Bitter melon (Momordica charantiaL.) bioactive composition and health benefits: A review

The Effects of Bitter Melon (Mormordica charantia) on Lipid Profile: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Research indicates that bitter melon could be useful in the management of dyslipidemia. Still, there is disagreement concerning the findings. This systematic study was undertaken to clarify the impact of consuming bitter melon on lipid profile. The databases Web of Science, Cochrane Library, PubMed, and Scopus were queried from inception until February 9, 2023. The study assessed triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) levels. The effect sizes were calculated using weighted mean differences (WMDs) and 95% confidence intervals (CIs). Eight randomized controlled trials (RCTs) with a total of 423 participants were included. Bitter melon consumption resulted in a significant decrease in plasma concentrations of TC (WMD; -9.71 mg/dL; CI: -17.69 to -1.74, p = 0.01) and TG (WMD; -10.24 mg/dL; CI: -19.92 to -0.56, p = 0.03), while bitter melon did not significantly lower blood LDL-C (WMD; -8.66 mg/dL; CI: -19.83 to 2.50, p = 0.12) and HDL-C concentrations (WMD; 0.54 mg/dL; CI: -2.38 to 3.45, p = 0.71). Subgroup analysis showed a significant decrease in TC and LDL-C and an increase in HDL-C at a dose of ≤ 2000 mg/day and an intervention period of ≤ 8 weeks. Also, the greatest impact of LDL-C and HDL-C was seen in diabetic and prediabetic people. Bitter melon supplementation positively impacts TC and TG levels. The limitations of this study were short-term trials (less than 3 months).

A comprehensive LCMS/MS characterization for the green extracted cucurbitane-triterpenoid glycosides from bitter melon (Momordica charantia) fruit

A first-time green extraction and LCMSMS analysis for karavilosides (KVs) VIII, X, and XI in different parts (skin, pith, and seed) of the fresh and dried fruit of bitter melon (BM) is reported herein. Ultrasonication for green extraction whereas, LCMS/MS for KVs quantification were used. More extract yield (675.80 ± 163.57 mg/g) was observed for the dried fruit parts compared to the fresh BM-fruit parts (513.20 ± 75.42 mg/g). The fresh skin (343.40 ± 54.07 mg/4g) and dried seeds (311.80 and 77.95 ± 38.98) exhibited more yield whereas, the solvent yield (mg/4mg) observed was; H2O (651.70) > EtOH (227.20) > EtAC (163.30) > ACT (146.80). The LCMS/MS yield for the KVs revealed a descending order; KVXI (2376.44 ppb) > KVX (639.17 ppb) > KVVIII (599.83 ppb). More correlation was seen for the solvent Vs extract yield whereas, the KVs revealed more correlation for the BM-fruit part (P = 0.05). The study comprehensively characterized the parts of fresh and dried BM-fruits in terms of extract yield and KVs amount.

Metabolome Revealed the Potential Mechanism of Fusarium Wilt Resistance in Bitter Gourd (Momordica charantia) Based on Liquid Chromatography with Mass Spectrometry

Fusarium wilt fungus infection of bitter gourd, a major melon vegetable crop, results in massive yield reduction. Through extensive testing, some Fusarium wilt-resistant bitter melon varieties have been produced, but the molecular mechanism of their resistance to the fungus remains unknown. Importantly, after bitter melon plants are infected with Fusarium oxysporum f. sp. momordicae (FOM), apart from altering their gene expression levels, numerous metabolites are produced because of the interaction with the fungus. In the current study, an untargeted metabolomics analysis was performed to investigate the metabolic difference between resistant and susceptible bitter gourd varieties at various timepoints postinoculation with FOM based on liquid chromatography with mass spectrometry. A total of 1,595 positive ion mode and 922 negative ion mode metabolites were identified. Between the resistant and susceptible bitter gourd varieties, 213 unique differentially abundant metabolites (DAMs) were identified, and they were mainly enriched in the alpha-linolenic acid metabolism pathway. By comparing the postinoculation with preinoculation timepoints in the resistant and susceptible bitter gourd varieties, 93 and 159 DAMs were identified, respectively. These DAMs were mainly related to beta-alanine metabolism, among others. Multiple metabolites in the biosynthesis of the phenylpropanoid pathway showed greater variability in the susceptible than the resistant varieties, which may be related to senescence and mortality in the susceptible variety. These results provide new insights into the understanding of metabolite changes after FOM infection and a theoretical foundation for the elucidation of the bitter gourd disease resistance mechanism.

Evaluate the effect of β-cyclodextrin on the sensory and physicochemical properties of bitter gourd extract during thermal processing

This study aims to evaluate the impact of β-cyclodextrin (β-CD) on the properties of the bitter gourd extract (BGE) under various heating conditions. In this work, the BGE and BGE supplemented with β-CD (0.75%) were heated at 60, 90, and 121 °C for 20 min before measuring the changes of bitterness, total saponin, polyphenol, antioxidant capacity, free amino acid, 5-hydroxymethylfurfural, browning intensity, and pH. It was found that β-CD mitigated the effect of heat treatment on the BGE, especially on saponins and color. Results also showed the debittering ability of β-CD was still preserved after heating duration. The bitter-masking and defensive mechanism of β-CD was also demonstrated using FTIR, thermogravimetric analysis, and molecular docking stimulation. These findings illustrated the addition of β-CD improved the thermal stability of the BGE, opening up the opportunities to incorporate BGE, which is promising in diabetes treatment but thermolabile, into heat-processed products.

Emerging therapeutic options in the management of diabetes: recent trends, challenges and future directions

Diabetes is a serious health issue that causes a progressive dysregulation of carbohydrate metabolism due to insufficient insulin hormone, leading to consistently high blood glucose levels. According to the epidemiological data, the prevalence of diabetes has been increasing globally, affecting millions of individuals. It is a long-term condition that increases the risk of various diseases caused by damage to small and large blood vessels. There are two main subtypes of diabetes: type 1 and type 2, with type 2 being the most prevalent. Genetic and molecular studies have identified several genetic variants and metabolic pathways that contribute to the development and progression of diabetes. Current treatments include gene therapy, stem cell therapy, statin therapy, and other drugs. Moreover, recent advancements in therapeutics have also focused on developing novel drugs targeting these pathways, including incretin mimetics, SGLT2 inhibitors, and GLP-1 receptor agonists, which have shown promising results in improving glycemic control and reducing the risk of complications. However, these treatments are often expensive, inaccessible to patients in underdeveloped countries, and can have severe side effects. Peptides, such as glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), are being explored as a potential therapy for diabetes. These peptides are postprandial glucose-dependent pancreatic beta-cell insulin secretagogues and have received much attention as a possible treatment option. Despite these advances, diabetes remains a major health challenge, and further research is needed to develop effective treatments and prevent its complications. This review covers various aspects of diabetes, including epidemiology, genetic and molecular basis, and recent advancements in therapeutics including herbal and synthetic peptides.

Seedling nanopriming with selenium-chitosan nanoparticles mitigates the adverse effects of salt stress by inducing multiple defence pathways in bitter melon plants

Advances in the nanotechnology fields provided crucial applications in plant sciences, contributing to the plant performance and health under stress and stress-free conditions. Amid the applications, selenium (Se), chitosan and their conjugated forms as nanoparticles (Se-CS NPs) have been revealed to have potential of alleviating the harmful effects of the stress on several crops and subsequently enhancing the growth and productivity. The present study was addressed to assay the potential effects of Se-CS NPs in reversing or buffering the harmful effects of salt stress on growth, photosynthesis, nutrient concentration, antioxidant system and defence transcript levels in bitter melon )Momordica charantia(. In addition, some secondary metabolite-related genes were explicitly examined. In this regard, the transcriptional levels of WRKY1, SOS1, PM H⁺-ATPase, SKOR, Mc5PTase7, SOAR1, MAP30, α-MMC, polypeptide-P and PAL were quantified. Our results demonstrated that Se-CS NPs increased growth parameters, photosynthesis parameters (SPAD, ^Fv/_Fm, Y(II)), antioxidant enzymatic activity (POD, SOD, CAT) and nutrient homeostasis (Na⁺/K⁺, Ca²⁺, and Cl^-) and induced the expression of genes in bitter melon plants under salt stress (p ≤ 0.05). Therefore, applying Se-CS NPs might be a simple and effective way of improving crop plants' overall health and yield under salt stress conditions.

The effect of carboxymethyl cellulose and β-cyclodextrin as debittering agents on bitterness and physicochemical properties of bitter gourd extract

Bitter gourd extract (BGE) is rich in antioxidants and anti-diabetic components that promote good human health; however, its bitter taste makes it challenging to use in food. In this study, the effect of carboxymethyl cellulose and β-cyclodextrin (β-CD) on the bitterness and properties of BGE were investigated. The bitterness intensity was evaluated by the trained sensory panel, and the physicochemical properties were also determined, including viscosity, total saponin, polyphenol content, antioxidant capacity, and α-amylase inhibition activity. It was found that the bitterness of BGE with 0.75%, w/v β-cyclodextrin decreased significantly by more than 90%. Additionally, FTIR, 1 H-NMR, and thermogravimetric analysis of BGE supplemented with β-CD confirmed the formation of a complex between β-CD and components of BGE. The findings of the current study also reveal that debittering agents did not inhibit the bioactivities of BGE.

Modulatory Effect of Medicinal Plants and Their Active Constituents on ATP-Sensitive Potassium Channels (KATP) in Diabetes

Hyperglycemia, which is a chronic metabolic condition caused by either a defect in insulin secretion or insulin resistance, is a hallmark of diabetes mellitus (DM). Sustained hyperglycemia leads to the onset and development of many health complications. Despite the number of available antidiabetic medications on the market, there is still a need for novel treatment agents with increased efficacy and fewer adverse effects. Many medicinal plants offer a rich supply of bioactive compounds that have remarkable pharmacological effects with less toxicity and side effects. According to published evidence, natural antidiabetic substances influence pancreatic β-cell development and proliferation, inhibit pancreatic β-cell death, and directly increase insulin output. Pancreatic ATP-sensitive potassium channels play an essential role in coupling glucose metabolism to the secretion of insulin. Although much of the literature is available on the antidiabetic effects of medicinal plants, very limited studies discuss their direct action on pancreatic KATP. The aim of this review is to focus on the modulatory effects of antidiabetic medicinal plants and their active constituents on pancreatic KATP. The KATP channel should be regarded as a key therapeutic milestone in the treatment of diabetes. Therefore, continuous research into the interaction of medicinal plants with the KATP channel is crucial.

Role of Fenugreek, Cinnamon, Curcuma longa, Berberine and Momordica charantia in Type 2 Diabetes Mellitus Treatment: A Review

Type 2 diabetes mellitus (T2DM) is a complex disease that has become a major global health concern. Given the efficacy of antidiabetic drugs, pharmacological therapy is considered the first-line treatment of T2DM; however, due to their potential side effects and high costs, new and cost-effective treatments with minimal side effects are needed. Medicinal plants have been used for centuries as part of traditional medicine to treat T2DM. Among these, fenugreek, cinnamon, Curcuma longa, berberine, and Momordica charantia have demonstrated different degrees of hypoglycemic activity in clinical studies and animal models. Therefore, the aim of this review is to synthesize the mechanisms of action of five medicinal plants, as well as the experimental and clinical evidence of their hypoglycemic activity from the published literature.

Accumulation of Antioxidative Phenolics and Carotenoids Using Thermal Processing in Different Stages of Momordica charantia Fruit

The bitter taste of M. charantia fruit limits its consumption, although the health benefits are well known. The thermal drying process is considered as an alternative method to reduce the bitterness. However, processing studies have rarely investigated physiochemical changes in fruit stages. The antioxidant activities and physiochemical properties of various fruit stages were investigated using different thermal treatments. The color of the thermally treated fruit varied depending on the temperature. When heat-treated for 3 days, the samples from the 30 °C and 90 °C treatments turned brown, while the color of the 60 °C sample did not change significantly. The antioxidant activities were increased in the thermally processed samples in a temperature-dependent manner, with an increase in phenolic compounds. In the 90 °C samples, the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity presented a 6.8-fold higher level than that of nonthermal treatment in mature yellow fruit (S3), whereas the activity showed about a 3.1-fold higher level in immature green (S1) and mature green (S2) fruits. Regardless of the stages, the carotenoid content tended to decrease with increasing temperature. In terms of antioxidant activities, these results suggested that mature yellow fruit is better for consumption using thermal processing.

Green Fabrication, Characterization of Zinc Oxide Nanoparticles Using Plant Extract of Momordica charantia and Curcuma zedoaria and Their Antibacterial and Antioxidant Activities

In recent years, the rapid increase in the resistance of microorganisms to antibiotics has produced major health issues. Novel applications for these compounds have been developed by integrating modern technologies such as nanotechnology and material science with the innate antibacterial activity of metals. The current study demonstrated the synthesis of zinc oxide nanoparticles (ZnO NPs) from Momordica charantia and Curcuma zedoaria plant extracts, as well as their antibacterial properties. The synthesis of ZnO NPs was confirmed via UV-visible spectroscopy, showing clear peaks at 375 and 350 nm for M. charantia and C. zedoaria, respectively. Scanning electron microscopy (SEM) analysis revealed crystals of irregular shapes for the majority of the nanoparticles synthesized from both plants. The existence of ZnO NPs was confirmed using X-ray diffraction while the particle size was calculated using Scherrer's equation, which was 19.65 for C. zedoaria and 17.02 for M. charantia. Different functional groups were detected through Fourier transform infrared spectroscopy analysis. The antibacterial activity of the ZnO NPs at three different concentrations (250, 500, and 1000 µg/ml) was assessed against three different bacterial strains, i.e., Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Pseudomonas aeruginosa (P. aeruginosa), using disc diffusion methods. The ZnO nanoparticles showed promising antibacterial activity against bacterial strains. For C. zedoaria, the highest growth inhibition was observed at a concentration of 1000 µg/ml, which was 18, 19, and 18 mm as compared to antibiotics (15, 11, and 15.6 mm) against E. coli, P. aeruginosa, and S. aureus, respectively. Similarly, at 1000 µg/ml of NPs, M. charantia showed the highest growth inhibition (18, 15, and 17 mm) as compared to antibiotics (15, 11, and 14.6 mm) against E. coli, P. aeruginosa, and S. aureus, respectively. In conclusion, compared to pure plant extract and antibiotics, ZnO NPs at a higher concentration (1000 µg/ml) exhibited a significant difference in zone of inhibition against all the bacterial strains. Different concentrations of ZnO using M. charantia and C. zedoaria caused increments in the scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The nanoparticles extracted using C. zedoaria exhibited higher antioxidant activity than M. charantia. Greenly synthesized ZnO nanoparticles have remarkable antibacterial properties and antioxidant activity, making them a promising contender for future pharmaceutical application.

An overview of bitter compounds in foodstuffs: Classifications, evaluation methods for sensory contribution, separation and identification techniques, and mechanism of bitter taste transduction

The bitter taste is generally considered an undesirable sensory attribute. However, bitter-tasting compounds can significantly affect the overall flavor of many foods and beverages and endow them with various beneficial effects on human health. To better understand the relationship between chemical structure and bitterness, this paper has summarized the bitter compounds in foodstuffs and classified them based on the basic skeletons. Only those bitter compounds that are confirmed by human sensory evaluation have been included in this paper. To develop food products that satisfy consumer preferences, correctly ranking the key bitter compounds in foodstuffs according to their contributions to the overall bitterness intensity is the precondition. Generally, three methods were applied to screen out the key bitter compounds in foods and beverages and evaluate their sensory contributions, including dose-over-threshold factors, taste dilution analysis, and spectrum descriptive analysis method. This paper has discussed in detail the mechanisms and applications of these three methods. Typical procedures for separating and identifying the main bitter compounds in foodstuffs have also been summarized. Additionally, the activation of human bitter taste receptors (TAS2Rs) and the mechanisms of bitter taste transduction are outlined. Ultimately, a conclusion has been drawn to highlight the current problems and propose potential directions for further research.

Transcriptome analysis provides insights into lignin synthesis and MAPK signaling pathway that strengthen the resistance of bitter gourd (Momordica charantia) to Fusarium wilt

Fusarium wilt is a typical soil-borne disease caused by Fusarium oxysporum f. sp. momordicae (FOM) in bitter gourd. In this study, by comparing sequencing data at multiple time points and considering the difference between resistant (R) and susceptible (S) varieties, differentially expressed genes were screened out. Short time-series expression miner analysis revealed the upregulated expression trend of genes, which were enriched in phenylpropanoid biosynthesis, plant-pathogen interaction, and mitogen-activated protein kinase signaling pathway. Further, observation of the microstructure revealed that the R variety may form tyloses earlier than the S variety to prevent mycelium diffusion from the xylem vessel. After Fusarium wilt infection, the enzymatic activities of superoxide dismutase, peroxidase, phenylalanine ammonia lyase, and catalaseas well as levels of superoxide anion and malondialdehyde were increased in the R variety higher than those in the S variety. This study provides a reference to elucidate the disease resistance mechanism of bitter gourd.

Antimicrobial Activities Evaluation and Phytochemical Screening of Some Selected Plant Materials Used in Traditional Medicine

Plant extracts are a source of valuable ingredients that can be used in many industries. This paper presents research on the content of selected bioactive compounds in extracts obtained from various plant materials. Raw materials have a documented use in traditional medicine not only in Poland. The tested plants were: bitter melon (fruit), elderberry (flowers, fruit, leaves), wild rose (fruit, flesh, seeds), mountain ash (fruit), guelder rose (fruit), and sea buckthorn (fruit, leaves, pomace). The main goal of these tests is to indicate the potential raw materials that may constitute an alternative source of bioactive compounds with antimicrobial activity. The plant material was tested for the content of bioactive antioxidant compounds and possible antimicrobial activity. The content of polyphenols (phenolic acids and flavonoids) was analyzed using UPLC/PDA, sterols, organic acids, and other bioactive compounds. The minimum inhibitory concentration (MIC) was determined. The total free phenolic acids (TPC) and total free flavonoids (TFC) of all plant raw materials was varied and ranged from 0.21 (mg RUTE/1 g of extract) to 38.30 mg RUTE/1 g of extract) for TFC. The concentration of sterols was, on average, about 10 mg/1 g of extract. The value of approx. 20 mg/1 g of the extract was recorded for bitter melon and beach rose. The content of organic acids was about 1.5 mg/1 g of the extract to even 13 mg/1 g of the extract for sea buckthorn berries. The most sensitive to the extracts' activity were the following bacteria: M. luteus, P. mirabilis, P. fragii, S. enteritidis, and E. coli. The tested plant materials can be used in various industries as a source of bioactive compounds of an antibacterial nature.

Development of a Fermented Bitter Gourd (Momordica charantia)–Grape Beverage Using Optimized Conditions

Bitter gourd beverages are well acclaimed for their health benefits, which have propelled their consumption. The beverages are prepared through a fermentation process, which is one of the oldest means of preserving and enhancing the flavour of many foods. Optimized conditions for the fermentation of a bitter gourd–grape beverage were investigated in our previous study. In the present study, a statistical comparison (one-way analysis of variance (ANOVA), Tukey’s honestly significant difference (HSD) test and an independent t-test)) of grape juice, bitter gourd juice and the fermented bitter gourd–grape beverage (with and without enzymes) was carried out to find significant differences among the products. Alcohol was found to be consistent for the four products with p > 0.05, whereas significant differences (p ≤ 0.05) in the pH, antioxidant activity (ferric reducing antioxidant assay (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS)), total titratable acidity (TTA), total soluble solids (TSS), total flavonoid content (TFC) and total phenolic content (TPC) were observed. The fermented bitter gourd–grape beverage (FBGGB) with enzymes had the highest antidiabetic potential content (27.07). The data obtained demonstrate that fermentation indeed enhances the biochemical function of vegetables (in this case, bitter gourd) and could thus be considered for the commercial processing of bitter gourd.

Effect of superfine grinding on physical properties, bioaccessibility, and anti-obesity activities of bitter melon powders

BACKGROUND

Bitter melon is widely applied to the treatment of diabetes and obesity, but few studies focus on the processing procedure of bitter melon. The differences in physical properties, bioaccessibility, and anti-obesity activity of bitter melon powder (BMP) produced with or without superfine grinding were investigated to optimize an effective processing procedure.

RESULTS

Results showed that superfine grinding could improve the physical properties of BMP, represented by greater bulk density, lower water-holding capacity, and higher bioactive compounds' solubilities. Superfine grinding remarkably affected the bioaccessibility of phenolics and the antioxidant capacity of bitter melon during in vitro digestion. Meanwhile, after a 4 week treatment, 25 μm BMP showed a greater anti-obesity activity with reduction in the serum insulin levels from 16.47 to 13.10 mIU L^-1 , reversing high-fat-diet-induced glucose intolerance, decreasing levels of serum lipids and hepatic lipid accumulation compared with the high-fat diet group.

CONCLUSION

In conclusion, superfine grinding was beneficial for improving the physical properties and bioaccessibility, simultaneously facilitating the anti-obesity activity of bitter melon, which will provide a reference for direct utilization of bitter melon as a health food to relieve symptoms of obesity. © 2022 Society of Chemical Industry.

Traditional Medicine Use among Type 2 Diabetes Patients in KZN

Background. Traditional medicine (TM) is widely used in both developing and developed countries to assist in the attempt to curtail the prevalence and increase in diabetes mellitus. Approximately 53% of South Africans use TM to prevent and treat their diseases. There is no conclusive evidence regarding the safety and effectiveness of TM versus prescribed medicine. The most common therapies used by diabetics in Africa include herbal treatments, nutritional products, spiritual healing, and relaxation techniques. Therefore, this study aimed to evaluate the use of TM in patients with T2DM who are on chronic therapy and living in KwaZulu-Natal. Method. This cross-sectional study was conducted at a district hospital, in which purposive sampling was used to recruit participants and data were collected using a structured questionnaire. Information collected included demographic data, information pertaining to home remedies/TM, and self-care practices employed by participants while using TM. Data were analyzed using Pearson’s chi-squared test, t-test, and multivariate logistic regressions to determine predictors of TM usage. Results. Only 92 (27%) of 340 participants reported using TM, with Indians being the most frequent users (58.24%). Approximately, 83.72% (n = 72) used TM in conjunction with prescribed medication. Most participants (56.32%) acquired TM knowledge from family. The most frequently used TM was lemon and honey, Aloe vera, bitter gourd, green tea, and cinnamon. Traditional medicine use among African participants was 0.56 times (OR = 0.56, 95% CI = 0.34, 0.93) lower than Indian participants. There were no significant predictors for TM usage among the variables tested. Conclusion. A low prevalence rate of TM usage in T2DM patients was found. A significant correlation was noted between ethnicity and TM use. Large-scale studies are required to determine the additive and synergistic effects of TM in health care. Consideration should also be given to integrating TM into mainstream health care.

Comparative Metabolomics study of flavonoids in the pericarp of different coloured bitter gourds (Momordica charantia L.)

Bitter gourd (Momordica charantia L.) is a member of Cucurbitaceae family and has long been used as a source of food and medicine for its rich bioactive components or secondary metabolites. However, there are relatively few large-scale detection, identification, and quantitative studies on flavonoids in the pericarp of bitter gourds of different colours. To determine the differences in the diversity and specificity of flavonoids in the pericarp of bitter gourd of different colours, the metabolic profiles in the pericarp of three coloured bitter gourd accessions, dark green (mo), pale green (lv), and white (bai), were analysed by ultra-performance liquid chromatography-tandem mass spectrometry. Priorly, it was confirmed that the different shades of green were caused by the content of chlorophyll. A total of 93 metabolites, including 90 flavonoids and three tannins, were detected in the current study. These 90 flavonoids included three isoflavones, nine dihydroflavones, seven flavanols, 34 flavonols, 26 flavonoids, four chalcones, five flavonoid carbonosides, and two dihydroflavonols. Compared to mo, both lv and bai had 21 and 25 different metabolites, respectively, while there were only nine different metabolites between lv and bai. The relative contents of vitexin and isovitexin increased with the deeper colour of the bitter gourd. Thus, the different metabolites in coloured bitter gourds are mainly involved in the biosynthesis of flavonols, flavonoid carbonosides, and flavonoids. This study enables identification of metabolic differences in the pericarp of bitter gourds of different colours. The results will be helpful for quality breeding of new bitter gourd varieties and shall provide a reference for their medical application.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s12298-022-01210-7.

Momordica charantia L.-Diabetes-Related Bioactivities, Quality Control, and Safety Considerations

Momordica charantia L. (Cucurbitaceae), commonly known as bitter gourd or bitter melon, is widely cultivated in many tropical and subtropical regions of the world, where its unripe fruits are eaten as a vegetable. Apart from its culinary use, M. charantia has a long history in traditional medicine, serving as stomachic, laxative or anthelmintic, and, most notably, for the treatment of diabetes and its complications. Its antidiabetic properties and its beneficial effects on blood glucose and lipid concentrations have been reported in numerous in vitro and in vivo studies, but the compounds responsible for the observed effects have not yet been adequately described. Early reports were made for charantin, a mixture of two sterol glucosides, and the polypeptide p-insulin, but their low concentrations in the fruits or their limited bioavailability cannot explain the observed therapeutic effects. Still, for many decades the search for more reasonable active principles was omitted. However, in the last years, research more and more focused on the particular cucurbitane-type triterpenoids abundant in the fruits and other parts of the plant. This mini review deals with compounds isolated from the bitter gourd and discusses their bioactivities in conjunction with eventual antidiabetic or adverse effects. Furthermore, methods for the quality control of bitter gourd fruits and preparations will be evaluated for their meaningfulness and their potential use in the standardization of commercial preparations.

Effect of Momordica charantia Administration on Anthropometric Measures and Metabolic Profile in Patients with Obesity: A Pilot Clinical Trial

The aim of this study was to evaluate the effect of Momordica charantia (MC) administration on anthropometric measures in patients with obesity. A randomized, double-blind, placebo-controlled pilot clinical trial was carried out in 24 patients with obesity. Twelve patients randomly received MC (2000 mg/day) for 12 weeks, and 12 patients received placebo. Body weight (BW), body mass index (BMI), waist circumference (WC), body fat percentage, as well as clinical and laboratory determinations, were evaluated before and after the intervention. Results showed that while reductions in BW, BMI, WC, and body fat percentage were observed in the MC group, these differences did not reach statistical significance. Significant decreases in triglycerides (TG) (1.9 ± 0.6 mM vs. 1.7 ± 0.7 mM, P ≤ .05) and very low-density lipoprotein (VLDL) (0.4 ± 0.1 mM vs. 0.3 ± 0.1 mM, P ≤ .05) levels were found after the intervention with MC. In contrast, significant increases in BW (83.0 ± 10.7 kg vs. 84.6 ± 9.1 kg, P ≤ .05) and BMI (31.9 ± 1.5 kg/m² vs. 33.0 ± 1.3 kg/m², P ≤ .05) were observed in the placebo group. In conclusion, no significant reductions in BW, BMI, WC, and body fat percentage were observed after MC administration; however, MC significantly decreased TG and VLDL levels. The protocol was registered at ClinicalTrials.gov with the identifier NCT04916379.

Antioxidant and 5α-Reductase Inhibitory Activity of Momordica charantia Extract, and Development and Characterization of Microemulsion

Momordica charantia (M. charantia) is rich in flavonoids, which possess a strong antioxidant capacity and may help prevent hair loss. This study aims to develop the microemulsion of M. charantia with antioxidant activity and 5α-reductase (5aR) inhibitory activity. The total phenolic content (TPC), antioxidant activity, and 5aR inhibitory activity of ethanolic and aqueous extracts of the fruit were investigated. The preparation of M. charantia extract-loaded microemulsion (MELM) was optimized and characterized the MELM. The aqueous extract of M. charantia fruit flesh displayed a TPC of 780.75 ± 24.82 mg Gallic acid equivalence/g of extract. ABTS (2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid), DPPH (2,2-diphenyl-1-picrylhydrazyl), and nitric oxide (NO) radical scavenging activities were observed in all the extracts. About 0.461 ± 0.003 mg finasteride equivalence/g of extract of 5aR inhibitory activity was detected in the aqueous extract of the inner tissue of M. charantia fruit. Based on NO radical scavenging and 5aR inhibitory activity, an aqueous extract of the inner tissue (pericarp with seed) of M. charantia fruit was used to prepare the MELM. The MELM was prepared using a different ratio of tween 80 and ethanol as Smix. The results showed that the 1:1 ratio of tween 80: ethanol produced microemulsion of an optimum size, zeta potential, and polydispersity index. The MELM samples were stored at 5, 30, and 40 °C for 12 weeks, and the stability was assessed. The results revealed that the size, zeta potential, and polydispersity index of the formulated MELM remained unchanged during the investigated time. This study primarily reports the 5aR inhibitory activity of M. charantia extract and the development of microemulsion. The prepared MELM could be further developed into cosmetic or pharmacological preparations to manage hair loss.

Microwave- and Ultrasound-Assisted Extraction of Cucurbitane-Type Triterpenoids from Momordica charantia L. Cultivars and Their Antiproliferative Effect on SAS Human Oral Cancer Cells

Cucurbitane-type triterpenoids are a major class of bioactive compounds present in bitter melon. In the present study, six different cultivars of bitter melon were extracted by using microwave- or ultrasound-assisted techniques to identify the prominent method that can extract the majority of cucurbitane-type triterpenoids. A UHPLC–MS/MS (ultra-high-performance liquid chromatography tandem mass spectrometry) system was used for the identification and quantification of ten cucurbitane-type triterpenoids. The results suggest that the use of microwave-assisted extraction on cultivars 4 and 5 produced higher amounts of the selected cucurbitane-type triterpenoids. The interpretation of principal component analysis also identified that cultivar 4 is significantly different from the others in which the compounds 3β,7β,25-trihydroxycucurbita-5,23(E)-dien-19-al and momordicine I were found in higher quantities. Upon further evaluation, it was also identified that these two triterpenoids can act as antiproliferative agents due to their effects on SAS human oral cancer cell lines.

Momordica balsamina: phytochemistry and pharmacological potential of a gifted species

Momordica balsamina L. (Cucurbitaceae), frequently named balsam apple, southern balsam pear or African pumpkin, is a vegetable with high nutritional value, being mostly used as food in sub-Saharan Africa. It has also been largely used in traditional medicine to treat several diseases, such as malaria fevers and diabetes. As a member of the Cucurbitaceae family, the main constituents are cucurbitane-type triterpenoids, with different oxidation patterns, named cucurbitacins. This review aims at summarizing our contribution to the phytochemical study of M. balsamina and the evaluation of the isolated cucurbitacins and derivatives as multidrug resistance reversers in cancer cells and bacteria. In this way, the selective antiproliferative activity against multidrug resistant cancer cells of cucurbitacins obtained from M. balsamina, their ability as P-glycoprotein inhibitors in cancer cells overexpressing this ABC transporter, as well as efflux pump inhibitors in resistant bacteria strains are reviewed. Moreover, the in vitro antimalarial activity of cucurbitacins and acyl derivatives against the blood and liver-stages of Plasmodium strains, and the in vivo activity of selected compounds is also reviewed. Besides our work, edible and medicinal uses, and other studies mainly reporting the biological activities of M. balsamina extracts, such as antidiabetic, antibacterial, anti-inflammatory, and antioxidant properties are also addressed.

Saponins from bitter melon reduce lipid accumulation via induction of autophagy in C. elegans and HepG2 cell line

Saponins from bitter melon (BMS) are well-known to have various biological activities, especially in the field of fat-lowering. However, many gaps remain in our knowledge of BMS-induced fat reduction and health benefits. Here, we aimed to investigate the precise mechanism of BMS in alleviating fat accumulation in C. elegans and HepG2 cell line. Results indicated that BMS showed strong fat-lowering and lifespan-extension properties. Lipidomic analysis illustrated that BMS could alter the lipid profile, especially represented by phosphatidylethanolamine (PE) increase, which plays an essential role in autophagy. Furthermore, we applied gene-deficient mutants and RNAi technology to confirm that BMS largely depended on daf-16/FoxO1 and hlh-30/TFEB mediated lipophagy to reduce fat deposition. In addition, BMS could ameliorate oil acid (OA)-induced fat accumulation in HepG2 cells by induction of autophagy-related proteins, such as the phosphorylated AMPK and LC3B. In conclusion, our results elucidated the underlying mechanism of bitter melon saponins interfering with lipid metabolism from the autophagy point of view, which provide new insights into a nutraceutical to mitigate obesity.

•

Bitter melon saponin (BMS) could inhibit fat accumulation and extended the lifespan of C. elegans.

•

Lipidomics analysis predicted autophagy may be a key pathway involved in the fat-lowering effects of BMS.

•

BMS induced daf-16/hlh-30 mediated lipophagy to confer fat-lowering benefit.

•

BMS regulated autophagy via activating AMPK phosphorylation and LC3B expressions in HepG2 cells.

Wound healing by topical application of Momordica charantia L. formulations on mice

Background and Aim

Momordica charantia is mainly characterized by its antimicrobial and antioxidant properties. The current study aimed to evaluate the healing activity of gel and cream formulations based on M. charantia on induced wounds in mice.

Materials and Methods

Acetonic extract of M. charantia was prepared and incorporated into gel and cream formulations. Mus musculus Balb/c (n=30) with induced injury were distributed into five groups: Group I (control - day 7), Group II (control - day 14), Group III (1% gel - day 7), and Group IV (1% gel - day 14) to which 1% M. charantia gel was dermally applied daily for 7 and 14 days, respectively, Group V (1% cream - day 7) and Group VI (1% cream - day 14) to which of M. charantia 1% cream were dermally applied daily for 7 and 14 days, respectively. Time of wound closure was determined during the experimentation; rats were euthanized with sodium pentobarbital 60 mg/kg/pc v.ip. for obtaining skin samples for histopathological analysis.

Results

Groups IV and VI showed a higher percentage of wound closure on day 14, and in histopathological analysis, effect was greater in Group VI with the presence of fibroblasts and abundant collagen and elastic fibers.

Conclusion

M. charantia gel and cream showed wound healing activity on induced wounded mice; the most effective treatment was M. charantia 1% cream formulation.

Bitter taste receptors: Genes, evolution and health

Bitter taste perception plays vital roles in animal behavior and fitness. By signaling the presence of toxins in foods, particularly noxious defense compounds found in plants, it enables animals to avoid exposure. In vertebrates, bitter perception is initiated by TAS2Rs, a family of G protein-coupled receptors expressed on the surface of taste buds. There, oriented toward the interior of the mouth, they monitor the contents of foods, drinks and other substances as they are ingested. When bitter compounds are encountered, TAS2Rs respond by triggering neural pathways leading to sensation. The importance of this role placed TAS2Rs under selective pressures in the course of their evolution, leaving signatures in patterns of gene gain and loss, sequence polymorphism, and population structure consistent with vertebrates' diverse feeding ecologies. The protective value of bitter taste is reduced in modern humans because contemporary food supplies are safe and abundant. However, this is not always the case. Some crops, particularly in the developing world, retain surprisingly high toxicity and bitterness remains an important measure of safety. Bitter perception also shapes health through its influence on preference driven behaviors such as diet choice, alcohol intake and tobacco use. Further, allelic variation in TAS2Rs is extensive, leading to individual differences in taste sensitivity that drive these behaviors, shaping susceptibility to disease. Thus, bitter taste perception occupies a critical intersection between ancient evolutionary processes and modern human health.

Evaluation of Growth, Yield, and Biochemical Attributes of Bitter Gourd (Momordica charantia L.) Cultivars under Karaj Conditions in Iran

Vegetative and reproductive characteristics, fruit yield, and biochemical compounds of six bitter melon cultivars (Iranshahr, Mestisa, No. 486, Local Japanese, Isfahan, and Ilocano) were evaluated under Karaj conditions in Iran. The phytochemical properties of the cultivars were evaluated using both shade-dried and freeze-dried samples at three fruit developmental stages (unripe, semi-ripe, and ripe). There were significant differences in the vegetative and reproductive characteristics among cultivars, where cv. No. 486 was superior to most vegetative attributes. The fruit yield of cultivars varied from 2.98–5.22 kg/plant. The number of days to male and female flower appearance ranged from 19.00–25.33 and from 25–33 days, respectively. The leaf charantin content was in the range of 4.83–11.08 μg/g. Fruit charantin content varied with developmental stage, drying method, and cultivar. The highest charantin content (13.84 ± 3.55 µg/g) was observed at the semi-ripe fruit stage, and it was much higher in the freeze-dried samples than the shade-dried samples. Cultivar No. 486 had the highest (15.43 ± 2.4 µg/g) charantin content, whereas the lowest charantin content (8.51 ± 1.15 µg/g) was recorded in cultivar cv. Local Japanese. The highest total phenol content (25.17 ± 2.27 mg GAE/g) was recorded in freeze-dried samples of ripe fruits of cv. No. 486, whereas the lowest phenol content was detected in the shade-dried samples of semi-ripe fruits of Isfahan. cv. Flavonoid content was higher with the shade-drying method, irrespective of cultivar. In conclusion, considering the fruit yield and active biological compounds in the studied cultivars, cv. No. 486 should be grown commercially because of its higher yield and production of other secondary metabolites.

In vivo anticancer effects of Momordica charantia seed fat on hepatocellular carcinoma in a rat model

BACKGROUND

Momordica charantia or bitter melon is a well-known vegetable with a number of therapeutic actions in Ayurvedic medicine. Alpha-eleostearic acid, a conjugated trienoic fatty acid present in bitter melon is proven to have anticancer properties. Crude seed oil from local bitter melon varieties could be an effective and economical anticancer therapy.

OBJECTIVE(S)

The study was conducted to evaluate the anticancer effect of the crude oil from the seeds of Matale green variety of bitter melon on a hepatocellular carcinoma-induced rat model.

MATERIALS AND METHODS

Hepatocellular carcinoma (HCC) was experimentally induced in Wistar rats. Crude seed oil of Matale green bitter melon (MGBM) was supplemented to one treatment group in concurrence with carcinoma induction and to another treatment group after the development of carcinoma. After 168 days, gross morphological, histopathological, biochemical, hematological and gene-expression analysis of treated and control groups were performed.

RESULTS

Oral supplementation of MGBM seed oil showed a statistically significant reduction (p < 0.05) in the average number, diameter and area of hepatic dysplastic nodules and a reduction in the size of histopathological neoplastic lesions in both treatment groups compared to the non-treated control group. The expression of tumor suppressor gene p53 and anti-apoptotic gene Bcl-2 were significantly increased while the expression of apoptotic gene caspase 3 was significantly reduced in the treatment group when MGBM supplementation was in concurrence with carcinogenesis (p < 0.05).

CONCLUSION

Crude seed oil from the MGBM has anticancer effects against experimentally induced HCC in Wistar rats, specially when supplemented in concurrence with carcinoma induction.

Thermal treatment enhances the α-glucosidase inhibitory activity of bitter melon (Momordica charantia) by increasing the free form of phenolic compounds and the contents of Maillard reaction products

Inhibition of α-glucosidase can slow carbohydrate metabolism, which is known as an effective strategy for diabetes treatment. The aim of this study is to evaluate the effect of thermal treatment (50, 60, and 70℃) for 15 days on the α-glucosidase inhibitory activity of bitter melon. The results show that the bitter melon heated at 70℃ for 12 days had the best α-glucosidase inhibitory effect. However, the amount of free polyphenols, 5-hydroxymethyl-2-furfural (5-HMF), and the browning degree of bitter melon generally increased with the time (15 days) and temperature of the thermal treatment, which is positively related to their antioxidant and α-glucosidase inhibitory activities. In conclusion, aged bitter melon shows great α-glucosidase inhibitory activity, which may be related to the increased free form of the involved phenolic compounds and Maillard reaction products. This suggests that thermal processing may be a good way to enhance the application of bitter melon for diabetes treatment. PRACTICAL APPLICATION: The thermal processing of bitter melon provides an application for diabetes treatment. This study demonstrated that heat-treated bitter melon can lower the blood glucose level; therefore, it can be used as a potential anti-hyperglycemic and functional food.

Bitter Melon (Momordica charantia L.) Fruit Bioactives Charantin and Vicine Potential for Diabetes Prophylaxis and Treatment

Natural products are gaining clinical significance in modern day health care systems to prevent diseases. Bitter melon, a health promoting vegetable, is traditionally used for medical nutrition therapy to cure diabetes but to reap maximum health claims, vigilant control of its substances in diet is crucial as part of curative action for effective diabetes management. In the present research, first phase focused on detection of key bioactive components, i.e., charantin and vicine in different parts of its fruit. In the second phase, normal and hyperglycemic Sprague Dawley rats were fed on skin, flesh and whole fruit of bitter melon at 150 and 300 mg/kg body weight and assessed for diabetes prophylaxis and treatment. The highest amount of charantin (0.16 ± 0.02 mg/g) was recorded in flesh while vicine was present in abundance in whole fruit (0.21 ± 0.01 μg/100 g). In normal rats, bitter melon supplementation was helpful in managing the onset of diabetes. Hyperglycemic rats showed diabetic complications including polydipsia, polyuria, glycosuria, renal hypertrophy and increased glomerular filtration rate. However, bitter melon consumption showed significant improvements in these parameters. The most potent dose was 300 mg/kg whole fruit that resulted in 31.64% lowering of blood glucose level and 27.35% increase in insulin level in hyperglycemic rats.

Bitter melon fruit extract enhances intracellular ATP production and insulin secretion from rat pancreatic β-cells

Bitter melon (Momordica charantia L.) has been shown to have various health-promoting activities, including antidiabetic and hypoglycaemic effects. Improvement in insulin sensitivity and increase in glucose utilisation in peripheral tissues have been reported, but the effect on insulin secretion from pancreatic β-cells remains unclear. In this study, we investigated the effect of bitter melon fruit on insulin secretion from β-cells and the underlying mechanism. The green fruit of bitter melon was freeze-dried and extracted with methanol. The bitter melon fruit extract (BMFE) was fractionated using ethyl acetate (fraction A), n-butanol (fraction B) and water (fraction C). Insulin secretory capacity from INS-1 rat insulinoma cell line and rat pancreatic islets, as well as glucose tolerance in rats by oral glucose tolerance test (OGTT), was measured using BMFE and fractions. ATP production in β-cells was also examined. BMFE augmented insulin secretion from INS-1 cells in a dose-dependent manner. The significant augmentation of insulin secretion was independent of the glucose dose. Fraction A (i.e. hydrophobic fraction), but not fractions B and C, augmented insulin secretion significantly at the same level as that by BMFE. This finding was also observed in pancreatic islets. In OGTT, BMFE and fraction A decreased blood glucose levels and increased serum insulin levels after glucose loading. The decrease in blood glucose levels was also observed in streptozotocin-induced diabetic rats. In addition, BMFE and fraction A increased the ATP content in β-cells. We concluded that hydrophobic components of BMFE increase ATP production and augment insulin secretion from β-cells, consequently decreasing blood glucose levels.

Metabolite Profile of Cucurbitane-Type Triterpenoids of Bitter Melon (Fruit of Momordica charantia) and Their Inhibitory Activity against Protein Tyrosine Phosphatases Relevant to Insulin Resistance

Qualitative analysis of cucurbitane-type triterpenoids of bitter melon (fruit of Momordica charantia L.) using ultraperformance liquid chromatography quadrupole time-of-flight mass spectrometry revealed 27 promising cucurbitane-type triterpenoids, and LC/MS-guided chemical analysis of M. charantia fruit extract led to the isolation and structural characterization of 22 cucurbitane-type triterpenoids (1-22), including 8 new cucurbitane-type triterpenoidal saponins, yeojoosides A-H (1-8). The structures of the new compounds (1-8) were elucidated by spectroscopic methods, including 1D and 2D NMR and high-resolution electrospray ionization mass spectrometry. Their absolute configurations were assigned by quantum chemical electronic circular dichroism calculations, chemical reactions, and DP4+ analysis using gauge-including atomic orbital NMR chemical shift calculations. All isolated compounds (1-22) were examined for inhibitory activity against protein tyrosine phosphatases relevant to insulin resistance. Nine compounds (7, 8, 9, 11, 14, 15, 19, 20, and 21) showed selective inhibitory effects of over 70% against PTPN2. The present results suggested that these compounds would be potential antidiabetic agents.

'BhAVI-23'-A spice-herb based dietary infusion possessing in-vitro anti-viral potential

Background

Viruses cause many life threatening human diseases. Recently, COVID-19 pandemic has challenged the health care systems worldwide. As a disease preventive approach and to bring relief to the severity of the symptoms, a infusion termed as Bhabha Anti-Viral Infusion-23 (‘BhAVI-23’) was conceptualized and formulated which comprised of 23 selected spices and herbals.

Objective

The present study was conducted to assess the in vitro antiviral potential of the formulation, BhaAVI-23.

Material and methods

The in-vitro anti-viral potential of BhAVI-23 was assessed through inhibition of HIV1 reverse transcriptase (RT) as well as through a novel P1 (virulent) bacteriphage based screening assay system. Anti-diabetic potential was assessed by non-enzymatic glycosylation of haemoglobin and the bioactive volatile components were detected through headspace gas chromatography followed by molecular docking analysis.

Results

The infusion displayed prominent anti-viral activity as evident from significant (57%) inhibition of the HIV1-RT as well as through reduction in the infectivity of P1 (virulent) bacteriophage. The infusion also exerted profound protection (∼64%) to non-enzymatic glycosylation of haemoglobin. Headspace gas chromatography and mass spectrometric analysis confirmed the presence of at least 47 major compounds. Docking analysis indicated possible interaction of α-pinene and eugenol with SARS-CoV spike protein.

Conclusion

This ‘BhAVI-23’ infusion displayed prominent in-vitro anti-viral and anti-diabetic potential in different model systems. These attributes have relevance as diabetic patients are more prone to COVID-19 morbidity. ‘BhAVI-23’ opens the avenue for its potential inclusion as a supportive health care system upon due regulatory approval during the current pandemic.

Mormodica charantia L. fruit and Genistein ameliorates type 2 diabetes in rats by preventing lipid accumulation, insulin resistance and enhancing beta cell function

PURPOSE

The present study was aimed at evaluating the role of Momordica charantia L. fruit and Genistein on beta cell, insulin resistance/sensitivity and lipid profile in type 2 diabetic rats.

METHODS

Thirty-five (35) albino rats were divided into seven (7) groups of 5 rats each comprising of five (5) non-diabetic and thirty (30) diabetic rats. Groups 1 and 2 served as the normal control and diabetic control groups respectively and received distill water, groups 3 and 4 received Mormodica charantia L. at 250 mg/kg and 500 mg/kg respectively. Groups 5 and 6 received Genistein at 10 mg/kg and 20 mg/kg respectively while group 7 received Metformin at 500 mg/kg the experiment lasted for four weeks. All the rats were euthanized at the end of the fourth week.

RESULTS

Lipid profile, glucose and insulin levels were determined from the analysis of serum parameters and the histology of the pancreas. A significant reduction (p < 0.05) in blood glucose levels was noticed in rats that received Momordica charantia L. (MC) and genistein when compared with diabetic control rats. A significant decrease (p < 0.05) in cholesterol, triglyceride, low density lipoprotein (LDL) and very low density lipoprotein (VLDL) levels were also noted in rats that received MC and Genistein when compared with the diabetic control rats. MC and Genistein significantly increased (P < 0.05) serum insulin level compared to the diabetic control rats. MC and Genistein significantly decreased (p < 0.05) homeostatic model assessment-insulin resistance (HOMA-IR) level compared with the diabetic control group. Pancreas of rats that received MC and Genistein showed regenerating beta-cells.

CONCLUSION

Momordica charantia L. fruit and Genistein were able to enhance beta cell function and prevent lipid accumulation and insulin resistance in type 2 diabetic rats.

Phytomedicinal relevance of South African Cucurbitaceae species and their safety assessment: A review

ETHNOPHARMACOLOGICAL RELEVANCE

South Africa has a very rich flora. Many of these species such as those in the Cucurbitaceae family are exploited as medicines for the treatment of various infections.

AIM OF THE REVIEW

The aim of the review was to synthesize the existing but scattered literature of some plant species in the Cucurbitaceae family used as sources of medicines in South Africa.

MATERIALS AND METHODS

A literature survey was carried out on the ethnopharmacology, phytochemistry, pharmacological relevance and safety assessment of the South African Cucurbitaceae used as medicines.

RESULTS

A total of 11 plants namely; Coccinia rehmannii Cogn., Cucumis africanus L.f., Cucumis anguria L. var. longaculeatus J.H.Kirkbr., Cucumis myriocarpus Naudin subsp. myriocarpus, Cucumis zeyheri Sond., Cucumis metuliferus E. Mey ex Naudin, Kedrostis nana (Lam) Cogn., Lagenaria siceraria (Molina) Standl., Momordica balsamina L., Momordica charantia L., and Momordica foetida Schumach. and Thonn were identified. Various traditional medicinal uses for these plants, from common ailments to life-threatening infections were reported. Biological activities including antidiabetic, antioxidant, antimicrobial, anticancer, anti-inflammatory and hepatoprotective were reported. However, some of the plants have not been investigated for some of the biological activities related to their traditional uses. In addition, most of the studies were carried out using non-standardized extracts. Thus, only a few studies on their bioactive constituents exist. Common compounds identified within the species are hydroxycinnamic and hydroxybenzoic acids such as sinapic, gallic, vanillic and salicylic acids; flavonoids such as naringenin, quercetin, kaempferol and rutin; fatty acids such as linoleic, palmitoleic, myristic and stearic acids; the saponin glycosides, momordicin alkaloids and cucurbitacins. However, most of these compounds have not been tested for biological activities. Cucurbitacins were implicated as a major class of toxic compounds present in the plants resulting in poisoning and death.

CONCLUSIONS

Adequate knowledge of the traditional use of these plants in medicine and the parts used are very important due to the presence of toxic substances and their wide usage. Proper screening of the safety of these plants and products derived from them calls for urgent attention.

Effects of Storage Time and Temperature on Antioxidants in Juice from Momordica charantia L. and Momordica charantia L. var. abbreviata Ser

This study determined the antioxidant activities of juice from Momordica charantia L. (MC) and MC var. abbreviata Ser. (MCVAS) by analyzing 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging ability, ferric reducing power (FRP), and total phenolic content (TPC). The effects of storage time and storage temperature on these antioxidant activities were investigated. Liquid chromatography-mass spectrometry was conducted to identify the major components of MC and MCVAS. The results revealed that the antioxidant activity of MCVAS was better than that of MC, possibly because of richer components of MCVAS. For MC and MCVAS, the scavenging concentrations of 50% DPPH were 3.33 and 1.19 mg/mL, respectively; moreover, the FRP values were 68.93 and 118.14 mg ascorbic acid equivalent/g dry weight, respectively; and the TPC values were 8.15 and 11.47 mg gallic acid equivalent/g dry weight, respectively. The antioxidant activities of MC and MCVAS decreased with storage time. High storage temperature decreased antioxidant activity more quickly than a low temperature. In addition, MC had exhibited a faster decline in DPPH scavenging ability and FRP than MCVAS during 24-day storage, but no difference was observed in TPC.

Effects of drying conditions in low-temperature microwave-assisted drying on bioactive compounds and antioxidant activity of dehydrated bitter melon (Momordica charantia L.)

Bitter melon (Momordica charantia L.) is a fruit that brings health benefits to consumers because the fruit is rich in bioactive compounds. In this work, a combination of low-temperature convective drying and microwave radiation was used to dehydrate sliced bitter melon. One-factor-at-a-time design was performed to evaluate the influence of microwave power density (1.5, 3.0, 4.5 W/g), drying temperatures (20, 25, and 30°C), and air velocity (1.0, 1.2 and 1.4 m/s) on the change of moisture content, nutrient levels (vitamin C and total phenolics), and the antioxidant activities (DPPH and FRAP assays) of the bitter melon. The obtained results showed that all investigated factors affected the rate of moisture removal. Microwave power density output and air-drying temperature strongly participated in the retention of nutrients. In this study, the drying process was driven by both heat and mass transfer processes, so the increase of air velocity prolonged the drying time causing more loss of nutrient levels and antioxidant activities. It was found that DPPH free radical scavenging ability directly correlated with total phenolic content, but the ferric-reducing antioxidant power was related to the presence of reductants including phenolic compounds, vitamin C, and other phytochemicals in bitter melons. This work determined that microwave power density and the air-drying temperature are the main two factors that should be used for further investigations.

Long-read bitter gourd (Momordica charantia) genome and the genomic architecture of nonclassic domestication

The genetic architecture of quantitative traits is determined by both Mendelian and polygenic factors, yet classic examples of plant domestication focused on selective sweep of newly mutated Mendelian genes. Here we report the chromosome-level genome assembly and the genomic investigation of a nonclassic domestication example, bitter gourd (Momordica charantia), an important Asian vegetable and medicinal plant of the family Cucurbitaceae. Population resequencing revealed the divergence between wild and South Asian cultivars about 6,000 y ago, followed by the separation of the Southeast Asian cultivars about 800 y ago, with the latter exhibiting more extreme trait divergence from wild progenitors and stronger signs of selection on fruit traits. Unlike some crops where the largest phenotypic changes and traces of selection happened between wild and cultivar groups, in bitter gourd large differences exist between two regional cultivar groups, likely reflecting the distinct consumer preferences in different countries. Despite breeding efforts toward increasing female flower proportion, a gynoecy locus exhibits complex patterns of balanced polymorphism among haplogroups, with potential signs of selective sweep within haplogroups likely reflecting artificial selection and introgression from cultivars back to wild accessions. Our study highlights the importance to investigate such nonclassic example of domestication showing signs of balancing selection and polygenic trait architecture in addition to classic selective sweep in Mendelian factors.

mcIRBP-19 of Bitter Melon Peptide Effectively Regulates Diabetes Mellitus (DM) Patients' Blood Sugar Levels

This study was conducted to test the effectiveness of a particular bitter melon peptide (BMP), with a specific sequence of 19 amino acids (mcIRBP-19), in regulating diabetic patients' blood glucose. In order to test the product with the specially processed BMP, a total of 142 diabetic patients were solicited as study subjects, of which 64 were assigned to an experiment group and 78 to a control group. Biochemical data were compared with a paired t-test to verify the significance of changes over different time periods. The clinical results showed that BMP started to improve the subjects' glycated hemoglobin (HbA1c) levels at the end of the second month (T2), with mean values being significantly lowered from 7.8 ± 1.4% (T0) to 7.5 ± 1.4% (T2) (p = 0.004). The values reduced continuously, eventually reaching 7.4 ± 1.1% (p = 0.000) at the end of the experiment (T3). HbA1c levels for the control group were 7.5 ± 1.2% in T0 and 7.5 ± 1.1% (T3), and not significantly different (p = 0.852) over the same period. This study provides clinical evidence that helps to verify the effectiveness of the new BMP product in regulating diabetic patients' blood sugar levels.

Bitter melon fruit extract has a hypoglycemic effect and reduces hepatic lipid accumulation in ob/ob mice

Bitter melon (Momordica charantia L.) is a vegetable and has been used as traditional medicine. Recently, we reported that bitter melon fruit extracts and its ethyl acetate (EtOAc)-soluble fraction markedly suppressed the expression of proinflammatory genes, including the inducible nitric oxide synthase gene. However, it is unclear whether bitter melon exhibits antidiabetic effects. In this study, we showed that cucurbitacin B, a cucurbitane-type triterpenoid, was present in an EtOAc-soluble fraction and suppressed nitric oxide production in hepatocytes. When the EtOAc-soluble fraction was administered for 7 days to ob/ob mice, a type 2 diabetes mellitus model, the mice fed with this fraction exhibited a significant decrease in body weight and blood glucose concentrations compared with the mice fed without the fraction. The administration of the fraction resulted in significant increases in serum insulin concentrations and the levels of both insulin receptor mRNA and protein in the ob/ob mouse liver. The EtOAc-soluble fraction decreased the interleukin-1β mRNA expression, as well as hepatic lipid accumulation in hepatocytes. Taken together, these results indicate that administration of an EtOAc-soluble fraction improved hyperglycemia and hepatic steatosis, suggesting that this fraction may be responsible for both the antidiabetic and anti-inflammatory effects of bitter melon fruit.

Possible molecular mechanisms of glucose-lowering activities of Momordica charantia (karela) in diabetes

Diabetes mellitus is a highly prevalent metabolic disorder which is characterized by impaired glucose tolerance, with a relative or absolute insulin deficiency and profound changes in the metabolism of macronutrients. Traditional and complementary medicine is therapeutic strategies that have both been applied to improving glycemic control. Momordica charantia is one of the plant-based, folk medicines that used for improving glycemic control. We aimed to review, the effects of M. charantia on blood glucose with a clarification of the molecular pathways involved. Of the compounds derived from the plants, the insulin-like peptide, charantin, and the alkaloid vicine, have been reported to have hypoglycemic effects. Different mechanisms contribute to the antidiabetic activities of M. charantia, these include increasing pancreatic insulin secretion, decreasing insulin resistance and increasing peripheral and skeletal muscle cell glucose utilization, inhibition of intestinal glucose absorption and suppressing of key enzymes in the gluconeogenic pathways.

Influence of different pasteurization techniques on antidiabetic, antioxidant and sensory quality of debittered bitter gourd juice during storage

Debittered bitter gourd juice was subjected to gamma irradiation doses of 0, 0.25, 0.5, 0.75, 1, 1.5 and 2.5 kGy and thermal pasteurization at temperatures of 65, 75, 85 and 95 °C. Shigella boydii was the most heat resistant pathogen tested (D₁₀ of 42.8 s at 65 °C) while Bacillus cereus was the most resistant pathogen to irradiation with a D₁₀ of 0.46 kGy. No significant (p < 0.05) effect of thermal pasteurization was observed on antidiabetic (α-amylase and α-glucosidase inhibition) activity, however, a 10% increase in α-glucosidase inhibition was observed in irradiated (2.5 kGy) samples. A significant (p < 0.05) but marginal reduction (up to 10%) was observed in antidiabetic activity during storage for a period of 90 days. Thermal pasteurization at 65 °C demonstrated significantly (p < 0.05) higher sensory quality as compared to irradiated (2.5 kGy) samples. This is first report on effect of pasteurization on antidiabetic activity of bitter gourd juice.