An unusual combination in papaya (Carica papaya): The good (glucosinolates) and the bad (cyanogenic glycosides)

Antioxidant activity of Flemingia praecox and Mucuna pruriens and their implications for male fertility improvement

Globally, 15-24% couples are unable to conceive naturally and 50% of cases of this problem are due to infertility in males. Of this, about 50% of male infertility problems are developed due to unknown reasons called as idiopathic infertility. It is well established that, reactive oxygen species (ROS) have negative impact on male fertility and are involved in 80% of total idiopathic male infertility cases. Medicinal plants are considered as an alternative approach for mitigating the health problems. The plants with good antioxidant capacity can improve the male infertility symptoms generated by ROS. Such medicinal plants can be used to alleviate the symptoms of male infertility with their diverse phytoconstituents. Mucuna pruriens is a well-accepted herb, with its seeds being used to improve the male fertility in various ways and one of the ways is by eliminating the ROS. In our field survey, another plant, Flemingia praecox, although less known, its roots are used in all problems related to the male fertility by tribal people of the Gadchiroli district of Maharashtra, India. The study was conducted to determine in vitro antioxidant potential of F. praecox and compared the results with the well-established male fertility improving plant M. pruriens with special emphasis on medicinally important roots of F. praecox and seeds of M. pruriens. The objective of the study was investigated by studying their total phenol (TPC) and flavonoid (TFC) content, antioxidant parameters (DPPH, FRAP, ABTS, DMPD, β-carotene bleaching and TAA) and finally DNA damage protection capacity of the plant extracts was studied. The plant parts used for the medicinal purposes have been investigated along with other major parts (leaves, stem and roots of both the plants) and compared with synthetic antioxidants, BHA, BHT and ascorbic acid. Moreover, the inhibition of two male infertility enzyme markers, PDE5 and arginase by F. praecox root and M. pruriens seed extract was also studied in vitro. The results showed that F. praecox possesses higher antioxidant activity than M. pruriens in the majority of studies as observed in TFC, DPPH, TAA, ABTS and DMPD assays. However, M. pruriens seeds showed best results in TPC, FRAP and DNA damage protection assay. F. praecox root extract also gave better PDE5 inhibition value than M. pruriens seeds. This study will help to establish the authenticity of F. praecox used by tribal people and will encourage its further use in managing the male infertility problems.

The Investigation of Phenylalanine, Glucosinolate, Benzylisothiocyanate (BITC) and Cyanogenic Glucoside of Papaya Fruits (Carica papaya L. cv. ‘Tainung No. 2’) under Different Development Stages between Seasons and Their Correlation with Bitter Taste

Papaya fruit is one of economic crops in Taiwan, mostly eaten as table fruits. In some Asian countries, unripe papaya fruit is eaten as salad and this led to trends in Taiwan as well. However, unripe papaya fruit may taste bitter during cool seasons. Glucosinolate and cyanogenic glucoside are among the substances that cause bitter taste in many plants, which can also be found in papaya. However, there is still no report about the relationship between seasons and bitter taste in papaya fruits. Thus, the purpose of this study is to investigate the glucosinolate biosynthesis and its correlation between bitterness intensity during cool and warm seasons. The bitterness intensity was highest at the young fruit stage and decreased as it developed. In addition, the bitterness intensity in cool season fruits is higher than in warm season fruits. Cyanogenic glucoside and BITC content showed negative correlation with bitterness intensity (r = −0.54 ***; −0.46 ***). Phenylalanine showed positive correlation with bitterness intensity (r = 0.35 ***), but its content did not reach the bitterness threshold concentration, which suggested that phenylalanine only acts as cyanogenic glucoside and glucosinolate precusors. Glucosinolate content showed positive correlation with bitterness intensity at different developmental stages (r = 0.805 ***). However, the correlation value in different lines/cultivars decreased (0.44 ***), suggesting that glucosinolate was not the only substance that caused bitter taste in immature papaya fruits.

Benefits of Fermented Papaya in Human Health

Fermented foods have been used for several years all over the world, due to their unique nutritional characteristics and because fermentation promotes conservation and food security. Moreover, fermented foods and beverages have a strong impact on human gut microbiota. Papaya is the fruit of the Carica papaya plant, traditionally used as a medicinal fruit, but there are also references to the use of the fermented form of this fruit. The main purpose of this review is to provide an improved understanding of fermented papaya nutritional and health applications. A literature search was conducted in the PubMed and Google Scholar databases. Both in vitro and in vivo studies were included. According to the retrieved studies, fermented papaya has proven to be an excellent antioxidant and an excellent nutraceutical adjuvant in combined therapies against several diseases, such as Alzheimer’s disease, allergic reactions, anticancer activity, and anemias. Therefore, it is concluded that fermented papaya has many benefits for human health and can be used as prevention or aid in the treatment of various diseases.

The Future of Carica papaya Leaf Extract as an Herbal Medicine Product

Carica papaya (papaya) leaf extract has been used for a long time in a traditional medicine to treat fever in some infectious diseases such as dengue, malaria, and chikungunya. The development of science and technology has subsequently made it possible to provide evidence that this plant is not only beneficial as an informal medication, but also that it has scientifically proven pharmacological and toxicological activities, which have led to its formal usage in professional health care systems. The development of formulations for use in nutraceuticals and cosmeceuticals has caused this product to be more valuable nowadays. The use of good manufacturing practice (GMP) standards, along with the ease of registering this product facilitated by policies of the national government, will absolutely increase the value of papaya leaf extract as a vital nutraceutical and cosmeceutical products in the near future. In this article, we review the potential of papaya leaf extract to be a high-value commodity in terms of its health effects as well as its industrial benefits.

Metabolic analysis of unripe papaya (Carica papaya L.) to promote its utilization as a functional food

Papaya (Carica papaya L.) is widely cultivated in tropical and subtropical countries. While ripe fruit is a popular food item globally, the unripe fruit is only consumed in some Asian countries. To promote the utilization of unripe papaya based on the compositional changes of biological active metabolites, we performed liquid chromatography-Orbitrap-mass spectrometry-based analysis to reveal the comprehensive metabolite profile of the peel and pulp of unripe and ripe papaya fruits. The number of peaks annotated as phenolics and aminocarboxylic acids increased in the pulp and peel of ripe fruit, respectively. Putative carpaine derivatives, known alkaloids with cardiovascular effects, decreased, while carpamic acid derivatives increased in the peel of ripe fruit. Furthermore, the functionality of unripe fruit, the benzyl glucosinolate content, total polyphenol content, and proteolytic activity were detectable after heating and powder processing treatments, suggesting a potential utilization in powdered form as functional material.

Volatile sulfur compounds in tropical fruits

Global production and demand for tropical fruits continues to grow each year as consumers are enticed by the exotic flavors and potential health benefits that these fruits possess. Volatile sulfur compounds (VSCs) are often responsible for the juicy, fresh aroma of tropical fruits. This poses a challenge for analytical chemists to identify these compounds as most often VSCs are found at low concentrations in most tropical fruits. The aim of this review is to discuss the extraction methods, enrichment techniques, and instrumentation utilized to identify and quantify VSCs in natural products. This will be followed by a discussion of the VSCs reported in tropical and subtropical fruits, with particular attention to the odor and taste attributes of each compound. Finally, the biogenesis and enzymatic formation of specific VSCs in tropical fruits will be highlighted along with the contribution each possesses to the aroma of their respective fruit.

Metabolomic profiling of the phytomedicinal constituents of Carica papaya L. leaves and seeds by 1H NMR spectroscopy and multivariate statistical analysis

Extracts from the Carica papaya L. plant are widely reported to contain metabolites with antibacterial, antioxidant and anticancer activity. This study aims to analyze the metabolic profiles of papaya leaves and seeds in order to gain insights into their phytomedicinal constituents. We performed metabolite fingerprinting using 1D and 2D 1H NMR experiments and used multivariate statistical analysis to identify those plant parts that contain the most concentrations of metabolites of phytomedicinal value. Secondary metabolites such as phenyl propanoids, including flavonoids, were found in greater concentrations in the leaves as compared to the seeds. UPLC-ESI-MS verified the presence of significant metabolites in the papaya extracts suggested by the NMR analysis. Interestingly, the concentration of eleven secondary metabolites namely caffeic, cinnamic, chlorogenic, quinic, coumaric, vanillic, and protocatechuic acids, naringenin, hesperidin, rutin, and kaempferol, were higher in young as compared to old papaya leaves. The results of the NMR analysis were corroborated by estimating the total phenolic and flavonoid content of the extracts. Estimation of antioxidant activity in leaves and seed extracts by DPPH and ABTS in-vitro assays and antioxidant capacity in C2C12 cell line also showed that papaya extracts exhibit high antioxidant activity.

Preparation and characterization of inclusion complex of benzyl isothiocyanate extracted from papaya seed with β-cyclodextrin

The inclusion complex of benzyl isothiocyanate (BITC), extracted from papaya seed with β-cyclodextrin (β-CD), was prepared. Different analytical techniques, such as Fourier transform infrared spectroscopy, thermal analysis, X-ray diffractometry, particle size distribution analysis and (1)H Nuclear magnetic resonance analysis, were used to investigate the characterization of the inclusion complex (BITC-β-CD). All these approaches indicated that the inclusion complex was capable of being formed. The inclusion complex exhibited different spectroscopic and thermodynamic features and properties from BITC, and we deduced the possible inclusion modes for BITC-β-CD. The calculated apparent stability constant of the BITC-β-CD was 600.8l/mol, and the aqueous solubility of BITC was indistinctively improved by phase solubility studies. The results illustrated that β-CD was a proper excipient for increasing the stability and controlled release of BITC. Thus, β-CD complexation technology would be a promising approach, in expanding the application of BITC as a food antibacterial agent.

Dietary Glucosinolates Sulforaphane, Phenethyl Isothiocyanate, Indole-3-Carbinol/3,3'-Diindolylmethane: Anti-Oxidative Stress/Inflammation, Nrf2, Epigenetics/Epigenomics and In Vivo Cancer Chemopreventive Efficacy

Glucosinolates are a group of sulfur-containing glycosides found in many plant species, including cruciferous vegetables such as broccoli, cabbage, brussels sprouts, and cauliflower. Accumulating evidence increasingly supports the beneficial effects of dietary glucosinolates on overall health, including as potential anti-cancer agents, because of their role in the prevention of the initiation of carcinogenesis via the induction of cellular defense detoxifying/antioxidant enzymes and their epigenetic mechanisms, including modification of the CpG methylation of cancer-related genes, histone modification regulation and changes in the expression of miRNAs. In this context, the defense mechanism mediated by Nrf2-antioxidative stress and anti-inflammatory signaling pathways can contribute to cellular protection against oxidative stress and reactive metabolites of carcinogens. In this review, we summarize the cancer chemopreventive role of naturally occurring glucosinolate derivatives as inhibitors of carcinogenesis, with particular emphasis on specific molecular targets and epigenetic alterations in in vitro and in vivo human cancer animal models.

Plant Chemical Defenses: Are all Constitutive Antimicrobial Metabolites Phytoanticipins?

A critical perspective on phytoanticipins, constitutive plant secondary metabolites with defensive roles against microbes is presented. This mini-review focuses on the chemical groups and structural types of defensive plant metabolites thus far not reviewed from the phytoanticipin perspective: i) fatty acid derivatives and polyketides, ii) terpenoids, iii) shikimates, phenylpropanoids and derivatives, and iv) benzylisoquinoline and pyrrolizidine alkaloids. The more traditional groups of phytoanticipins are briefly summarized, with particular focus on the latest results: i) benzoxazinoids, ii) cyanogenic glycosides, iii) glucosinolates and their metabolic products, and iv) saponins. Current evidence suggests that a better understanding of the functions of plant metabolites will drive their application to protect crops against microbial diseases.

Synthesis of the allelochemical alliarinoside present in garlic mustard (Alliaria petiolata), an invasive plant species in North America

The allelochemical alliarinoside present in garlic mustard (Alliaria petiolata), an invasive plant species in North America, was chemically synthesized using an efficient and practical synthetic strategy based on a simple reaction sequence. Commercially available 1,2,3,4,6-penta-O-acetyl-β-D-glucopyranose was converted into prop-2-enyl 2',3',4',6'-tetra-O-acetyl-β-D-glucopyranoside and subjected to epoxidation. In a one-pot reaction, ring-opening of the epoxide using TMSCN under solvent free conditions followed by treatment of the formed trimethylsilyloxy nitrile with pyridine and phosphoryl chloride, afforded the acetylated β-unsaturated nitriles (Z)-4-(2',3',4',6'-tetra-O-β-D-glucopyranosyloxy)but-2-enenitrile and its isomer (E)-4-(2',3',4',6'-tetra-O-β-D-glucopyranosyloxy)but-2-enenitrile. Deacetylation of Z- and/or E-isomers afforded the target molecules alliarinoside and its isomer.