ability to synthesize a variety of secondary metabolites to cope with the negative effects of stress. Here, we focus on how individual environmental variables influence the accumulation of plant secondary metabolites. A total of 48 articles were found to be relevant to the review topic during our systematic review. The review showed the influence of different environmental variables on SMs production and accumulation is complex suggesting the relationship are not only species-specific but also related to increases and decline in SMs by up to 50 %. Therefore, this review improves our understanding of plant SMs ability to adapt to key environmental factors. This can aid in the efficient and long-term optimization of cultivation techniques under ambient environmental conditions in order to maximize the quality and quantity of SMs in plants.

Chitosan and putrescine modulate reactive oxygen species metabolism and physiological responses during chili fruit ripening

We investigated the combined effect of chitosan (CHT) and putrescine (PUT) on the postharvest shelf life of Capsicum fruit concerning the metabolism of reactive oxygen species (ROS) through direct and indirect effects on ripening characters cell wall hydrolyzing enzyme and ROS metabolism. The PUT and CHT directly affected quality indices like color, firmness and water loss with a concomitant oxidative bust in the development of O₂^•- and H₂O₂ in fruit pulp. This was accompanied by significant suppression of respiratory flux, a decrease of total soluble solids and ascorbic acid content throughout postharvest storage. PUT applied with CHT modified the oxidative metabolism of fruits by a significant reduction in the level of O₂^•- and H₂O₂ content. In addition, a significant accumulation of total polyamine under respective treatment was reasonably correlated with both ROS producing enzyme as well as H₂O₂ and O₂^•-. Wall hydrolyzing enzymes like pectin methyl esterase and cellulase had marked downregulation both under PUT and CHT + PUT treatment. Moreover, on close observation, the combinational effects of PUT and CHT had better effects in the regulation of those enzymes as compared to individual treatment. Fruits restore higher antioxidative capacities as evident with superoxide dismutase (SOD), guaiacol peroxidases (GPX), ascorbate peroxidase (APX) catalase (CAT), glutathione peroxidase (GPX), NADPH oxidase (NOX) and glutathione reductase (GR), indicating their roles on fruit coat softening. Finally, the treatment of PUT and CHT in combination increased shelf life vis-à-vis the quality of fruit.

Pathological Impact on the Phyllosphere Microbiota of Artemisia argyi by Haze

The pathological impact of haze upon the phyllosphere microbiota awaits investigation. A moderate degree of haze environment and a clean control were selected in Chengdu, China. Artemisia argyi, a ubiquitously distributed and extensively applied Chinese herb, was also chosen for experiment. Total genome DNA was extracted from leaf samples, and for metagenome sequencing, an Illumina HiSeq 2500 platform was applied. The results showed that the gene numbers of phyllosphere microbiota derived from haze leaves were lower than those of the clean control. The phyllosphere microbiota derived from both haze and clean groups shared the same top ten phyla; the abundances of Proteobacteria, Actinomycetes and Anorthococcuso of the haze group were substantially increased, while Ascomycetes and Basidiomycetes decreased. At the genus level, the abundances of Nocardia, Paracoccus, Marmoricola and Knoelia from haze leaves were markedly increased, while the yeasts were statistically decreased. KEGG retrieval demonstrated that the functional genes were most annotated to metabolism. An interesting find of this work is that the phyllosphere microbiota responsible for the synthesis of primary and secondary metabolites in A. argyi were significantly increased under a haze environment. Relatively enriched genes annotated by eggNOG belong to replication, recombination and repair, and genes classified into the glycoside hydrolase and glycosyltransferase enzymes were significantly increased. In summary, we found that both structure and function of phyllosphere microbiota are globally impacted by haze, while primary and secondary metabolites responsible for haze tolerance were considerably increased. These results suggest an adaptive strategy of plants for tolerating and confronting haze damage.

A novel soft sensor based warning system for hazardous ground-level ozone using advanced damped least squares neural network

Estimation of hazardous air pollutants in the urban environment for maintaining public safety is a significant concern to mankind. In this paper, we have developed an efficient air quality warning system based on a low-cost and robust ground-level ozone soft sensor. The soft sensor was developed based on a novel technique of damped least squares neural network (DLSNN) with greedy backward elimination (GBE) for the estimation of hazardous ground-level ozone. Only three meteorological factors were used as input variables in the estimation of ground-level ozone and we have used weighted k-nearest neighbors (WkNN) classifier with fast response for development of air quality warning system. We have chosen the urban areas of Taiwan for this study and have analyzed seasonal variations in the ground-level ozone concentration of various cities in Taiwan as part of this work. Moreover, descriptive statistics and linear dependence of ozone concentration based on Spearman correlation coefficient, Kendall's tau coefficient, and Pearson coefficient are calculated. The proposed DLSNN/GBE method exhibited excellent performance resulting in very low mean square error (MSE), mean absolute error (MAE), and high coefficient of determination (R²) compared to other traditional approaches in ozone concentration estimation. We have achieved a good fit in the determination of ozone concentration from meteorological features of atmosphere. Moreover, the excellent performance of proposed urban air quality warning system was evident from the good F1-score value of 0.952 achieved by the WkNN classifier.

Ozonation as a Method of Abiotic Elicitation Improving the Health-Promoting Properties of Plant Products-A Review

In this review, the primary objective was to systematize knowledge about the possibility of improving the health-promoting properties of raw plant products, defined as an increase in the content of bioactive compounds, by using ozone. The greatest attention has been paid to the postharvest treatment of plant raw materials with ozone because of its widespread use. The effect of this treatment on the health-promoting properties depends on the following different factors: type and variety of the fruit or vegetable, form and method of ozone treatment, and dosage of ozone. It seems that ozone applied in the form of ozonated water works more gently than in gaseous form. Relatively high concentration and long contact time used simultaneously might result in increased oxidative stress which leads to the degradation of quality. The majority of the literature demonstrates the degradation of vitamin C and deterioration of color after treatment with ozone. Unfortunately, it is not clear if ozone can be used as an elicitor to improve the quality of the raw material. Most sources prove that the best results in increasing the content of bioactive components can be obtained by applying ozone at a relatively low concentration for a short time immediately after harvest.

Silver Can Induce Oxidative Stress in Parallel to Other Chemical Elicitors to Modulate the Ripening of Chili Cultivars

Two chili cultivars, i.e., cv. Bullet and cv. Tejaswini, were evaluated on postharvest related ripening characteristics with varying durations under hydrogen peroxide, putrescine and silver treatments. The reducing sugar was inversely related to the maximum values at 7 days of ripening. Silver and putrescine were the most regulatory in terms of changing of the total carbohydrate content as compared to hydrolysis of the total reducing sugar. Regarding pectin methylesterase activity, both chilies were consistent, regardless of the number of days of incubation. Still, putrescine and silver were significant contributors to variations in cv. Bullet and cv. Tejaswani. For the pigment content, lycopene and chlorophyll increased in a linear manner, although these treatments significantly varied over time. Hydrogen peroxide and putrescine were responsible for the maximum accumulation of lycopene for both the cultivars, whereas, only cv. Tejaswani displayed maximum carotenoid for putrescine. Silver for both chili varieties was the most inhibitory for lycopene and carotenoid content. Superoxide had a good impact on the accumulation of lipid peroxides, irrespective of the chili variety. The maximum accumulation of lipid peroxide was recorded at seven days of treatment. Phenolics and flavonoids were in decreasing order for both the chili varieties, progressing through the days of the study period in a similar manner. Silver was the main contributor to variations in the phenolics and flavonoid contents in cv. Tejaswani. The solubilization of total carbohydrate into reducing sugar was in an inverse relationship, with the maximum values being reached at 7 days of ripening.

Synthesis of amide derivatives containing capsaicin and their antioxidant and antibacterial activities

The capsaicin in hot peppers is an important biological active substance that is widely used in food and medicine. In this work, six capsaicin derivatives such as N-(4-Hydroxy-3-acetophenone benzyl)acrylamide (A), 2-hydroxy-3-(octyloxy)phenyl-5-acrylamidemethylbenzene phenyl methanone (B), N-(2,5-dihydroxybenzene)acetamide (C), N-(5-acetamidemethyl benzene-2,4-dihydroxybenzene)acetamide (D), 4-acetamideme thylbenzene-2-benzylphenol (E), and N-(2-methyl-4-hydroxy-5-methylthiobenzene)acetamide (F) were synthesized via the Friedel-Crafts (F-C) alkylation reaction and were characterized using IR, ¹ H NMR, and HRMS. The antioxidant activity of compounds was evaluated using the reducing power and DPPH radical (DPPH·) scavenging assays, and Vitamin C (Vc) was used as a control. The antibacterial activity was tested using minimum inhibition concentration (MIC) and antibacterial rate assays, and Escherichia coli and Staphylococcus aureus were used as the tested strain. The results showed that all six capsaicin derivatives had certain antioxidant and antibacterial activities, and the activities increased with increasing mass concentration. The best properties were obtained for compounds C and F; the antioxidant activity of compound C was similar to Vc and the MIC of compound F was 0.0313 mg/ml, its antibacterial rate was greater than 99% at 3 mg/ml. PRACTICAL APPLICATIONS: As a vegetable, peppers can be eaten fresh or processed to other forms such as pepper powder or pepper jam, and it is very popular because of its long history, unique flavor, and special functions. Our current study shows that capsaicin derivatives have good antioxidant and antibacterial activities, and therefore, the present study of capsaicin derivatives with good activity provides a good foundation for future applications in natural food additives and medicine.

Differential Nitrogen Nutrition Modifies Polyamines and the Amino-Acid Profile of Sweet Pepper Under Salinity Stress

The horticultural industry demands high-quality resources to achieve excellence in yield and optimal revenues. Nitrogen is a pivotal nutrient to accomplish these goals for plant growth and product quality. However, competition for water in semi-arid regions can force the use of brackish waters, which can impair N uptake. The lower N uptake can be due to several reasons, such as an antagonism between ions, an absence of ATP, and/or alteration of N metabolism. The effect of supplying N asNO 3 - alone or in combination withNH 4 + , coupled with low or high salinity (8 or 20 mM NaCl), has been studied in sweet pepper fruits (Capsicum annuum L. cv. Melchor). The application ofNH 4 + at high salinity affected chromatic parameters (a∗, b∗, and C∗), while chlorophyll a and b levels declined and β-carotene increased. The concentrations of P, K, Ca, Mg, and Cu were reduced in the fruits of plants irrigated withNH 4 + . The concentration of Na was only reduced whenNH 4 + was supplied. Likewise, the concentration of total phenolics was also reduced at high salinity. However, total protein was unaffected. The amino acid profile was altered by the supply ofNH 4 + , which reduced the concentrations of histidine and phenylalanine. Moreover, the concentrations of putrescine and cadaverine were increased byNH 4 + at high salinity, whereas that of cadaverine was reduced byNH 4 + at low salinity. The observed changes in fruit quality triggered by salinity, under the conditions of this study, should be borne in mind for this crop with regard to the envisaged palliative effect of the supply of N-NH 4 + .

Brazilian Capsicum peppers: capsaicinoid content and antioxidant activity

BACKGROUND

Capsicum peppers are known as a source of capsaicinoids, phenolic compounds and antioxidants. Brazilian Capsicum peppers are important spices used in foods worldwide. However, little information is available on the chemical composition and antioxidant activity of these peppers.

RESULTS

Capsaicin, dihydrocapsaicin, total phenolic compounds and antioxidant activity were investigated in extracts of three Brazilian peppers: Capsicum frutescens, C. chinense and C. baccatum var. pendulum, in two different harvest years and at two ripening stages. The bioactive compound content was dependent on harvest year, and changes in the concentration profiles were found for capsaicin. Mature fruits of C. chinense harvested in the first year had the highest capsaicin concentration (2.04 mg g^-1 fresh pepper), and mature fruits of C. frutescens harvested in the same first year had the highest dihydrocapsaicin content (0.95 mg g^-1 fresh pepper). Mature fruits of C. frutescens harvested in the first year showed the major total phenolic compound content (2.46 mg g^-1 fresh pepper). The total phenolic compound content was directly related to antioxidant activity.

CONCLUSION

Our results suggest that phenolic compounds significantly contribute to the antioxidant activity of the investigated peppers. Also, these data add valued novel information that enhances current knowledge of Brazilian pepper fruits. © 2017 Society of Chemical Industry.