The total phenol content in aqueous samples was determined using the Folin–Ciocalteu assay. The samples were mixed with diluted Folin–Ciocalteu reagent and sodium carbonate and left react. The blue complex mixture was measured at 750 nm. With a calibration curve obtained using gallic acid, we determined the total phenolic content, expressed as milligram of gallic acid equivalents .The method reported in was used for the total flavonoid content determination. Using a suitable solvent to extract the sample, we obtained a flavonoid–AlCl3 complex. The absorbance of the complex was measured at a certain wavelength, and the flavonoid concentration was calculated using a standard curve. Quercetin was used as a standard, and the flavonoid content was expressed in terms of quercetin equivalent .The assay to determine 5-lipoxygenase activity involves measuring the conversion of arachidonic acid to leukotriene. This is typically achieved by incubating the enzyme with the substrate, arachidonic acid, and assessing the production of leukotriene products, often using techniques like high-performance liquid chromatography or enzyme immunoassays. The method described by Viji and Helen was used to assess the extracts’ effect on lipoxygenase.The phenolic aqueous extract was used to determine the percentage of α-amylase enzyme inhibitory activity. The α-amylase assay is a method for quantifying the activity of the enzyme α-amylase, which breaks down starch into simpler sugars. This assay typically involves mixing the enzyme with a starch substrate, letting it react, 25 liter pot and then measuring the conversion of starch to reducing sugars using colorimetric reagents, often with spectrophotometry
The α-glucosidase assay is a method used to measure the activity of the enzyme α-glucosidase, which catalyzes the hydrolysis of disaccharides into glucose. This assay involves incubating the enzyme with a substrate like p-nitrophenyl-α-D-glucopyranoside and then measuring the release of p-nitro phenol, typically using spectrophotometry, as an indicator of enzymatic activity. The phenolic aqueous extract was used to determine the percentage of α-glucosidase enzyme inhibitory activity.Wild-type D. melanogaster Harwich strain flies were reared using the method described by Oyeniran et al. in the Drosophila Laboratory unit of FUTA. This method indicates the temperature, humidity, and nutrition conditions to preserve the wild-type strain. For best health and reproduction, we used suitable containers with standard Drosophila food medium, controlling the population density and providing fresh medium on a regular basis.The choice of the eggplant flour concentration in the formulated food was based on a preliminary study on fly survival rate where various concentrations between 0.1 and 2% were used. Flies 3–5 days old were separated into 8 groups, with 40 flies per vial. The experimental groups and design are shown in Table 2. The incubator was set at 25 ± 1 ◦C. The fruit flies were sacrificed, and the obtained tissue homogenates were extracted. The tissue extracts were used to carry out in vivo assays for the determination of protein content, α-amylase activity, α-glucosidase activity, glucose level—using the Sigma Randox kit and expressing it in mg/dL—ROS level, MDA content, total thiol, CAT activity, GST activity, and SOD activity.As shown in Table 1 and Supplementary Figures S2 and S3, it was found that the ripe fruits contained considerable amounts of phenolic compounds such as phenol, cinnamic acid, quercetin, chlorogenic acid, and myricetin. All the polyphenols found in the ripe fruits were also found in the unripe fruits.
The ripe fruits had a total phenolic content of 2205.43 mg/100 g, while the unripe fruits contained 2354.94 mg/100 g of phenolic compounds. This suggests that the ripe fruits could be as useful as the unripe fruits and should not be discarded. This clearly shows how useful nutrients which could be utilized in food products’ development are wasted in farms due to lack of information.This study compared the effects of ripe and unripe fruit diets on diabetes in order to evaluate their biological potential; however, our main focus was on the effects of ripe fruits, which are not always reported in studies because ripe fruits are considered waste. Due to ripening, about 60% of indigenous eggplant Solanum anguivi lam fruits in Nigeria are left to waste in farms, because the ripe fruit is given little or no importance.Meanwhile, this unwanted fruit is rich in viable phytochemicals, as reviewed in [36], which explained the benefits of phyto-compounds such as hesperidin—known as a bioflavonoid with anti-inflammatory, skin-lightening, antimicrobial, and wound healing properties—and naringin—which was found to have broad pharmacological potential. In addition, myricetin was previously reported to have neuroprotective, analgesic, antihypertensive, antidiabetic. and hypolipemic potential. This clearly shows that many beneficial bio-active compounds from nature are wasted yearly due to the early ripening of fruits and vegetables as well as inadequate/poor storage facilities. This present study showed that the ripe fruit contains more vitamins and minerals than the unripe one, which are essential for the proper functioning of the body. Vitamins are essential nutrients that are needed in the body and are involved in cell regulation, body metabolism, growth, and development, physiological processes, such as iron absorption, and the immune response. We found that the levels of vitamins A, C, E, and carotenoids and of some minerals increased with ripening, which confirmed a previous report; the change in coloration of the Solanum anguivi lam fruit could be due to the synthesis of alpha-carotene and beta-carotene, precursors of vitamin A.
COX and 5-LOX metabolic products such as prostanoids and leukotrienes are implicated in degenerative diseases such as cancer progression and may represent important targets for cancer chemoprevention or treatment. From the in vitro results, the bio-active compounds present in the ripe eggplant extract could serve as dual inhibitors of inflammatory enzymes, able to block the COX and the 5-LOX metabolic pathways better than synthetic drugs . The ripe eggplant extrac bio-active compounds, as shown from the results, have either additive or synergistic effects on the two major enzymes in arachidonic acid metabolic pathways, thus inhibiting their inflammatory activities. Secondly, it could be suggested that eggplant extracts and related diet also possess another advantage, as they have small or no gastric toxicity, being natural products with a balancing effect compared with synthesized non-steroidal anti-inflammatory drugs such as sulindac and aspirin, which are commonly used but cause major side effects, such as ulcerative colitis, due to non-selective COX inhibition. This study clearly shows that the eggplant, especially if ripe, could display an enhanced anti-inflammatory potency based on polyphenol structure, which contains almost the same structural and functional groups as the above-mentioned drugs. This observation confirms the need to utilize natural products such as eggplant for non-selective dual COX/5-LOX inhibition without side effects. Some reports indicated that some plant products such as curcumin, tea, silymarin, resveratrol, and green and black tea, rich in polyphenols, are used as natural dual enzyme inhibitors, which means that eggplant extracts or and its related diets could exert beneficial, therapeutic effects through the modulation of COX and LOX metabolic pathways. In addition, it was also confirmed that chronic inflammation is implicated in the pathophysiology of diabetes, especially type-2 diabetes, and to that end, targeting inflammation may help ameliorate diabetes, preventing its sequence and other metabolic complications, which means that an eggplant-supplemented diet could exert multiple beneficial functions. Bio-active compounds such as vitamins, carotenoids, phenolic compounds, and flavonoids, which seem to be abundant in fruits, 25 liter plant pot whether ripe or unripe, could be the reason behind the low weight gain, the increased survival, and the decreased mortality rate of the flies. This study confirmed what was reported in [5], i.e., that diabetic fruit flies administered a high-sucrose diet show obesity-linked lipogenesis caused by the repartition of fatty acids toward esterification, away from fatty acid β-oxidation, possibly by increasing malonyl-CoA. Moreover, there is a relationship between movement and weight gain which is also linked to obesity, meaning that a healthy lifestyle involving exercise and nutritious food rich in phyto-compounds, minerals, vitamins, and fiber, and with a low GI could holistically enable body wellness, as suggested by Nwanna et al.. It was also observed that the ripe eggplant-inclusive diet was able to elicit positive effects better than the unripe fruit-inclusive diet, at the same time reducing the glucose,MDA, and thiol levels in the diabetic subjects compare to the untreated subject. There is connection between diabetes mellitus, oxidative stress, and reduced antioxidant activity, while the biomarkers of oxidative stress are related to reactive oxygen species, MDA, and thiols. Thiol is an organic compound containing a sulfur atom. It is also referred to as mercaptan.
Thiol acts as an antioxidant, stabilizing free radicals by accepting their unpaired electron. This means that a ripe eggplant diet, with its bio-active compounds, contains relatively more antioxidant molecules than an unripe eggplant diet. Furthermore, an increase in endogenous antioxidant enzyme activities was observed in the groups treated with the supplemented diet, and diabetes causes tissue injury in flies as a result of the increased production of ROS. The elevation in the activity of these enzymes might be a result of the scavenging ability of the bio-active compounds in the fruit diet, which eliminated the ROS species and exerted their effects by restoring the activity of antioxidative enzymes. SOD is an enzymatic antioxidant that defends against free radicals by converting superoxide anions to compounds with less damaging effects like hydrogen peroxide; it serves as the first-line defense mechanism against pro-oxidative injury in tissues, which is important for lifespan extension and survival of Drosophila melanogaster. CAT is an enzyme that converts lesser damaging compounds such as peroxides and H2O2 to water and molecular oxygen. CAT activity was reduced in the sucrose-treated and control groups; this could also be explained by the accumulation of H2O2. We found that the inclusive diet increased the activities of SOD and CAT, which suggests a quick response to fight free radicals by reducing the endogenous H2O2 that was generated and diminishing the toxic effects it could cause. GST is needed to prevent damage and serves as a defense mechanism. The ability of the Solanum anguivi lam fruits, whether ripe or unripe, to restore the damaged antioxidant enzymes status in sucrose-induced diabetic flies cannot be overemphasized. It is interesting that the fruit contains high levels of bioflavonoid compounds such as hesperdin, naringin, and myricetin, with high binding affinity for all the proteins of interest in this study; these compounds could serve as good inhibitors of the enzymes associated with diabetes and inflammation, although it was earlier reported that they have numerous biological properties such as anti-microbial, anti-lipidemic, anti-cancer, and antioxidant properties. Ripening increases the levels of some of these bio-active compounds, which further confirms the report of Nwanna et al. of the immerse benefit of the eggplant fruit especially, the wild species.Tephritid fruit flies are well-known agricultural pests, and there are approximately 4500 species worldwide . As typical herbivores, host plant expansion is an important survival strategy for tephritid flies, especially when introduced into new areas. Host plant expansion is the ability of an herbivore to use novel host plants without losing their ability to use their original hosts , which facilitates the establishment of tephritids when entering new geographic areas and expanding their damage . Therefore, understanding the mechanism of host plant expansion will be helpful for the control of tephritid pests. Host expansion is well documented in the most destructive species of the genera Anastrepha, Bactrocera, Ceratitis, Dacus, and Rhagoletis among tephritid flies because they have expanded their range worldwide . For example, the ancestral hosts of Zeugodacus cucurbitae in India are primarily cucurbits, but it began to infest papaya in Hawaii , and it expanded its host range to include mango in Africa . The peach fruit fy Bactrocera zonata expanded to oranges and tomatoes when introduced from southeastern Asia to Egypt . Because of the typical frugivorous pest, the tephritids spend some stages of life from eggs and larvae to pupae in the fruit of host plants. Therefore, the microenvironment of host fruits to which flies try to expand will have an important infuence on the survival and adaptation of fruit flies. Therefore, when tephritids successfully expand their host range from ancestral host fruits to new hosts, they must adapt well to the chemical and non-chemical properties of the microenvironment from the novel host fruits, including theirphytochemicals, color, and phenology. The color of the host fruit is an important cue to many fruit-infesting insects when selecting a new host .