The triterpenoids of the bitter gourd (Momordica Charantia) and their pharmacological activities: A review

Antibacterial and phytotoxicological properties assessment of Momordica charantia extract-based ZnO nanoparticles

BACKGROUND

Utilizing the fruit extract of bitter melon (Momordica charantia), zinc nanoparticles (ZnO-NPs) were synthesized through a green approach, a novel endeavor in current literature. The primary objective was to evaluate the phytotoxic and growth-promoting effects of these ZnO-NPs on wheat, chosen as a test plant. Structural characterization using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy revealed the hexagonal wurtzite crystal structure of ZnO-NPs and identified spherical M. charantia-produced (MC)-ZnO-NPs ranging in size from 48 to 150 nm.

RESULTS

At a concentration of 2000 mg L-1 , both MC- and raw-ZnO-NPs augmented wheat germination percentages. Furthermore, raw-ZnO-NPs at 4000 mg L-1 demonstrated the highest chlorophyll content. Despite the plant's increased accumulation of MC-ZnO-NPs, no statistically significant toxic effects were observed. The antibacterial efficacy of ZnO-NPs was assessed against Gram-positive and Gram-negative microorganisms. MC-ZnO-NPs exhibited a 67.9% inhibition zone against Escherichia coli at 0.04 mg L-1 , while raw-ZnO-NPs exhibited 75.6% inhibition at the same concentration.

CONCLUSION

The study suggests that ZnO-NPs synthesized from M. charantia exhibit both growth-promoting effects on wheat without significant phytotoxicity and potent antibacterial properties, particularly against Escherichia coli. However, further investigations are warranted to comprehensively understand the interactions between ZnO-NPs and plants. Future research should focus on M. charantia, exploring its enhanced effects on plant growth, development and antibacterial attributes. These findings hold promise for potential agricultural applications, emphasizing the need for detailed phytotoxicological assessments of ZnO-NPs. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The metabolic effect of Momordica charantia cannot be determined based on the available clinical evidence: a systematic review and meta-analysis of randomized clinical trials

Several studies have shown that Momordica charantia L. (Cucurbitaceae, bitter melon) has beneficial effects on metabolic syndrome (MetS) parameters and exerts antidiabetic, anti-hyperlipidemic, and anti-obesity activities. Since the findings of these studies are contradictory, the goal of this systematic review and meta-analysis was to assess the efficacy of bitter melon in the treatment of metabolic syndrome, with special emphasis on the anti-diabetic effect. Embase, Cochrane, PubMed, and Web of Science databases were searched for randomized controlled human trials (RCTs). The meta-analysis was reported according to the PRISMA statement. The primary outcomes of the review are body weight, BMI, fasting blood glucose, glycated hemoglobin A1c, systolic blood pressure, diastolic blood pressure, serum triglyceride, HDL, LDL, and total cholesterol levels. Nine studies were included in the meta-analysis with 414 patients in total and 4-16 weeks of follow-up. In case of the meta-analysis of change scores, no significant effect could be observed for bitter melon treatment over placebo on fasting blood glucose level (MD = -0.03; 95% CI: -0.38 to 0.31; I2 = 34%), HbA1c level (MD = -0.12; 95% CI: -0.35 to 0.11; I2 = 56%), HDL (MD = -0.04; 95% CI: -0.17 to 0.09; I2 = 66%), LDL (MD = -0.10; 95% CI: -0.28 to 0.08; I2 = 37%), total cholesterol (MD = -0.04; 95% CI: -0.17 to 0.09; I2 = 66%,), body weight (MD = -1.00; 95% CI: -2.59-0.59; I2 = 97%), BMI (MD = -0.42; 95% CI: -0.99-0.14; I2 = 95%), systolic blood pressure (MD = 1.01; 95% CI: -1.07-3.09; I2 = 0%) and diastolic blood pressure levels (MD = 0.24; 95% CI: -1.04-1.53; I2 = 0%). Momordica treatment was not associated with a notable change in ALT, AST, and creatinine levels compared to the placebo, which supports the safety of this plant. However, the power was overall low and the meta-analyzed studies were also too short to reliably detect long-term metabolic effects. This highlights the need for additional research into this plant in carefully planned clinical trials of longer duration.

Plant regeneration from embryogenic callus-derived from immature leaves of Momordica charantia L

Bitter melon (Momordica charantia L.), a widely cultivated food and medicinal plant native to the world's subtropics and tropics, is a Cucurbitaceae rich in carotenoids. However, the low seed germination frequency and progeny variability associated with the production of this plant have a substantial impact on its growth and yield. These constraints affect the availability and exploitation of this crop, especially the fruits, which are rich in secondary metabolites such as β-carotene and α-carotene. In vitro regeneration would help overcome the obstacle linked to the germination of this plant and increase its yield and utilization. A reproducible in vitro organogenesis protocol was established using bitter melon embryogenic callus derived from immature leaf explants of in vivo grown seedlings and in vitro plantlets. Regeneration via callus was conducted on MSB5 media augmented with different plant growth regulator concentrations. The maximum frequency of callus formation (95.09 %) was produced in MSB5 media incorporated with 1.2 mg L-1 NAA augmented with 0.5 mg L-1 TDZ. MSB5 medium with no growth regulators was observed to be the most suitable for the shoot and root formation from the callus, producing a significantly high shoot percentage of 90.91 % and 21.53 shoots per explants, and the highest rooting frequency and root number of 88.92 % and 6.23 roots per explant, respectively, from leaf-derived callus of in vitro plantlets. The elongated plantlets had grown to a significantly higher average height of 12.20 cm on media added with 0.75 mg L-1 GA3. This reproducible method for regenerating bitter melon plantlets could facilitate mass multiplication, conservation, and commercial field production.

New insights into the bioactive polysaccharides, proteins, and triterpenoids isolated from bitter melon (Momordica charantia) and their relevance for nutraceutical and food application: A review

The recent trend in infectious diseases and chronic disorders has dramatically increased consumers' interest in functional foods. As a result, the research of bioactive ingredients with potential for nutraceutical and food application has rapidly become a topic of interest. In this optic, the plant Momordica charantia (M. charantia) has recently attracted the most attention owing to its numerous biological properties including anti-diabetic, anti-obesity, anti-inflammatory, anti-cancers among others. However, the current literature on M. charantia has mainly been concerned with the plant extract while little is known on the specific bioactive compounds responsible for the plant's health benefits. Hence, the present review aims to provide a comprehensive overview of the recent research progress on bioactives isolated from M. charantia, focusing on polysaccharides, proteins, and triterpenoids. Thus, this review provides an up-to-date account of the different extraction methods used to isolate M. charantia bioactives. In addition, the structural features and biological properties are presented. Moreover, this review discusses the current and promising applications of M. charantia bioactives with relevance to the nutraceutical and food industries. The information provided in this review will serve as a theoretical basis and practical support for the formulation of products enriched with M. charantia bioactives.

Microwave assisted fluidized bed drying of bitter gourd: Modelling and optimization of process conditions based on bioactive components

Bitter gourds were dried under varied drying conditions in a microwave assisted fluidized bed dryer, and the process was optimized using response surface methodology. Microwave power, temperature and air velocity were used as process variables for drying and the process parameters were varied between 360 and 720 W, 40-60 °C and 10-14 m/s, respectively. The responses determined for deciding the optimal criteria were vitamin C, total phenolics, IC₅₀, total chlorophyll content, vitamin A content, rehydration ratio, hardness and total color change of the dried bitter gourd. Statistical analyses were done by using response surface methodology, which showed that independent variables affected the responses to a varied extent. The optimum drying conditions of 550.89 W microwave power, 55.87 °C temperature, and 13.52 m/s air velocity were established for microwave assisted fluidized bed drying to obtain highest desirability for the dried bitter gourd. At optimum conditions, validation experiment was done to ensure the suitability of models. Temperature and drying time plays an important role in the deterioration of bioactive components. Faster and shorter heating led to the greater retention of bioactive components. Taking the aforesaid results into consideration, our study recommended MAFBD as a promising technique with minimum changes in quality attributes of bitter gourd.

Cytotoxicity and maternal toxicity attributed to exposure to Momordica charantia L. (Cucurbitaceae) dry leaf extract

Momordica charantia L. (Cucurbitaceae), popularly known as "bitter melon" or "bitter gourd," is a climbing plant well-adapted to tropical countries. This plant is used traditionally to treat several conditions including diabetes mellitus, inflammation, liver dysfunctions, and cancer. Given the widespread ethnopharmacological use, this study aimed to examine the cytogenetic, maternal, and developmental toxicity attributed to exposure to dry extract of M. charantia leaves using Allium cepa and Wistar rats as test models. First, phytochemical characterization of the dry extract by high performance liquid chromatography (HPLC) analyses was performed. Then, Allium cepa roots were exposed to three different concentrations of the dry extract (0.25, 0.5, or 1 mg/ml) to determine the mitotic index, frequency of chromosomal aberrations, and nuclear abnormalities. In addition, pregnant Wistar rats were administered either 500; 1,000 or 2,000 mg/kg dry extract during the gestational period (GD) days 6-15, and subsequently possible toxic effect on the dams and fetuses were recorded. HPLC analyses confirmed rutin as the main secondary metabolite present in the dry extract. In the Allium cepa test, the dry extract was cytotoxic. In Wistar rats, dry extract administration reduced water and feed intake and mean body mass gain, indicating maternal toxicity during the organogenesis period. However, the dry extract did not markedly affect reproductive outcome parameters evaluated. Regarding developmental toxicity assessment, the dry extract treatment did not significantly alter number of skeletal malformations in the offspring. Data demonstrated that the dry extract of M. charantia leaves presents cytotoxicity and low maternal toxicity, indicating indiscriminate use needs to be avoided.

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.

Evaluation of Dermal Toxicity and Wound Healing Activity of Cnestis ferruginea Vahl ex DC

Cnestisferruginea is a tropical plant, which is traditionally used in the treatment and management of various conditions including skin infections and wounds. The aim of this study was to investigate the dermal toxicity and wound healing potential of C. ferruginea. Ten millimeter full-thickness mucosal wounds were created on the dorsal midportion of the Sprague Dawley rats. Wounds were treated with 10, 5, and 2.5% w/w aqueous creams, prepared from the methanol extract of the root bark of C. ferruginea (CFM). The wound tissues were harvested on day 21 for histology studies. Compared with the untreated group, 10, 5, and 2.5% w/w CFM-treated wounds significantly reduced the wound size over the study period ( $P<0.0001$ ). Tissue histology revealed a healed wound with well-regenerated collagen and skin appendages with no pus cells. A skin irritation test was conducted on CFM, as well as the dermal toxicity of CFM was determined in the repeated dose and acute dermal toxicity bioassays. These tests revealed that CFM showed no toxic effect on the skin and showed that CFM was not a skin irritant. C. ferruginea exhibited wound healing activity, which gives credence to its folkloric use.

Structure determination, bitterness evaluation and hepatic gluconeogenesis inhibitory activity of triterpenoids from the Momordica charantia fruit

Triterpenoids are hypoglycemic substances and flavor components of Momordica charantia L., whether their bitterness correlated with hypoglycemic potential remain unknown. Thus, triterpenoids in M. charantia were isolated by phytochemical methods and identified by spectroscopic analysis. The bitterness levels and hypoglycaemic activity of isolated triterpenoids were evaluated by electronic tongue and hepatic gluconeogenesis assay. Eighteen triterpenoids including two new ones, Momordicoside Y and Z, were identified. Among the six identified bitter triterpenoids, karaviloside III, goyaglycoside C, and momordicoside F2 were bitterer than caffeine (P < 0.05), with caffeine equivalent (CE) values of 289.19, 4.32, and 41.24 mg CE/mg, respectively. Momordicoside Y, charantoside C, momordicoside F1, and momordicoside G could inhibit hepatic gluconeogenesis by 23.9%, 36.2%, 33.4%, 34.4% at 40 μM, respectively. These four compounds could interact with active site of phosphoenolpyruvate carboxykinase in molecular docking simulation. No correlation was observed between hepatic gluconeogenesis inhibitory activity and bitterness of triterpenoids.