Antioxidant and antidiabetic properties of Chinese and Indian bitter melons (Momordica charantia L.)

Influence of Extraction Techniques and Solvents on the Antioxidant and Biological Potential of Different Parts of Scorzonera undulata

The genus Scorzonera has various medicinal values. Species belonging to this genus were traditionally used as drugs or in food. The current study aimed to determine the phytochemical composition, antioxidant activity, and biological properties of the tuber, leaf, and flower of Scorzonera undulata extracts, collected from the southwest of Tunisia. Phenolic compounds from the three parts were extracted using two solvents (water and ethanol) and two extraction techniques (maceration and ultrasound). The total phenolic content was measured by the Folin–Ciocalteu assay. Furthermore, the chemical composition of Scorzonera undulata extract was also investigated by the LC-ESI–MS method using phenolic acid and flavonoid standards. The variation of the extraction methods induced a variation in the real potentialities of the three parts in terms of bioactive molecules. However, the aerial part of S. undulata (leaves and flowers) showed, in general, the highest phenolic contents. Twenty-five volatile compounds have been detected by GC-MS in S. undulata extracts; among them, fourteen were identified before derivatization. The DPPH test showed that the aerial part of the plant has a higher antioxidant activity compared to the tuber (25.06% at 50 µg/mL for the leaf ethanolic extract obtained by ultrasound extraction). For most biological activities (anti-Xanthine, anti-inflammatory, and antidiabetic (alpha-amylase and alpha-glucosidase)), the aerial parts (flowers and leaves) of the plant showed the highest inhibition than tubers.

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.

Anti-adipogenic activities of pheophorbide a and pyropheophorbide a isolated from wild bitter gourd (Momordica charantia L. var. abbreviata Seringe) in vitro

BACKGROUND

The wild bitter gourd (WBG) is a commonly consumed vegetable in Asia that has antioxidant and hypoglycemic properties. The present study aimed to investigate the anti-adipogenic activities of isolated compounds from WBG on 8-day differentiated cultures of 3 T3-L1 adipocytes that were then stained with Oil Red O (ORO) or diamidino-2-phenylindole (DAPI).

RESULTS

ORO stains of the methanol extracts of de-seeded HM86 cultivar of WBG (WBG-M) and the ethyl acetate fractions (WBG-M-EA) showed anti-adipogenic activities against differentiated adipocytes. Two chlorophyll-degraded compounds, pheophorbide a (1) and pyropheophorbide a (2), were isolated from WBG-M-EA. Treatments with 1 (5, 10, and 20 μmol L^-1 ) and 2 (2.5, 5, and 10 μmol L^-1 ) showed dose-dependent reductions in lipid accumulations and reduced nuclear DAPI stains in differentiated 3 T3-L1 adipocytes. The concentrations for 50% inhibition against lipid accumulations of 1 and 2, respectively, were 16.05 and 7.04 μmol L^-1 . Treatments with 1 and 2 showed enhanced lactate dehydrogenase release in the first 4-day cell mitotic clonal expansions during the differentiating cultural processes, although the effect was less on the non-differentiating cultural processes. Thus, 1 and 2 were more toxic to differentiating adipocytes than to non-differentiated pre-adipocytes, which partly resulted in anti-adipogenic activities with lowered lipid accumulations.

CONCLUSION

Both 1 and 2 showed anti-adipogenic activities in cell models. These chlorophyll-degraded compounds commonly exist in several vegetables during storage or edible seaweeds, which will provide resources for further investigations aiming to test anti-obesity in animal studies. © 2022 Society of Chemical Industry.

Physicochemical and Functional Characterization of Newly Designed Biopolymeric-Based Encapsulates with Probiotic Culture and Charantin

The identification of novel sources of synbiotic agents with desirable functionality is an emerging concept. In the present study, novel encapsulates containing probiotic L. acidophilus LA-05^® (LA) and Charantin (CT) were produced by freeze-drying technique using pure Whey Protein Isolate (WPI), pure Maltodextrin (MD), and their combination (WPI + MD) in 1:1 core ratio, respectively. The obtained microparticles, namely WPI + LA + CT, MD + LA + CT, and WPI + MD + LA + CT were tested for their physicochemical properties. Among all formulations, combined carriers (WPI + MD) exhibited the highest encapsulation yields for LA (98%) and CT (75%). Microparticles showed a mean d (4, 3) ranging from 50.393 ± 1.26 to 68.412 ± 3.22 μm. The Scanning Electron Microscopy revealed uniformly amorphous and glass-like structures, with a noticeably reduced porosity when materials were combined. In addition, Fourier Transform Infrared spectroscopy highlighted the formation of strong hydrogen bonds supporting the interactions between the carrier materials (WPI and MD) and CT. In addition, the thermal stability of the combined WPI + MD was superior to that of pure WPI and pure MD, as depicted by the Thermogravimetric and Differential Scanning Calorimetry analysis. More interestingly, co-encapsulation with CT enhanced LA viability (8.91 ± 0.3 log CFU/g) and Cells Surface Hydrophobicity (82%) in vitro, in a prebiotic-like manner. Correspondingly, CT content was heightened when co-encapsulated with LA. Besides, WPI + MD + LA + CT microparticles exhibited higher antioxidant activity (79%), α-amylase inhibitory activity (83%), and lipase inhibitory activity (68%) than single carrier ones. Furthermore, LA viable count (7.95 ± 0.1 log CFU/g) and CT content (78%) were the highest in the blended carrier materials after 30 days of storage at 4 °C. Synbiotic microparticle WPI + MD + LA + CT represents an effective and promising approach for the co-delivery of probiotic culture and bioactive compounds in the digestive tract, with enhanced functionality and storage properties.

Biocompatible Platinum Nanoclusters Prepared Using Bitter Gourd Polysaccharide for Colorimetric Detection of Ascorbic Acid

Ascorbic acid is an organic compound with antioxidant properties that can protect the human body from the threat of free radicals. Therefore, it is important to detect the existence and measure the concentration of ascorbic acid to regulate its content in the human body. In this work, we prepared bitter gourd polysaccharide (BGP)-stabilized platinum nanoclusters (Pt-BGP NCs) by reacting BGP with K2PtCl4. Pt-BGP NCs and catalyzed the decomposition of H2O2 to generate •OH radicals, which could oxidize TMB to form oxidized TMB (oxTMB), indicating their peroxidase-like properties. The kinetics followed the Michaelis-Menten equation. Furthermore, the colorimetric detection of ascorbic acid using Pt-BGP NCs showed high selectivity and a low detection limit of 0.191 μM. The accuracy of real sample detection using Pt-BGP NCs was as high as 98.9%. More importantly, Pt-BGP NCs had high cell biocompatibility and extremely low hemolysis rate due to the component of BGP. In summary, the prepared Pt-BGP NCs with reductive activity and good biocompatibility have good application prospects in colorimetric detection of ascorbic acid.

Bitter gourd (Momordica charantia) possess developmental toxicity as revealed by screening the seeds and fruit extracts in zebrafish embryos

Background

Bitter gourd (Momordica charantia) has attracted the focus of researchers owing to its excellent anti-diabetic action. The beneficial effect of Momordica charantia on heart has been reported by in vitro and in vivo studies. However the developmental toxicity or potential risk of M. charantia on fetus heart development is largely unknown. Hence this study was designed to find out the developmental toxicity of M. charantia using zebrafish (Danio rerio) embryos.

Methods

The crude extracts were prepared from fruit and seeds of M. charantia. The Zebrafish embryos were exposed to serial dilution of each of the crude extract. The biologically active fractions were fractionated by C18 column using high pressure liquid chromatography. Fourier-transform infrared spectroscopy and gas chromatography coupled with mass spectrophotometry was done to identify chemical constituents in fruit and seed extract of M. charantia.

Results

The seed extract of M. charantia was lethal with LD₅₀ values of 50 μg/ml to zebrafish embryos and multiple anomalies were observed in zebrafish embryos at sub-lethal concentration. However, the fruit extract was much safe and exposing the zebrafish embryos even to 200 μg/ml did not result any lethality. The fruit extract induced severe cardiac hypertrophy in treated embryos. The time window treatment showed that M. charantia perturbed the cardiac myoblast specification process in treated zebrafish embryos. The Fourier-transform infrared spectroscopy analyses revealed diverse chemical group in the active fruit fraction and five new type of compounds were identified in the crude seeds extract of M. charantia by gas chromatography and mass spectrophotometry.

Conclusion

The teratogenicity of seeds extract and cardiac toxicity by the fruit extract of M. charantia warned that the supplementation made from the fruit and seeds of M. charantia should be used with much care in pregnant diabetic patients to avoid possible damage to developing fetus.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2599-0) contains supplementary material, which is available to authorized users.